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Sample records for lhcb vertex detector

  1. The LHCb Vertex Locator (VELO) Pixel Detector Upgrade

    NASA Astrophysics Data System (ADS)

    Buchanan, E.

    2017-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. There is a planned upgrade during Long Shutdown 2 (LS2), expected in 2019, which will allow the detector to run at higher luminosities by transforming the entire readout to a trigger-less system. This will include a substantial upgrade of the Vertex Locator (VELO), the silicon tracker that surrounds the LHCb interaction region. The VELO is moving from silicon strip technology to hybrid pixel sensors, where silicon sensors are bonded to VeloPix ASICs. Sensor prototypes have undergone rigorous testing using the Timepix3 Telescope at the SPS, CERN. The main components of the upgrade are summarised and testbeam results presented.

  2. Evaporative CO2 cooling using microchannels etched in silicon for the future LHCb vertex detector

    NASA Astrophysics Data System (ADS)

    Nomerotski, A.; Buytart, J.; Collins, P.; Dumps, R.; Greening, E.; John, M.; Mapelli, A.; Leflat, A.; Li, Y.; Romagnoli, G.; Verlaat, B.

    2013-04-01

    The extreme radiation dose received by vertex detectors at the Large Hadron Collider dictates stringent requirements on their cooling systems. To be robust against radiation damage, sensors should be maintained below -20°C and at the same time, the considerable heat load generated in the readout chips and the sensors must be removed. Evaporative CO2 cooling using microchannels etched in a silicon plane in thermal contact with the readout chips is an attractive option. In this paper, we present the first results of microchannel prototypes with circulating, two-phase CO2 and compare them to simulations. We also discuss a practical design of upgraded VELO detector for the LHCb experiment employing this approach.

  3. Vertex detectors

    SciTech Connect

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10{sup {minus}13} s, among them the {tau} lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation.

  4. The upgrade of the LHCb Vertex Locator

    NASA Astrophysics Data System (ADS)

    Bird, T.

    2014-12-01

    The LHCb experiment is set for a significant upgrade, which will be ready for Run 3 of the LHC in 2020. This upgrade will allow LHCb to run at a significantly higher instantaneous luminosity and collect an integrated luminosity of 50fb-1 by the end of Run 4. In this process the Vertex Locator (VELO) detector will be upgraded to a pixel-based silicon detector. The upgraded VELO will improve upon the current detector by being closer to the beams and having lower material modules with microchannel cooling and a thinner RF-foil. Simulations have shown that it will maintain its excellent performance, even after the radiation damage caused by collecting an integrated luminosity of 50fb-1.

  5. Upgrade of the LHCb Vertex Locator

    NASA Astrophysics Data System (ADS)

    Leflat, A.

    2014-08-01

    The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz. All data reduction algorithms will be executed in a high-level software farm, with access to all event information. This will enable the detector to run at luminosities of 1-2 × 1033/cm2/s and probe physics beyond the Standard Model in the heavy sector with unprecedented precision. The upgraded VELO must be low mass, radiation hard and vacuum compatible. It must be capable of fast pattern recognition and track reconstruction and will be required to drive data to the outside world at speeds of up to 2.5 Tbit/s. This challenge is being met with a new Vertex Locator (VELO) design based on hybrid pixel detectors positioned to within 5 mm of the LHC colliding beams. The sensors have 55 × 55 μm square pixels and the VELOPix ASIC which is being developed for the readout is based on the Timepix/Medipix family of chips. The hottest ASIC will have to cope with pixel hit rates of up to 900 MHz. The material budget will be optimised with the use of evaporative CO2 coolant circulating in microchannels within a thin silicon substrate. Microchannel cooling brings many advantages: very efficient heat transfer with almost no temperature gradients across the module, no CTE mismatch with silicon components, and low material contribution. This is a breakthrough technology being developed for LHCb. LHCb is also focussing effort on the construction of a lightweight foil to separate the primary and secondary LHC vacua, the development of high speed cables and radiation qualification of the module. The 40 MHz readout will also bring significant conceptual changes to the way in which the upgrade trigger is operated. Work is in progress to incorporate momentum and impact parameter information into the trigger at the earliest possible stage, using the fast pattern recognition capabilities of the upgraded detector. The current status of the VELO upgrade will

  6. The CLIC Vertex Detector

    NASA Astrophysics Data System (ADS)

    Dannheim, D.

    2015-03-01

    The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a measurement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → Wb will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit timing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin planar or active HV-CMOS sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. This contribution reviews the requirements and design optimisation for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensors, readout and detector integration.

  7. Vertex Detector Cable Considerations

    SciTech Connect

    Cooper, William E.; /Fermilab

    2009-02-01

    Vertex detector cable requirements are considered within the context of the SiD concept. Cable material should be limited so that the number of radiation lengths represented is consistent with the material budget. In order to take advantage of the proposed accelerator beam structure and allow cooling by flow of dry gas, 'pulsed power' is assumed. Potential approaches to power distribution, cable paths, and cable design for operation in a 5 T magnetic field are described.

  8. Upgrade of the LHCb VELO detector

    NASA Astrophysics Data System (ADS)

    Williams, Mark

    2017-01-01

    The LHCb experiment is a single-arm forward spectrometer optimised for performing heavy-flavour physics analyses, using proton-proton collisions provided by the LHC machine. A major upgrade of the LHCb experiment will take place prior to the start of Run 3 operations in 2021. The upgraded Vertex Locator (VELO) is an essential component of this upgrade. Its main role is to enable high precision track and vertex reconstruction, with data-driven readout to the software trigger at 40 MHz, in the higher-luminosity environment of Run 3. To achieve this goal, significant improvements are planned with respect to the current detector, including a switch from microstrips to pixels, upgraded electronics, and a new cooling system. I will briefly motiviate the need for an upgrade, describe the main aspects of the VELO upgrade design, and show highlights of recent sensor characterisation studies using the CERN SPS test beam.

  9. The STAR Vertex Position Detector

    NASA Astrophysics Data System (ADS)

    Llope, W. J.; Zhou, J.; Nussbaum, T.; Hoffmann, G. W.; Asselta, K.; Brandenburg, J. D.; Butterworth, J.; Camarda, T.; Christie, W.; Crawford, H. J.; Dong, X.; Engelage, J.; Eppley, G.; Geurts, F.; Hammond, J.; Judd, E.; McDonald, D. L.; Perkins, C.; Ruan, L.; Scheblein, J.; Schambach, J. J.; Soja, R.; Xin, K.; Yang, C.

    2014-09-01

    The 2×3 channel pseudo Vertex Position Detector (pVPD) in the STAR experiment at RHIC has been upgraded to a 2×19 channel detector in the same acceptance, called the Vertex Position Detector (VPD). This detector is fully integrated into the STAR trigger system and provides the primary input to the minimum-bias trigger in Au+Au collisions. The information from the detector is used both in the STAR Level-0 trigger and offline to measure the location of the primary collision vertex along the beam pipe and the event "start time" needed by other fast-timing detectors in STAR. The offline timing resolution of single detector channels in full-energy Au+Au collisions is ~100 ps, resulting in a start time resolution of a few tens of picoseconds and a resolution on the primary vertex location of ~1 cm.

  10. Belle II Silicon Vertex Detector

    NASA Astrophysics Data System (ADS)

    Dutta, D.; Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Bulla, L.; Caria, G.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; De Pietro, G.; Divekar, S. T.; Doležal, Z.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C.; Kandra, J.; Kambara, N.; Kang, K. H.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kumar, R.; Kun, W.; Kvasnička, P.; La Licata, C.; Lanceri, L.; Lettenbicher, J.; Libby, J.; Lueck, T.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Resmi, P. K.; Rozanska, M.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Watanuki, S.; Watanabe, M.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.; Zani, L.

    2017-02-01

    The Belle II experiment at the SuperKEKB asymmetric energy e+e‑ collider in KEK, Japan will operate at an instantaneous luminosity 40 times larger than that of its predecessor, Belle. It is built with an aim of collecting a huge amount of data (50 ab‑1 by 2025) for precise CP violation measurements and new physics search. Thus, we need an accurate vertex determination and reconstruction of low momentum tracks which will be achieved with the help of vertex detector (VXD). The Belle II VXD consists of two layers of DEPFET pixels (`Pixel Detector') and four layers of double-sided silicon microstrip sensors (`Silicon Vertex Detector'), assembled over carbon fibre ribs. In this paper, we discuss about the Belle II Silicon Vertex Detector, especially its design and key features; we also present its module (`ladder') assembly and testing procedures.

  11. STAR Vertex Detector Upgrade Development

    SciTech Connect

    Greiner, Leo C.; Matis, Howard S.; Stezelberger, Thorsten; Vu,Chinh Q.; Wieman, Howard; Szelezniak, Michal; Sun, Xiangming

    2008-01-28

    We report on the development and prototyping efforts undertaken with the goal of producing a micro-vertex detector for the STAR experiment at the RHIC accelerator at BNL. We present the basic detector requirements and show a sensor development path, conceptual mechanical design candidates and readout architecture. Prototyping and beam test results with current generation MimoSTAR-2 sensors and a readout system featuring FPGA based on-the-fly hit finding and data sparsification are also presented.

  12. Belle II silicon vertex detector

    NASA Astrophysics Data System (ADS)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Enami, K.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2016-09-01

    The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by an inner tracking device comprising two layers of pixelated silicon detector and four layers of silicon vertex detector based on double-sided microstrip sensors. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector.

  13. The CDF Silicon Vertex Detector

    SciTech Connect

    Tkaczyk, S.; Carter, H.; Flaugher, B.

    1993-09-01

    A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the detector in the radiation environment are discussed. The device has been taking colliding beams data since May of 1992, performing at its best design specifications and enhancing the physics program of CDF.

  14. CLIC vertex detector R&D

    NASA Astrophysics Data System (ADS)

    Alipour Tehrani, Niloufar

    2016-07-01

    A vertex detector concept is under development for the proposed multi-TeV linear e+e- Compact Linear Collider (CLIC). To perform precision physics measurements in a challenging environment, the CLIC vertex detector pushes the technological requirements to the limits. This paper reviews the requirements for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensor, readout, powering and cooling.

  15. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    NASA Astrophysics Data System (ADS)

    Rihl, M.

    2017-02-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam-gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam-beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam-gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam-gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  16. On-detector Electronics for the LHCb VELO Upgrade

    NASA Astrophysics Data System (ADS)

    Naik, S.

    2017-02-01

    The LHCb Experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. The experiment will be upgraded to a trigger-less system reading out the full detector at a 40 MHz event rate with all selection algorithms executed in a CPU farm. The upgraded Vertex Locator will be a hybrid pixel detector read out by the VeloPix ASIC with on-chip zero-suppression. The overview of the system and the design of the VELO on-detector electronics that include the front-end hybrid, the opto-conversion and power distribution boards will be summarised. The results from the evaluation of these prototypes and further enhancement techniques will be discussed.

  17. The LHCb Detector at the LHC

    NASA Astrophysics Data System (ADS)

    LHCb Collaboration; Alves, A. Augusto, Jr.; Filho, L. M. Andrade; Barbosa, A. F.; Bediaga, I.; Cernicchiaro, G.; Guerrer, G.; Lima, H. P., Jr.; Machado, A. A.; Magnin, J.; Marujo, F.; de Miranda, J. M.; Reis, A.; Santos, A.; Toledo, A.; Akiba, K.; Amato, S.; de Paula, B.; de Paula, L.; da Silva, T.; Gandelman, M.; Lopes, J. H.; Maréchal, B.; Moraes, D.; Polycarpo, E.; Rodrigues, F.; Ballansat, J.; Bastian, Y.; Boget, D.; DeBonis, I.; Coco, V.; David, P. Y.; Decamp, D.; Delebecque, P.; Drancourt, C.; Dumont-Dayot, N.; Girard, C.; Lieunard, B.; Minard, M. N.; Pietrzyk, B.; Rambure, T.; Rospabe, G.; T'Jampens, S.; Ajaltouni, Z.; Bohner, G.; Bonnefoy, R.; Borras, D.; Carloganu, C.; Chanal, H.; Conte, E.; Cornat, R.; Crouau, M.; Delage, E.; Deschamps, O.; Henrard, P.; Jacquet, P.; Lacan, C.; Laubser, J.; Lecoq, J.; Lefèvre, R.; Magne, M.; Martemiyanov, M.; Mercier, M.-L.; Monteil, S.; Niess, V.; Perret, P.; Reinmuth, G.; Robert, A.; Suchorski, S.; Arnaud, K.; Aslanides, E.; Babel, J.; Benchouk, C.; Cachemiche, J.-P.; Cogan, J.; Derue, F.; Dinkespiler, B.; Duval, P.-Y.; Garonne, V.; Favard, S.; LeGac, R.; Leon, F.; Leroy, O.; Liotard, P.-L.; Marin, F.; Menouni, M.; Ollive, P.; Poss, S.; Roche, A.; Sapunov, M.; Tocco, L.; Viaud, B.; Tsaregorodtsev, A.; Amhis, Y.; Barrand, G.; Barsuk, S.; Beigbeder, C.; Beneyton, R.; Breton, D.; Callot, O.; Charlet, D.; D'Almagne, B.; Duarte, O.; Fulda-Quenzer, F.; Jacholkowska, A.; Jean-Marie, B.; Lefrancois, J.; Machefert, F.; Robbe, P.; Schune, M.-H.; Tocut, V.; Videau, I.; Benayoun, M.; David, P.; DelBuono, L.; Gilles, G.; Domke, M.; Futterschneider, H.; Ilgner, Ch; Kapusta, P.; Kolander, M.; Krause, R.; Lieng, M.; Nedos, M.; Rudloff, K.; Schleich, S.; Schwierz, R.; Spaan, B.; Wacker, K.; Warda, K.; Agari, M.; Bauer, C.; Baumeister, D.; Bulian, N.; Fuchs, H. P.; Fallot-Burghardt, W.; Glebe, T.; Hofmann, W.; Knöpfle, K. T.; Löchner, S.; Ludwig, A.; Maciuc, F.; Sanchez Nieto, F.; Schmelling, M.; Schwingenheuer, B.; Sexauer, E.; Smale, N. J.; Trunk, U.; Voss, H.; Albrecht, J.; Bachmann, S.; Blouw, J.; Deissenroth, M.; Deppe, H.; Dreis, H. B.; Eisele, F.; Haas, T.; Hansmann-Menzemer, S.; Hennenberger, S.; Knopf, J.; Moch, M.; Perieanu, A.; Rabenecker, S.; Rausch, A.; Rummel, C.; Rusnyak, R.; Schiller, M.; Stange, U.; Uwer, U.; Walter, M.; Ziegler, R.; Avoni, G.; Balbi, G.; Bonifazi, F.; Bortolotti, D.; Carbone, A.; D'Antone, I.; Galli, D.; Gregori, D.; Lax, I.; Marconi, U.; Peco, G.; Vagnoni, V.; Valenti, G.; Vecchi, S.; Bonivento, W.; Cardini, A.; Cadeddu, S.; DeLeo, V.; Deplano, C.; Furcas, S.; Lai, A.; Oldeman, R.; Raspino, D.; Saitta, B.; Serra, N.; Baldini, W.; Brusa, S.; Chiozzi, S.; Cotta Ramusino, A.; Evangelisti, F.; Franconieri, A.; Germani, S.; Gianoli, A.; Guoming, L.; Landi, L.; Malaguti, R.; Padoan, C.; Pennini, C.; Savriè, M.; Squerzanti, S.; Zhao, T.; Zhu, M.; Bizzeti, A.; Graziani, G.; Lenti, M.; Lenzi, M.; Maletta, F.; Pennazzi, S.; Passaleva, G.; Veltri, M.; Alfonsi, M.; Anelli, M.; Balla, A.; Battisti, A.; Bencivenni, G.; Campana, P.; Carletti, M.; Ciambrone, P.; Corradi, G.; Dané, E.; Di Virgilio, A.; DeSimone, P.; Felici, G.; Forti, C.; Gatta, M.; Lanfranchi, G.; Murtas, F.; Pistilli, M.; Poli Lener, M.; Rosellini, R.; Santoni, M.; Saputi, A.; Sarti, A.; Sciubba, A.; Zossi, A.; Ameri, M.; Cuneo, S.; Fontanelli, F.; Gracco, V.; Miní, G.; Parodi, M.; Petrolini, A.; Sannino, M.; Vinci, A.; Alemi, M.; Arnaboldi, C.; Bellunato, T.; Calvi, M.; Chignoli, F.; DeLucia, A.; Galotta, G.; Mazza, R.; Matteuzzi, C.; Musy, M.; Negri, P.; Perego, D.; Pessina, G.; Auriemma, G.; Bocci, V.; Buccheri, A.; Chiodi, G.; Di Marco, S.; Iacoangeli, F.; Martellotti, G.; Nobrega, R.; Pelosi, A.; Penso, G.; Pinci, D.; Rinaldi, W.; Rossi, A.; Santacesaria, R.; Satriano, C.; Carboni, G.; Iannilli, M.; Massafferri Rodrigues, A.; Messi, R.; Paoluzzi, G.; Sabatino, G.; Santovetti, E.; Satta, A.; Amoraal, J.; van Apeldoorn, G.; Arink, R.; van Bakel, N.; Band, H.; Bauer, Th; Berkien, A.; van Beuzekom, M.; Bos, E.; Bron, Ch; Ceelie, L.; Doets, M.; van der Eijk, R.; Fransen, J.-P.; de Groen, P.; Gromov, V.; Hierck, R.; Homma, J.; Hommels, B.; Hoogland, W.; Jans, E.; Jansen, F.; Jansen, L.; Jaspers, M.; Kaan, B.; Koene, B.; Koopstra, J.; Kroes, F.; Kraan, M.; Langedijk, J.; Merk, M.; Mos, S.; Munneke, B.; Palacios, J.; Papadelis, A.; Pellegrino, A.; van Petten, O.; du Pree, T.; Roeland, E.; Ruckstuhl, W.; Schimmel, A.; Schuijlenburg, H.; Sluijk, T.; Spelt, J.; Stolte, J.; Terrier, H.; Tuning, N.; Van Lysebetten, A.; Vankov, P.; Verkooijen, J.; Verlaat, B.; Vink, W.; de Vries, H.; Wiggers, L.; Ybeles Smit, G.; Zaitsev, N.; Zupan, M.; Zwart, A.; van den Brand, J.; Bulten, H. J.; de Jong, M.; Ketel, T.; Klous, S.; Kos, J.; M'charek, B.; Mul, F.; Raven, G.; Simioni, E.; Cheng, J.; Dai, G.; Deng, Z.; Gao, Y.; Gong, G.; Gong, H.; He, J.; Hou, L.; Li, J.; Qian, W.; Shao, B.; Xue, T.; Yang, Z.; Zeng, M.; Muryn, B.; Ciba, K.; Oblakowska-Mucha, A.; Blocki, J.; Galuszka, K.; Hajduk, L.; Michalowski, J.; Natkaniec, Z.; Polok, G.; Stodulski, M.; Witek, M.; Brzozowski, K.; Chlopik, A.; Gawor, P.; Guzik, Z.; Nawrot, A.; Srednicki, A.; Syryczynski, K.; Szczekowski, M.; Anghel, D. V.; Cimpean, A.; Coca, C.; Constantin, F.; Cristian, P.; Dumitru, D. D.; Dumitru, D. T.; Giolu, G.; Kusko, C.; Magureanu, C.; Mihon, Gh; Orlandea, M.; Pavel, C.; Petrescu, R.; Popescu, S.; Preda, T.; Rosca, A.; Rusu, V. L.; Stoica, R.; Stoica, S.; Tarta, P. D.; Filippov, S.; Gavrilov, Yu; Golyshkin, L.; Gushchin, E.; Karavichev, O.; Klubakov, V.; Kravchuk, L.; Kutuzov, V.; Laptev, S.; Popov, S.; Aref'ev, A.; Bobchenko, B.; Dolgoshein, V.; Egorychev, V.; Golutvin, A.; Gushchin, O.; Konoplyannikov, A.; Korolko, I.; Kvaratskheliya, T.; Machikhiliyan, I.; Malyshev, S.; Mayatskaya, E.; Prokudin, M.; Rusinov, D.; Rusinov, V.; Shatalov, P.; Shchutska, L.; Tarkovskiy, E.; Tayduganov, A.; Voronchev, K.; Zhiryakova, O.; Bobrov, A.; Bondar, A.; Eidelman, S.; Kozlinsky, A.; Shekhtman, L.; Beloous, K. S.; Dzhelyadin, R. I.; Gelitsky, Yu V.; Gouz, Yu P.; Kachnov, K. G.; Kobelev, A. S.; Matveev, V. D.; Novikov, V. P.; Obraztsov, V. F.; Ostankov, A. P.; Romanovsky, V. I.; Rykalin, V. I.; Soldatov, A. P.; Soldatov, M. M.; Tchernov, E. N.; Yushchenko, O. P.; Bochin, B.; Bondar, N.; Fedorov, O.; Golovtsov, V.; Guets, S.; Kashchuk, A.; Lazarev, V.; Maev, O.; Neustroev, P.; Sagidova, N.; Spiridenkov, E.; Volkov, S.; Vorobyev, An; Vorobyov, A.; Aguilo, E.; Bota, S.; Calvo, M.; Comerma, A.; Cano, X.; Dieguez, A.; Herms, A.; Lopez, E.; Luengo, S.; Garra, J.; Garrido, Ll; Gascon, D.; Gaspar de Valenzuela, A.; Gonzalez, C.; Graciani, R.; Grauges, E.; Perez Calero, A.; Picatoste, E.; Riera, J.; Rosello, M.; Ruiz, H.; Vilasis, X.; Xirgu, X.; Adeva, B.; Cid Vidal, X.; MartÉnez Santos, D.; Esperante Pereira, D.; Fungueiriño Pazos, J. L.; Gallas Torreira, A.; Gómez, C. Lois; Pazos Alvarez, A.; Pérez Trigo, E.; Pló Casasús, M.; Rodriguez Cobo, C.; Rodríguez Pérez, P.; Saborido, J. J.; Seco, M.; Vazquez Regueiro, P.; Bartalini, P.; Bay, A.; Bettler, M.-O.; Blanc, F.; Borel, J.; Carron, B.; Currat, C.; Conti, G.; Dormond, O.; Ermoline, Y.; Fauland, P.; Fernandez, L.; Frei, R.; Gagliardi, G.; Gueissaz, N.; Haefeli, G.; Hicheur, A.; Jacoby, C.; Jalocha, P.; Jimenez-Otero, S.; Hertig, J.-P.; Knecht, M.; Legger, F.; Locatelli, L.; Moser, J.-R.; Needham, M.; Nicolas, L.; Perrin-Giacomin, A.; Perroud, J.-P.; Potterat, C.; Ronga, F.; Schneider, O.; Schietinger, T.; Steele, D.; Studer, L.; Tareb, M.; Tran, M. T.; van Hunen, J.; Vervink, K.; Villa, S.; Zwahlen, N.; Bernet, R.; Büchler, A.; Gassner, J.; Lehner, F.; Sakhelashvili, T.; Salzmann, C.; Sievers, P.; Steiner, S.; Steinkamp, O.; Straumann, U.; van Tilburg, J.; Vollhardt, A.; Volyanskyy, D.; Ziegler, M.; Dovbnya, A.; Ranyuk, Yu; Shapoval, I.; Borisova, M.; Iakovenko, V.; Kyva, V.; Kovalchuk, O.; Okhrimenko, O.; Pugatch, V.; Pylypchenko, Yu; Adinolfi, M.; Brook, N. H.; Head, R. D.; Imong, J. P.; Lessnoff, K. A.; Metlica, F. C. D.; Muir, A. J.; Rademacker, J. H.; Solomin, A.; Szczypka, P. M.; Barham, C.; Buszello, C.; Dickens, J.; Gibson, V.; Haines, S.; Harrison, K.; Jones, C. R.; Katvars, S.; Kerzel, U.; Lazzeroni, C.; Li, Y. Y.; Rogers, G.; Storey, J.; Skottowe, H.; Wotton, S. A.; Adye, T. J.; Densham, C. J.; Easo, S.; Franek, B.; Loveridge, P.; Morrow, D.; Morris, J. V.; Nandakumar, R.; Nardulli, J.; Papanestis, A.; Patrick, G. N.; Ricciardi, S.; Woodward, M. L.; Zhang, Z.; Chamonal, R. J. U.; Clark, P. J.; Clarke, P.; Eisenhardt, S.; Gilardi, N.; Khan, A.; Kim, Y. M.; Lambert, R.; Lawrence, J.; Main, A.; McCarron, J.; Mclean, C.; Muheim, F.; Osorio-Oliveros, A. F.; Playfer, S.; Styles, N.; Xie, Y.; Bates, A.; Carson, L.; da Cunha Marinho, F.; Doherty, F.; Eklund, L.; Gersabeck, M.; Haddad, L.; Macgregor, A. A.; Melone, J.; McEwan, F.; Petrie, D. M.; Paterson, S. K.; Parkes, C.; Pickford, A.; Rakotomiaramanana, B.; Rodrigues, E.; Saavedra, A. F.; Soler, F. J. P.; Szumlak, T.; Viret, S.; Allebone, L.; Awunor, O.; Back, J.; Barber, G.; Barnes, C.; Cameron, B.; Clark, D.; Clark, I.; Dornan, P.; Duane, A.; Eames, C.; Egede, U.; Girone, M.; Greenwood, S.; Hallam, R.; Hare, R.; Howard, A.; Jolly, S.; Kasey, V.; Khaleeq, M.; Koppenburg, P.; Miller, D.; Plackett, R.; Price, D.; Reece, W.; Savage, P.; Savidge, T.; Simmons, B.; Vidal-Sitjes, G.; Websdale, D.; Affolder, A.; Anderson, J. S.; Biagi, S. F.; Bowcock, T. J. V.; Carroll, J. L.; Casse, G.; Cooke, P.; Donleavy, S.; Dwyer, L.; Hennessy, K.; Huse, T.; Hutchcroft, D.; Jones, D.; Lockwood, M.; McCubbin, M.; McNulty, R.; Muskett, D.; Noor, A.; Patel, G. D.; Rinnert, K.; Shears, T.; Smith, N. A.; Southern, G.; Stavitski, I.; Sutcliffe, P.; Tobin, M.; Traynor, S. M.; Turner, P.; Whitley, M.; Wormald, M.; Wright, V.; Bibby, J. H.; Brisbane, S.; Brock, M.; Charles, M.; Cioffi, C.; Gligorov, V. V.; Handford, T.; Harnew, N.; Harris, F.; John, M. J. J.; Jones, M.; Libby, J.; Martin, L.; McArthur, I. A.; Muresan, R.; Newby, C.; Ottewell, B.; Powell, A.; Rotolo, N.; Senanayake, R. S.; Somerville, L.; Soroko, A.; Spradlin, P.; Sullivan, P.; Stokes-Rees, I.; Topp-Jorgensen, S.; Xing, F.; Wilkinson, G.; Artuso, M.; Belyaev, I.; Blusk, S.; Lefeuvre, G.; Menaa, N.; Menaa-Sia, R.; Mountain, R.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Abadie, L.; Aglieri-Rinella, G.; Albrecht, E.; André, J.; Anelli, G.; Arnaud, N.; Augustinus, A.; Bal, F.; Barandela Pazos, M. C.; Barczyk, A.; Bargiotti, M.; Batista Lopes, J.; Behrendt, O.; Berni, S.; Binko, P.; Bobillier, V.; Braem, A.; Brarda, L.; Buytaert, J.; Camilleri, L.; Cambpell, M.; Castellani, G.; Cataneo, F.; Cattaneo, M.; Chadaj, B.; Charpentier, P.; Cherukuwada, S.; Chesi, E.; Christiansen, J.; Chytracek, R.; Clemencic, M.; Closier, J.; Collins, P.; Colrain, P.; Cooke, O.; Corajod, B.; Corti, G.; D'Ambrosio, C.; Damodaran, B.; David, C.; de Capua, S.; Decreuse, G.; Degaudenzi, H.; Dijkstra, H.; Droulez, J.-P.; Duarte Ramos, D.; Dufey, J. P.; Dumps, R.; Eckstein, D.; Ferro-Luzzi, M.; Fiedler, F.; Filthaut, F.; Flegel, W.; Forty, R.; Fournier, C.; Frank, M.; Frei, C.; Gaidioz, B.; Gaspar, C.; Gayde, J.-C.; Gavillet, P.; Go, A.; Gracia Abril, G.; Graulich, J.-S.; Giudici, P.-A.; Guirao Elias, A.; Guglielmini, P.; Gys, T.; Hahn, F.; Haider, S.; Harvey, J.; Hay, B.; Hernando Morata, J.-A.; Herranz Alvarez, J.; van Herwijnen, E.; Hilke, H. J.; von Holtey, G.; Hulsbergen, W.; Jacobsson, R.; Jamet, O.; Joram, C.; Jost, B.; Kanaya, N.; Knaster Refolio, J.; Koestner, S.; Koratzinos, M.; Kristic, R.; Lacarrère, D.; Lasseur, C.; Lastovicka, T.; Laub, M.; Liko, D.; Lippmann, C.; Lindner, R.; Losasso, M.; Maier, A.; Mair, K.; Maley, P.; Mato Vila, P.; Moine, G.; Morant, J.; Moritz, M.; Moscicki, J.; Muecke, M.; Mueller, H.; Nakada, T.; Neufeld, N.; Ocariz, J.; Padilla Aranda, C.; Parzefall, U.; Patel, M.; Pepe-Altarelli, M.; Piedigrossi, D.; Pivk, M.; Pokorski, W.; Ponce, S.; Ranjard, F.; Riegler, W.; Renaud, J.; Roiser, S.; Rossi, A.; Roy, L.; Ruf, T.; Ruffinoni, D.; Saladino, S.; Sambade Varela, A.; Santinelli, R.; Schmelling, S.; Schmidt, B.; Schneider, T.; Schöning, A.; Schopper, A.; Seguinot, J.; Snoeys, W.; Smith, A.; Smith, A. C.; Somogyi, P.; Stoica, R.; Tejessy, W.; Teubert, F.; Thomas, E.; Toledo Alarcon, J.; Ullaland, O.; Valassi, A.; Vannerem, P.; Veness, R.; Wicht, P.; Wiedner, D.; Witzeling, W.; Wright, A.; Wyllie, K.; Ypsilantis, T.

    2008-08-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.

  18. Construction of the CDF silicon vertex detector

    SciTech Connect

    Skarha, J.; Barnett, B.; Boswell, C.; Snider, F.; Spies, A.; Tseng, J.; Vejcik, S. ); Carter, H.; Flaugher, B.; Gonzales, B.; Hrycyk, M.; Nelson, C.; Segler, S.; Shaw, T.; Tkaczyk, S.; Turner, K.; Wesson, T. ); Carithers, W.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneider, O.; Wester

    1992-04-01

    Technical details and methods used in constructing the CDF silicon vertex detector are presented. This description includes a discussion of the foam-carbon fiber composite structure used to silicon microstrip detectors and the procedure for achievement of 5 {mu}m detector alignment. The construction of the beryllium barrel structure, which houses the detector assemblies, is also described. In addition, the 10 {mu}m placement accuracy of the detectors in the barrel structure is discussed and the detector cooling and mounting systems are described. 12 refs.

  19. The HERA-B vertex detector system

    NASA Astrophysics Data System (ADS)

    Bauer, C.; Bräuer, M.; Glebe, T.; Hofmann, W.; Jagla, T.; Klefenz, F.; Knöpfle, K. T.; Pugatch, V.; Schmelling, M.; Schwingenheuer, B.; Sexauer, E.; Trunk, U.; Wanke, R.; Zurheide, F.; Abt, I.; Dressel, M.; Kisel, I.; Masciocchi, S.; Moshous, B.; Perschke, T.; Sang, M.; Schaller, S.; Wagner, W.

    2000-10-01

    The HERA-B experiment is being built to measure CP violation in the B-system using internal targets at the HERA proton storage ring at DESY. This paper presents an overview of its vertex detector which - apart from an additional superlayer - is realized by a system of 20 Roman pots containing seven superlayers of double-sided silicon microstrip detectors that are operated at 10 mm distance from the proton beam in a high-radiation environment.

  20. Silicon technologies for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Spannagel, S.

    2017-06-01

    CLIC is a proposed linear e+e- collider designed to provide particle collisions at center-of-mass energies of up to 3 TeV. Precise measurements of the properties of the top quark and the Higgs boson, as well as searches for Beyond the Standard Model physics require a highly performant CLIC detector. In particular the vertex detector must provide a single point resolution of only a few micrometers while not exceeding the envisaged material budget of around 0.2% X0 per layer. Beam-beam interactions and beamstrahlung processes impose an additional requirement on the timestamping capabilities of the vertex detector of about 10 ns. These goals can only be met by using novel techniques in the sensor and ASIC design as well as in the detector construction. The R&D program for the CLIC vertex detector explores various technologies in order to meet these demands. The feasibility of planar sensors with a thickness of 50-150 μm, including different active edge designs, are evaluated using Timepix3 ASICs. First prototypes of the CLICpix readout ASIC, implemented in 65 nm CMOS technology and with a pixel size of 25×25μm 2, have been produced and tested in particle beams. An updated version of the ASIC with a larger pixel matrix and improved precision of the time-over-threshold and time-of-arrival measurements has been submitted. Different hybridization concepts have been developed for the interconnection between the sensor and readout ASIC, ranging from small-pitch bump bonding of planar sensors to capacitive coupling of active HV-CMOS sensors. Detector simulations based on Geant 4 and TCAD are compared with experimental results to assess and optimize the performance of the various designs. This contribution gives an overview of the R&D program undertaken for the CLIC vertex detector and presents performance measurements of the prototype detectors currently under investigation.

  1. Internal Alignment of the SLD Vertex Detector

    SciTech Connect

    Jackson, D.J.; Wickens, F.J.; Su, D.; /SLAC

    2007-12-03

    The tracking resolution and vertex finding capabilities of the SLD experiment depended upon a precise knowledge of the location and orientation of the elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool was employed to unfold the detector geometry corrections from the track data in the VXD3. The algorithm was adapted to perform an optimal {chi}{sup 2} minimization by careful treatment of the track hit residual measurement errors. The tracking resolution obtained with the aligned geometry achieved the design performance. Comments are given on how this method could be used for other trackers.

  2. The Belle II Silicon Vertex Detector

    NASA Astrophysics Data System (ADS)

    Friedl, M.; Ackermann, K.; Aihara, H.; Aziz, T.; Bergauer, T.; Bozek, A.; Campbell, A.; Dingfelder, J.; Drasal, Z.; Frankenberger, A.; Gadow, K.; Gfall, I.; Haba, J.; Hara, K.; Hara, T.; Higuchi, T.; Himori, S.; Irmler, C.; Ishikawa, A.; Joo, C.; Kah, D. H.; Kang, K. H.; Kato, E.; Kiesling, C.; Kodys, P.; Kohriki, T.; Koike, S.; Kvasnicka, P.; Marinas, C.; Mayekar, S. N.; Mibe, T.; Mohanty, G. B.; Moll, A.; Negishi, K.; Nakayama, H.; Natkaniec, Z.; Niebuhr, C.; Onuki, Y.; Ostrowicz, W.; Park, H.; Rao, K. K.; Ritter, M.; Rozanska, M.; Saito, T.; Sakai, K.; Sato, N.; Schmid, S.; Schnell, M.; Shimizu, N.; Steininger, H.; Tanaka, S.; Tanida, K.; Taylor, G.; Tsuboyama, T.; Ueno, K.; Uozumi, S.; Ushiroda, Y.; Valentan, M.; Yamamoto, H.

    2013-12-01

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×1035 cm-2 s-1 in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13 m2 and 223,744 channels-twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.

  3. Mechanical design of the CDF SVX II silicon vertex detector

    SciTech Connect

    Skarha, J.E.

    1994-08-01

    A next generation silicon vertex detector is planned at CDF for the 1998 Tevatron collider run with the Main Injector. The SVX II silicon vertex detector will allow high luminosity data-taking, enable online triggering of secondary vertex production, and greatly increase the acceptance for heavy flavor physics at CDF. The design specifications, geometric layout, and early mechanical prototyping work for this detector are discussed.

  4. The Belle II Silicon Vertex Detector

    NASA Astrophysics Data System (ADS)

    Friedl, M.; Bergauer, T.; Dolejschi, P.; Frankenberger, A.; Gfall, I.; Irmler, C.; Obermayer, T.; Onuki, Y.; Smiljic, D.; Tsuboyama, T.; Valentan, M.

    The KEKB factory (Tsukuba, Japan) has been shut down in mid-2010 after reaching a total integrated luminosity of 1ab-1. Recently, the work on an upgrade of the collider (SuperKEKB), aiming at an ultimate luminosity of 8×1035 cm-2s-1, has started. This is 40 times the peak value of the previous system and thus also requires a redesign of the Belle detector (leading to Belle II), especially its Silicon Vertex Detector (SVD), which surrounds the beam pipe. Similar to its predecessor, the future Belle II SVD will again consist of four layers of double-sided silicon strip sensors (DSSD), but at higher radii. Moreover, a double-layer PiXel Detector (PXD) will complement the SVD as the innermost sensing device. All DSSDs will be made from 6" silicon wafers and read out by APV25 chips, which were originally developed for the CMS experiment. That system was proven to meet the requirements for Belle II in matters of occupancy and dead time. Since the KEKB factory operates at relatively low energy, material inside the active volume has to be minimized in order to reduce multiple scattering. This can be achieved by the Origami chip-on-sensor concept, including a very light-weight mechanical support structure made from carbon fiber reinforced Airex foam. Moreover, CO2 cooling for the front-end chips will ensure high efficiency at minimum material budget.

  5. The PHENIX Forward Silicon Vertex Detector

    NASA Astrophysics Data System (ADS)

    Aidala, C.; Anaya, L.; Anderssen, E.; Bambaugh, A.; Barron, A.; Boissevain, J. G.; Bok, J.; Boose, S.; Brooks, M. L.; Butsyk, S.; Cepeda, M.; Chacon, P.; Chacon, S.; Chavez, L.; Cote, T.; D'Agostino, C.; Datta, A.; DeBlasio, K.; DelMonte, L.; Desmond, E. J.; Durham, J. M.; Fields, D.; Finger, M.; Gingu, C.; Gonzales, B.; Haggerty, J. S.; Hawke, T.; van Hecke, H. W.; Herron, M.; Hoff, J.; Huang, J.; Jiang, X.; Johnson, T.; Jonas, M.; Kapustinsky, J. S.; Key, A.; Kunde, G. J.; Kurtz, J.; LaBounty, J.; Lee, D. M.; Lee, K. B.; Leitch, M. J.; Lenz, M.; Lenz, W.; Liu, M. X.; Lynch, D.; Mannel, E.; McGaughey, P. L.; Meles, A.; Meredith, B.; Nguyen, H.; O'Brien, E.; Pak, R.; Papavassiliou, V.; Pate, S.; Pereira, H.; Perera, G. D. N.; Phillips, M.; Pisani, R.; Polizzo, S.; Poncione, R. J.; Popule, J.; Prokop, M.; Purschke, M. L.; Purwar, A. K.; Ronzhina, N.; Silva, C. L.; Slunečka, M.; Smith, R.; Sondheim, W. E.; Spendier, K.; Stoffer, M.; Tennant, E.; Thomas, D.; Tomášek, M.; Veicht, A.; Vrba, V.; Wang, X. R.; Wei, F.; Winter, D.; Yarema, R.; You, Z.; Younus, I.; Zimmerman, A.; Zimmerman, T.

    2014-08-01

    A new silicon detector has been developed to provide the PHENIX experiment with precise charged particle tracking at forward and backward rapidity. The Forward Silicon Vertex Tracker (FVTX) was installed in PHENIX prior to the 2012 run period of the Relativistic Heavy Ion Collider (RHIC). The FVTX is composed of two annular endcaps, each with four stations of silicon mini-strip sensors, covering a rapidity range of 1.2<|η|<2.2 that closely matches the two existing PHENIX muon arms. Each station consists of 48 individual silicon sensors, each of which contains two columns of mini-strips with 75 μm pitch in the radial direction and lengths in the ϕ direction varying from 3.4 mm at the inner radius to 11.5 mm at the outer radius. The FVTX has approximately 0.54 million strips in each endcap. These are read out with FPHX chips, developed in collaboration with Fermilab, which are wire bonded directly to the mini-strips. The maximum strip occupancy reached in central Au-Au collisions is approximately 2.8%. The precision tracking provided by this device makes the identification of muons from secondary vertices away from the primary event vertex possible. The expected distance of closest approach (DCA) resolution of 200 μm or better for particles with a transverse momentum of 5 GeV/c will allow identification of muons from relatively long-lived particles, such as D and B mesons, through their broader DCA distributions.

  6. The vertex detector for the Lepton/Photon collaboration

    SciTech Connect

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

    1991-12-31

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

  7. Drift chamber vertex detectors for SLC/LEP

    SciTech Connect

    Hayes, K.G.

    1987-03-01

    The short but measurable lifetimes of the b and c quarks and the tau lepton have motivated the development of high precision tracking detectors capable of providing information on the decay vertex topology of events containing these particles. This paper reviews the OPAL, L3, and MARK II experiments vertex drift chambers.

  8. SVX{prime}, the new CDF silicon vertex detector

    SciTech Connect

    Cihangir, S.; Gillespie, G.; Gonzalez, H.

    1994-08-26

    The Collider Detector at Fermilab (CDF) radiation hardened silicon vertex detector (SVX{prime}) is described. The new detector has several improvements over its predecessor such as better signal to noise and higher efficiency. It`s expected to have a radiation tolerance in excess of 1 Mrad. It has been taking data for several months and some preliminary results are shown.

  9. Full Offline Reconstruction in Real Time with the LHCb Detector

    NASA Astrophysics Data System (ADS)

    Dziurda, Agnieszka

    2016-11-01

    This document describes the novel, unique in High Energy Physics, real-time alignment and calibration of the full LHCb detector. The LHCb experiment has been designed as a dedicated heavy flavour physics experiment focused on the reconstruction of c and b hadrons. The LHCb detector is a single-arm forward spectrometer, which measures proton-proton interactions at the LHC. The operational bunch crossing rate is several orders of magnitude above the current abilities of data recording and storage. Therefore, a trigger system has been implemented to reduce this rate to an acceptable value. The LHCb trigger system has been redesigned during the 2013-2015 long shutdown,achieving offline-quality alignment and calibration online. It also allows analyses to be performed entirely at the trigger level. In addition, having the best performing reconstruction in the trigger gives the possibility to fully use the particle identification selection criteria and greatly increases the efficiency, in particular for the selection of charm and strange hadron decays. This results in enhancing the physics programme of the LHCb experiment.

  10. Status and upgrade plans of the Belle silicon vertex detector

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Arakawa, T.; Asano, Y.; Aso, T.; Bakich, A.; Barbero, M.; Browder, T.; Chang, M. C.; Chao, Y.; Chen, K. F.; Chidzik, S.; Chouvikov, A.; Choi, Y. K.; Das, A.; Dalseno, J.; Fratina, S.; Friedl, M.; Fujiyama, Y.; Haba, J.; Hara, K.; Hara, T.; Harrop, B.; Hayashi, K.; Hazumi, M.; Heffernan, D.; Higuchi, T.; Hirakawa, T.; Irmler, C.; Ishino, H.; Joshi, N. K.; Kajiwara, S.; Kakuno, H.; Kameshima, T.; Kawasaki, T.; Kibayashi, A.; Kim, Y. J.; Koike, S.; Korpar, S.; Križan, P.; Kurashiro, H.; Kusaka, A.; Marlow, D.; Miyake, H.; Moloney, G. R.; Nakahama, Y.; Natkaniec, Z.; Okuno, S.; Ono, S.; Ostrowicz, W.; Ozaki, H.; Peak, L.; Pernicka, M.; Rosen, M.; Rozanska, M.; Sato, N.; Schmid, S.; Schümann, J.; Stanič, S.; Steininger, H.; Sumisawa, K.; Tajima, O.; Takahashi, T.; Tamura, N.; Tanaka, M.; Tani, N.; Taylor, G. N.; Trabelsi, K.; Tsuboyama, T.; Uchida, K.; Ueno, K.; Ushiroda, Y.; Varner, G.; Varvell, K.; Velikzhanin, Y. S.; Wang, C. C.; Wang, M. Z.; Watanabe, M.; Watanabe, Y.; Yamamoto, H.; Yamashita, Y.; Ziegler, T.

    2007-12-01

    The second generation of Belle Silicon Vertex Detector (SVD) has been efficiently operated for more than three years. With increasing beam-induced background, a degradation of the detector performance is expected. To avoid such a difficulty, we are planing a next upgrade, the third generation of the SVD. Currently, its design is almost finalized.

  11. RAVE—a Detector-independent vertex reconstruction toolkit

    NASA Astrophysics Data System (ADS)

    Waltenberger, Wolfgang; Mitaroff, Winfried; Moser, Fabian

    2007-10-01

    A detector-independent toolkit for vertex reconstruction (RAVE ) is being developed, along with a standalone framework (VERTIGO ) for testing, analyzing and debugging. The core algorithms represent state of the art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available. VERTIGO = "vertex reconstruction toolkit and interface to generic objects".

  12. Vertex detectors: The state of the art and future prospects

    SciTech Connect

    Damerell, C.J.S.

    1997-01-01

    We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD`s and APS`s) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now.

  13. The SVX II Silicon Vertex Detector at CDF

    NASA Astrophysics Data System (ADS)

    Valls, Juan A.

    1999-08-01

    The Silicon VerteX detector (SVX II) for the CDF experiment at the Tevatron p overlinep collider is a 3-barrel 5-layer device with double-sided, AC-coupled silicon strip detectors. The readout is based on a custom IC, the SVX3 chip, capable of simultaneous acquisition, digitization and readout operation (dead-timeless). In this paper we report on the SVX II design and project status including mechanical design, frontend electronics, and data acquisition.

  14. STAR Vertex Detector Upgrade-HFT Pixel Development

    SciTech Connect

    Szelezniak, Michal; Greiner, Leo C.; Matis, Howard S.; Ritter, Hans Georg; Sun Xiangming; Thomas, James H.; Wieman, Howard H.; Anderssen, Eric; Stezelberger, Thorsten; Vu, Chinh Q.

    2009-03-10

    Development and prototyping efforts directed towards construction of a new vertex detector for the STAR experiment at the RHIC accelerator at BNL are presented. This new detector will extend the physics range of STAR by allowing for precision measurements of yields and spectra of particles containing heavy quarks. The innermost central part of the new detector is a high resolution pixel-type detector (PIXEL). PIXEL requirements are discussed as well as a conceptual mechanical design, a sensor development path, and a detector readout architecture. Selected progress with sensor prototypes dedicated to the PIXEL detector is summarized and the approach chosen for the readout system architecture validated in tests of hardware prototypes is discussed.

  15. Heavy flavour physics at colliders with silicon strip vertex detectors

    NASA Astrophysics Data System (ADS)

    Schwarz, Andreas S.

    1994-03-01

    The physics of heavy flavours has played a dominant role in high energy physics research ever since the discovery of charm in 1974, followed by the τ lepton in 1975 and bottom in 1977. With the startup of the large experiments at the e+e- colliders LEP and the SLC a new type of detector system has now come into operation which has a major impact on the studies of heavy flavours: the silicon strip vertex detector. The basic design priciples of these novel detector systems are outlined and three representative experimental realizations are discussed. The impact of these detectors on the studies of the properties of heavy flavours is just emerging and focuses on the measurement of lifetimes and the tagging of the presence of heavy flavour hadrons in hadronic events. The tools that are being developed for these studies are described as well as details of representative analyses. The potential of these devices and the associated technological developments that were necessary for their application in the colding beam environment is reflected in a plethora of new proposals to build sophisticated silicon detector systems for a large variety of future high energy physics applications. Two examples will be briefly sketched, a vertex detector for an asymmetric e+e- bottom factory and a large scale tracking system for a multipurpose detector at one of the new large hadron colliders.

  16. Silicon vertex detector upgrade in the ALPHA experiment

    NASA Astrophysics Data System (ADS)

    Amole, C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Burrows, C.; Butler, E.; Capra, A.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Isaac, C. A.; Jonsell, S.; Kurchaninov, L.; Little, A.; Madsen, N.; McKenna, J. T. K.; Menary, S.; Napoli, S. C.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Rasmussen, C. Ø.; Robicheaux, F.; Sacramento, R. L.; Stracka, S.; Sampson, J. A.; Sarid, E.; Seddon, D.; Silveira, D. M.; So, C.; Thompson, R. I.; Tharp, T.; Thornhill, J.; Tooley, M. P.; van der Werf, D. P.; Wells, D.

    2013-12-01

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA's analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA's new neutral atom trap.

  17. Performance of the LHCb RICH detector at the LHC.

    PubMed

    Adinolfi, M; Aglieri Rinella, G; Albrecht, E; Bellunato, T; Benson, S; Blake, T; Blanks, C; Brisbane, S; Brook, N H; Calvi, M; Cameron, B; Cardinale, R; Carson, L; Contu, A; Coombes, M; D'Ambrosio, C; Easo, S; Egede, U; Eisenhardt, S; Fanchini, E; Fitzpatrick, C; Fontanelli, F; Forty, R; Frei, C; Gandini, P; Gao, R; Garra Tico, J; Giachero, A; Gibson, V; Gotti, C; Gregson, S; Gys, T; Haines, S C; Hampson, T; Harnew, N; Hill, D; Hunt, P; John, M; Jones, C R; Johnson, D; Kanaya, N; Katvars, S; Kerzel, U; Kim, Y M; Koblitz, S; Kucharczyk, M; Lambert, D; Main, A; Maino, M; Malde, S; Mangiafave, N; Matteuzzi, C; Mini', G; Mollen, A; Morant, J; Mountain, R; Morris, J V; Muheim, F; Muresan, R; Nardulli, J; Owen, P; Papanestis, A; Patel, M; Patrick, G N; Perego, D L; Pessina, G; Petrolini, A; Piedigrossi, D; Plackett, R; Playfer, S; Powell, A; Rademacker, J H; Ricciardi, S; Rogers, G J; Sail, P; Sannino, M; Savidge, T; Sepp, I; Sigurdsson, S; Soler, F J P; Solomin, A; Soomro, F; Sparkes, A; Spradlin, P; Storaci, B; Thomas, C; Topp-Joergensen, S; Torr, N; Ullaland, O; Vervink, K; Voong, D; Websdale, D; Wilkinson, G; Wotton, S A; Wyllie, K; Xing, F; Young, R

    The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (π, K, p) is achieved.

  18. A MAPS based vertex detector for the STAR experiment at RHIC

    SciTech Connect

    Anderssen, E; Ritter, H G; Schambach, J; Sun, X; Szelezniak, M; Thomas, J; Vu, C; Wieman, H

    2011-09-11

    The STAR experiment at RHIC is in the process of upgrading the inner detector region of the experiment to improve the vertex resolution. We describe the current design of a MAPS based vertex detector, which is the innermost and highest resolution detector of the set of three planned upgrade detectors. This detector will enable the identification of decay vertices displaced from the interaction vertex by 100-150 {micro}m and extend the capabilities of the STAR detector in the heavy flavor domain. We present selected detector design characteristics and prototyping results, which help to validate the design in preparation for the construction of the detector.

  19. The FIRST experiment: interaction region and MAPS vertex detector

    NASA Astrophysics Data System (ADS)

    Spiriti, E.; de Napoli, M.; Romano, F.; FIRST Collaboration

    2011-06-01

    The improvement of the precision of the measurement of the nuclear cross-section, in order to fulfill the requirements of the actual Monte Carlo simulations for hadrontherapy and space radioprotection, is the main goal of the FIRST experiment. After a brief introduction on the treatment planning in hadrontherapy, this paper describes main characteristics and components of the experiment. The features of the interaction region detectors and their main needs (low material budget, high angular coverage, two tracks resolution and large trigger rate) are discussed. Special emphasis is devoted in discussing the new silicon pixel vertex detector, in particular its new developed data acquisition and its characterization with the first test results obtained with a prototype of the detector.

  20. The Belle II silicon vertex detector assembly and mechanics

    NASA Astrophysics Data System (ADS)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Bulla, L.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Lueck, T.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2017-02-01

    The Belle II experiment at the asymmetric SuperKEKB collider in Japan will operate at an instantaneous luminosity approximately 50 times greater than its predecessor (Belle). The central feature of the experiment is a vertex detector comprising two layers of pixelated silicon detectors (PXD) and four layers of double-sided silicon microstrip detectors (SVD). One of the key measurements for Belle II is CP violation asymmetry in the decays of beauty and charm hadrons, which hinges on a precise charged-track vertex determination and low-momentum track measurement. Towards this goal, a proper assembly of the SVD components with precise alignment ought to be performed and the geometrical tolerances should be checked to fall within the design limits. We present an overview of the assembly procedure that is being followed, which includes the precision gluing of the SVD module components, wire-bonding of the various electrical components, and precision 3D coordinate measurements of the final SVD modules. Finally, some results from the latest test-beam are reported.

  1. Electronics cooling of Phenix multiplicity and vertex detector

    SciTech Connect

    Chen, Z.; Gregory, W.S.

    1996-08-01

    The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-chip modules must be below 40 C. Using COSMOS/M HSTAR for the Heat Transfer analysis, a finite element model of a typical MCM plate was created to simulate a 9m/s airflow and 9m/s mixed flow composed of 50% helium and 50% air respectively, with convective heat transfer on both sides of the plate. The results using a mixed flow of helium and air show that the average maximum temperature reached by the MCMs is 37.5 C. The maximum temperature which is represented by the hot spots on the MCM is 39.43 C for the helium and air mixture which meets the design temperature requirement 40 C. To maintain the Multiplicity and Vertex Detector at optimized operational status, the configuration of the plenum chamber, the power dissipated by the silicon chips, the fluid flow velocity and comparison on the MCM design parameters will be discussed.

  2. Low-mass materials and vertex detector systems

    DOE PAGES

    Cooper, William E.

    2014-01-01

    Physics requirements set the material budget and the precision and stability necessary in low-mass vertex detector systems. Operational considerations, along with physics requirements, set the operating environment to be provided and determine the heat to be removed. Representative materials for fulfilling those requirements are described and properties of the materials are tabulated. A figure of merit is proposed to aid in material selection. Multi-layer structures are examined as a method to allow material to be used effectively, thereby reducing material contributions. Lastly, comments are made on future directions to be considered in using present materials effectively and in developing newmore » materials.« less

  3. Low-mass materials and vertex detector systems

    SciTech Connect

    Cooper, William E.

    2014-01-01

    Physics requirements set the material budget and the precision and stability necessary in low-mass vertex detector systems. Operational considerations, along with physics requirements, set the operating environment to be provided and determine the heat to be removed. Representative materials for fulfilling those requirements are described and properties of the materials are tabulated. A figure of merit is proposed to aid in material selection. Multi-layer structures are examined as a method to allow material to be used effectively, thereby reducing material contributions. Lastly, comments are made on future directions to be considered in using present materials effectively and in developing new materials.

  4. The silicon vertex detector of HERA-B

    SciTech Connect

    Moshous, Basil

    1998-02-01

    HERA-B is an experiment to study CP violation in the B system using an internal target at the DESY HERA proton ring(820 GeV). The main goal is to measure the asymmetry in the 'gold plated' decays of B{sup 0}, B-bar{sup 0}{yields}J/{psi}K{sub s}{sup 0} yielding a measurement of the angle {beta} of the unitarity triangle. From the semileptonic decay channels of the b, b-bar-hadron produced in association with the B{sup 0},B-bar{sup 0} can be used to tag the flavor of the B{sup 0}. The purpose of the Vertex Detector System is to provide the track coordinates for reconstructing the J/{psi}{yields}e{sup +}e{sup -}, {mu}{sup +}{mu}{sup -} secondary decay vertices and the impact parameters of all tagging particles.

  5. The silicon vertex detector of the Belle II experiment

    NASA Astrophysics Data System (ADS)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rao, K. K.; Rashevskaya, I.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.; Belle SVD Collaboration, II

    2016-07-01

    The silicon vertex detector of the Belle II experiment, structured in a lantern shape, consists of four layers of ladders, fabricated from two to five silicon sensors. The APV25 readout ASIC chips are mounted on one side of the ladder to minimize the signal path for reducing the capacitive noise; signals from the sensor backside are transmitted to the chip by bent flexible fan-out circuits. The ladder is assembled using several dedicated jigs. Sensor motion on the jig is minimized by vacuum chucking. The gluing procedure provides such a rigid foundation that later leads to the desired wire bonding performance. The full ladder with electrically functional sensors is consistently completed with a fully developed assembly procedure, and its sensor offsets from the design values are found to be less than 200 μm. The potential functionality of the ladder is also demonstrated by the radioactive source test.

  6. CDF Run IIb Silicon Vertex Detector DAQ Upgrade

    SciTech Connect

    S. Behari et al.

    2003-12-18

    The CDF particle detector operates in the beamline of the Tevatron proton-antiproton collider at Fermilab, Batavia, IL. The Tevatron is expected to undergo luminosity upgrades (Run IIb) in the future, resulting in a higher number of interactions per beam crossing. To operate in this dense radiation environment, an upgrade of CDF's silicon vertex detector (SVX) subsystem and a corresponding upgrade of its VME-based DAQ system has been explored. Prototypes of all the Run IIb SVX DAQ components have been constructed, assembled into a test stand and operated successfully using an adapted version of CDF's network-capable DAQ software. In addition, a PCI-based DAQ system has been developed as a fast and inexpensive tool for silicon detector and DAQ component testing in the production phase. In this paper they present an overview of the Run IIb silicon DAQ upgrade, emphasizing the new features and improvements incorporated into the constituent VME boards, and discuss a PCI-based DAQ system developed to facilitate production tests.

  7. The TORCH time-of-flight detector for particle identification and photon vertex association

    NASA Astrophysics Data System (ADS)

    Castillo García, L.; Brook, N.; Cussans, D.; Föhl, K.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Piedigrossi, D.; Rademacker, J.; Ros García, A.; van Dijk, M.

    2017-02-01

    TORCH (Time Of internally Reflected CHerenkov light) is a novel time-of-flight detector, designed to provide π /K/p particle identification up to 0~ 1 GeV/c momentum and beyond. To achieve this, a time resolution of ~ 15 ps combining information from 0~ 3 detected photons is required over a 10 m flight path. Large areas can be covered with TORCH, nominally up to 30 m2. One such application is for the LHCb experiment, to complement the particle identification capabilities of its RICH detectors. TORCH has a DIRC-like construction with 10 mm-thick synthetic amorphous fused-silica plates as a radiator. Cherenkov photons propagate by total internal reflection to the plate edges and there are focussed onto an array of position-sensitive photodetectors. Custom-built micro-channel plate photo-multipliers (MCP-PMTs) are being developed in collaboration with industry to provide the lifetime, granularity and time resolution to meet the TORCH specifications. In the present paper, laboratory tests of the MCP-PMTs developed for TORCH and its readout electronics are presented. Test beam measurements of a prototype TORCH detector in a low-momentum mixed beam of pions and protons are highlighted. Time resolutions for individual photons approaching 100 ps is achieved, after correction for dispersion effects in the quartz medium. In addition to the particle identification capabilities, the high-precision timing information that TORCH provides could be used at the high-luminosity LHC to associate high-energy photons with the correct primary interaction vertex amongst the many expected.

  8. From vertex detectors to inner trackers with CMOS pixel sensors

    NASA Astrophysics Data System (ADS)

    Besson, A.; Pérez, A. Pérez; Spiriti, E.; Baudot, J.; Claus, G.; Goffe, M.; Winter, M.

    2017-02-01

    The use of CMOS Pixel Sensors (CPS) for high resolution and low material vertex detectors has been validated with the 2014 and 2015 physics runs of the STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner tracking devices, with 10-100 times larger sensitive area, which require therefore a sensor design privileging power saving, response uniformity and robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was considered as too poorly suited to upcoming applications like the upgraded ALICE Inner Tracking System (ITS), which requires sensors with one order of magnitude improvement on readout speed and improved radiation tolerance. This triggered the exploration of a deeper sub-micron CMOS technology, Tower-Jazz 180 nm, for the design of a CPS well adapted for the new ALICE-ITS running conditions. This paper reports the R & D results for the conception of a CPS well adapted for the ALICE-ITS.

  9. First experience and results from the HERA-/B vertex detector system

    NASA Astrophysics Data System (ADS)

    Bauer, C.; Baumann, I.; Bräuer, M.; Eberle, M.; Fallot-Burghardt, W.; Grigoriev, E.; Hofmann, W.; Hüpper, A.; Klefenz, F.; Knöpfle, K. T.; Leffers, G.; Perschke, T.; Rieling, J.; Schmelling, M.; Schwingenheuer, B.; Sexauer, E.; Seybold, L.; Spengler, J.; StDenis, R.; Trunk, U.; Wanke, R.; Abt, I.; Fox, H.; Moshous, B.; Riechmann, K.; Rietz, M.; Ruebsam, R.; Wagner, W.

    1998-11-01

    The HERA- B collaboration is building a detector to realize the ambitious goal of observing CP violation in decays of neutral B-mesons. A central element of the apparatus is the silicon vertex detector used to selectively trigger on these decays in a high charged particle multiplicity background environment and to reconstruct secondary vertices from such decays with high precision. The vertex detector, the supporting infrastructure and first results using prototype detectors are described. Results include imaging of the proton interaction region on the HERA- B target, hit distributions in the detector planes, and alignment of the detectors with each other and the target.

  10. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  11. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Tehrani, N. Alipour; Arfaoui, S.; Benoit, M.; Dannheim, D.; Dette, K.; Hynds, D.; Kulis, S.; Perić, I.; Petrič, M.; Redford, S.; Sicking, E.; Valerio, P.

    2016-07-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor, where efficiencies of greater than 99% have been achieved at -60 V substrate bias, with a single hit resolution of 6.1 μm . Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  12. Operating Hybrid Photon Detectors in the LHCb RICH counters at high occupancy

    NASA Astrophysics Data System (ADS)

    Eisenhardt, Stephan

    2014-12-01

    We report about the experiences in the operation of the Hybrid Photon Detectors in the Ring Imaging Cherenkov Detectors of the LHCb experiment during the first run period, 2010-2012. Of particular interest is the ageing due to the deterioration of the vacuum quality of the tubes, leading to an increase of ion feedback.

  13. Novel real-time alignment and calibration of the LHCb detector and its performance

    NASA Astrophysics Data System (ADS)

    Borghi, S.

    2017-02-01

    The LHCb detector is a forward spectrometer at the LHC, designed to perform high precision studies of B and D hadrons. In Run II of the LHC, a new scheme for the software trigger at LHCb allows splitting the triggering of events in two stages, giving room to perform the detector alignment and calibration in real time. In the novel detector alignment and calibration strategy for Run II, data collected at the start of the fill are processed in a few minutes and used to update the alignment constants, while the calibration constants are evaluated for each run. This allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. The larger timing budget, available in the trigger, allows us to perform the same track reconstruction online and offline. This enables LHCb to achieve the best reconstruction performance already in the trigger, and allows physics analyses to be performed directly on the data produced by the trigger reconstruction. The novel real-time processing strategy at LHCb is discussed from both the technical and operational point of view. The overall performance of the LHCb detector on the data of Run II is presented as well.

  14. SVX II a silicon vertex detector for run II of the tevatron

    SciTech Connect

    Bortoletto, D.

    1994-11-01

    A microstrip silicon detector SVX II has been proposed for the upgrade of the vertex detector of the CDF experiment to be installed for run II of the Tevatron in 1998. Three barrels of four layers of double sided detectors will cover the interaction region. The requirement of the silicon tracker and the specification of the sensors are discussed together with the proposed R&D to verify the performance of the prototypes detectors produced by Sintef, Micron and Hamamatsu.

  15. SPY: A monitoring system for the silicon vertex detector of CDF

    SciTech Connect

    Bedeschi, F.; Galeotti, S.; Gherarducci, F.; Mariotti, M.; Morsani, F.; Passuello, D.; Tartarelli, F.; Grieco, G.M.; Nelson, C.; Tkaczyk, S.; Harber, C.; Ristori, L.; Bailey, M.; Sciacca, G.F.; Turini, N.; Cei, M.

    1993-12-01

    The authors describe the basic principles and the fundamentals of the design of the system of monitoring the CDF silicon vertex detector. Also described are some results and possible future developments of this promising way of checking complex detectors with high amount of channels.

  16. Locating the neutrino interaction vertex with the help of electronic detectors in the OPERA experiment

    NASA Astrophysics Data System (ADS)

    Gornushkin, Yu. A.; Dmitrievsky, S. G.; Chukanov, A. V.

    2015-01-01

    The OPERA experiment is designed for the direct observation of the appearance of ντ from νμ → ντ oscillation in a νμ beam. A description of the procedure of neutrino interaction vertex localization (Brick Finding) by electronic detectors of a hybrid OPERA setup is presented. The procedure includes muon track and hadronic shower axis reconstruction and a determination of the target bricks with the highest probability to contain the vertex.

  17. Multiplicity-Vertex Detector Electronics Development for Heavy-Ion Detectors

    SciTech Connect

    Britton, C.L., Jr.; Bryan, W.L.; Emery, M.S.

    1995-12-31

    This paper presents the electronics work performed to date for the Multiplicity-Vertex Detector (MVD) for the PHENIX collaboration at RHIC. The detector consists of approximately 34,000 channels of both silicon strips and silicon pads. The per-channel signal processing chain consists of a pre-amplifier gain stage, a current mode summed multiplicity discriminator, a 64 deep analog memory (simultaneous read/write), an analog correlator, and a 10-bit microsecs ADC. The system controller or Heap Manager, supplies all timing control, data buffering, and data formatting for a single 256-channel multi-chip module (MCM). Each chip set is partitioned into 32-channel sets. Prototype performance for the various blocks will be presented as well as the ionizing radiation damage performance of the 1.2 mu nwell CMOS process used for fabrication.

  18. TORCH - Cherenkov and Time-of-Flight PID Detector for the LHCb Upgrade at CERN

    NASA Astrophysics Data System (ADS)

    Föhl, K.; Brook, N.; Castillo García, L.; Conneely, T.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Milnes, J.; Piedigrossi, D.; Rademacker, J.; Ros Garcì a, A.; van Dijk, M.

    2016-05-01

    TORCH is a large-area precision time-of-flight detector, based on Cherenkov light production and propagation in a quartz radiator plate, which is read out at its edges. TORCH is proposed for the LHCb experiment at CERN to provide positive particle identification for kaons, and is currently in the Research-and-Development phase. A brief overview of the micro-channel plate photon sensor development, the custom-made electronics, and an introduction to the current test beam activities is given. Optical readout solutions are presented for the potential use of BaBar DIRC bar boxes as part of the TORCH configuration in LHCb.

  19. VXD3: The SLD vertex detector upgrade based on a 307 Mpixel CCD system

    SciTech Connect

    The SLD Collaboration

    1995-07-01

    The SLD Collaboration is building a new CCD vertex detector (VXD3) comprising 96 3.2 Mpixel CCDs of 13 cm{sup 2} each for a total of 307 million pixels. This system is an upgrade of the Pioneering CCD vertex detector VXD2 which has operated in SLD since 1992. The CCDs of VXD3 are mounted on beryllium ladders in three cylinders, providing three space point measurements along each track of about 5 microns resolution in all three coordinates. The design and construction of VXD3 builds on three years of successful performance of VXD2. Significant improvements are achieved with VXD3 in impact parameters resolution (about a factor of two) and acceptance ({approximately}20%) through optimized geometry and reduced material. New readout electronics have been developed for this system. This new vertex detector will be installed in late 1995 for the future runs of SLD.

  20. Design and performance of the SLD Vertex Detector, a 120 Mpixel tracking system

    SciTech Connect

    Agnew, G.D.; Cotton, R.; Damerell, C.J.S.

    1992-03-01

    This paper describes the design, construction, and initial operation of the SLD Vertex Detector, the first device to employ charge coupled devices (CCDs) on a large scale in a high energy physics experiment. The Vertex Detector comprises 480 CCDs, with a total of 120 Mpixels. Each pixel functions as an independent particle detecting element, providing space point measurements of charged particle tracks with a typical precision of 5 {mu}m in each co-ordinate. The CCDs are arranged in four concentric cylinders just outside the beam pipe which surrounds the e{sup +}e{sup {minus}} collision point of the SLAC Linear Collider (SLC). The Vertex Detector is a powerful tool for distinguishing secondary vertex tracks, produced by decay in flight of heavy flavour hadrons or tau leptons, from tracks produced at the primary event vertex. Because the colliding beam environment imposes severe constraints on the design of such a detector, a six year R&D programme was needed to develop solutions to a number of problems. The requirements include a low-mass structure (to minimise multiple scattering) both for mechanical support and to provide signal paths for the CCDS; operation at low temperature with a high degree of mechanical stability; and relatively high speed CCD readout, signal processing, and data sparsification. The lessons learned through the long R&D period should be useful for the construction of large arrays of CCDs or smart pixel devices in the future, in a number of areas of science and technology.

  1. Real-time alignment and cali bration of the LHCb Detector in Run II

    NASA Astrophysics Data System (ADS)

    Dujany, Giulio; Storaci, Barbara

    2015-12-01

    Stable, precise spatial alignment and PID calibration are necessary to achieve optimal detector performance. During Run2, LHCb will have a new real-time detector alignment and calibration to allow equivalent performance in the online and offline reconstruction to be reached. This offers the opportunity to optimise the event selection by applying stronger constraints, and to use hadronic particle identification at the trigger level. The computing time constraints are met through the use of a new dedicated framework using the multi-core farm infrastructure for the trigger. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from the operative and physics performance point of view. Specific challenges of this configuration are discussed, as well as the designed framework and its performance.

  2. Operation of the CDF Silicon Vertex Detector with colliding beams at Fermilab

    SciTech Connect

    Bedeschi, F.; Bolognesi, V.; Dell'Agnello, S.; Galeotti, S.; Grieco, G.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Ristori, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F. ); Bailey, M.W.; Garfinkel, A.F.; Kruse, M.C.; Shaw, N.M. ); Carithers, W.C.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneide

    1992-10-01

    In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution and efficiency are given.

  3. Mechanics and Assembly of the Silicon Vertex Detector for the PHENIX Experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Sondheim, Walter; The Phenix Collaboration

    The PHENIX experiment at the Relativistic Heavy-Ion Collider explores the phase diagram of strongly interacting matter through collisions of beam of heavy nuclei. A second physics program addresses the spin structure of the nucleon through collisions of beams of polarized protons. The PHENIX apparatus has been particularly designed for lepton-pair measurements and comprises detectors for charged-particle tracking, particle identification, calorimetry and collision centrality monitors. Los mass detector systems and high-rate capability have been central to its concept. Recently a silicon vertex detector has been added to the experiment. It will extend the capabilities of PHENIX towards more refined studies involving heavy flavor physics with direct detection of decays. The presented article addresses technical aspects of the vertex detector's mechanical construction and the assembly of its components. It contains various detailed information and may be of interest to a larger scientific and engineering community in the fields of high -energy and heavy-ion physics.

  4. The track finding algorithm of the Belle II vertex detectors

    NASA Astrophysics Data System (ADS)

    Bilka, Tadeas; Braun, Nils; Casarosa, Giulia; Frost, Oliver; Frühwirth, Rudolf; Hauth, Thomas; Heck, Martin; Kandra, Jakub; Kodys, Peter; Kvasnicka, Peter; Lettenbichler, Jakob; Lück, Thomas; Madlener, Thomas; Metzner, Felix; Nadler, Moritz; Oberhof, Benjamin; Paoloni, Eugenio; Prim, Markus; Ritter, Martin; Schlüter, Tobias; Schnell, Michael; Spruck, Bjoern; Trusov, Viktor; Wagner, Jonas; Wessel, Christian; Ziegler, Michael

    2017-08-01

    The Belle II experiment is a high energy multi purpose particle detector operated at the asymmetric e+e- - collider SuperKEKB in Tsukuba (Japan). In this work we describe the algorithm performing the pattern recognition for inner tracking detector which consists of two layers of pixel detectors and four layers of double sided silicon strip detectors arranged around the interaction region. The track finding algorithm will be used both during the High Level Trigger on-line track reconstruction and during the off-line full reconstruction. It must provide good efficiency down to momenta as low as 50 MeV/c where material effects are sizeable even in an extremely thin detector as the VXD. In addition it has to be able to cope with the high occupancy of the Belle II detectors due to the background. The underlying concept of the track finding algorithm, as well as details of the implementation are outlined. The algorithm is proven to run with good performance on simulated ϒ(4S) → BB¯ events with an efficiency for reconstructing tracks of above 90% over a wide range of momentum.

  5. The LHCb VELO upgrade

    NASA Astrophysics Data System (ADS)

    Dosil Suárez, Álvaro

    2016-07-01

    The upgrade of the LHCb experiment, planned for 2019, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm. The upgraded detector will run at luminosities of 2×1033 cm-2 s-1 and probe physics beyond the Standard Model in the heavy flavour sector with unprecedented precision. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The detector comprises silicon pixel sensors with 55×55 μm2 pitch, read out by the VeloPix ASIC, based on the TimePix/MediPix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The detector halves are retracted when the beams are injected and closed at stable beams, positioning the first sensitive pixel at 5.1 mm from the beams. The material budget will be minimised by the use of evaporative CO2 coolant circulating in microchannels within 400 μm thick silicon substrates.

  6. LHCb Scintillating Fiber detector front end electronics design and quality assurance

    NASA Astrophysics Data System (ADS)

    Vink, W. E. W.; Pellegrino, A.; Ietswaard, G. C. M.; Verkooijen, J. C.; Carneiro, U.; Massefferi, A.

    2017-03-01

    The on-detector electronics of the LHCb Scintillating Fiber Detector consists of multiple PCBs assembled in a unit called Read Out Box, capable of reading out 2048 channels with an output rate of 70 Gbps. There are three types of boards: PACIFIC, Clusterization and Master Board. The Pacific Boards host PACIFIC ASICs, with pre-amplifier and comparator stages producing two bits of data per channel. A cluster-finding algorithm is then run in an FPGA on the Clusterization Board. The Master Board distributes fast and slow control, and power. We describe the design, production and test of prototype PCBs.

  7. Detectors for Linear Colliders: Tracking and Vertexing (2/4)

    ScienceCinema

    None

    2016-07-12

    Efficient and precise determination of the flavour of partons in multi-hadron final states is essential to the anticipated LC physics program. This makes tracking in the vicinity of the interaction region of great importance. Tracking extrapolation and momentum resolution are specified by precise physics requirements. The R&D; towards detectors able to meet these specifications will be discussed, together with some of their application beyond particle physics.

  8. VXD3: The SLD vertex detector upgrade based on a 307 MPixel CCD system

    SciTech Connect

    Brau, J.E.; SLD Collaboration

    1995-12-01

    The SLD upgrade CCD vertex detector (VXD3) is described. Its 307 million pixels are assembled from 96 3.2 Mpixel CCDs of 13 cm{sup 2} each. The system has evolved from the pioneering CCD vertex detector VXD2, which has operated in SLD since 1992. The CCDs of VXD3 are mounted on beryllium ladders in three cylinders, providing three space point measurements along each track of about 5 microns resolution in all three co-ordinates. Significant improvements are achieved with VXD3 in impact parameter resolution (about a factor of two) and acceptance ({approximately}20%) through optimized geometry and reduced material. New readout electronics have been developed for this system.

  9. Internal Alignment of the SLD Vertex Detector using a Matrix Singular Value Decomposition Technique

    SciTech Connect

    Su, Dong

    2002-01-03

    The tracking resolution and vertex finding capabilities of the SLD experiment depend upon a precise knowledge of the location and orientation of the 96 elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the deterministic procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool is employed to unfold the detector geometry corrections from the track hit residual data in the VXD3. The algorithm is adapted to perform an optimal {chi}{sup 2} minimization by careful treatment of the errors and correlations in the residual measurements. The general form of the problems that might be solved with this technique is discussed. The tracking resolution obtained with the aligned geometry is compared with the starting point, based on an optical survey of the CCDs, and is shown to achieve the design performance.

  10. ILCRoot tracker and vertex detector response to MARS15 simulated backgrounds in muon collider

    SciTech Connect

    Terentiev, N.K.; Di Benedetto, V.; Gatto, C.; Mazzacane, A.; Mokhov, N.V.; Striganov, S.I.; /Fermilab

    2011-10-01

    Results from a simulation of the background for a muon collider, and the response of a silicon tracking detector to this background are presented. The background caused by decays of the 750-GeV muon beams was simulated using the MARS15 program, which included the infrastructure of the beam line elements near the detector and the 10{sup o} nozzles that shield the detector from this background. The ILCRoot framework, along with the Geant4 program, was used to simulate the response of the tracker and vertex silicon detectors to the muon-decay background remaining after the shielding nozzles. Results include the hit distributions in these detectors, the fractions of type-specific background particles producing these hits and illustrate the use of timing of the hits to suppress the muon beam background.

  11. LHCb VELO upgrade

    NASA Astrophysics Data System (ADS)

    Hennessy, Karol

    2017-02-01

    The upgrade of the LHCb experiment, scheduled for LHC Run-III, scheduled to start in 2021, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm enabling the detector to run at luminosities of 2×1033 cm-2 s-1. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The upgraded VELO will provide fast pattern recognition and track reconstruction to the software trigger. The silicon pixel sensors have 55×55 μm2 pitch, and are read out by the VeloPix ASIC, from the Timepix/Medipix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate of more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The foil will be manufactured through milling and possibly thinned further by chemical etching. The material budget will be minimised by the use of evaporative CO2 coolant circulating in microchannels within 400 μm thick silicon substrates. The current status of the VELO upgrade is described and latest results from operation of irradiated sensor assemblies are presented.

  12. Exploratory study of a novel low occupancy vertex detector architecture based on high precision timing for high luminosity particle colliders

    NASA Astrophysics Data System (ADS)

    Orel, Peter; Varner, Gary S.; Niknejadi, Pardis

    2017-06-01

    Vertex detectors provide space-time coordinates for the traversing charged particle decay products closest to the interaction point. Resolving these increasingly intense particle fluences at high luminosity particle colliders, such as SuperKEKB, is an ever growing challenge. This results in a non-negligible occupancy of the vertex detector using existing low material budget techniques. Consequently, new approaches are being studied that meet the vertexing requirements while lowering the occupancy. In this paper, we introduce a novel vertex detector architecture. Its design relies on an asynchronous digital pixel matrix in combination with a readout based on high precision time-of-flight measurement. Denoted the Timing Vertex Detector (TVD), it consists of a binary pixel array, a transmission line for signal collection, and a readout ASIC. The TVD aims to have a spatial resolution comparable to the existing Belle2 vertex detector. At the same time it offers a reduced occupancy by a factor of ten while decreasing the channel count by almost three orders of magnitude. Consequently, reducing the event size from about 1 MB/event to about 5.9 kB/event.

  13. A MAPS Based Micro-Vertex Detector for the STAR Experiment

    SciTech Connect

    Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; Greiner, Leo; Silber, Joe; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal; Videbaek, Flemming; Vu, Chinh; Wieman, Howard; Woodmansee, Sam

    2015-06-18

    For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector’s vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensor (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m2. Each sensor of this PiXeL (“PXL”) sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ~3.8 cm2. This sensor architecture features 185.6 μs readout time and 170 mW/cm2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.

  14. A MAPS Based Micro-Vertex Detector for the STAR Experiment

    DOE PAGES

    Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; ...

    2015-06-18

    For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector’s vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensormore » (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m2. Each sensor of this PiXeL (“PXL”) sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ~3.8 cm2. This sensor architecture features 185.6 μs readout time and 170 mW/cm2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.« less

  15. PACIFIC: the readout ASIC for the SciFi Tracker of the upgraded LHCb detector

    NASA Astrophysics Data System (ADS)

    Mazorra, J.; Chanal, H.; Comerma, A.; Gascón, D.; Gómez, S.; Han, X.; Pillet, N.; Vandaele, R.

    2016-02-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and will switch to a 40 MHz readout rate using a trigger-less software based system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with the higher detector occupancy and radiation damage. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed and a custom ASIC, called the low-Power ASIC for the sCIntillating FIbres traCker (PACIFIC), will be used to digitise the signals from the SiPMs. This article presents an overview of the R&D for the PACIFIC. It is a 64-channel ASIC implemented in 130 nm CMOS technology, aiming at a radiation tolerant design with a power consumption below 10 mW per channel. It interfaces directly with the SiPM anode through a current mode input, and provides a configurable non-linear 2-bit per channel digital output. The SiPM signal is acquired by a current conveyor and processed with a fast shaper and a gated integrator. The digitization is performed using a three threshold non-linear flash ADC operating at 40 MHz. Simulation and test results show the PACIFIC chip prototypes functioning well.

  16. A bottom collider vertex detector design, Monte-Carlo simulation and analysis package

    SciTech Connect

    Lebrun, P.

    1990-10-01

    A detailed simulation of the BCD vertex detector is underway. Specifications and global design issues are briefly reviewed. The BCD design based on double sided strip detector is described in more detail. The GEANT3-based Monte-Carlo program and the analysis package used to estimate detector performance are discussed in detail. The current status of the expected resolution and signal to noise ratio for the golden'' CP violating mode B{sub d} {yields} {pi}{sup +}{pi}{sup {minus}} is presented. These calculations have been done at FNAL energy ({radical}s = 2.0 TeV). Emphasis is placed on design issues, analysis techniques and related software rather than physics potentials. 20 refs., 46 figs.

  17. Design and performance of beam test electronics for the PHENIX Multiplicity Vertex Detector

    SciTech Connect

    Britton, C.L. Jr.; Bryan, W.L.; Emery, M.S.

    1996-12-31

    The system architecture and test results of the custom circuits and beam test system for the Multiplicity-Vertex Detector (MVD) for the PHENIX detector collaboration at the Relativistic Heavy Ion Collider (RHIC) are presented in this paper. The final detector per-channel signal processing chain will consist of a preamplifier-gain stage, a current-mode summed multiplicity discriminator, a 64-deep analog memory (simultaneous read-write), a post-memory analog correlator, and a 10-bit 5 {mu}s ADC. The Heap Manager provides all timing control, data buffering, and data formatting for a single 256-channel multi-chip module (MCM). Each chip set is partitioned into 32-channel sets. Beam test (16-cell deep memory) performance for the various blocks will be presented as well as the ionizing radiation damage performance of the 1.2 {mu} n-well CMOS process used for preamplifier fabrication.

  18. The micro-vertex-detector of the PANDA experiment at Darmstadt

    NASA Astrophysics Data System (ADS)

    Stockmanns, Tobias

    2006-11-01

    The "AntiProton ANnihilations at DArmstadt"—experiment, short PANDA, is one of the main experiments of the "Facility for Antiproton and Ion Research" (FAIR) which replaces and extends the existing GSI-facility at Darmstadt. The main physics goals at the beginning of the experiment in 2012 will be precision spectroscopy of charmonium states, an establishment of gluonic excitations, the search for modifications of meson properties in the nuclear medium and precision γ-ray spectroscopy of single and double hypernuclei. For many of these physics goals an identification of D-mesons via the detection of a secondary vertex with a decay length in the order of 100 μm is essential. Therefore, a special micro-vertex-detector (MVD) is foreseen which allows a precise tracking of all charged particles. Several different technology options from monolithic active pixels to hybrid pixel detectors are on the market. Unfortunately, none of these techniques fully meets the requirements of the PANDA experiment. Different technologies are compared with respect to the requirements of PANDA. In addition, a possible design of the MVD will be shown, which features a combination of hybrid pixel modules, whose layout might be adopted from ATLAS or other LHC experiments, for the inner layers and silicon strip detectors for the outer layers.

  19. TGV32: A 32-channel preamplifier chip for the multiplicity vertex detector at PHENIX

    SciTech Connect

    Britton, C.L. Jr.; Ericson, M.N.; Frank, S.S.

    1997-12-31

    The TGV32, a 32-channel preamplifier-multiplicity discriminator chip for the Multiplicity Vertex Detector (MVD) at PHENIX, is a unique silicon preamplifier in that it provides both an analog output for storage in an analog memory and a weighted summed-current output for conversion to a channel multiplicity count. The architecture and test results of the chip are presented. Details about the design of the preamplifier, discriminator, and programmable digital-analog converters (DACs) performance as well as the process variations are presented. The chip is fabricated in a 1.2-{micro}m, n-well, CMOS process.

  20. A vertically integrated pixel readout device for the Vertex Detector at the International Linear Collider

    SciTech Connect

    Deptuch, Grzegorz; Christian, David; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab

    2008-12-01

    3D-Integrated Circuit technology enables higher densities of electronic circuitry per unit area without the use of nanoscale processes. It is advantageous for mixed mode design with precise analog circuitry because processes with conservative feature sizes typically present lower process dispersions and tolerate higher power supply voltages, resulting in larger separation of a signal from the noise floor. Heterogeneous wafers (different foundries or different process families) may be combined with some 3D integration methods, leading to the optimization of each tier in the 3D stack. Tracking and vertexing in future High-Energy Physics (HEP) experiments involves construction of detectors composed of up to a few billions of channels. Readout electronics must record the position and time of each measurement with the highest achievable precision. This paper reviews a prototype of the first 3D readout chip for HEP, designed for a vertex detector at the International Linear Collider. The prototype features 20 x 20 {micro}m{sup 2} pixels, laid out in an array of 64 x 64 elements and was fabricated in a 3-tier 0.18 {micro}m Fully Depleted SOI CMOS process at MIT-Lincoln Laboratory. The tests showed correct functional operation of the structure. The chip performs a zero-suppressed readout. Successive submissions are planned in a commercial 3D bulk 0.13 {micro}m CMOS process to overcome some of the disadvantages of an FDSOI process.

  1. Design of the cooling systems for the multiplicity and vertex detector

    SciTech Connect

    Bernardin, J.D.; Cunningham, R.

    1997-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is being constructed to investigate a phase of matter termed the quark-gluon plasma. The plasma will be produced through the collision of two heavy ions. The multiplicity and vertex detector (MVD) located in the center of PHENIX will characterize the events, determine the collision point, and act as a central trigger. This report presents the final mechanical designs of the cooling systems for the Multiplicity and Vertex Detector (MVD). In particular, the design procedure and layouts are discussed for two different air cooling systems for the multichip modules and MVD enclosure, and a liquid cooling system for the low dropout voltage regulators. First of all, experimental prototype cooling system test results used to drive the final mechanical designs are summarized and discussed. Next, the cooling system requirements and design calculation for the various subsystem components are presented along with detailed lists of supply vendors, components, and costs. Finally, safety measures incorporated in the final mechanical design and operation procedures for each of the subsystems are detailed.

  2. A bonding study toward the quality assurance of Belle-II silicon vertex detector modules

    NASA Astrophysics Data System (ADS)

    Kang, K. H.; Jeon, H. B.; Park, H.; Uozumi, S.; Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Joo, C. W.; Kandra, J.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Pilo, F.; Profeti, A.; Rao, K. K.; Rashevskaia, I.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2016-09-01

    A silicon vertex detector (SVD) for the Belle-II experiment comprises four layers of double-sided silicon strip detectors (DSSDs), assembled in a ladder-like structure. Each ladder module of the outermost SVD layer has four rectangular and one trapezoidal DSSDs supported by two carbon-fiber ribs. In order to achieve a good signal-to-noise ratio and minimize material budget, a novel chip-on-sensor "Origami" method has been employed for the three rectangular sensors that are sandwiched between the backward rectangular and forward (slanted) trapezoidal sensors. This paper describes the bonding procedures developed for making electrical connections between sensors and signal fan-out flex circuits (i.e., pitch adapters), and between pitch adapters and readout chips as well as the results in terms of the achieved bonding quality and pull force.

  3. First LHC transverse beam size measurements with the beam gas vertex detector

    NASA Astrophysics Data System (ADS)

    Alexopoulos, A.; Barchel, C.; Bay, A.; Blanc, F.; Bravin, E.; Bregliozzi, G.; Chritin, N.; Dehning, B.; Ferro-Luzzi, M.; Gianì, S.; Giovannozzi, M.; Girard, O.; Greim, R.; Haefeli, G.; Hopchev, P.; Jacobsson, R.; Jensen, L.; Rhodri Jones, O.; Kain, V.; Karpinski, W.; Kirn, T.; Kuonen, A.; Matev, R.; Nakada, T.; Rihl, M.; Salustino Guimaraes, V.; Schael, S.; Schneider, O.; Schultz von Dratzig, A.; Schwering, G.; Tobin, M.; Veness, R.; Veyrat, Q.; Vlachos, S.; Wlochal, M.; Wiirkner, B.; Xu, Z.

    2017-07-01

    The Beam Gas Vertex detector (BGV) is an innovative beam profile monitor based on the reconstruction of beam-gas interaction vertices which is being developed as part of the High Luminosity LHC project. Tracks are identified using several planes of scintillating fibres, located outside the beam vacuum chamber and perpendicular to the beam axis. The gas pressure in the interaction volume is adjusted such as to provide an adequate trigger rate, without disturbing the beam. A BGV demonstrator monitoring one of the two LHC beams was fully installed and commissioned in 2016. First data and beam size measurements show that the complete detector and data acquisition system is operating as expected. The BGV operating parameters are now being optimised and the reconstruction algorithms developed to produce accurate and fast reconstruction on a CPU farm in order to provide real time beam profile measurements to the LHC operators. Research supported by the HL-LHC project

  4. A high rate, low radiation length Micro-Vertex-Detector for the P¯ANDA experiment

    NASA Astrophysics Data System (ADS)

    Stockmanns, Tobias

    2011-09-01

    The Micro-Vertex-Detector (MVD) of the P¯ANDA experiment is the innermost tracking detector. Its most challenging task is the identification of D-meson pairs by their delayed decay point which is about 100- 500 μm from the production point. In addition to the necessary high spatial resolution, it needs a time resolution on the order of 10 ns, a moderate radiation hardness, an untriggered readout of hit data up to 500 MBit/s and a low radiation length. To meet these challenging requirements an intense R&D program is ongoing on all parts of the MVD. This article gives an overview of the ongoing technical developments with a focus on the pixel part of the project.

  5. Front-end module readout and control electronics for the PHENIX Multiplicity Vertex Detector

    SciTech Connect

    Ericson, M.N.; Allen, M.D.; Boissevain, J.

    1997-11-01

    Front-end module (FEM) readout and control are implemented as modular, high-density, reprogrammable functions in the PHENIX Multiplicity Vertex Detector. FEM control is performed by the heap manager, an FPGA-based circuit in the FEM unit. Each FEM has 256 channels of front-end electronics, readout, and control, all located on an MCM. Data readout, formatting, and control are performed by the heap manager along with 4 interface units that reside outside the MVD detector cylinder. This paper discusses the application of a generic heap manager and the addition of 4 interface module types to meet the specific control and data readout needs of the MVD. Unit functioning, interfaces, timing, data format, and communication rates will be discussed in detail. In addition, subsystem issues regarding mode control, serial architecture and functions, error handling, and FPGA implementation and programming will be presented.

  6. The prototype of the Micro Vertex Detector of the CBM Experiment

    NASA Astrophysics Data System (ADS)

    Koziel, Michal; Amar-Youcef, Samir; Bialas, Norbert; Deveaux, Michael; Fröhlich, Ingo; Li, Qiyan; Michel, Jan; Milanović, Borislav; Müntz, Christian; Neumann, Bertram; Schrader, Christoph; Stroth, Joachim; Tischler, Tobias; Weirich, Roland; Wiebusch, Michael

    2013-12-01

    The Compressed Baryonic Matter (CBM) Experiment is one of the core experiments of the future FAIR facility at Darmstadt, Germany. This fixed-target experiment will explore the phase diagram of strongly interacting matter in the regime of highest net baryon densities with numerous probes, among them open charm. Reconstructing those short lived particles requires a vacuum compatible Micro Vertex Detector (MVD) with unprecedented properties. Its sensor technology has to feature a spatial resolution of <5 μm, a non-ionizing radiation tolerance of >1013 neq/cm2, an ionizing radiation tolerance of >3 Mrad and a time resolution of a few 10 μs. The MVD-prototype project aimed to study the integration the CMOS Monolithic Active Pixel Sensors foreseen for the MVD into an ultra light (0.3% X0) and a vacuum compatible detector system based on a cooling support made of CVD-diamond.

  7. SALT, a dedicated readout chip for high precision tracking silicon strip detectors at the LHCb Upgrade

    NASA Astrophysics Data System (ADS)

    Bugiel, Sz.; Dasgupta, R.; Firlej, M.; Fiutowski, T.; Idzik, M.; Kuczynska, M.; Moron, J.; Swientek, K.; Szumlak, T.

    2016-02-01

    The Upstream Tracker (UT) silicon strip detector, one of the central parts of the tracker system of the modernised LHCb experiment, will use a new 128-channel readout ASIC called SALT. It will extract and digitise analogue signals from the UT sensors, perform digital signal processing and transmit a serial output data. The SALT is being designed in CMOS 130 nm process and uses a novel architecture comprising of analog front-end and fast (40 MSps) ultra-low power (<0.5 mW) 6-bit ADC in each channel. The prototype ASICs of important functional blocks, like analogue front-end, 6-bit SAR ADC, PLL, and DLL, were designed, fabricated and tested. A prototype of an 8-channel version of the SALT chip, comprising all important functionalities was also designed and fabricated. The architecture and design of the SALT, together with the selected preliminary tests results, are presented.

  8. LHCb RICH Upgrade: an overview of the photon detector and electronic system

    NASA Astrophysics Data System (ADS)

    Cassina, L.

    2016-01-01

    The LHCb experiment is one of the four large detectors operating at the LHC at CERN and it is mainly devoted to CP violation measurements and to the search for new physics in rare decays of beauty and charm hadrons. The data from the two Ring Image Cherenkov (RICH-1 and RICH-2) detectors are essential to identify particles in a wide momentum range. From 2019 onwards 14 TeV collisions with luminosities reaching up to 2 × 1033 cm-2s-1 with 25 ns bunch spacing are planned, with the goal of collecting 5 fb-1 of data per year. In order to avoid degradation of the PID performance at such high rate (40 MHz), the RICH detector has to be upgraded. New photodetectors (Multi-anode photomultiplier tubes, MaPMTs) have been chosen and will be read out using an 8-channel chip, named CLARO, designed to sustain a photon counting rate up to 40 MHz, while minimizing the power consumption and the cross-talk. A 128-bit digital register allows selection of thresholds and attenuation values and provides features useful for testing and debugging. Photosensors and electronics are arranged in basic units, the first prototypes of which have been tested in charged particle beams in autumn 2014. An overview of the CLARO features and of the readout electronics is presented.

  9. Overview of the Micro Vertex Detector for the P bar ANDA experiment

    NASA Astrophysics Data System (ADS)

    Calvo, Daniela

    2017-02-01

    The P bar ANDA experiment is devoted to study interactions between cooled antiproton beams and a fixed target (the interaction rate is of about 107 events/s), hydrogen or heavier nuclei. The innermost tracker of P bar ANDA is the Micro Vertex Detector (MVD), specially designed to ensure the secondary vertex resolution for the discrimination of short-lived charmonium states. Hybrid epitaxial silicon pixels and double-sided silicon microstrips will equip four barrels, arranged around the interaction point, and six forward disks. The experiment features a triggerless architecture with a master clock of 160 MHz, therefore the MVD has to run with a continuous data transmission where the hits need precise timestamps. The energy loss of the particles in the sensor will be measured as well. The challenging request of a triggerless readout suggested to develop custom readout chips for both pixel (ToPix) and microstrip (PASTA) devices. To validate components and the triggerless readout architecture, prototypes have been built and tested. After an overview of the MVD, the technological aspects and performances of some prototypes will be reported.

  10. The MAPS-based vertex detector for the STAR experiment: Lessons learned and performance

    NASA Astrophysics Data System (ADS)

    Contin, Giacomo

    2016-09-01

    The PiXeL detector (PXL) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. The PXL, together with the Intermediate Silicon Tracker (IST) and the Silicon Strip Detector (SSD), form the Heavy Flavor Tracker (HFT), which has been designed to improve the vertex resolution and extend the STAR measurement capabilities in the heavy flavor domain, providing a clean probe for studying the Quark-Gluon Plasma. The two PXL layers are placed at a radius of 2.8 and 8 cm from the beam line, respectively, and is based on ultra-thin high resolution MAPS sensors. The sensor features 20.7 μm pixel pitch, 185.6 μs readout time and 170 mW/cm2 power dissipation. The detector is air-cooled, allowing a global material budget of 0.4% radiation length on the innermost layer. A novel mechanical approach to detector insertion allows for fast installation and integration of the pixel sub detector. The HFT took data in Au+Au collisions at 200 GeV during the 2014 RHIC run. Modified during the RHIC shutdown to improve its reliability, material budget, and tracking capabilities, the HFT took data in p+p and p+Au collisions at √sNN=200 GeV in the 2015 RHIC run. In this paper we present detector specifications, experience from the construction and operations, and lessons learned. We also show preliminary results from 2014 Au+Au data analyses, demonstrating the capabilities of charm reconstruction with the HFT.

  11. Recent results with HV-CMOS and planar sensors for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Alipour Tehrani, Niloufar

    2017-02-01

    The physics aims for the future multi-TeV e+e- Compact Linear Collider (CLIC) impose high precision requirements on the vertex detector which has to match the experimental conditions, such as the time structure of the collisions and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of 3 μm , 10 ns time stamping capabilities, low mass (∼0.2% X0 per layer), low power dissipation and pulsed power operation. Recent results of test beam measurements and GEANT4 simulations for assemblies with Timepix3 ASICs and thin active-edge sensors are presented. The 65 nm CLICpix readout ASIC with 25 μm pitch was bump bonded to planar silicon sensors and also capacitively coupled through a thin layer of glue to active HV-CMOS sensors. Test beam results for these two hybridisation concepts are presented.

  12. Exploitation of secondary vertex information at the CDF detector. Final report, 1991--1994

    SciTech Connect

    Amidei, D.

    1995-11-01

    In the proposal for this work, submitted in November 1990, the author described the application of silicon micro-vertex tracking to hadron collider physics, and outlined a plan of involvement in the first such application, at the CDF Detector, studying p{anti p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. The proposal included discussion on the use of silicon tracking in B physics measurements, and also some speculation on the ability of silicon tracking to aid in identification of the top quark. In the five years since this proposal, the author has played a significant role in the installation and commissioning of the first such silicon tracking device at a hadron collider, and the utilization of this device in the discovery of the top quark and the study of B production mechanisms. This paper is a summary of this work.

  13. An experimental investigation of airflow-induced vibrations within the multiplicity and vertex detector

    SciTech Connect

    Bernardin, J.D.; Bosze, E.; Boissevain, J.; Simon-Gillo, J.

    1997-07-01

    This report summarizes an experimental investigation of vibrations within the multiplicity and vertex detector (MVD). In particular, the maximum displacements of several MVD components were determined from accelerometer measurements of vibrations induced by an electronics air-cooling system. For an MVD inlet air volumetric flow rate of 0.022 m{sup 3}/s, maximum displacements of several MVD components including a multi-chip module, the Rohacell inlet air plenum, and an aluminum structural cross support, were found to be on the order of 1.5 {mu}m. Consequently, it was concluded that air induced vibrations will not significantly interfere with the MVD`s long-term structural integrity or operating performance. 2 refs., 3 figs., 1 tab.

  14. The silicon Micro Vertex Detector of the P bar ANDA experiment

    NASA Astrophysics Data System (ADS)

    Calvo, D.; Panda Collaboration

    2013-08-01

    The P bar ANDA experiment will make use of cooled antiproton beams of unprecedented quality that will become available at the Facility for Antiproton and Ion Research in Darmstadt, featuring a 1.5-15 GeV/c momentum range. The physics program includes measurements of hyperons produced at low energies, spectroscopy of charmonium and open-charm mesons. To handle the forward peaked particle distribution due to the Lorentz boost, the apparatus is arranged in an asymmetric layout around the interaction point. In particular the Micro Vertex Detector based on silicon devices will have a rather unusual geometry. The MVD features fast data readout, since the experiment is triggerless, particle identification over the full range of energies, limited material budget and good spatial and time resolution. The status of the MVD design is shown and the present prototypes are described.

  15. The beam test measurements of the Belle II vertex detector modules

    NASA Astrophysics Data System (ADS)

    Bilka, T.

    2017-03-01

    The Belle II experiment designed to study CP Violation and Beyond Standard model physics at the decays of B-mesons is quickly approaching its first physics run with the SuperKEKB accelerator (Tsukuba, Japan) already under commissioning. To operate in the unique conditions of the Belle II experiment, its vertex detector (VXD) is a six layers silicon detector with two innermost layers of DEPFET active pixel modules and four layers of double-sided strip modules. A section of it will become a commissioning detector for the first collisions of the next-generation high luminosity B-factory. The same setup, from cooling services, mechanical support or sensors and front-end electronics to DAQ, including the software and alignment framework, is tested under an electron beam provided by DESY facilities. We present the basic characteristics of the pixel and strip modules and the setup under test, including software and alignment framework—as close to the final system as possible.

  16. Readout, first- and second-level triggers of the new Belle silicon vertex detector

    NASA Astrophysics Data System (ADS)

    Friedl, M.; Abe, R.; Abe, T.; Aihara, H.; Asano, Y.; Aso, T.; Bakich, A.; Browder, T.; Chang, M. C.; Chao, Y.; Chen, K. F.; Chidzik, S.; Dalseno, J.; Dowd, R.; Dragic, J.; Everton, C. W.; Fernholz, R.; Fujii, H.; Gao, Z. W.; Gordon, A.; Guo, Y. N.; Haba, J.; Hara, K.; Hara, T.; Harada, Y.; Haruyama, T.; Hasuko, K.; Hayashi, K.; Hazumi, M.; Heenan, E. M.; Higuchi, T.; Hirai, H.; Hitomi, N.; Igarashi, A.; Igarashi, Y.; Ikeda, H.; Ishino, H.; Itoh, K.; Iwaida, S.; Kaneko, J.; Kapusta, P.; Karawatzki, R.; Kasami, K.; Kawai, H.; Kawasaki, T.; Kibayashi, A.; Koike, S.; Korpar, S.; Križan, P.; Kurashiro, H.; Kusaka, A.; Lesiak, T.; Limosani, A.; Lin, W. C.; Marlow, D.; Matsumoto, H.; Mikami, Y.; Miyake, H.; Moloney, G. R.; Mori, T.; Nakadaira, T.; Nakano, Y.; Natkaniec, Z.; Nozaki, S.; Ohkubo, R.; Ohno, F.; Okuno, S.; Onuki, Y.; Ostrowicz, W.; Ozaki, H.; Peak, L.; Pernicka, M.; Rosen, M.; Rozanska, M.; Sato, N.; Schmid, S.; Shibata, T.; Stamen, R.; Stanič, S.; Steininger, H.; Sumisawa, K.; Suzuki, J.; Tajima, H.; Tajima, O.; Takahashi, K.; Takasaki, F.; Tamura, N.; Tanaka, M.; Taylor, G. N.; Terazaki, H.; Tomura, T.; Trabelsi, K.; Trischuk, W.; Tsuboyama, T.; Uchida, K.; Ueno, K.; Ueno, K.; Uozaki, N.; Ushiroda, Y.; Vahsen, S.; Varner, G.; Varvell, K.; Velikzhanin, Y. S.; Wang, C. C.; Wang, M. Z.; Watanabe, M.; Watanabe, Y.; Yamada, Y.; Yamamoto, H.; Yamashita, Y.; Yamashita, Y.; Yamauchi, M.; Yanai, H.; Yang, R.; Yasu, Y.; Yokoyama, M.; Ziegler, T.; Žontar, D.

    2004-12-01

    A major upgrade of the Silicon Vertex Detector (SVD 2.0) of the Belle experiment at the KEKB factory was installed along with new front-end and back-end electronics systems during the summer shutdown period in 2003 to cope with higher particle rates, improve the track resolution and meet the increasing requirements of radiation tolerance. The SVD 2.0 detector modules are read out by VA1TA chips which provide "fast or" (hit) signals that are combined by the back-end FADCTF modules to coarse, but immediate level 0 track trigger signals at rates of several tens of a kHz. Moreover, the digitized detector signals are compared to threshold lookup tables in the FADCTFs to pass on hit information on a single strip basis to the subsequent level 1.5 trigger system, which reduces the rate below the kHz range. Both FADCTF and level 1.5 electronics make use of parallel real-time processing in Field Programmable Gate Arrays (FPGAs), while further data acquisition and event building is done by PC farms running Linux. The new readout system hardware is described and the first results obtained with cosmics are shown.

  17. Track reconstruction in the inhomogeneous magnetic field for Vertex Detector of NA61/SHINE experiment at CERN SPS

    NASA Astrophysics Data System (ADS)

    Merzlaya, Anastasia; NA61/SHINE collaboration

    2017-01-01

    The heavy-ion programme of the NA61/SHINE experiment at CERN SPS is expanding to allow precise measurements of exotic particles with lifetime few hundred microns. A Vertex Detector for open charm measurements at the SPS is being constructed by the NA61/SHINE Collaboration to meet the challenges of high spatial resolution of secondary vertices and efficiency of track registration. This task is solved by the application of the coordinate sensitive CMOS Monolithic Active Pixel Sensors with extremely low material budget in the new Vertex Detector. A small-acceptance version of the Vertex Detector is being tested this year, later it will be expanded to a large-acceptance version. Simulation studies will be presented. A method of track reconstruction in the inhomogeneous magnetic field for the Vertex Detector was developed and implemented. Numerical calculations show the possibility of high precision measurements in heavy ion collisions of strange and multi strange particles, as well as heavy flavours, like charmed particles.

  18. Recent progress in sensor- and mechanics-R&D for the Belle II Silicon Vertex Detector

    NASA Astrophysics Data System (ADS)

    Bergauer, T.; Doljeschi, P.; Frankenberger, A.; Friedl, M.; Gfall, I.; Irmler, C.; Onuki, Y.; Smiljic, D.; Tsuboyama, T.; Valentan, M.

    2013-08-01

    The Belle experiment at the KEKB electron/positron collider in Tsukuba (Japan) was successfully running for more than ten years. A major update of the machine to SuperKEKB is now foreseen until 2015, aiming a peak luminosity which is 40 times the peak value of the previous system. This also requires a redesign of the Belle detector (leading to Belle II) and especially its Silicon Vertex Detector (SVD), which surrounds the beam pipe. The future Belle II SVD will consist of four layers of double-sided silicon strip sensors based on 6 in. silicon wafers. Three of the four layers will be equipped with trapezoidal sensors in the slanted forward region. Moreover, two inner layers with pixel detectors based on DEPFET technology will complement the SVD as innermost detector. Since the KEKB-factory operates at relatively low energy, material inside the active volume has to be minimized in order to reduce multiple scattering. This can be achieved by arranging the sensors in the so-called "Origami chip-on-sensor concept", and a very light-weight mechanical support structure made from carbon fiber reinforced Airex foam. Moreover, CO2 cooling for the front-end chips will ensure high efficiency at minimum material budget. In this paper, an overview of the future Belle II SVD design will be given, covering the silicon sensors, the readout electronics and the mechanics. A strong emphasis will be given to our R&D work on double-sided sensors where different p-stop layouts for the n-side of the detectors were compared. Moreover, this paper gives updated numbers for the mechanical dimensions of the ladders and their radii.

  19. Production and quality assurance of a Scintillating Fibre detector for the LHCb experiment

    NASA Astrophysics Data System (ADS)

    Nieswand, S.

    2017-02-01

    To deal with the instantaneous luminosity of the LHC after the Long Shutdown 2 in 2018/19, several subsystems of the LHCb detector have to be exchanged or upgraded. For this purpose, the Scintillating Fibre (SciFi) Tracker is being built to replace the current downstream tracking system. The base of this new tracker are 2.5m long scintillating fibres (varnothing 250µm) in which light is generated by passing charged particles. The fibres are arranged in six-layer fibre mats which are read out with the help of silicon photomultipliers (SiPMs) at the edge of the tracker's acceptance. The tracker will cover an area larger than 340m2. To produce the required total of 1024 fibre mats, serial production was set up at several production sites. To assure the quality of the fibre mats, they are subject to various tests during the production. The different production steps as well as the quality assurance measurements will be presented.

  20. The pixel detector readout ASIC for the MicroVertex Detector of the PANDA experiment

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Calvo, D.; De Remigis, P.; Kugathasan, T.; Mignone, M.; Rivetti, A.; Toscano, L.; Wheadon, R.

    2013-08-01

    The silicon pixel detector of the PANDA experiment is characterized by both high track density and the absence of a hardware trigger signal, thus leading to a huge amount of data to be acquired and transmitted to the DAQ. In order to cope with such challenging requirements, an ASIC based custom solution for the electronic readout has been chosen. The ASIC, named ToPiX, will provide the time position of each hit and a measure of the charge released with the Time over Threshold (ToT) technique. A reduced scale prototype in a CMOS 0.13 μm technology has been designed and tested. The prototype includes four columns made of 128 pixel cells, four columns of 32 cells and the end of column readout with a 32 cells deep FIFO for each double column. Each cell embeds a charge amplifier with constant current feedback capacitor discharge, a comparator with per cell adjustable threshold, 12-bits leading and trailing edge register for time and ToT measurement and an 8 bits configuration register. All the readout logic has been SEU-hardened by design using either Hamming encoding or triple modular redundancy. The chip has been tested both electrically via a test pulse input and connected to a detector in a beam test.

  1. Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector

    NASA Astrophysics Data System (ADS)

    Rescigno, R.; Finck, Ch.; Juliani, D.; Spiriti, E.; Baudot, J.; Abou-Haidar, Z.; Agodi, C.; Alvarez, M. A. G.; Aumann, T.; Battistoni, G.; Bocci, A.; Böhlen, T. T.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Gallardo, M. I.; Golosio, B.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Krimmer, J.; Kurz, N.; Labalme, M.; Leifels, Y.; Le Fevre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Oliva, P.; Paoloni, A.; Patera, V.; Piersanti, L.; Pleskac, R.; Quesada, J. M.; Randazzo, N.; Romano, F.; Rossi, D.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Tropea, S.; Vanstalle, M.; Younis, H.

    2014-12-01

    Hadrontherapy treatments use charged particles (e.g. protons and carbon ions) to treat tumors. During a therapeutic treatment with carbon ions, the beam undergoes nuclear fragmentation processes giving rise to significant yields of secondary charged particles. An accurate prediction of these production rates is necessary to estimate precisely the dose deposited into the tumours and the surrounding healthy tissues. Nowadays, a limited set of double differential carbon fragmentation cross-section is available. Experimental data are necessary to benchmark Monte Carlo simulations for their use in hadrontherapy. The purpose of the FIRST experiment is to study nuclear fragmentation processes of ions with kinetic energy in the range from 100 to 1000 MeV/u. Tracks are reconstructed using information from a pixel silicon detector based on the CMOS technology. The performances achieved using this device for hadrontherapy purpose are discussed. For each reconstruction step (clustering, tracking and vertexing), different methods are implemented. The algorithm performances and the accuracy on reconstructed observables are evaluated on the basis of simulated and experimental data.

  2. Developments towards the LHCb VELO upgrade

    NASA Astrophysics Data System (ADS)

    Cid Vidal, Xabier

    2016-09-01

    The Vertex Locator (VELO) is a silicon strip detector surrounding the interaction region of the LHCb experiment. The upgrade of the VELO is planned to be installed in 2019-2020, and the current detector will be replaced by a hybrid pixel system equipped with electronics capable of reading out at a rate of 40 MHz. The new detector is designed to withstand the radiation dose expected at an integrated luminosity of 50 fb-1. The detector will be composed of silicon pixel sensors, read out by the VeloPix ASIC that is being developed based on the TimePix/MediPix family. The prototype sensors for the VELO upgrade are being irradiated in five different facilities and the post-irradiation performance is being measured with testbeams, and in the lab. These proceedings present the VELO upgrade and briefly discuss the results of the sensor testing campaign.

  3. DETECTORS AND EXPERIMENTAL METHODS: Decay vertex reconstruction and 3-dimensional lifetime determination at BESIII

    NASA Astrophysics Data System (ADS)

    Xu, Min; He, Kang-Lin; Zhang, Zi-Ping; Wang, Yi-Fang; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; Han, Lei; Han, Shao-Qing; He, Miao; Hu, Ji-Feng; Hu, Xiao-Wei; Huang, Bin; Huang, Xing-Tao; Jia, Lu-Kui; Ji, Xiao-Bin; Li, Hai-Bo; Li, Wei-Dong; Liang, Yu-Tie; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Ying; Liu, Yong; Luo, Tao; Lü, Qi-Wen; Ma, Qiu-Mei; Ma, Xiang; Mao, Ya-Jun; Mao, Ze-Pu; Mo, Xiao-Hu; Ning, Fei-Peng; Ping, Rong-Gang; Qiu, Jin-Fa; Song, Wen-Bo; Sun, Sheng-Sen; Sun, Xiao-Dong; Sun, Yong-Zhao; Tian, Hao-Lai; Wang, Ji-Ke; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Wu, Zhi; Xie, Yu-Guang; Yan, Jie; Yan, Liang; Yao, Jian; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Lei; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Yong-Sheng; Zou, Jia-Heng

    2009-06-01

    This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as K0S, Λ, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.

  4. Novel real-time alignment and calibration of LHCb detector for Run II and tracking for the upgrade.

    NASA Astrophysics Data System (ADS)

    Quagliani, Renato; LHCb Collaboration

    2016-10-01

    LHCb has introduced a novel real-time detector alignment and calibration strategy for LHC Run II. Data collected at the start of the fill is processed in a few minutes and used to update the alignment, while the calibration constants are evaluated for each run. The procedure aims to improve the quality of the online selection and performance stability. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. A similar scheme is planned to be used for Run III foreseen to start in 2020. At that time LHCb will run at an instantaneous luminosity of 2 x 1033 cm-2 s-1 and a fully software based trigger strategy will be used. The new running conditions and the tighter timing constraints in the software trigger (only 13 ms per event are available) represent a big challenge for track reconstruction. The new software based trigger strategy implies a full detector read-out at the collision rate of 40 MHz. High performance and timing constraints are ensured by a new tracking system and a fast and efficient track reconstruction strategy.

  5. The ``Roman pot'' spectrometer and the vertex detector of experiment UA4 at the CERN SPS collider

    NASA Astrophysics Data System (ADS)

    Battiston, R.; Bechini, A.; Bosi, F.; Bozzo, M.; Braccini, P. L.; Buskens, J.; Carbonara, F.; Carrara, R.; Castaldi, R.; Cazzola, U.; Cervelli, F.; Chiefari, G.; Drago, E.; Gorini, R.; Haguenauer, M.; Koene, B.; Maleyran, R.; Manna, F.; Matthiae, G.; Merola, L.; Morelli, A.; Napolitano, M.; Palladino, V.; Rewiersma, P.; Robert, M.; Roiron, G.; Sanguinetti, G.; Schuijlenburg, H.; Sciacca, G.; Sette, G.; Van Swol, R.; Timmermans, J.; Traspedini, L.; Vannini, C.; Velasco, J.; Visco, F.

    1985-07-01

    We describe the apparatus used in experiment UA4 to study proton-antiproton elastic and inelastic interactions at the CERN SPS Collider. Elastically scattered particles, travelling at very small angles, are observed by detectors placed inside movable sections ("Roman pots") of the SPS vacuum chamber. The deflection in the field of the machine quadrupoles allow the measurement of the particle momentum. Inelastic interactions are observed by a left-right symmetric system of trigger counter hodoscopes and drift-chamber telescopes. The apparatus reconstructs the interaction vertex and measures the pseudorapidity η of charged particles in the range 2.5 < ‖ η‖ < 5.6.

  6. An experimental investigation of an air cooling scheme for the multichip modules of the multiplicity and vertex detector

    SciTech Connect

    Bernardin, J.D.; Bosze, E.; Boissevain, J.; Simon-Gillo, J.

    1997-07-01

    This report presents a summary of an experimental investigation of an electronics air cooling system for the multiplicity and vertex detector (MVD), a device used to determine and characterize the collision location of two accelerated heavy ions. Measurements of the flow rates of the cooling air and the temperatures of the air and electronic components were used to assess and optimize the performance of the proposed air cooling system, identify potential assembly problems and system limitations, and provide the necessary information for designing and sizing the final MVD cooling system components.

  7. Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency

    NASA Astrophysics Data System (ADS)

    Anderlini, L.; Anelli, M.; Archilli, F.; Auriemma, G.; Baldini, W.; Bencivenni, G.; Bizzeti, A.; Bocci, V.; Bondar, N.; Bonivento, W.; Bochin, B.; Bozzi, C.; Brundu, D.; Cadeddu, S.; Campana, P.; Carboni, G.; Cardini, A.; Carletti, M.; Casu, L.; Chubykin, A.; Ciambrone, P.; Dané, E.; De Simone, P.; Falabella, A.; Felici, G.; Fiore, M.; Fontana, M.; Fresch, P.; Furfaro, E.; Graziani, G.; Kashchuk, A.; Kotriakhova, S.; Lai, A.; Lanfranchi, G.; Loi, A.; Maev, O.; Manca, G.; Martellotti, G.; Neustroev, P.; Oldeman, R. G. C.; Palutan, M.; Passaleva, G.; Penso, G.; Pinci, D.; Polycarpo, E.; Saitta, B.; Santacesaria, R.; Santimaria, M.; Santovetti, E.; Saputi, A.; Sarti, A.; Satriano, C.; Satta, A.; Schmidt, B.; Schneider, T.; Sciascia, B.; Sciubba, A.; Siddi, B. G.; Tellarini, G.; Vacca, C.; Vazquez-Gomez, R.; Vecchi, S.; Veltri, M.; Vorobyev, A.

    2016-04-01

    A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from ~ 70 ns to ~ 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity.

  8. Vacuum-compatible, ultra-low material budget Micro-Vertex Detector of the compressed baryonic matter experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Koziel, Michal; Amar-Youcef, Samir; Bialas, Norbert; Deveaux, Michael; Fröhlich, Ingo; Klaus, Philipp; Michel, Jan; Milanović, Borislav; Müntz, Christian; Stroth, Joachim; Tischler, Tobias; Weirich, Roland; Wiebusch, Michael

    2017-02-01

    The Compressed Baryonic Matter (CBM) Experiment is one of the core experiments of the future FAIR facility near Darmstadt (Germany). The fixed-target experiment will explore the phase diagram of strongly interacting matter in the regime of high net baryon densities with numerous probes, among them open charm mesons. The Micro Vertex Detector (MVD) will provide the secondary vertex resolution of ∼ 50 μm along the beam axis, contribute to the background rejection in dielectron spectroscopy, and to the reconstruction of weak decays. The detector comprises four stations placed at 5, 10, 15, and 20 cm downstream the target and inside the target vacuum. The stations will be populated with highly granular CMOS Monolithic Active Pixel Sensors, which will feature a spatial resolution of < 5 μm, a non-ionizing radiation tolerance of >1013neq /cm2, an ionizing radiation tolerance of ∼ 3 Mrad, and a readout speed of a few 10 μs/frame. This work introduces the MVD-PRESTO project, which aims at integrating a precursor of the second station of the CBM-MVD meeting the following requirements: material budget of x /X0 < 0.5 %, vacuum compatibility, double-sided sensor integration on a Thermal Pyrolytic Graphite (TPG) carrier, and heat evacuation of about 350 mW/cm2/sensor with a temperature gradient of a few K/cm.

  9. Development of a pixel sensor with fine space-time resolution based on SOI technology for the ILC vertex detector

    NASA Astrophysics Data System (ADS)

    Ono, Shun; Togawa, Manabu; Tsuji, Ryoji; Mori, Teppei; Yamada, Miho; Arai, Yasuo; Tsuboyama, Toru; Hanagaki, Kazunori

    2017-02-01

    We have been developing a new monolithic pixel sensor with silicon-on-insulator (SOI) technology for the International Linear Collider (ILC) vertex detector system. The SOI monolithic pixel detector is realized using standard CMOS circuits fabricated on a fully depleted sensor layer. The new SOI sensor SOFIST can store both the position and timing information of charged particles in each 20×20 μm2 pixel. The position resolution is further improved by the position weighted with the charges spread to multiple pixels. The pixel also records the hit timing with an embedded time-stamp circuit. The sensor chip has column-parallel analog-to-digital conversion (ADC) circuits and zero-suppression logic for high-speed data readout. We are designing and evaluating some prototype sensor chips for optimizing and minimizing the pixel circuit.

  10. Design and standalone characterisation of a capacitively coupled HV-CMOS sensor chip for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Kremastiotis, I.; Ballabriga, R.; Campbell, M.; Dannheim, D.; Fiergolski, A.; Hynds, D.; Kulis, S.; Peric, I.

    2017-09-01

    The concept of capacitive coupling between sensors and readout chips is under study for the vertex detector at the proposed high-energy CLIC electron positron collider. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is an active High-Voltage CMOS sensor, designed to be capacitively coupled to the CLICpix2 readout chip. The chip is implemented in a commercial 180 nm HV-CMOS process and contains a matrix of 128×128 square pixels with 25μm pitch. First prototypes have been produced with a standard resistivity of ~20 Ωcm for the substrate and tested in standalone mode. The results show a rise time of ~20 ns, charge gain of 190 mV/ke‑ and ~40 e‑ RMS noise for a power consumption of 4.8μW/pixel. The main design aspects, as well as standalone measurement results, are presented.

  11. The LHCb Silicon Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark

    2016-09-01

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  12. Dark photons from charm mesons at LHCb

    NASA Astrophysics Data System (ADS)

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2015-12-01

    We propose a search for dark photons A' at the LHCb experiment using the charm meson decay D*(2007 )0→D0A'. At nominal luminosity, D*0→D0γ decays will be produced at about 700 kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically mixed dark photon, LHCb is then sensitive to dark photons that decay as A'→e+e-. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the A' decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for D*0→D0A' and the excellent invariant-mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the A' parameter space. Both search strategies rely on the planned upgrade to a triggerless-readout system at LHCb in Run 3, which will permit the identification of low-momentum electron-positron pairs online during data taking. For dark photon masses below about 100 MeV, LHCb can explore nearly all of the dark photon parameter space between existing prompt-A' and beam-dump limits.

  13. The LHCb Upgrade

    NASA Astrophysics Data System (ADS)

    Jacobsson, Richard

    2013-11-01

    With the demonstration that LHCb can successfully perform forward precision measurements with event pileup, the operation and trigger strategy evolved significantly during the LHC Run 1 allowing LHCb to collect over 3fb-1 at centre-of-mass energies of 7TeV and 8TeV. Increased bandwidth opened the door for LHCb to extend the physics program. The additional statistics and well managed systematic effects together with the stable trigger and data taking conditions have led to a very large number of world-class measurements and dominance in heavy flavour physics [1], in addition to a reputation of an excellent forward general purpose detector at the LHC. Long Shutdown (LS) 1 (2013-2014) will allow LHCb to fully explore the large statistics collected and prepare LHCb for Run 2 (2015 - 2017). However, even after an additional expected integrated luminosity of 5-6 fb-1 in Run 2, many of the LHCb precision measurements will remain limited by statistics, and some exploratory physics modes will not even be accessible yet. With the need for reconstructing the event topology in order to efficiently trigger on the beauty and the charm hadrons decays, the current 1 MHz readout limit is the main bottle neck to run at higher luminosity and with higher trigger efficiencies. LHCb will therefore undergo a major upgrade in LS 2 ( 2018 - 2019) aimed at collecting an order of magnitude more data by 2028. The upgrade consists of a full readout at the LHC bunch crossing rate ( 40 MHz) with the ultimate flexibility of only a software trigger. In order to increase the instantaneous luminosity up to 2x1033cm-2s-1, several sub-detector upgrades are also underway to cope with the higher occupancies and radiation dose.

  14. High-luminosity primary vertex selection in top-quark studies using the Collider Detector at Fermilab

    SciTech Connect

    Buzatu, Adrian; /McGill U.

    2006-08-01

    Improving our ability to identify the top quark pair (t{bar t}) primary vertex (PV) on an event-by-event basis is essential for many analyses in the lepton-plus-jets channel performed by the Collider Detector at Fermilab (CDF) Collaboration. We compare the algorithm currently used by CDF (A1) with another algorithm (A2) using Monte Carlo simulation at high instantaneous luminosities. We confirm that A1 is more efficient than A2 at selecting the t{bar t} PV at all PV multiplicities, both with efficiencies larger than 99%. Event selection rejects events with a distance larger than 5 cm along the proton beam between the t{bar t} PV and the charged lepton. We find flat distributions for the signal over background significance of this cut for all cut values larger than 1 cm, for all PV multiplicities and for both algorithms. We conclude that any cut value larger than 1 cm is acceptable for both algorithms under the Tevatron's expected instantaneous luminosity improvements.

  15. Power and area efficient 4-bit column-level ADC in a CMOS pixel sensor for the ILD vertex detector

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Morel, F.; Hu-Guo, Ch; Hu, Y.

    2013-01-01

    A 48 × 64 pixels prototype CMOS pixel sensor (CPS) integrated with 4-bit column-level, self triggered ADCs for the outer layers of the ILD vertex detector (VTX) was developed and fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation. The ADCs accommodating the pixel read out in a rolling shutter mode complete the conversion by performing a multi-bit/step approximation. The design was optimised for power saving at sampling frequency. The prototype sensor is currently at the stage of being started testing and evaluation. So what is described is based on post simulation results rather than test data. This 4-bit ADC dissipates, at a 3-V supply and 6.25-MS/s sampling rate, 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. Its footprint amounts to 35 × 545 μm2.

  16. The LHCb Upgrade

    NASA Astrophysics Data System (ADS)

    Piucci, Alessio

    2017-07-01

    During the LHC Run 1 the LHCb experiment has successfully performed a large number of high precision measurements in heavy flavour physics using 3 fb-1 of data collected at centre-of-mass energies of 7 TeV and 8 TeV. In LHC Run 2 the LHCb is expected to integrate an additional 5 fb-1 data, however many of the measurements will remain limited by statistics. For this reason LHCb will undergo in 2020 a major upgrade during the Long Shutdown 2 of LHC, with the aim to collect 50 fb-1 of data by 2028. To achieve this goal the LHCb detector readout rate will be upgraded from the current 1 MHz to the LHC bunch crossing rate of 40 MHz. The luminosity delivered to the experiment will increase by a factor five, up to 2 ṡ 1033 cm-2 s-1. The online selection of events will be uniquely performed by a pure software trigger, improving the trigger efficiencies. In order to sustain the increased luminosity and readout rate, all the sub-detectors will be upgraded. The architecture of the upgraded DAQ system and trigger strategy will be presented, as well an overview of the sub-detector upgrades.

  17. The LHCb Turbo stream

    NASA Astrophysics Data System (ADS)

    Puig, A.

    2016-07-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  18. The CDF silicon vertex tracker

    SciTech Connect

    A. Cerri et al.

    2000-10-10

    Real time pattern recognition is becoming a key issue in many position sensitive detector applications. The CDF collaboration is building SVT: a specialized electronic device designed to perform real time track reconstruction using the silicon vertex detector (SVX II). This will strongly improve the CDF capability of triggering on events containing b quarks, usually characterized by the presence of a secondary vertex. SVT is designed to reconstruct in real time charged particles trajectories using data coming from the Silicon Vertex detector and the Central Outer Tracker drift chamber. The SVT architecture and algorithm have been specially tuned to minimize processing time without degrading parameter resolution.

  19. Highlights from the LHCb ion physics program

    NASA Astrophysics Data System (ADS)

    Schmelling, Michael; LHCb collaboration

    2017-01-01

    Following the successful participation of LHCb in the 2013 proton-lead run of the LHC, in 2015 the collaboration decided to further extend its physics program to study also lead-lead collisions and fixed target interactions. These proceedings discuss the physics reach of the detector and the first results from the LHCb ion physics and fixed target program.

  20. VeloPix: the pixel ASIC for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Poikela, T.; De Gaspari, M.; Plosila, J.; Westerlund, T.; Ballabriga, R.; Buytaert, J.; Campbell, M.; Llopart, X.; Wyllie, K.; Gromov, V.; van Beuzekom, M.; Zivkovic, V.

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 along with the other subsystems of LHCb in order to enable full readout at 40 MHz, with the data fed directly to the software triggering algorithms. The upgraded VELO is a lightweight hybrid pixel detector operating in vacuum in close proximity to the LHC beams. The readout will be provided by a dedicated front-end ASIC, dubbed VeloPix, matched to the LHCb readout requirements and the 55 × 55 μm VELO pixel dimensions. The chip is closely related to the Timepix3, from the Medipix family of ASICs. The principal challenge that the chip has to meet is a hit rate of up to 900 Mhits/s, resulting in a required output bandwidth of more than 16 Gbit/s. The occupancy across the chip is also very non-uniform, and the radiation levels reach an integrated 400 Mrad over the lifetime of the detector.VeloPix is a binary pixel readout chip with a data driven readout, designed in 130 nm CMOS technology. The pixels are combined into groups of 2 × 4 super pixels, enabling a shared logic and a reduction of bandwidth due to combined address and time stamp information. The pixel hits are combined with other simultaneous hits in the same super pixel, time stamped, and immediately driven off-chip. The analog front-end must be sufficiently fast to accurately time stamp the data, with a small enough dead time to minimize data loss in the most occupied regions of the chip. The data is driven off chip with a custom designed high speed serialiser. The current status of the ASIC design, the chip architecture and the simulations will be described.

  1. Development and test of the CO2 evaporative cooling system for the LHCb UT Tracker Upgrade

    NASA Astrophysics Data System (ADS)

    Coelli, S.

    2017-03-01

    The LHCb upgrade requires a new silicon strip tracker detector placed between the vertex locator and the magnet. The new detector will have improved performance in charged particle tracking and triggering. The front-end electronics will be in the active area, close to the sensors: this is a key feature driving the mechanical and cooling detector design, together with the requirement to make the sensors work below -5°C, to withstand radiation damage. The new design exploits a cooling system based on CO2 evaporation at temperatures around -25°C. The support structure for the sensor modules is a lightweight carbon fiber mechanical structure embedding a cooling pipe, designed to pass underneath the read-out ASICs, which are the main thermal power sources to be cooled down. Here a description of the detector will be given, with a main focus on the cooling system and on the progress done to its qualification.

  2. CDF - Secondary vertex trigger

    SciTech Connect

    D. Lucchesi

    2002-10-25

    At the beginning of 2002 a new data taking with an upgraded trigger system started for the CDF collaboration. One of the major improvements is the track trigger. A fast processor reconstructs tracks in the central drift chamber and the Silicon Vertex Tracker combines these tracks with the silicon vertex detector information to have track parameters with a precision as good as the offine reconstruction. This system allows CDF to trigger on tracks significantly displaced from the primary vertex with high efficiency for signal events like charm and beauty and to keep low background rates. The performances, in terms of resolution and efficiency, of both the processors are illustrated and the firsts physics results are discussed.

  3. Evaporative CO2 microchannel cooling for the LHCb VELO pixel upgrade

    NASA Astrophysics Data System (ADS)

    de Aguiar Francisco, O. A.; Buytaert, J.; Collins, P.; Dumps, R.; John, M.; Mapelli, A.; Romagnoli, G.

    2015-05-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO2 circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO2, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO2 cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use of restrictions implemented before the entrance to a race track like layout of the main cooling channels. The coolant flow and pressure drop have been simulated as well as the thermal performance of the device. This proceeding describes the design and optimization of the cooling system for LHCb and the latest prototyping results.

  4. A fast, low-power, 6-bit SAR ADC for readout of strip detectors in the LHCb Upgrade experiment

    NASA Astrophysics Data System (ADS)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moron, J.; Swientek, K.

    2014-07-01

    The readout of silicon strip sensors in the upgraded Tracker System of Large Hadron Collider beauty (LHCb) experiment will require a novel complex Application Specific Integrated Circuit (ASIC). The ASIC will extract and digitise analogue signal from the sensor and subsequently will perform digital processing and serial data transmission. One of the key processing blocks, placed in each channel, will be an Analogue to Digital Converter (ADC). A prototype of fast, low-power 6-bit Successive Approximation Register (SAR) ADC was designed, fabricated and tested. The measurements of ADC prototypes confirmed simulation results showing excellent overall performance. In particular, very good resolution with Effective Number Of Bits (ENOB) 5.85 was obtained together with very low power consumption of 0.35 mW at 40 MS/s sampling rate. The results of the performed static and dynamic measurements confirm excellent ADC operation for higher sampling rates up to 80 MS/s.

  5. A time-based front-end ASIC for the silicon micro strip sensors of the bar PANDA Micro Vertex Detector

    NASA Astrophysics Data System (ADS)

    Di Pietro, V.; Brinkmann, K.-Th.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Zambanini, A.

    2016-03-01

    The bar PANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA (bar PANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels.

  6. LHCb Upgrade: Scintillating Fibre Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark; LHCb Upgrade Scintillating Fibre Tracker Group

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  7. Proposed Inclusive Dark Photon Search at LHCb

    NASA Astrophysics Data System (ADS)

    Ilten, Philip; Soreq, Yotam; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-06-01

    We propose an inclusive search for dark photons A' at the LHCb experiment based on both prompt and displaced dimuon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A'→μ+μ- rate can be directly inferred from the off-shell photon γ*→μ+μ- rate, making this a fully data-driven search. For run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  8. Heavy Flavour and Quarkonia production at LHCb

    NASA Astrophysics Data System (ADS)

    Müller, Katharina; LHCb Collaboration

    2017-07-01

    The LHCb detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring heavy quark and quarkonia production properties. Recent LHCb measurements of inclusive and differential cross-sections of the production of J/ψ and ϒ resonances, as well as charm, bottom and top quarks, in pp collisions at different centre-of-mass energies are presented. Finally, results on the associated production of ϒ and open charm hadrons and the exclusive production of charmonium are discussed.

  9. Towards a high performance vertex detector based on 3D integration of deep N-well MAPS

    NASA Astrophysics Data System (ADS)

    Re, V.

    2010-06-01

    The development of deep N-Well (DNW) CMOS active pixel sensors was driven by the ambitious goal of designing a monolithic device with similar functionalities as in hybrid pixel readout chips, such as pixel-level sparsification and time stamping. The implementation of the DNW MAPS concept in a 3D vertical integration process naturally leads the designer towards putting more intelligence in the chip and in the pixels themselves, achieving novel device structures based on the interconnection of two or more layers fabricated in the same technology. These devices are read out with a data-push scheme that makes it possible to use pixel data for the generation of a flexible level 1 track trigger, based on associative memories, with short latency and high efficiency. This paper gives an update of the present status of DNW MAPS design in both 2D and 3D versions, and presents a discussion of the architectures that are being devised for the Layer 0 of the SuperB Silicon Vertex Tracker.

  10. Distributed analysis at LHCb

    NASA Astrophysics Data System (ADS)

    Williams, Mike; Egede, Ulrik; Paterson, Stuart; LHCb Collaboration

    2011-12-01

    The distributed analysis experience to date at LHCb has been positive: job success rates are high and wait times for high-priority jobs are low. LHCb users access the grid using the GANGA job-management package, while the LHCb virtual organization manages its resources using the DIRAC package. This clear division of labor has benefitted LHCb and its users greatly; it is a major reason why distributed analysis at LHCb has been so successful. The newly formed LHCb distributed analysis support team has also proved to be a success.

  11. Measurements of hadronic B decays to excited-charm mesons, observation of a new charm resonance and construction of a silicon vertex detector for CLEO II.V

    NASA Astrophysics Data System (ADS)

    Nelson, Timothy Knight

    We describe measurements of the branching ratios B(B --->D*+p- p-total) =(29.2+/-4.5+/-3.8+/-3.1) ×10-4 B(B- --> D*+p- p -non- res)=( 9.7+/-3.6+/-1.5+/-1.9)× 10- 4 B(B---> D1(2420) 0p-) B(D1( 2420)0--> D*+p- )= (6.9+1.8-1.4 +/-1.1+/-0.4)× 10-4 B(B---> D01( j= / )p- ) B(D01 (j= /) -->D* +p-) = ( 10.6+/-1.9+/-1.7+/-2.3)× 10-4 B(B---> D*2( 2460)0p- )B(D *2( 2460)0--> D*+p- )= (3.1+/- 0.84+/-0.46+/-0.28)×10 -4, using data collected by the CLEO II detector. These measurements provide the first observation of the D01(j=/) with a mass and width of 2.461+0.053- 0.049GeV and 290+110 - 91MeV respectively. The mixing angles between the partial waves and strong phase shifts among the resonances are also measured assuming one possible parameterization of the amplitude. A method allowing full reconstruction of the signal without reconstruction of the D meson in the final state is used. The measurements are extracted using an four-dimensional, unbinned, maximum- likelihood fit to the distributions of the D*+p- mass and the decay angles. The primary element of the CLEO II.V upgrade was the installation of a three-layer Silicon Vertexing Detector. The design and construction of this detector are described in detail.

  12. LHCbDirac: distributed computing in LHCb

    NASA Astrophysics Data System (ADS)

    Stagni, F.; Charpentier, P.; Graciani, R.; Tsaregorodtsev, A.; Closier, J.; Mathe, Z.; Ubeda, M.; Zhelezov, A.; Lanciotti, E.; Romanovskiy, V.; Ciba, K. D.; Casajus, A.; Roiser, S.; Sapunov, M.; Remenska, D.; Bernardoff, V.; Santana, R.; Nandakumar, R.

    2012-12-01

    We present LHCbDirac, an extension of the DIRAC community Grid solution that handles LHCb specificities. The DIRAC software has been developed for many years within LHCb only. Nowadays it is a generic software, used by many scientific communities worldwide. Each community wanting to take advantage of DIRAC has to develop an extension, containing all the necessary code for handling their specific cases. LHCbDirac is an actively developed extension, implementing the LHCb computing model and workflows handling all the distributed computing activities of LHCb. Such activities include real data processing (reconstruction, stripping and streaming), Monte-Carlo simulation and data replication. Other activities are groups and user analysis, data management, resources management and monitoring, data provenance, accounting for user and production jobs. LHCbDirac also provides extensions of the DIRAC interfaces, including a secure web client, python APIs and CLIs. Before putting in production a new release, a number of certification tests are run in a dedicated setup. This contribution highlights the versatility of the system, also presenting the experience with real data processing, data and resources management, monitoring for activities and resources.

  13. The LHCb trigger and its upgrade

    NASA Astrophysics Data System (ADS)

    Dziurda, A.

    2016-07-01

    The current LHCb trigger system consists of a hardware level, which reduces the LHC inelastic collision rate of 30 MHz, at which the entire detector is read out. In a second level, implemented in a farm of 20 k parallel-processing CPUs, the event rate is reduced to about 5 kHz. We review the performance of the LHCb trigger system during Run I of the LHC. Special attention is given to the use of multivariate analyses in the High Level Trigger. The major bottleneck for hadronic decays is the hardware trigger. LHCb plans a major upgrade of the detector and DAQ system in the LHC shutdown of 2018, enabling a purely software based trigger to process the full 30 MHz of inelastic collisions delivered by the LHC. We demonstrate that the planned architecture will be able to meet this challenge.

  14. Vertex finding with deformable templates at LHC

    NASA Astrophysics Data System (ADS)

    Stepanov, Nikita; Khanov, Alexandre

    1997-02-01

    We present a novel vertex finding technique. The task is formulated as a discrete-continuous optimisation problem in a way similar to the deformable templates approach for the track finding. Unlike the track finding problem, "elastic hedgehogs" rather than elastic arms are used as deformable templates. They are initialised by a set of procedures which provide zero level approximation for vertex positions and track parameters at the vertex point. The algorithm was evaluated using the simulated events for the LHC CMS detector and demonstrated good performance.

  15. LHCb Physics and 2010-11 prospects

    SciTech Connect

    Perazzini, Stefano

    2011-10-24

    LHCb is one of the four major experiments operating at the Large Hadron Collider, and is specifically dedicated to the measurement of CP-violation and rare decays in the beauty and charm quark sectors. By employing data from early LHC runs it is possible to assess the performance of the detector and to better understand the potential of the LHCb flavour programme. After a brief introduction of the motivations and of the relevant physics goals, the prospects about key CP-violation and rare decay measurements will be presented. Emphasis will be given to those topics where results with particular sensitivity to New Physics are expected during the 2010-11 run.

  16. Forward physics with the LHCb experiment

    SciTech Connect

    Volyanskyy, Dmytro; Collaboration: LHCb Collaboration

    2013-04-15

    Due to its unique pseudorapidity coverage and the ability to perform measurements at low transverse momenta p{sub T}, the LHCb detector allows a unique insight into particle production in the forward region at the LHC. Using large samples of proton-proton collision data accumulated at {radical}(s) = 7TeV, the LHCb collaboration has performed a series of dedicated analyses providing important input to the knowledge of the parton density functions, underlying event activity, low Bjorken-x QCD dynamics and exclusive processes. Some of these are briefly summarised here.

  17. Performance of the LHCb tracking system in Run I of the LHC

    NASA Astrophysics Data System (ADS)

    Davis, Adam C. S.

    2016-07-01

    The LHCb tracking system consists of a Vertex Locator around the interaction point, a tracking station with four layers of silicon strip detectors in front of the magnet, and three straw-tube and silicon strip tracking stations behind the magnet. This system allows reconstruction of charged particles with a high efficiency (> 95 % for particles with momentum p > 5 GeV) and excellent momentum resolution (0.5% for particles with p < 20 GeV). The high momentum resolution results in narrow mass peaks, leading to a high signal-to-background ratio in such key channels as Bs0 → μμ. The excellent performance of the tracking system yields a decay time resolution of 50 fs, allowing to resolve the fast B0s oscillation with a mixing frequency of 17.7 ps-1. Such a decay time resolution is an essential element in studies of time dependent CP violation. I present an overview of the track reconstruction in LHCb and its performance in Run I of the LHC. I highlight the challenges and improvements of the track reconstruction from Run II onward, including efforts to improve the timing of the online reconstruction and approaches to unify the online and offline reconstruction.

  18. Implications of LHCb measurements and future prospects

    NASA Astrophysics Data System (ADS)

    Bharucha, A.; Bigi, I. I.; Bobeth, C.; Bobrowski, M.; Brod, J.; Buras, A. J.; Davies, C. T. H.; Datta, A.; Delaunay, C.; Descotes-Genon, S.; Ellis, J.; Feldmann, T.; Fleischer, R.; Gedalia, O.; Girrbach, J.; Guadagnoli, D.; Hiller, G.; Hochberg, Y.; Hurth, T.; Isidori, G.; Jäger, S.; Jung, M.; Kagan, A.; Kamenik, J. F.; Lenz, A.; Ligeti, Z.; London, D.; Mahmoudi, F.; Matias, J.; Nandi, S.; Nir, Y.; Paradisi, P.; Perez, G.; Petrov, A. A.; Rattazzi, R.; Sharpe, S. R.; Silvestrini, L.; Soni, A.; Straub, D. M.; van Dyk, D.; Virto, J.; Wang, Y.-M.; Weiler, A.; Zupan, J.; Aaij, R.; Abellan Beteta, C.; Adametz, A.; Adeva, B.; Adinolfi, M.; Adrover, C.; Affolder, A.; Ajaltouni, Z.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amhis, Y.; Anderlini, L.; Anderson, J.; Andreassen, R.; Anelli, M.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Bachmann, S.; Back, J. J.; Baesso, C.; Baldini, W.; Band, H.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Bates, A.; Bauer, Th.; Bay, A.; Beddow, J.; Bediaga, I.; Beigbeder-Beau, C.; Belogurov, S.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Benayoun, M.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernard, F.; Bernet, R.; Bettler, M.-O.; van Beuzekom, M.; van Beveren, V.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Bjørnstad, P. M.; Blake, T.; Blanc, F.; Blanks, C.; Blouw, J.; Blusk, S.; Bobrov, A.; Bocci, V.; Bochin, B.; Boer Rookhuizen, H.; Bogdanova, G.; Bonaccorsi, E.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brambach, T.; van den Brand, J.; Brarda, L.; Bressieux, J.; Brett, D.; Britsch, M.; Britton, T.; Brook, N. H.; Brown, H.; Büchler-Germann, A.; Burducea, I.; Bursche, A.; Buytaert, J.; Cacérès, T.; Cachemiche, J.-P.; Cadeddu, S.; Callot, O.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carranza-Mejia, H.; Carson, L.; Carvalho Akiba, K.; Casajus Ramo, A.; Casse, G.; Cattaneo, M.; Cauet, Ch.; Ceelie, L.; Chadaj, B.; Chanal, H.; Charles, M.; Charlet, D.; Charpentier, Ph.; Chebbi, M.; Chen, P.; Chiapolini, N.; Chrzaszcz, M.; Ciambrone, P.; Ciba, K.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coca, C.; Coco, V.; Cogan, J.; Cogneras, E.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Corajod, B.; Corti, G.; Couturier, B.; Cowan, G. A.; Craik, D.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; D'Antone, I.; David, P.; David, P. N. Y.; De Bonis, I.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Groen, P.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Decamp, D.; Deckenhoff, M.; Decreuse, G.; Degaudenzi, H.; Del Buono, L.; Deplano, C.; Derkach, D.; Deschamps, O.; Dettori, F.; Di Canto, A.; Dickens, J.; Dijkstra, H.; Diniz Batista, P.; Dogaru, M.; Domingo Bonal, F.; Domke, M.; Donleavy, S.; Dordei, F.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Drancourt, C.; Duarte, O.; Dumps, R.; Dupertuis, F.; Duval, P.-Y.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; van Eijk, D.; Eisenhardt, S.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Elsby, D.; Evangelisti, F.; Falabella, A.; Färber, C.; Fardell, G.; Farinelli, C.; Farry, S.; Faulkner, P. J. W.; Fave, V.; Felici, G.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fitzpatrick, C.; Föhr, C.; Fontana, M.; Fontanelli, F.; Forty, R.; Fournier, C.; Francisco, O.; Frank, M.; Frei, C.; Frei, R.; Frosini, M.; Fuchs, H.; Furcas, S.; Gallas Torreira, A.; Galli, D.; Gandelman, M.; Gandini, P.; Gao, Y.; Garofoli, J.; Garosi, P.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Gets, S.; Ghez, Ph.; Giachero, A.; Gibson, V.; Gligorov, V. V.; Göbel, C.; Golovtsov, V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gong, G.; Gong, H.; Gordon, H.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Gromov, V.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Guzik, Z.; Gys, T.; Hachon, F.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hampson, T.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Harrison, P. F.; Hartmann, T.; He, J.; van der Heijden, B.; Heijne, V.; Hennessy, K.; Henrard, P.; Hernando Morata, J. A.; van Herwijnen, E.; Hicks, E.; Hill, D.; Hoballah, M.; Hofmann, W.; Hombach, C.; Hopchev, P.; Hulsbergen, W.; Hunt, P.; Huse, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Iakovenko, V.; Ilten, P.; Imong, J.; Jacobsson, R.; Jaeger, A.; Jamet, O.; Jans, E.; Jansen, F.; Jansen, L.; Jansweijer, P.; Jaton, P.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Jost, B.; Kaballo, M.; Kandybei, S.; Karacson, M.; Karavichev, O.; Karbach, T. M.; Kashchuk, A.; Kechadi, T.; Kenyon, I. R.; Kerzel, U.; Ketel, T.; Keune, A.; Khanji, B.; Kihm, T.; Kluit, R.; Kochebina, O.; Komarov, V.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kos, J.; Kozlinskiy, A.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Kristic, R.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucharczyk, M.; Kudenko, Y.; Kudryavtsev, V.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanciotti, E.; Landi, L.; Lanfranchi, G.; Langenbruch, C.; Laptev, S.; Latham, T.; Lax, I.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Li, Y.; Li Gioi, L.; Likhoded, A.; Liles, M.; Lindner, R.; Linn, C.; Liu, B.; Liu, G.; von Loeben, J.; Lopes, J. H.; Lopez Asamar, E.; Lopez-March, N.; Lu, H.; Luisier, J.; Luo, H.; Mac Raighne, A.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Maino, M.; Malde, S.; Manca, G.; Mancinelli, G.; Mangiafave, N.; Marconi, U.; Märki, R.; Marks, J.; Martellotti, G.; Martens, A.; Martín Sánchez, A.; Martinelli, M.; Martinez Santos, D.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Matveev, M.; Maurice, E.; Mauricio, J.; Mazurov, A.; McCarthy, J.; McNulty, R.; Meadows, B.; Meissner, M.; Mejia, H.; Mendez-Munoz, V.; Merk, M.; Milanes, D. A.; Minard, M.-N.; Molina Rodriguez, J.; Monteil, S.; Moran, D.; Morawski, P.; Mountain, R.; Mous, I.; Muheim, F.; Mul, F.; Müller, K.; Munneke, B.; Muresan, R.; Muryn, B.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Nawrot, A.; Needham, M.; Neufeld, N.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Nicol, M.; Niess, V.; Nikitin, N.; Nikodem, T.; Nikolaiko, Y.; Nisar, S.; Nomerotski, A.; Novoselov, A.; Oblakowska-Mucha, A.; Obraztsov, V.; Oggero, S.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Orlandea, M.; Ostankov, A.; Otalora Goicochea, J. M.; van Overbeek, M.; Owen, P.; Pal, B. K.; Palano, A.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Parkes, C.; Parkinson, C. J.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrick, G. N.; Patrignani, C.; Pavel-Nicorescu, C.; Pazos Alvarez, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perego, D. L.; Perez Trigo, E.; Pérez-Calero Yzquierdo, A.; Perret, P.; Perrin-Terrin, M.; Pessina, G.; Petridis, K.; Petrolini, A.; van Petten, O.; Phan, A.; Picatoste Olloqui, E.; Piedigrossi, D.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Playfer, S.; Plo Casasus, M.; Polci, F.; Polok, G.; Poluektov, A.; Polycarpo, E.; Popov, D.; Popovici, B.; Potterat, C.; Powell, A.; Prisciandaro, J.; Pugatch, M.; Pugatch, V.; Puig Navarro, A.; Qian, W.; Rademacker, J. H.; Rakotomiaramanana, B.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redford, S.; Reid, M. M.; dos Reis, A. C.; Rethore, F.; Ricciardi, S.; Richards, A.; Rinnert, K.; Rives Molina, V.; Roa Romero, D. A.; Robbe, P.; Rodrigues, E.; Rodriguez Perez, P.; Roeland, E.; Rogers, G. J.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; de Roo, K.; Rouvinet, J.; Roy, L.; Rudloff, K.; Ruf, T.; Ruiz, H.; Sabatino, G.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salzmann, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Saornil Gamarra, S.; Sapunov, M.; Saputi, A.; Sarti, A.; Satriano, C.; Satta, A.; Savidge, T.; Savrie, M.; Schaack, P.; Schiller, M.; Schimmel, A.; Schindler, H.; Schleich, S.; Schlupp, M.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schneider, T.; Schopper, A.; Schuijlenburg, H.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Seco, M.; Semennikov, A.; Senderowska, K.; Sepp, I.; Serra, N.; Serrano, J.; Seyfert, P.; Shao, B.; Shapkin, M.; Shapoval, I.; Shatalov, P.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, O.; Shevchenko, V.; Shires, A.; Sigurdsson, S.; Silva Coutinho, R.; Skwarnicki, T.; Slater, M. W.; Sluijk, T.; Smith, N. A.; Smith, E.; Smith, M.; Sobczak, K.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Sparkes, A.; Spradlin, P.; Squerzanti, S.; Stagni, F.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Stoica, S.; Stone, S.; Storaci, B.; Straticiuc, M.; Straumann, U.; Subbiah, V. K.; Swientek, S.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Teklishyn, M.; Teodorescu, E.; Teubert, F.; Thomas, C.; Thomas, E.; Tikhonov, A.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tocut, V.; Tolk, S.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Tran, M. T.; Tresch, M.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ullaland, O.; Urner, D.; Uwer, U.; Vagnoni, V.; Valenti, G.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vilasis-Cardona, X.; Vink, W.; Volkov, S.; Volkov, V.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; Voss, H.; Vouters, G.; Waldi, R.; Wallace, R.; Wandernoth, S.; Wang, J.; Ward, D. R.; Warda, K.; Watson, N. K.; Webber, A. D.; Websdale, D.; Wenerke, P.; Whitehead, M.; Wicht, J.; Wiedner, D.; Wiggers, L.; Wilkinson, G.; Williams, M. P.; Williams, M.; Wilson, F. F.; Wishahi, J.; Witek, M.; Witzeling, W.; Wotton, S. A.; Wright, S.; Wu, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Xue, T.; Yang, Z.; Young, R.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zappon, F.; Zavertyaev, M.; Zeng, M.; Zhang, F.; Zhang, L.; Zhang, W. C.; Zhang, Y.; Zhelezov, A.; Zhong, L.; Zverev, E.; Zvyagin, A.; Zwart, A.

    2013-04-01

    During 2011 the LHCb experiment at CERN collected 1.0 fb-1 of √{s} = 7 TeV pp collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.

  19. Medical Imaging Inspired Vertex Reconstruction at LHC

    NASA Astrophysics Data System (ADS)

    Hageböck, S.; von Toerne, E.

    2012-12-01

    Three-dimensional image reconstruction in medical applications (PET or X-ray CT) utilizes sophisticated filter algorithms to linear trajectories of coincident photon pairs or x-rays. The goal is to reconstruct an image of an emitter density distribution. In a similar manner, tracks in particle physics originate from vertices that need to be distinguished from background track combinations. In this study it is investigated if vertex reconstruction in high energy proton collisions may benefit from medical imaging methods. A new method of vertex finding, the Medical Imaging Vertexer (MIV), is presented based on a three-dimensional filtered backprojection algorithm. It is compared to the open-source RAVE vertexing package. The performance of the vertex finding algorithms is evaluated as a function of instantaneous luminosity using simulated LHC collisions. Tracks in these collisions are described by a simplified detector model which is inspired by the tracking performance of the LHC experiments. At high luminosities (25 pileup vertices and more), the medical imaging approach finds vertices with a higher efficiency and purity than the RAVE “Adaptive Vertex Reconstructor” algorithm. It is also much faster if more than 25 vertices are to be reconstructed because the amount of CPU time rises linearly with the number of tracks whereas it rises quadratically for the adaptive vertex fitter AVR.

  20. Java Vertexing Tools

    SciTech Connect

    Strube, Jan; Graf, Norman; /SLAC

    2006-03-03

    This document describes the implementation of the topological vertex finding algorithm ZVTOP within the org.lcsim reconstruction and analysis framework. At the present date, Java vertexing tools allow users to perform topological vertexing on tracks that have been obtained from a Fast MC simulation. An implementation that will be able to handle fully reconstructed events is being designed from the ground up for longevity and maintainability.

  1. Search for anomalous couplings in the W tb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Amako, K.; Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Biesuz, N. V.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. W.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerda Alberich, L.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chan, Y. L.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. 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C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2016-04-01

    The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb-1 of proton-proton collision data at √{s}=7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured to be 0 .37 ± 0 .07 (stat.⊕syst.). The phase δ - between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be -0 .014 π ± 0 .036 π (stat.⊕syst.). The correlation in the measurement of these parameters is 0 .15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g R and V L, yielding Re[ g R /V L] ∈ [-0 .36 , 0 .10] and Im[ g R /V L] ∈ [-0 .17 , 0 .23] with a correlation of 0 .11. The results are in good agreement with the predictions of the Standard Model. [Figure not available: see fulltext.

  2. Search for anomalous couplings in the W tb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector

    DOE PAGES

    Aad, G.; Abbott, B.; Abdallah, J.; ...

    2016-04-05

    The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb-1 of proton-proton collision data at √s=7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured tomore » be 0.37 ± 0.07 (stat.⊕syst.). The phase δ - between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be -0.014π ± 0.036π (stat.⊕syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g R and V L, yielding Re[g R /V L] ϵ [-0.36, 0.10] and Im[g R /V L] ϵ [-0.17, 0.23] with a correlation of 0.11. We find the results are in good agreement with the predictions of the Standard Model.« less

  3. Lifetime tests for MAC vertex chamber

    SciTech Connect

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions. (LEW)

  4. The LHCb upgrade: plans and physics potential

    NASA Astrophysics Data System (ADS)

    Marconi, U.

    2017-04-01

    LHCb is performing a large number of world-class precision measurements in heavy flavour physics. However, yet by the end of the LHC Run 2, many of these measurements will remain limited by statistics, even though adding the expected integrated luminosity of 5 - 6 fb-1. The main obstacle preventing LHCb to run the present detector at higher luminosities, with enhanced trigger efficiencies, is the current 1 MHz readout system limitation. The detector will therefore undergo a major upgrade in the Long Shutdown 2 (2018 - 2019) aiming at collecting an order of magnitude more data by 2028. The upgrade consists of a new readout system operating at the LHC bunch crossing rate of 40 MHz. The data acquisition system will exploit the ultimate flexibility of a software trigger. The instantaneous luminosity will increase to 2 ×1033 cm-2s-1, five times higher than presently. In order to cope with the higher expected occupancies and radiation doses several sub-detector upgrades are underway. The physics potential of LHCb shall improve considerably, as will be discussed.

  5. TELL1: development of a common readout board for LHCb

    NASA Astrophysics Data System (ADS)

    Legger, Federica; Bay, Aurelio; Haefeli, Guido; Locatelli, Laurent

    2004-12-01

    LHCb is one of the four experiments currently under construction at LHC (Large Hadron Collider) at CERN, and its aim is the study of b-quark physics (LHCb Collaboration, CERN-LHCC/98-4). LHCb trigger strategy is based on three levels, and will reduce the event rate from 40 MHz to a few hundred Hz (LHCb Collaboration, CERN/LHCC 2003-031, LHCb TDR 10, September 2003). The first two levels (L0 and L1) will use signals from some part of the detector in order to take fast decisions, while the last one, called High Level Trigger (HLT), will have access to the full event data. An "off detector" readout board (TELL1) has been developed and will be used by the majority of LHCb subdetectors. It takes L0 accepted data as input and, after data processing which includes event synchronization, L1 Trigger pre-processing and zero suppression, L1 buffering, and HLT zero suppression, the output is sent to L1 Trigger and HLT .

  6. Radiative decays at LHCb

    NASA Astrophysics Data System (ADS)

    Giubega, L. E.

    2016-12-01

    Precise measurements on rare radiative B decays are performed with the LHCb experiment at LHC. The LHCb results regarding the ratio of branching fractions for two radiative decays, B 0 → K *0 γ and B s → ϕ γ, the direct CP asymmetry in B 0 → K *0 γ decay channel and the observation of the photon polarization in the B ± → K ±π∓π± γ decay, are included. The first two measurements were performed in 1 fb-1 of pp collisions data and the third one in 3 fb-1 of data, respectively.

  7. Probing the W tb vertex structure in t-channel single-top-quark production and decay in pp collisions at √{s}=8 TeV with the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Gonzalez, B. Alvarez; Piqueras, D. Álvarez; Alviggi, M. G.; Amadio, B. T.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. 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K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisits, M.-S.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska-Blenessy, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Navarro, L. Barranco; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Benitez, J.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bylund, O. Bessidskaia; Bessner, M.; Besson, N.; Betancourt, C.; Bethani, A.; Bethke, S.; Bevan, A. J.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; De Mendizabal, J. Bilbao; Billoud, T. R. V.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biondi, S.; Bisanz, T.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blue, A.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. 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Crispin; Cristinziani, M.; Croft, V.; Crosetti, G.; Cueto, A.; Donszelmann, T. Cuhadar; Cummings, J.; Curatolo, M.; Cúth, J.; Czirr, H.; Czodrowski, P.; D'amen, G.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dado, T.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Hoffmann, M. Dano; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Dawe, E.; Dawson, I.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Maria, A.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Dehghanian, N.; Deigaard, I.; Del Gaudio, M.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Pietra, M. Della; della Volpe, D.; Delmastro, M.; Delsart, P. A.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Clemente, W. K.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Micco, B.; Di Nardo, R.; Di Petrillo, K. F.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Cornell, S. Díez; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dolejsi, J.; Dolezal, Z.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Du, Y.; Duarte-Campderros, J.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Dudder, A. Chr.; Duffield, E. M.; Duflot, L.; Dührssen, M.; Dumancic, M.; Duncan, A. K.; Dunford, M.; Yildiz, H. Duran; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edwards, N. C.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellajosyula, V.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Ennis, J. S.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, F.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farina, C.; Farina, E. 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L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Astigarraga, M. E. Pozo; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Ratti, M. G.; Rauch, D. M.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Ravinovich, I.; Raymond, M.; Read, A. L.; Readioff, N. P.; Reale, M.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reed, R. G.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reiss, A.; Rembser, C.; Ren, H.; Rescigno, M.; Resconi, S.; Resseguie, E. D.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rimoldi, M.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Rizzi, C.; Roberts, R. T.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Rodina, Y.; Perez, A. Rodriguez; Rodriguez, D. Rodriguez; Roe, S.; Rogan, C. S.; Røhne, O.; Roloff, J.; Romaniouk, A.; Romano, M.; Saez, S. M. Romano; Adam, E. Romero; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosien, N.-A.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryu, S.; Ryzhov, A.; Rzehorz, G. F.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Sadrozinski, H. F.-W.; Sadykov, R.; Tehrani, F. Safai; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Loyola, J. E. Salazar; Salek, D.; De Bruin, P. H. Sales; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sánchez, J.; Martinez, V. Sanchez; Pineda, A. Sanchez; Sandaker, H.; Sandbach, R. L.; Sandhoff, M.; Sandoval, C.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Castillo, I. Santoyo; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sato, K.; Sauvan, E.; Savage, G.; Savard, P.; Savic, N.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schachtner, B. M.; Schaefer, D.; Schaefer, L.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schier, S.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt-Sommerfeld, K. R.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, S.; Schneider, B.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schott, M.; Schouwenberg, J. F. P.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schuh, N.; Schulte, A.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwartzman, A.; Schwarz, T. A.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shaikh, N. W.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shirabe, S.; Shiyakova, M.; Shmeleva, A.; Saadi, D. Shoaleh; Shochet, M. J.; Shojaii, S.; Shope, D. R.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Sicho, P.; Sickles, A. M.; Sidebo, P. E.; Haddad, E. Sideras; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silverstein, S. B.; Simak, V.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simon, M.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Siral, I.; Sivoklokov, S. Yu.; Sjölin, J.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Slovak, R.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smiesko, J.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, J. W.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snyder, I. M.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Sanchez, C. A. Solans; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sood, A.; Sopczak, A.; Sopko, V.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Denis, R. D. St.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Stark, S. H.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Suster, C. J. E.; Sutton, M. 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A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Pastor, E. Torró; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Cakir, I. Turk; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Santurio, E. Valdes; Valencic, N.; Valentinetti, S.; Valero, A.; Valéry, L.; Valkar, S.; Ferrer, J. A. Valls; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Perez, M. Villaplana; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vishwakarma, A.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, Q.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wobisch, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Wong, K. H. Yau; Ye, J.; Ye, S.; Yeletskikh, I.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zacharis, G.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Y.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zwalinski, L.

    2017-04-01

    To probe the W tb vertex structure, top-quark and W -boson polarisation observables are measured from t-channel single-top-quark events produced in proton-proton collisions at a centre-of-mass energy of 8 TeV. The dataset corresponds to an integrated luminosity of 20.2 fb-1, recorded with the ATLAS detector at the LHC. Selected events contain one isolated electron or muon, large missing transverse momentum and exactly two jets, with one of them identified as likely to contain a b-hadron. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from background. The polarisation observables are extracted from asymmetries in angular distributions measured with respect to spin quantisation axes appropriately chosen for the top quark and the W boson. The asymmetry measurements are performed at parton level by correcting the observed angular distributions for detector effects and hadronisation after subtracting the background contributions. The measured top-quark and W -boson polarisation values are in agreement with the Standard Model predictions. Limits on the imaginary part of the anomalous coupling g R are also set from model-independent measurements. [Figure not available: see fulltext.

  8. Probing the W tb vertex structure in t-channel single-top-quark production and decay in pp collisions at $$ \\sqrt{s}=8 $$ TeV with the ATLAS detector

    DOE PAGES

    Aaboud, M.; Aad, G.; Abbott, B.; ...

    2017-04-20

    To probe the W tb vertex structure, top-quark and W -boson polarisation observables are measured from t-channel single-top-quark events produced in proton-proton collisions at a centre-of-mass energy of 8 TeV. The dataset corresponds to an integrated luminosity of 20.2 fb–1, recorded with the ATLAS detector at the LHC. Selected events contain one isolated electron or muon, large missing transverse momentum and exactly two jets, with one of them identified as likely to contain a b-hadron. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from background. The polarisation observables are extracted from asymmetries in angular distributions measured with respectmore » to spin quantisation axes appropriately chosen for the top quark and the W boson. The asymmetry measurements are performed at parton level by correcting the observed angular distributions for detector effects and hadronisation after subtracting the background contributions. Here, the measured top-quark and W -boson polarisation values are in agreement with the Standard Model predictions. Limits on the imaginary part of the anomalous coupling gR are also set from model-independent measurements.« less

  9. Probing the W tb vertex structure in t-channel single-top-quark production and decay in pp collisions at √s=8 TeV with the ATLAS detector

    DOE PAGES

    Aaboud, M; Aad, G; Abbott, B; ...

    2017-04-01

    © 2017, The Author(s). To probe the W tb vertex structure, top-quark and W -boson polarisation observables are measured from t-channel single-top-quark events produced in proton-proton collisions at a centre-of-mass energy of 8 TeV. The dataset corresponds to an integrated luminosity of 20.2 fb −1 , recorded with the ATLAS detector at the LHC. Selected events contain one isolated electron or muon, large missing transverse momentum and exactly two jets, with one of them identified as likely to contain a b-hadron. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from background. The polarisation observables are extracted from asymmetriesmore » in angular distributions measured with respect to spin quantisation axes appropriately chosen for the top quark and the W boson. The asymmetry measurements are performed at parton level by correcting the observed angular distributions for detector effects and hadronisation after subtracting the background contributions. The measured top-quark and W -boson polarisation values are in agreement with the Standard Model predictions. Limits on the imaginary part of the anomalous coupling g R are also set from model-independent measurements.[Figure not available: see fulltext.].« less

  10. Search for anomalous couplings in the W tb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector

    SciTech Connect

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Amako, K.; Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. 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B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopczak, A.; Sopko, B.; Sopko, V.; Sorin, V.; Sosa, D.; Sosebee, M.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Spearman, W. R.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Staerz, S.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Succurro, A.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, F. E.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thun, R. P.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Ueda, I.; Ueno, R.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Velz, T.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2016-04-05

    The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb-1 of proton-proton collision data at √s=7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured to be 0.37 ± 0.07 (stat.⊕syst.). The phase δ - between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be -0.014π ± 0.036π (stat.⊕syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g R and V L, yielding Re[g R /V L] ϵ [-0.36, 0.10] and Im[g R /V L] ϵ [-0.17, 0.23] with a correlation of 0.11. We find the results are in good agreement with the predictions of the Standard Model.

  11. A pixel unit-cell targeting 16 ns resolution and radiation hardness in a column read-out particle vertex detector

    SciTech Connect

    Wright, M.; Millaud, J.; Nygren, D.

    1992-10-01

    A pixel unit cell (PUC) circuit architecture, optimized for a column read out architecture, is reported. Each PUC contains an integrator, active filter, comparator, and optional analog store. The time-over-threshold (TOT) discriminator allows an all-digital interface to the array periphery readout while passing an analog measure of collected charge. Use of (existing) radiation hard processes, to build a detector bump-bonded to a pixel readout array, is targeted. Here, emphasis is on a qualitative explanation of how the unique circuit implementation benefits operation for Super Collider (SSC) detector application.

  12. ILC Vertex Tracker R&D

    SciTech Connect

    Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac

    2007-10-01

    This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department

  13. The CDF silicon vertex trigger

    SciTech Connect

    B. Ashmanskas; A. Barchiesi; A. Bardi

    2003-06-23

    The CDF experiment's Silicon Vertex Trigger is a system of 150 custom 9U VME boards that reconstructs axial tracks in the CDF silicon strip detector in a 15 {mu}sec pipeline. SVT's 35 {mu}m impact parameter resolution enables CDF's Level 2 trigger to distinguish primary and secondary particles, and hence to collect large samples of hadronic bottom and charm decays. We review some of SVT's key design features. Speed is achieved with custom VLSI pattern recognition, linearized track fitting, pipelining, and parallel processing. Testing and reliability are aided by built-in logic state analysis and test-data sourcing at each board's input and output, a common inter-board data link, and a universal ''Merger'' board for data fan-in/fan-out. Speed and adaptability are enhanced by use of modern FPGAs.

  14. Optimization of the LHCb track reconstruction

    NASA Astrophysics Data System (ADS)

    Storaci, Barbara

    2015-12-01

    The LHCb track reconstruction uses sophisticated pattern recognition algorithms to reconstruct trajectories of charged particles. Their main feature is the use of a Hough- transform like approach to connect track segments from different sub-detectors, allowing for having no tracking stations in the magnet of LHCb. While yielding a high efficiency, the track reconstruction is a major contributor to the overall timing budget of the software trigger of LHCb, and will continue to be so in the light of the higher track multiplicity expected from Run II of the LHC. In view of this fact, key parts of the pattern recognition have been revised and redesigned. In this document the main features which were studied are presented. A staged approach strategy for the track reconstruction in the software trigger was investigated: it allows unifying complementary sets of tracks coming from the different stages of the high level trigger, resulting in a more flexible trigger strategy and a better overlap between online and offline reconstructed tracks. Furthermore the use of parallelism was investigated, using SIMD instructions for time-critical parts of the software.

  15. Radiative decays at LHCb

    SciTech Connect

    Giubega, L. E.; Collaboration: LHCb Collaboration

    2016-12-15

    Precise measurements on rare radiative B decays are performed with the LHCb experiment at LHC. The LHCb results regarding the ratio of branching fractions for two radiative decays, B{sup 0} → K{sup *0}γ and B{sub s} → ϕγ, the direct CP asymmetry in B{sup 0} → K{sup *0}γ decay channel and the observation of the photon polarization in the B{sup ±} → K{sup ±}π{sup ∓}π{sup ±}γ decay, are included. The first two measurements were performed in 1 fb{sup –1} of pp collisions data and the third one in 3 fb{sup –1} of data, respectively.

  16. Electroweak penguins at LHCb

    NASA Astrophysics Data System (ADS)

    He, Jibo; LHCb Collaboration

    2016-04-01

    Electroweak penguin decays are flavour-changing neutral current processes, and are highly suppressed in the Standard Model. They can only proceed via loop diagrams. Such decays may receive contributions from New Physics and change their decay behaviours like decay rate and angular distribution. Studying the properties of these decays thus provides a powerful method to probe for New Physics. In this contribution the most recent LHCb results on electroweak penguin decays are reported.

  17. Charmonia Production at Lhcb

    NASA Astrophysics Data System (ADS)

    Artamonov, Alexander

    2013-12-01

    In this article we present a short review on measurements of charmonia production at the LHCb experiment carried out during 2010, 2011 and 2012 data taking periods. The review covers the production of J/ψ, ψ(2S), χc, J/ψJ/ψ, as well as J/ψ in association with open charm. We also review the measurement of J/ψ polarization. The results are compared to theoretical predictions.

  18. Recent developments in high precision vertex chambers at SLAC

    SciTech Connect

    Rust, D.R.

    1984-04-01

    Three detectors MARK II, MAC, AND HRS are using or planning small drift chambers placed as close as possible to the interaction print at PEP. There is also a program of development for a gaseous vertex detector for MARK II at SLC. All these programs are reviewed. 13 references.

  19. A large Scintillating Fibre Tracker for LHCb

    NASA Astrophysics Data System (ADS)

    Greim, R.

    2017-02-01

    The LHCb experiment will be upgraded during LHC Long Shutdown 2 to be able to record data at a higher instantaneous luminosity. The readout rate is currently limited to 1 MHz by the Level 1 trigger. In order to achieve the target integrated luminosity of 50 fb-1 during LHC Run 3, all subdetectors have to be read out by a 40 MHz trigger-less readout system. Especially, the current tracking detectors downstream of the LHCb dipole magnet suffer from large detector dead times and a small granularity in the Outer Tracker, which consists of proportional straw tubes. Therefore, the Downstream Tracker will be replaced by a Scintillating Fibre Tracker with Silicon Photomultiplier readout. The total sensitive area of 340 m2 is made up of 2.5 m long fibre mats consisting of six staggered layers of 250 μm thin scintillating fibres. The scintillation light created by the charged particles traversing the fibre mats is transported to the fibre ends via total internal reflection and detected by state-of-the-art multi-channel SiPM arrays. This paper presents the detector concept, design, challenges, custom-made readout chips, as well as laboratory and beam test results.

  20. B-physics prospects with the LHCb experiment

    SciTech Connect

    Harnew, N.

    2008-04-15

    This paper summarizes the B-physics prospects of the LHCb experiment. Firstly, a brief introduction to the CKM matrix and the mechanism of CP violation in the Standard Model is given. The advantages of the LHCb experiment for B-physics exploitation will then be described, together with a short description of the detector components. Finally, the LHCb physics aims and prospects will be summarized, focusing on the measurements of sin(2{beta}) in tree and gluonic penguin diagrams, sin(2{alpha}) in B{sub d}{sup 0} {sup {yields}} {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup 0}, neutral B-meson oscillations and the B{sub s}{sup 0} mixing phase, and the measurement of {gamma} using a variety of complementary methods.

  1. Prospect of D0 Mixing and Cpv at LHCb

    NASA Astrophysics Data System (ADS)

    Spradlin, Patrick

    Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm studies, recording enormous statistics with a detector tailored for flavor physics. This article presents recent charm CPV and mixing studies from LHCb, including LHCb's first CP asymmetry measurement with 37 pb-1 of data collected in 2010. The difference of the CP asymmetries of D0 decays to the K-K+ and π-π+ final states is determined to be Δ {A}CP = (-0.28 ± 0.70 ± 0.25 ) updates to the material presented at the 4th International Workshop on Charm Physics are included.

  2. LHCb calorimeters high voltage system

    NASA Astrophysics Data System (ADS)

    Gilitsky, Yu.; Golutvin, A.; Konoplyannikov, A.; Lefrancois, J.; Perret, P.; Schopper, A.; Soldatov, M.; Yakimchuk, V.

    2007-02-01

    The calorimeter system in LHCb aims to identify electrons, photons and hadrons. All calorimeters are equipped with Hamamatsu photo tubes as devices for light to signal conversion. Eight thousand R7899-20 tubes are used for electromagnetic and hadronic calorimeters and two hundred 64 channels multi-anode R7600-00-M64 for Scintillator-Pad/Preshower detectors. The calorimeter high voltage (HV) system is based on a Cockroft Walton (CW) voltage converter and a control board connected to the Experiment Control System (ECS) by serial bus. The base of each photomultiplier tube (PMT) is built with a high voltage converter and constructed on an individual printed circuit board, using compact surface mount components. The base is attached directly to the PMT. There are no HV cables in the system. A Field Programmable Gate Array (FPGA) is used on the control board as an interface between the ECS and the 200 control channels. The FPGA includes also additional functionalities allowing automated monitoring and ramp up of the high voltage values. This paper describes the HV system architecture, some technical details of the electronics implementation and summarizes the system performance. This safe and low power consumption HV electronic system for the photomultiplier tubes can be used for various biomedical apparatus too.

  3. Biricodar. Vertex Pharmaceuticals.

    PubMed

    Dey, Saibal

    2002-05-01

    Vertex is developing biricodar as a chemosensitizing agent designed to restore the effectiveness of chemotherapeutic agents in tumor multidrug resistance. By November 1998, phase II trials had commenced for biricodar, in combination with chemotherapy, for five common cancer indications: breast, ovarian, soft-tissue sarcomas, small cell lung cancer and prostate cancer. Phase II trials were ongoing in January 2002. By March 2000, Vertex was the sole developer of biricodar, as an agreement made in 1996 with BioChem Pharma (now Shire Pharmaceuticals), for the development and marketing of biricodar in Canada was terminated. Biricodar is the free base compound, which also has a citrate salt analog known as VX-710-3. Vertex has published three patents, WO-09615101, WO-09636630 and WO-09736869, disclosing derivatives of biricodar that are claimed for the treatment of multidrug resistant protein and P-glycoprotein-mediated multidrug resistant tumors. In January 2002, a Banc of America analyst report forecast that biricodar had a 30% chance of reaching the market with a launch date in the second half of 2005, with peak sales estimated at $250 million.

  4. LHCb Topological Trigger Reoptimization

    NASA Astrophysics Data System (ADS)

    Likhomanenko, Tatiana; Ilten, Philip; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; Williams, Michael

    2015-12-01

    The main b-physics trigger algorithm used by the LHCb experiment is the so- called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger, which utilized a custom boosted decision tree algorithm, selected a nearly 100% pure sample of b-hadrons with a typical efficiency of 60-70%; its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and neural networks. The topological trigger algorithm is designed to select all ’interesting” decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. Methods studied include cascading, ensembling and blending techniques. Furthermore, novel boosting techniques have been implemented that will help reduce systematic uncertainties in Run 2 measurements. We demonstrate that the reoptimized topological trigger is expected to significantly improve on the Run 1 performance for a wide range of b-hadron decays.

  5. Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

    NASA Astrophysics Data System (ADS)

    Baszczyk, M. K.; Benettoni, M.; Calabrese, R.; Cardinale, R.; Carniti, P.; Cassina, L.; Cavallero, G.; Cojocariu, L.; Cotta Ramusino, A.; D'Ambrosio, C.; Dorosz, P. A.; Easo, S.; Eisenhardt, S.; Fiorini, M.; Frei, C.; Gambetta, S.; Gibson, V.; Gotti, C.; Harnew, N.; He, J.; Keizer, F.; Kucewicz, W.; Maciuc, F.; Maino, M.; Malaguti, R.; Matteuzzi, C.; McCann, M.; Morris, A.; Muheim, F.; Papanestis, A.; Pessina, G.; Petrolini, A.; Piedigrossi, D.; Pistone, A.; Placinta, V. M.; Sigurdsson, S.; Simi, G.; Smith, J.; Spradlin, P.; Tomassetti, L.; Wotton, S. A.

    2017-01-01

    The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  6. LHCb experience with LFC replication

    NASA Astrophysics Data System (ADS)

    Bonifazi, F.; Carbone, A.; Perez, E. D.; D'Apice, A.; dell'Agnello, L.; Duellmann, D.; Girone, M.; Re, G. L.; Martelli, B.; Peco, G.; Ricci, P. P.; Sapunenko, V.; Vagnoni, V.; Vitlacil, D.

    2008-07-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  7. LHCb Tag Collector

    NASA Astrophysics Data System (ADS)

    Fuente Fernández, Paloma; Clemencic, Marco; Cousin, Nicolas; LHCb Collaboration

    2011-12-01

    The LHCb physics software consists of hundreds of packages, each of which is developed by one or more physicists. When the developers have some code changes that they would like released, they commit them to the version control system, and enter the revision number into a database. These changes have to be integrated into a new release of each of the physics analysis applications. Tests are then performed by a nightly build system, which rebuilds various configurations of the whole software stack and executes a suite of run-time functionality tests. A Tag Collector system has been developed using solid standard technologies to cover both the use cases of developers and integration managers. A simple Web interface, based on an AJAX-like technology, is available. Integration with SVN and Nightly Build System, is possible via a Python API. Data are stored in a relational database with the help of an ORM (Object-Relational Mapping) library.

  8. B Decay Charm Counting via Topological Vertexing

    SciTech Connect

    Chou, Aaron S

    2001-10-15

    We present a new and unique measurement of the branching fractions of b hadrons to states with 0, 1, and 2 open charm hadrons, using a sample of 350,000 hadronic Z{sup 0} decays collected during the SLD/SLC 97-98 run. The method takes advantage of the excellent vertexing resolution of the VXD3, a pixel-based CCD vertex detector, which allows the separation of B and cascade D decay vertices. A fit of the vertex count and the decay length distributions to distribution shapes predicted by Monte Carlo simulation allows the extraction of the inclusive branching fractions. We measure: BR(B {yields} (0D)X) = (3.7{+-}1.1(stat) {+-} 2.1(syst))%; and BR(B {yields} (2D)X) = (17.9{+-}1.4(stat) {+-} 3.3(syst))% where B and D represent mixtures of open b and open c hadrons. The corresponding charm count, N{sub c} = 1.188 {+-} 0.010 {+-} 0.040 {+-} 0.006 is consistent with previous measurement averages but slightly closer to theoretical expectations.

  9. The Mark II Vertex Drift Chamber

    SciTech Connect

    Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

  10. Magnetic wormholes and vertex operators

    SciTech Connect

    Singh, H. )

    1994-10-15

    We consider wormhole solutions in 2+1 Euclidean dimensions. A duality transformation is introduced to derive a new action from the magnetic wormhole action of Gupta, Hughes, Preskill, and Wise. The classical solution is presented. The vertex operators corresponding to the wormhole are derived. Conformally coupled scalars and spinors are considered in the wormhole background and the vertex operators are computed.

  11. SIMD studies in the LHCb reconstruction software

    NASA Astrophysics Data System (ADS)

    Cámpora Pérez, Daniel Hugo; Couturier, Ben

    2015-12-01

    During the data taking process in the LHC at CERN, millions of collisions are recorded every second by the LHCb Detector. The LHCb Online computing farm, counting around 15000 cores, is dedicated to the reconstruction of the events in real-time, in order to filter those with interesting Physics. The ones kept are later analysed Offline in a more precise fashion on the Grid. This imposes very stringent requirements on the reconstruction software, which has to be as efficient as possible. Modern CPUs support so-called vector-extensions, which extend their Instruction Sets, allowing for concurrent execution across functional units. Several libraries expose the Single Instruction Multiple Data programming paradigm to issue these instructions. The use of vectorisation in our codebase can provide performance boosts, leading ultimately to Physics reconstruction enhancements. In this paper, we present vectorisation studies of significant reconstruction algorithms. A variety of vectorisation libraries are analysed and compared in terms of design, maintainability and performance. We also present the steps taken to systematically measure the performance of the released software, to ensure the consistency of the run-time of the vectorised software.

  12. SVT: an online silicon vertex tracker for the CDF upgrade

    SciTech Connect

    Bardi, A.; Belforte, S.; Berryhill, J.; CDF Collaboration

    1997-07-01

    The SVT is an online tracker for the CDF upgrade which will reconstruct 2D tracks using information from the Silicon VerteX detector (SVXII) and Central Outer Tracker (COT). The precision measurement of the track impact parameter will then be used to select and record large samples of B hadrons. We discuss the overall architecture, algorithms, and hardware implementation of the system.

  13. A measurement of the Z sup 0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at E sub cm = 91 GeV

    SciTech Connect

    Koetke, D.S.

    1992-06-01

    Using the precision vertex detectors of the Mark 2 at the SLC, an impact parameter tag was developed to select a sample of hadronic Z{degree} decays enriched in its fraction of bottom quark events. The nominal tagging method requires that there be at least three tracks whose impact parameters are inconsistent with the track having originated at the electron-position interaction point. A tagging efficiency for b{bar b} events of 50% with a enriched sample purity of 85% was achieved. This impact parameter tag was used to measure the fraction hadronic Z{degree} decays which produce b{bar b} events, F{sub b}. It is found that F{sub b} = 0.232{sub {minus}0.045}{sup +0.053} (stat) {sub {minus}0.021}{sup +0.025} (syst). This result is consistent with those found using other tagging methods as well as the Standard Model prediction of 0.217. The b{bar b}-enriched event sample was also used to measure the difference between the average charged multiplicity of b{bar b} events and that of all hadronic Z{degree} decays, {delta}{bar n}{sub b} = 2.11 {plus minus} 1.82(stat) {plus minus} 0.57(syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b{bar b} events is {bar n}{sub b}=23.05 {plus minus} 1.82 (stat) {plus minus} 0.60 (syst). Subtracting the contribution to the multiplicity from B hadron decays yields the multiplicity of the b{bar b} non-leading system, {bar n}{sub nl} = 12.04 {plus minus} 1.82 (stat) {plus minus} 0.63(syst). Comparing this non-leading multiplicity to the total hadronic multiplicity data at lower energy supports the hypothesis that the non-leading particle production is independent of the flavor of the initial quarks.

  14. A measurement of the Z{sup 0} hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at E{sub cm} = 91 GeV

    SciTech Connect

    Koetke, D.S.

    1992-06-01

    Using the precision vertex detectors of the Mark 2 at the SLC, an impact parameter tag was developed to select a sample of hadronic Z{degree} decays enriched in its fraction of bottom quark events. The nominal tagging method requires that there be at least three tracks whose impact parameters are inconsistent with the track having originated at the electron-position interaction point. A tagging efficiency for b{bar b} events of 50% with a enriched sample purity of 85% was achieved. This impact parameter tag was used to measure the fraction hadronic Z{degree} decays which produce b{bar b} events, F{sub b}. It is found that F{sub b} = 0.232{sub {minus}0.045}{sup +0.053} (stat) {sub {minus}0.021}{sup +0.025} (syst). This result is consistent with those found using other tagging methods as well as the Standard Model prediction of 0.217. The b{bar b}-enriched event sample was also used to measure the difference between the average charged multiplicity of b{bar b} events and that of all hadronic Z{degree} decays, {delta}{bar n}{sub b} = 2.11 {plus_minus} 1.82(stat) {plus_minus} 0.57(syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b{bar b} events is {bar n}{sub b}=23.05 {plus_minus} 1.82 (stat) {plus_minus} 0.60 (syst). Subtracting the contribution to the multiplicity from B hadron decays yields the multiplicity of the b{bar b} non-leading system, {bar n}{sub nl} = 12.04 {plus_minus} 1.82 (stat) {plus_minus} 0.63(syst). Comparing this non-leading multiplicity to the total hadronic multiplicity data at lower energy supports the hypothesis that the non-leading particle production is independent of the flavor of the initial quarks.

  15. On Making a Distinguished Vertex Minimum Degree by Vertex Deletion

    NASA Astrophysics Data System (ADS)

    Betzler, Nadja; Bredereck, Robert; Niedermeier, Rolf; Uhlmann, Johannes

    For directed and undirected graphs, we study the problem to make a distinguished vertex the unique minimum-(in)degree vertex through deletion of a minimum number of vertices. The corresponding NP-hard optimization problems are motivated by applications concerning control in elections and social network analysis. Continuing previous work for the directed case, we show that the problem is W[2]-hard when parameterized by the graph's feedback arc set number, whereas it becomes fixed-parameter tractable when combining the parameters "feedback vertex set number" and "number of vertices to delete". For the so far unstudied undirected case, we show that the problem is NP-hard and W[1]-hard when parameterized by the "number of vertices to delete". On the positive side, we show fixed-parameter tractability for several parameterizations measuring tree-likeness, including a vertex-linear problem kernel with respect to the parameter "feedback edge set number". On the contrary, we show a non-existence result concerning polynomial-size problem kernels for the combined parameter "vertex cover number and number of vertices to delete", implying corresponding nonexistence results when replacing vertex cover number by treewidth or feedback vertex set number.

  16. First results with charmless two-body B-decays at LHCb, and future prospects

    ScienceCinema

    None

    2016-07-12

    LHCb is an experiment which is designed to perform flavour physics measurements at the LHC. Charged two-body charmless B decays (e.g. B^0 -> Kpi, pipi, B_s->KK, etc) receive significant contributions from loop diagrams and are thus sensitive probes of New Physics. Study of these modes is therefore an important physics goal of LHCb. First results will be presented, using around 37 pb^{-1} of data collected at \\sqrt{s}=7 TeV in 2010. These results illustrate the power of the LHCb trigger system and particle identification capabilities of the RICH detectors in isolating clean samples of each final state, and include preliminary measurements of direct CP-violation in certain key modes. The prospects for these measurements in the coming run will be presented. A brief survey will also be given of results and prospect in other areas of the LHCb physics programme.

  17. First results with charmless two-body B-decays at LHCb, and future prospects

    SciTech Connect

    2011-02-22

    LHCb is an experiment which is designed to perform flavour physics measurements at the LHC. Charged two-body charmless B decays (e.g. B^0 -> Kpi, pipi, B_s->KK, etc) receive significant contributions from loop diagrams and are thus sensitive probes of New Physics. Study of these modes is therefore an important physics goal of LHCb. First results will be presented, using around 37 pb^{-1} of data collected at \\sqrt{s}=7 TeV in 2010. These results illustrate the power of the LHCb trigger system and particle identification capabilities of the RICH detectors in isolating clean samples of each final state, and include preliminary measurements of direct CP-violation in certain key modes. The prospects for these measurements in the coming run will be presented. A brief survey will also be given of results and prospect in other areas of the LHCb physics programme.

  18. Detectors

    DOEpatents

    Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan; Allander, Krag

    2002-01-01

    The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

  19. The RAVE/VERTIGO vertex reconstruction toolkit and framework

    NASA Astrophysics Data System (ADS)

    Waltenberger, W.; Mitaroff, W.; Moser, F.; Pflugfelder, B.; Riedel, H. V.

    2008-07-01

    A detector-independent toolkit for vertex reconstruction (RAVE1) is being developed, along with a standalone framework (VERTIGO2) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.

  20. Ab initio dynamical vertex approximation

    NASA Astrophysics Data System (ADS)

    Galler, Anna; Thunström, Patrik; Gunacker, Patrik; Tomczak, Jan M.; Held, Karsten

    2017-03-01

    Diagrammatic extensions of dynamical mean-field theory (DMFT) such as the dynamical vertex approximation (DΓ A) allow us to include nonlocal correlations beyond DMFT on all length scales and proved their worth for model calculations. Here, we develop and implement an Ab initio DΓ A approach (AbinitioDΓ A ) for electronic structure calculations of materials. The starting point is the two-particle irreducible vertex in the two particle-hole channels which is approximated by the bare nonlocal Coulomb interaction and all local vertex corrections. From this, we calculate the full nonlocal vertex and the nonlocal self-energy through the Bethe-Salpeter equation. The AbinitioDΓ A approach naturally generates all local DMFT correlations and all nonlocal G W contributions, but also further nonlocal correlations beyond: mixed terms of the former two and nonlocal spin fluctuations. We apply this new methodology to the prototypical correlated metal SrVO3.

  1. Vertex upgrading problems for VLSI

    SciTech Connect

    Paik, D.

    1991-01-01

    The author examines vertex modification (splitting, deleting and upgrading) problems that arise in VLSI CAD and other application areas. The problems he considers differ from previously studied vertex-deletion problems in that he is interested in modifying vertices in a dag so that the resulting dag has no path whose length exceeds a prespecified amount. Vertex-modification problems can be used to model the scan register placement problem in VLSI design, placement of signal boosters in lossy circuits, satellite uplink/downlink placement in communication networks, etc. The approach adopted is to first determine which of these problems are NP-hard. Pseudo polynomial time algorithms and fast heuristics for the NP-hard versions are explored. Fast polynomial time algorithms for other versions are developed. Experimentation using the ISCAS benchmark circuits are also performed.

  2. Silicon drift devices for track and vertex detection at the SSC

    SciTech Connect

    Chen, W.; Kraner, H.; Li, Z.; Ng, C.; Radeka, V.; Rehak, P.; Rescia, S. ); Clark, J.; Henderson, S.; Hsu, L.; Oliver, J.; Wilson, R. ); Clemen, M.; Humanic, T.; Kraus, D.; Vilkelis, G.; Yu, B. ); McDonald, K.; Lu, C.; Wall, M. ); Vacchi, A. ); Bert

    1990-01-01

    We report on the recent progress in the study of Semiconductor Drift (Memory) Detectors intended for an inner tracking and vertexing system for the SSC. The systematic studies and the calibration of the existing detectors and the simulated performance in the actual SSC environment are highlighted. 5 refs., 22 figs., 1 tab.

  3. Vertex Models of Epithelial Morphogenesis

    PubMed Central

    Fletcher, Alexander G.; Osterfield, Miriam; Baker, Ruth E.; Shvartsman, Stanislav Y.

    2014-01-01

    The dynamic behavior of epithelial cell sheets plays a central role during numerous developmental processes. Genetic and imaging studies of epithelial morphogenesis in a wide range of organisms have led to increasingly detailed mechanisms of cell sheet dynamics. Computational models offer a useful means by which to investigate and test these mechanisms, and have played a key role in the study of cell-cell interactions. A variety of modeling approaches can be used to simulate the balance of forces within an epithelial sheet. Vertex models are a class of such models that consider cells as individual objects, approximated by two-dimensional polygons representing cellular interfaces, in which each vertex moves in response to forces due to growth, interfacial tension, and pressure within each cell. Vertex models are used to study cellular processes within epithelia, including cell motility, adhesion, mitosis, and delamination. This review summarizes how vertex models have been used to provide insight into developmental processes and highlights current challenges in this area, including progressing these models from two to three dimensions and developing new tools for model validation. PMID:24896108

  4. A Macdonald refined topological vertex

    NASA Astrophysics Data System (ADS)

    Foda, Omar; Wu, Jian-Feng

    2017-07-01

    We consider the refined topological vertex of Iqbal et al (2009 J. High Energy Phys. JHEP10(2009)069), as a function of two parameters ≤ft\\lgroup x, y \\right\\rgroup , and deform it by introducing the Macdonald parameters ≤ft\\lgroup q, t \\right\\rgroup , as in the work of Vuletić on plane partitions (Vuletić M 2009 Trans. Am. Math. Soc. 361 2789-804), to obtain ‘a Macdonald refined topological vertex’. In the limit q → t , we recover the refined topological vertex of Iqbal et al and in the limit x → y , we obtain a qt-deformation of the original topological vertex of Aganagic et al (2005 Commun. Math. Phys. 25 425-78). Copies of the vertex can be glued to obtain qt-deformed 5D instanton partition functions that have well-defined 4D limits and, for generic values of ≤ft\\lgroup q, t\\right\\rgroup , contain infinite-towers of poles for every pole present in the limit q → t .

  5. Neutral B-meson Mixing and CP Violation at LHCb

    NASA Astrophysics Data System (ADS)

    Oblakowska-Mucha, A.; LHCb Collaboration

    2016-11-01

    The LHCb detector is a single-arm forward spectrometer that collects data at the LHC, designed for studies of flavour physics with high precision. We present a selection of recent measurements of mixing and CP-violating parameters, including sin 2β and weak phase ϕ s, using several decays. A good understanding of the pollution from sub-leading penguin to pologies in these measurements can be achieved by measuring CP violation and polarization in the decay Bs 0→Jψ⁄K 0* and B 0→Jψ⁄ ρ 0. All results here presented are obtained using the full Run I dataset.

  6. SciFi - A large scintillating fibre tracker for LHCb

    NASA Astrophysics Data System (ADS)

    Kirn, Thomas

    2017-02-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. Concept, design and operational parameters are driven by the challenging LHC environment including significant ionising and neutron radiation levels. Over a total active surface of 360 m2 the SciFi Tracker will use scintillating fibres (∅ = 0.25 mm) read out by state-of-the-art multi-channel Silicon Photomultipliers (SiPMs) arrays. A custom ASIC will be used to digitise the signals from the SiPMs. The project is now at the transition from R&D to series production. We will present the evolution of the design and the latest lab and test beam results.

  7. Production, measurement and simulation of a low mass flex cable for multi gigabit/s readout for the LHCb VELO upgrade

    NASA Astrophysics Data System (ADS)

    Lemos Cid, E.; Buytaert, J.; Gallas Torreira, A. A.; Esperante Pereira, D.; Ronning, P. Arne; Visniakov, J.; Sanchez, M. G.; Vazquez Regueiro, P.

    2013-01-01

    The goal of this project is to examine the feasibility of data transmission up to ~ 5 Gbit/s on a short ( ~ 60 cm) low mass flex cable, for the readout of the upgraded vertex detector (VELO) of the LHCb experiment. They will be in a vacuum and very high radiation environment and also partly in the particle acceptance. For the full system 1600 readout links will be required. A set of single-ended and differential (edge-coupled) striplines, with a variety of line parameters have been prototyped using a material specifically tailored for this type of application (Dupont Pyralux AP-plus polyimide). To reduce mass, the total thickness of the cable is kept to 0.7 mm. We will present measurements of the characteristic impedance, insertion and return loss, obtained both from time and frequency domain, as well as a comparison with simulations and expectations. Also the effectiveness of grounded guard traces and the use of ground via holes to reduce crosstalk will be reported. From the measurements we were also able to extract the material properties such as the dielectric constant and loss factor up to several GHz. The measurements were done with a Vector Network Analyzer (VNA), TDR/TDT Digital Sampling Oscilloscope, serial PRBS generator and analyzer for eye diagram and CAD tools such as Agilent ADS and ANSYS HFSS simulators.

  8. The LHCb Experience on the Grid from the DIRAC Accounting Data

    NASA Astrophysics Data System (ADS)

    Casajús, Adrian; Graciani, Ricardo; Puig, Albert; Vázquez, Ricardo; LHCb Collaboration

    2011-12-01

    DIRAC is the software framework developed by LHCb to manage all its computing operations on the Grid. Since 2003 it has been used for large scale Monte Carlo simulation productions and for user analysis of these data. Since the end of 2009, with the start-up of LHC, DIRAC also takes care of the distribution, reconstruction, selection and analysis of the physics data taken by the detector apparatus. During 2009, DIRAC executed almost 5 million jobs for LHCb. In order to execute this workload slightly over 6 million of pilot jobs were submitted, out of which approximately one third were aborted by the Grid infrastructure. In 2010, thanks to their improved efficiency, DIRAC pilots are able, on average, to match and execute between 2 and 3 LHCb jobs during their lifetime, largely reducing the load on the Grid infrastructure. Given the large amount of submitted jobs and used resources, it becomes essential to store detailed information about their execution to track the behaviour of the system. The DIRAC Accounting system takes care, among other things, to collect and store data concerning the execution of jobs and pilots, making it available to everyone via the public interface of the LHCb DIRAC web portal in the form of time-binned accumulated distributions. The analysis of the raw accounting data stored allow us to improve and debug the system performance, as well as, to give a detailed picture on how LHCb uses its Grid resources. A new tool has been developed to extract the raw records from the DIRAC Accounting database and to transform them into ROOT files for subsequent study. This contribution presents an analysis of such data both for LHCb jobs and the corresponding pilots, including resource usage, number of pilots per job, job efficiency and other relevant variables that will help to further improving the LHCb Grid experience.

  9. A Novel Vertex Affinity for Community Detection

    SciTech Connect

    Yoo, Andy; Sanders, Geoffrey; Henson, Van; Vassilevski, Panayot

    2015-10-05

    We propose a novel vertex affinity measure in this paper. The new vertex affinity quantifies the proximity between two vertices in terms of their clustering strength and is ideal for such graph analytics applications as community detection. We also developed a framework that combines simple graph searches and resistance circuit formulas to compute the vertex affinity efficiently. We study the properties of the new affinity measure empirically in comparison to those of other popular vertex proximity metrics. Our results show that the existing metrics are ill-suited for community detection due to their lack of fundamental properties that are essential for correctly capturing inter- and intra-cluster vertex proximity.

  10. A nonperturbative fermion-boson vertex

    NASA Astrophysics Data System (ADS)

    Bashir, A.; Raya, A.

    2002-07-01

    We calculate the massive fermion propagator at one-loop order in QED3. The Ward-Takahashi identity (WTI) relates the propagator to the vertex. This allows us to split the vertex into its longitudinal and transverse parts. The former is fixed by the WTI. Following the scheme of Ball and Chiu later modified by Kizilersu et. al., we calculate the full vertex at one-loop order. A mere subtraction of the longitudinal part of the vertex gives us the transverse part. The alpha dependence in the transverse vertex can be eliminated by making use of the perturbative expressions for the wavefunction renormalization function and the mass function of complicated arguments of the incoming and outgoing fermion momenta. This leads us to a vertex which is nonperturbative in nature. We also calculate an effective vertex for which the arguments of the unknown functions have no angular dependence, making it particularly suitable for numerical studies of dynamical symmetry breaking.

  11. Refining the shifted topological vertex

    SciTech Connect

    Drissi, L. B.; Jehjouh, H.; Saidi, E. H.

    2009-01-15

    We study aspects of the refining and shifting properties of the 3d MacMahon function C{sub 3}(q) used in topological string theory and BKP hierarchy. We derive the explicit expressions of the shifted topological vertex S{sub {lambda}}{sub {mu}}{sub {nu}}(q) and its refined version T{sub {lambda}}{sub {mu}}{sub {nu}}(q,t). These vertices complete results in literature.

  12. Forward Tracking with the silicon vertex detector at the CDF experiment in RUN II. Spurrekonstruktion in Vorwärtsrichtung mit dem Silizium-Vertexdetektor des CDF-Experiments in RUN II

    SciTech Connect

    Scheidle, Thorsten

    2007-02-01

    The Standard Model of particle physics describes the fundamental particles of matter and their interactions. In order to test the Standard Model, determine free parameters and search for new particles beyond the Standard Model, large accelerator complexes produce particle collisions which are recorded by large detectors. Until the start of the Large Hadron Collider at CERN, the Tevatron accelerator at Fermilab provides particle collisions with the highest center-of-mass energy of √s = 1.96 TeV. The two multipurpose detector systems CDF and DØ record the collisions. A multipurpose detector system is built of several specialized sub-detectors to measure different particle properties. A particle which passes the detector deposits energy by interacting with the detector material. A silicon strip detector and a wire drift chamber detect charged particles close to the collision point. The energy loss in these systems is relatively small, instead many different small energy depositions are produced by one passing particle. These so-called hits can be combined to a track, indicating the path of the particle. A homogeneous magnetic field surrounding the tracking system forces a charged particle to a helix path which allows a momentum measurement by measuring the curvature. The reconstruction of particle tracks is a non-trivial task. First all position measurements belonging to a particle along a hypothetical helix have to be found and then all position information has to be combined to a reconstructed track and its parameters. I focused my work on the track reconstruction in the silicon detector which provides a good position resolution of the measurements.

  13. Performance of the CDF Online Silicon Vertex Tracker

    SciTech Connect

    R. Carosi et al.

    2002-03-27

    The Online Silicon Vertex Tracker (SVT) is the new trigger processor dedicated to the 2-D reconstruction of charged particle trajectories at the Level 2 of the CDF trigger. The SVT links the digitized pulse heights found within the Silicon Vertex detector to the tracks reconstructed in the Central Outer Tracker by the Level 1 fast track finder. Preliminary tests of the system took place during the October 2000 commissioning run of the Tevatron Collider. During the April-October 2001 data taking it was possible to evaluate the performance of the system. In this paper we review the tracking algorithms implemented in the SVT and we report on the performance achieved during the early phase of run II.

  14. Pentaquarks and Tetraquarks at LHCb

    NASA Astrophysics Data System (ADS)

    Stone, S.

    Exotic resonant structures found in $\\Lambda^0_b$ and $\\overline{B}^0$ decays into charmonium in the LHCb experiment are discussed. Examination of the $J/\\psi p$ system in $\\Lambda^0_b\\to J/\\psi K^- p$ decays shows two states each of which must be composed of $uudc\\overline{c}$ quarks, and thus are called charmonium pentaquarks. Their masses are $4380\\pm 8\\pm 29$~MeV and $4449.8\\pm 1.7\\pm 2.5$~MeV, and their corresponding widths ($\\Gamma$) are $205\\pm 18\\pm 86$ MeV, and $39\\pm 5\\pm 19$ MeV. The preferred $J^P$ assignments are of opposite parity, with one state having spin 3/2 and the other 5/2. Models of internal binding of the pentaquark states are discussed. Finally, another mesonic state is discussed, the $Z(4430)^-$ that decays into $\\psi' \\pi^-$ and was first observed by the Belle collaboration in $B^0\\to \\psi' K^+\\pi^-$ decays. Using a sample of approximately 25,000 signal events, LHCb determines the $J^{P}$ to be $1^{+}$.

  15. Spinfoam Cosmology with the Proper Vertex

    NASA Astrophysics Data System (ADS)

    Vilensky, Ilya

    2017-01-01

    A modification of the EPRL vertex amplitude in the spin-foam framework of quantum gravity - so-called ``proper vertex amplitude'' - has been developed to enable correct semi-classical behavior to conform to the classical Regge calculus. The proper vertex amplitude is defined by projecting to the single gravitational sector. The amplitude is recast into an exponentiated form and we derive the asymptotic form of the projector part of the action. This enables us to study the asymptotics of the proper vertex by applying extended stationary phase methods. We use the proper vertex amplitude to investigate transition amplitudes between coherent quantum boundary states of cosmological geometries. In particular, Hartle-Hawking no-boundary states are computed in the proper vertex framework. We confirm that in the classical limit the Hartle-Hawking wavefunction satisfies the Hamiltonian constraint. Partly supported by NSF grants PHY-1205968 and PHY-1505490.

  16. Vertex representations of quantum affine algebras.

    PubMed

    Frenkel, I B; Jing, N

    1988-12-01

    We construct vertex representations of quantum affine algebras of ADE type, which were first introduced in greater generality by Drinfeld and Jimbo. The limiting special case of our construction is the untwisted vertex representation of affine Lie algebras of Frenkel-Kac and Segal. Our representation is given by means of a new type of vertex operator corresponding to the simple roots and satisfying the defining relations. In the case of the quantum affine algebra of type A, we introduce vertex operators corresponding to all the roots and determine their commutation relations. This provides an analogue of a Chevalley basis of the affine Lie algebra [unk](n) in the basic representation.

  17. Prospects for the search of at LHCb

    NASA Astrophysics Data System (ADS)

    Lucio Martinez, Miriam

    2017-01-01

    The sensitivity of the LHCb experiment to is analyzed in light of the 2011, 2012 and 2016 data and the oportunity of having a full software trigger with the LHCb upgrade. Two strategies are considered: the full reconstruction of the decay products and the partial reconstruction using only the dilepton pair and kinematic constraints. In both cases, the sensitivity achieved can surpass the world's current best measurement. Both approaches could be statistically combined to further improve the result.

  18. Displaced vertex searches for sterile neutrinos at future lepton colliders

    NASA Astrophysics Data System (ADS)

    Antusch, Stefan; Cazzato, Eros; Fischer, Oliver

    2016-12-01

    We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC's Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as 10-11.

  19. DIRAC: reliable data management for LHCb

    NASA Astrophysics Data System (ADS)

    Smith, A. C.; Tsaregorodtsev, A.

    2008-07-01

    DIRAC, LHCb's Grid Workload and Data Management System, utilizes WLCG resources and middleware components to perform distributed computing tasks satisfying LHCb's Computing Model. The Data Management System (DMS) handles data transfer and data access within LHCb. Its scope ranges from the output of the LHCb Online system to Grid-enabled storage for all data types. It supports metadata for these files in replica and bookkeeping catalogues, allowing dataset selection and localization. The DMS controls the movement of files in a redundant fashion whilst providing utilities for accessing all metadata. To do these tasks effectively the DMS requires complete self integrity between its components and external physical storage. The DMS provides highly redundant management of all LHCb data to leverage available storage resources and to manage transient errors in underlying services. It provides data driven and reliable distribution of files as well as reliable job output upload, utilizing VO Boxes at LHCb Tier1 sites to prevent data loss. This paper presents several examples of mechanisms implemented in the DMS to increase reliability, availability and integrity, highlighting successful design choices and limitations discovered.

  20. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb.

    PubMed

    Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Anderson, J; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; d'Argent, P; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Birnkraut, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Borsato, M; Bowcock, T J V; Bowen, E; Bozzi, C; Brett, D; Britsch, M; Britton, T; Brodzicka, J; Brook, N H; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casanova Mohr, R; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chefdeville, M; Chen, S; Cheung, S F; Chiapolini, N; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Counts, I; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dalseno, J; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Silva, W; De Simone, P; Dean, C T; Decamp, D; Deckenhoff, M; Del Buono, L; Déléage, N; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Di Ruscio, F; Dijkstra, H; Donleavy, S; Dordei, F; Dorigo, M; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dreimanis, K; Dujany, G; Dupertuis, F; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Färber, C; Farinelli, C; Farley, N; Farry, S; Fay, R; Ferguson, D; Fernandez Albor, V; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fol, P; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garofoli, J; Garra Tico, J; Garrido, L; Gascon, D; Gaspar, C; Gauld, R; Gavardi, L; Gazzoni, G; Geraci, A; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianelle, A; Gianì, S; Gibson, V; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grillo, L; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Hampson, T; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heijne, V; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hulsbergen, W; Humair, T; Hussain, N; Hutchcroft, D; Hynds, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khanji, B; Khurewathanakul, C; Klaver, S; Klimaszewski, K; Kochebina, O; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kurek, K; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Liles, M; Lindner, R; Linn, C; Lionetto, F; Liu, B; Lohn, S; Longstaff, I; Lopes, J H; Lucchesi, D; Luo, H; Lupato, A; Luppi, E; Lupton, O; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Manning, P; Mapelli, A; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Märki, R; Marks, J; Martellotti, G; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; McSkelly, B; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M N; Mitzel, D S; Molina Rodriguez, J; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Müller, J; Müller, K; Müller, V; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, C J G; Osorio Rodrigues, B; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parkes, C; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Pistone, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rakotomiaramanana, B; Rama, M; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redi, F; Reichert, S; Reid, M M; Dos Reis, A C; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rotondo, M; Rouvinet, J; Ruf, T; Ruiz, H; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schune, M H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sepp, I; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Silva Coutinho, R; Simi, G; Sirendi, M; Skidmore, N; Skillicorn, I; Skwarnicki, T; Smith, E; Smith, E; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Steinkamp, O; Stenyakin, O; Sterpka, F; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Stroili, R; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Tekampe, T; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Todd, J; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Trabelsi, K; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wiedner, D; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L

    A search is performed for heavy long-lived charged particles using 3.0 [Formula: see text] of proton-proton collisions collected at [Formula: see text][Formula: see text] 7 and 8  TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkov detectors to distinguish the heavy, slow-moving particles from muons. No evidence is found for the production of such long-lived states. The results are expressed as limits on the Drell-Yan production of pairs of long-lived particles, with both particles in the LHCb pseudorapidity acceptance, [Formula: see text]. The mass-dependent cross-section upper limits are in the range 2-4 fb (at 95 % CL) for masses between 14 and 309 [Formula: see text].

  1. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A., Jr.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casanova Mohr, R.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S. F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Counts, I.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Dean, C. T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garofoli, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Geraci, A.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Gianì, S.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J. P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M. N.; Mitzel, D. S.; Molina Rodriguez, J.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M. H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepp, I.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Simi, G.; Sirendi, M.; Skidmore, N.; Skillicorn, I.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Sterpka, F.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Stroili, R.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wiedner, D.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.

    2015-12-01

    A search is performed for heavy long-lived charged particles using 3.0 fb^{-1} of proton-proton collisions collected at √{s} = 7 and 8 TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkov detectors to distinguish the heavy, slow-moving particles from muons. No evidence is found for the production of such long-lived states. The results are expressed as limits on the Drell-Yan production of pairs of long-lived particles, with both particles in the LHCb pseudorapidity acceptance, 1.8 < η < 4.9. The mass-dependent cross-section upper limits are in the range 2-4 fb (at 95 % CL) for masses between 14 and 309 { GeV/c^2}.

  2. Measuring the D0 lifetime at the LHCb Masterclass

    NASA Astrophysics Data System (ADS)

    Trišović, Ana

    2016-04-01

    The LHCb Event Display was made for educational purposes at the European Organization for Nuclear Research, CERN in Geneva, Switzerland. The project was implemented as a stand-alone application using C++ and ROOT, a framework developed by CERN for data analysis. This paper outlines the development and architecture of the application in detail, as well as the motivation for the development and the goals of the exercise. The application focuses on the visualization of events recorded by the LHCb detector, where an event represents a set of charged particle tracks in one proton-proton collision. The application allows students to save this information and calculate the invariant mass for any pair of particles. Furthermore, the students can use additional calculating tools in the application and build up a histogram of these invariant masses. The goal for the students is to find a D0 particle in the event, which decays into the two different particles selected by the students. Even if a student doesn't find all the decays successfully, they will be able to complete the exercise and get a meaningful set of results. The application also offers detailed instructions and inline help available in five languages: English, Italian, French, German and Romanian.

  3. Domination Number of Vertex Amalgamation of Graphs

    NASA Astrophysics Data System (ADS)

    Wahyuni, Y.; Utoyo, M. I.; Slamin

    2017-06-01

    For a graph G = (V, E), a subset S of V is called a dominating set if every vertex x in V is either in S or adjacent to a vertex in S. The domination number γ ( G ) is the minimum cardinality of the dominating set of G. The dominating set of G with a minimum cardinality denoted by γ ( G )-set. Let G 1, G 2, …, Gt be subgraphs of the graph G. If the union of all these subgraphs is G and their intersection is {v}, then we say that G is the vertex-amalgamation of G 1, G 2, …, Gt at vertex v. Based on the membership of the common vertex v in the γ ( Gi )-set, there exist three conditions to be considered. First, if v elements of every γ ( Gi )-set, second if there is no γ ( Gi )-set containing v, and third if either v is element of γ ( Gi )-set for 1 ≤ i ≤ p or there is no γ ( Gi )-set containing v for p < i ≤ t . For these three conditions, the domination number of G as vertex-amalgamation of G 1, G 2, …, Gt at vertex v can be determined.

  4. The LHCb Online Framework for Experiment Protection, and Global Operational Control and Monitoring

    NASA Astrophysics Data System (ADS)

    Alessio, F.; Jacobsson, R.; Schleich, S.

    2011-12-01

    The complexity and extreme parameters of the LHC, such as the stored energy, the collision frequency, the high risk of adverse background conditions and potentially damaging beam losses have demanded an unprecedented connectivity between the operation of the accelerator and the experiments at both hardware and software level. LHCb has been at the forefront of developing a software framework and hardware which connects to all of the LHC communication interfaces for timing, control and monitoring of the machine and beam parameters, in addition to its own local systems for beam and background monitoring. The framework also includes failsafe connectivity with the beam interlock system. The framework drives the global operation of the detector and is integrated into the readout control. It provides the shifters with the tools needed to take fast and well-guided decisions to run the LHCb experiment safely and efficiently. In particular, it has allowed the detector to be operated with only two shifters already at the LHC pilot run. The requirements include reliability and clarity for the shifters, and the possibility to retrieve the past conditions for offline analysis. All essential parameters are archived and an interactive analysis tool has been developed which provides overviews of the experimental performance and which allows post-analysis of any anomaly in the operation. This paper describes the architecture and the many functions, including the basis of the automation of the LHCb operational procedure and detector controls, and the information exchange between LHCb and the LHC, and finally the shifter and expert tools for monitoring the experimental conditions.

  5. Lorentzian proper vertex amplitude: Asymptotics

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan; Vilensky, Ilya; Zipfel, Antonia

    2016-09-01

    In previous work, the Lorentzian proper vertex amplitude for a spin-foam model of quantum gravity was derived. In the present work, the asymptotics of this amplitude are studied in the semiclassical limit. The starting point of the analysis is an expression for the amplitude as an action integral with action differing from that in the Engle-Pereira-Rovelli-Livine (EPRL) case by an extra "projector" term. This extra term scales linearly with spins only in the asymptotic limit, and is discontinuous on a (lower dimensional) submanifold of the integration domain in the sense that its value at each such point depends on the direction of approach. New tools are introduced to generalize stationary phase methods to this case. For the case of boundary data which can be glued to a nondegenerate Lorentzian 4-simplex, the asymptotic limit of the amplitude is shown to equal the single Feynman term, showing that the extra term in the asymptotics of the EPRL amplitude has been eliminated.

  6. A New Nightly Build System for LHCb

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Couturier, B.

    2014-06-01

    The nightly build system used so far by LHCb has been implemented as an extension of the system developed by CERN PH/SFT group (as presented at CHEP2010). Although this version has been working for many years, it has several limitations in terms of extensibility, management and ease of use, so that it was decided to develop a new version based on a continuous integration system. In this paper we describe a new implementation of the LHCb Nightly Build System based on the open source continuous integration system Jenkins and report on the experience of configuring a complex build workflow in Jenkins.

  7. An ASIC for fast single photon counting in the LHCb RICH upgrade

    NASA Astrophysics Data System (ADS)

    Gotti, C.

    2017-03-01

    The LHCb experiment will be upgraded during the second LHC long shutdown (years 2019–2020) to operate at higher luminosity. The new triggerless architecture of LHCb requires data from the entire detector to be read out at 40 MHz. The basic element of the front-end electronics of the Ring Imaging Cherenkov (RICH) detector upgrade is the "Elementary Cell" (EC), a readout system for multianode photomultiplier tubes designed to minimise parasitic capacitance at the anodes, to obtain a fast readout with low noise and low crosstalk. At the heart of the EC is the CLARO, an 8 channel, low power and radiation hard front-end ASIC designed in 0.35 μm CMOS technology. Each channel compares the charge signals from the photomultiplier anodes with a programmable threshold, and gives a digital pulse at the output when the threshold is exceeded. Baseline recovery occurs in less than 25 ns for typical single photon signals. In the LHCb RICH upgrade environment, the chips will have to withstand radiation up to a total ionising dose of 2 kGy (200 krad) and neutron and hadron fluences up to 03×112 cm‑2 and following irradiation, the chips have been shown to tolerate such doses with a margin of safety.

  8. The Vertex Algebra M(1)+ and Certain Affine Vertex Algebras of Level -1

    NASA Astrophysics Data System (ADS)

    Adamović, Dražen; Perše, Ozren

    2012-07-01

    We give a coset realization of the vertex operator algebra M(1)^+ with central charge ℓ. We realize M(1) ^+ as a commutant of certain affine vertex algebras of level -1 in the vertex algebra L_{C_{ℓ} ^{(1)}}(-1/2 Λ_0) ⊗ L_{C_{ℓ} ^{(1)}}(-1/2 Λ_0). We show that the simple vertex algebra L_{C_{ℓ} ^{(1)}}(-Λ_0) can be (conformally) embedded into L_{A_{2 ℓ -1} ^{(1)}} (-Λ_0) and find the corresponding decomposition. We also study certain coset subalgebras inside L_{C_{ℓ} ^{(1)}}(-Λ_0).

  9. Calibration of the LHCb calorimetric system

    NASA Astrophysics Data System (ADS)

    Pereima, D.

    2017-06-01

    The calorimeter system of LHCb provides information for the hardware Level-0 trigger for selection of events with high transverse energy electrons, hadrons and photons and also participates in offline particle identification and reconstruction. The main instruments and methods developed for monitoring and calibration of electromagnetic and hadron calorimeters are presented.

  10. LHCb Conditions database operation assistance systems

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Shapoval, I.; Cattaneo, M.; Degaudenzi, H.; Santinelli, R.

    2012-12-01

    The Conditions Database (CondDB) of the LHCb experiment provides versioned, time dependent geometry and conditions data for all LHCb data processing applications (simulation, high level trigger (HLT), reconstruction, analysis) in a heterogeneous computing environment ranging from user laptops to the HLT farm and the Grid. These different use cases impose front-end support for multiple database technologies (Oracle and SQLite are used). Sophisticated distribution tools are required to ensure timely and robust delivery of updates to all environments. The content of the database has to be managed to ensure that updates are internally consistent and externally compatible with multiple versions of the physics application software. In this paper we describe three systems that we have developed to address these issues. The first system is a CondDB state tracking extension to the Oracle 3D Streams replication technology, to trap cases when the CondDB replication was corrupted. Second, an automated distribution system for the SQLite-based CondDB, providing also smart backup and checkout mechanisms for the CondDB managers and LHCb users respectively. And, finally, a system to verify and monitor the internal (CondDB self-consistency) and external (LHCb physics software vs. CondDB) compatibility. The former two systems are used in production in the LHCb experiment and have achieved the desired goal of higher flexibility and robustness for the management and operation of the CondDB. The latter one has been fully designed and is passing currently to the implementation stage.

  11. Quantum vertex model for reversible classical computing

    NASA Astrophysics Data System (ADS)

    Chamon, C.; Mucciolo, E. R.; Ruckenstein, A. E.; Yang, Z.-C.

    2017-05-01

    Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state. We use thermal annealing with and without `learning' to explore typical computational problems. We also construct a mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating an approach to reversible classical computation based on state-of-the-art implementations of quantum annealing.

  12. Quantum vertex model for reversible classical computing.

    PubMed

    Chamon, C; Mucciolo, E R; Ruckenstein, A E; Yang, Z-C

    2017-05-12

    Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state. We use thermal annealing with and without 'learning' to explore typical computational problems. We also construct a mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating an approach to reversible classical computation based on state-of-the-art implementations of quantum annealing.

  13. Quantum vertex model for reversible classical computing

    PubMed Central

    Chamon, C.; Mucciolo, E. R.; Ruckenstein, A. E.; Yang, Z.-C.

    2017-01-01

    Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state. We use thermal annealing with and without ‘learning' to explore typical computational problems. We also construct a mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating an approach to reversible classical computation based on state-of-the-art implementations of quantum annealing. PMID:28497790

  14. The LHCb Simulation Application, Gauss: Design, Evolution and Experience

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Corti, G.; Easo, S.; Jones, C. R.; Miglioranzi, S.; Pappagallo, M.; Robbe, P.; LHCb Collaboration

    2011-12-01

    The LHCb simulation application, Gauss, is based on the Gaudi framework and on experiment basic components such as the Event Model and Detector Description. Gauss also depends on external libraries for the generation of the primary events (PYTHIA 6, EvtGen, etc.) and on GEANT4 for particle transport in the experimental setup. The application supports the production of different types of events from minimum bias to B physics signals and particle guns. It is used for purely generator-level studies as well as full simulations. Gauss is used both directly by users and in massive central productions on the grid. The design and implementation of the application and its evolution due to evolving requirements will be described as in the case of the recently adopted Python-based configuration or the possibility of taking into account detectors conditions via a Simulation Conditions database. The challenge of supporting at the same time the flexibililty needed for the different tasks for which it is used, from evaluation of physics reach to background modeling, together with the stability and reliabilty of the code will also be described.

  15. A Monitoring System for the LHCb Data Flow

    NASA Astrophysics Data System (ADS)

    Barbosa, João; Gaspar, Clara; Jost, Beat; Frank, Markus; Cardoso, Luis G.

    2017-06-01

    The LHCb experiment uses the LHC accelerator for the collisions that produce the physics data necessary for analysis. The data produced by the detector by measuring the results of the collisions at a rate of 40 MHz are read out by a complex data acquisition (DAQ) system, which is summarily described in this paper. Distributed systems of such dimensions rely on monitoring and control systems that account for the numerous faults that can happen throughout the whole operation. With this in mind, a new system was created to extend the monitoring of the readout system, in this case by providing an overview of what is happening in each stage of the DAQ process, starting in the hardware trigger performed right after the detector measurements and ending in the local storage of the experiment. This system, a complement to the current run control (experimental control system), intends to shorten reaction times when a problem occurs by providing the operators with detailed information of where a certain fault is occurring. The architecture of the tool and its utilization by the experiment operators are described in this paper.

  16. Performance of the ALICE secondary vertex b-tagging algorithm

    NASA Astrophysics Data System (ADS)

    Eyyubova, G.; Kramarik, L.

    2016-11-01

    The identification of jets originating from beauty quarks in heavy-ion collisions is important to study the properties of the hot and dense matter produced in such collisions. A variety of algorithms for b-jet tagging was elaborated at the LHC experments. They rely on the properties of B hadrons, i.e. their long lifetime, large mass and large multiplicity of decay products. In this work, the b-tagging algorithm based on displaced secondary-vertex topologies is described. We present Monte Carlo based performance studies of the algorithm for charged jets reconstructed with the ALICE tracking system in p-Pb collisions at √sNN = 5.02 TeV. The tagging efficiency, rejection rate and the correction of the smearing effects of non-ideal detector response are presented.

  17. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  18. The LHCb trigger: Algorithms and performance

    NASA Astrophysics Data System (ADS)

    Ruiz, Hugo; LHCb Collaboration

    2010-11-01

    This article describes the hardware architecture of the LHCb trigger system, as well as the algorithms that it executes in order to identify the relevant B meson decays. The expected performance on simulated data and the trigger commissioning status and plans are also presented. The LHCb trigger consists of two phases: the Level 0 and the High Level Trigger. The former is synchronous and implemented in custom electronics, and it reduces the rate to 1 MHz. The High Level Trigger is a C++ algorithm running in a farm of about 1000 16-core computing nodes and further reducing the rate to 2 kHz. The Level 0 efficiency computed on B meson events that would be offline-selected range between 90% for decays containing muons and 50% for purely hadronic decays, the later suffering from higher light quark backgrounds. Overall High Level Trigger efficiencies range between 60% and 80%.

  19. Pentaquarks and possible anomalies at LHCb

    NASA Astrophysics Data System (ADS)

    Lafferty, G.

    2016-07-01

    With the LHC Run 1 data, the LHCb experiment discovered two pentaquark states and has evidence for a number of possible anomalies in the flavour sector. The possible anomalies include indications of violations of lepton flavour universality, deviations from Standard Model predictions in several B-meson decay modes that are mediated by flavour-changing neutral currents, and further evidence for a discrepancy between inclusive and exclusive measurements of the CKM matrix element |Vub|.

  20. Pentaquarks and Possible Anomalies at LHCb

    NASA Astrophysics Data System (ADS)

    Lafferty, G.

    With the LHC Run 1 data, the LHCb experiment discovered two pentaquark states and has evidence for a number of possible anomalies in the avour sector. The possible anomalies include indications of violations of lepton avour universality, deviations from Standard Model predictions in several B-meson decay modes that are mediated by avour-changing neutral currents, and further evidence for a discrepancy between inclusive and exclusive measurements of the CKM matrix element |Vub|.

  1. b and c spectroscopy at LHCb

    NASA Astrophysics Data System (ADS)

    de Simone, Patrizia

    2014-06-01

    The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from pp collisions at the CERN Large Hadron Collider. It has recorded the world's largest data sample of beauty and charm hadrons, enabling precise studies into the spectroscopy of such particles, including discoveries of new states and measurements of their properties such as masses, width and quantum numbers. The latest results in this area are reviewed.

  2. The 16-vertex model and its even and odd 8-vertex subcases on the square lattice

    NASA Astrophysics Data System (ADS)

    Assis, Michael

    2017-09-01

    We survey and enlarge the known mappings of the 16-vertex model, with emphasis on mappings between the even and odd 8-vertex subcases of the general model, also giving new mappings between these models, valid on finite toroidal lattices. In particular, we find new mappings between the models by using their algebraic invariants with respect to the SL(2)× SL(2) symmetry of the 16-vertex model; we also find a larger set of weak-graph transformations. We show many examples of models with negative weights which map to models with only positive weights. Using the algebraic invariant relations of the even and odd 8-vertex models, we find the complete set of points in the complex field plane of the square lattice Ising model in a field which map to the even or odd 8-vertex models; these points also correspond to the set of free-fermionic points of the model. We do not find any new integrable points, but we find a new mapping between the odd 8-vertex model and the square lattice Ising model at magnetic field H= iπ/(2β) , valid on finite toroidal lattices. We also show directly through various examples that mappings via algebraic invariants do not fully exhaust the possible mappings a model may have with another model. We construct a new solution to the odd 8-vertex free-fermion model which is valid on the finite lattice, since the previous known solution resulted from a mapping valid only in the thermodynamic limit. Finally, we detail for the first time the phase transitions of the column staggered free-fermion 8-vertex model, and show that it can be mapped to the bi-partite staggered free-fermion model.

  3. The Belle II Detector

    NASA Astrophysics Data System (ADS)

    Piilonen, Leo; Belle Collaboration, II

    2017-01-01

    The Belle II detector is now under construction at the KEK laboratory in Japan. This project represents a substantial upgrade of the Belle detector (and the KEKB accelerator). The Belle II experiment will record 50 ab-1 of data, a factor of 50 more than that recorded by Belle. This large data set, combined with the low backgrounds and high trigger efficiencies characteristic of an e+e- experiment, should provide unprecedented sensitivity to new physics signatures in B and D meson decays, and in τ lepton decays. The detector comprises many forefront subsystems. The vertex detector consists of two inner layers of silicon DEPFET pixels and four outer layers of double-sided silicon strips. These layers surround a beryllium beam pipe having a radius of only 10 mm. Outside of the vertex detector is a large-radius, small-cell drift chamber, an ``imaging time-of-propagation'' detector based on Cerenkov radiation for particle identification, and scintillating fibers and resistive plate chambers used to identify muons. The detector will begin commissioning in 2017.

  4. ARIADNE: a Tracking System for Relationships in LHCb Metadata

    NASA Astrophysics Data System (ADS)

    Shapoval, I.; Clemencic, M.; Cattaneo, M.

    2014-06-01

    The data processing model of the LHCb experiment implies handling of an evolving set of heterogeneous metadata entities and relationships between them. The entities range from software and databases states to architecture specificators and software/data deployment locations. For instance, there is an important relationship between the LHCb Conditions Database (CondDB), which provides versioned, time dependent geometry and conditions data, and the LHCb software, which is the data processing applications (used for simulation, high level triggering, reconstruction and analysis of physics data). The evolution of CondDB and of the LHCb applications is a weakly-homomorphic process. It means that relationships between a CondDB state and LHCb application state may not be preserved across different database and application generations. These issues may lead to various kinds of problems in the LHCb production, varying from unexpected application crashes to incorrect data processing results. In this paper we present Ariadne - a generic metadata relationships tracking system based on the novel NoSQL Neo4j graph database. Its aim is to track and analyze many thousands of evolving relationships for cases such as the one described above, and several others, which would otherwise remain unmanaged and potentially harmful. The highlights of the paper include the system's implementation and management details, infrastructure needed for running it, security issues, first experience of usage in the LHCb production and potential of the system to be applied to a wider set of LHCb tasks.

  5. Jet reconstruction in LHCb searching for Higgs-like particles

    NASA Astrophysics Data System (ADS)

    Camboni, Alessandro

    2009-06-01

    One of the greatest challenges in High Energy Physics is the discovery of the Higgs boson which is responsible for the Standard Model particles mass generation. Below ~150 GeV/c2 the Higgs decay into two b-quarks, H → bbar b dominates. The two quarks form a string which fragments, giving rise to hadronization in jets containing b-hadrons. The study is focused on the channel where the Higgs boson is produced in association with a gauge boson decaying leptonically H + W → bbar b + lv and H + Z → bbar b + ll and Higgs masses are in the range 115 - 140 GeV/c2. The gauge bosons decay produces hard leptons quite often isolated from the b-jets. Hence an isolated lepton with high transverse momentum is required in order to reject the large QCD background. The aim of this work is to explore the feasibility to observe Higgs-like particles at the LHCb experiment at CERN by exploiting the detector capabilities to identify b-jets.

  6. The 40 MHz trigger-less DAQ for the LHCb Upgrade

    NASA Astrophysics Data System (ADS)

    Campora Perez, D. H.; Falabella, A.; Galli, D.; Giacomini, F.; Gligorov, V.; Manzali, M.; Marconi, U.; Neufeld, N.; Otto, A.; Pisani, F.; Vagnoni, V. M.

    2016-07-01

    The LHCb experiment will undergo a major upgrade during the second long shutdown (2018-2019), aiming to let LHCb collect an order of magnitude more data with respect to Run 1 and Run 2. The maximum readout rate of 1 MHz is the main limitation of the present LHCb trigger. The upgraded detector, apart from major detector upgrades, foresees a full read-out, running at the LHC bunch crossing frequency of 40 MHz, using an entirely software based trigger. A new high-throughput PCIe Generation 3 based read-out board, named PCIe40, has been designed for this purpose. The read-out board will allow an efficient and cost-effective implementation of the DAQ system by means of high-speed PC networks. The network-based DAQ system reads data fragments, performs the event building, and transports events to the High-Level Trigger at an estimated aggregate rate of about 32 Tbit/s. Different architecture for the DAQ can be implemented, such as push, pull and traffic shaping with barrel-shifter. Possible technology candidates for the foreseen event-builder under study are InfiniBand and Gigabit Ethernet. In order to define the best implementation of the event-builder we are performing tests of the event-builder on different platforms with different technologies. For testing we are using an event-builder evaluator, which consists of a flexible software implementation, to be used on small size test beds as well as on HPC scale facilities. The architecture of DAQ system and up to date performance results will be presented.

  7. Particle Identification on an FPGA Accelerated Compute Platform for the LHCb Upgrade

    NASA Astrophysics Data System (ADS)

    Fäerber, Christian; Schwemmer, Rainer; Machen, Jonathan; Neufeld, Niko

    2017-07-01

    The current LHCb readout system will be upgraded in 2018 to a “triggerless” readout of the entire detector at the Large Hadron Collider collision rate of 40 MHz. The corresponding bandwidth from the detector down to the foreseen dedicated computing farm (event filter farm), which acts as the trigger, has to be increased by a factor of almost 100 from currently 500 Gb/s up to 40 Tb/s. The event filter farm will preanalyze the data and will select the events on an event by event basis. This will reduce the bandwidth down to a manageable size to write the interesting physics data to tape. The design of such a system is a challenging task, and the reason why different new technologies are considered and have to be investigated for the different parts of the system. For the usage in the event building farm or in the event filter farm (trigger), an experimental field programmable gate array (FPGA) accelerated computing platform is considered and, therefore, tested. FPGA compute accelerators are used more and more in standard servers such as for Microsoft Bing search or Baidu search. The platform we use hosts a general Intel CPU and a high-performance FPGA linked via the high-speed Intel QuickPath Interconnect. An accelerator is implemented on the FPGA. It is very likely that these platforms, which are built, in general, for high-performance computing, are also very interesting for the high-energy physics community. First, the performance results of smaller test cases performed at the beginning are presented. Afterward, a part of the existing LHCb RICH particle identification is tested and is ported to the experimental FPGA accelerated platform. We have compared the performance of the LHCb RICH particle identification running on a normal CPU with the performance of the same algorithm, which is running on the Xeon-FPGA compute accelerator platform.

  8. Optimized Vertex Method and Hybrid Reliability

    NASA Technical Reports Server (NTRS)

    Smith, Steven A.; Krishnamurthy, T.; Mason, B. H.

    2002-01-01

    A method of calculating the fuzzy response of a system is presented. This method, called the Optimized Vertex Method (OVM), is based upon the vertex method but requires considerably fewer function evaluations. The method is demonstrated by calculating the response membership function of strain-energy release rate for a bonded joint with a crack. The possibility of failure of the bonded joint was determined over a range of loads. After completing the possibilistic analysis, the possibilistic (fuzzy) membership functions were transformed to probability density functions and the probability of failure of the bonded joint was calculated. This approach is called a possibility-based hybrid reliability assessment. The possibility and probability of failure are presented and compared to a Monte Carlo Simulation (MCS) of the bonded joint.

  9. Complex growing networks with intrinsic vertex fitness

    SciTech Connect

    Bedogne, C.; Rodgers, G. J.

    2006-10-15

    One of the major questions in complex network research is to identify the range of mechanisms by which a complex network can self organize into a scale-free state. In this paper we investigate the interplay between a fitness linking mechanism and both random and preferential attachment. In our models, each vertex is assigned a fitness x, drawn from a probability distribution {rho}(x). In Model A, at each time step a vertex is added and joined to an existing vertex, selected at random, with probability p and an edge is introduced between vertices with fitnesses x and y, with a rate f(x,y), with probability 1-p. Model B differs from Model A in that, with probability p, edges are added with preferential attachment rather than randomly. The analysis of Model A shows that, for every fixed fitness x, the network's degree distribution decays exponentially. In Model B we recover instead a power-law degree distribution whose exponent depends only on p, and we show how this result can be generalized. The properties of a number of particular networks are examined.

  10. Spin wave Feynman diagram vertex computation package

    NASA Astrophysics Data System (ADS)

    Price, Alexander; Javernick, Philip; Datta, Trinanjan

    Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.

  11. Very rapid phosphorylation kinetics suggest a unique role for Lhcb2 during state transitions in Arabidopsis

    PubMed Central

    Leoni, Claudia; Pietrzykowska, Malgorzata; Kiss, Anett Z; Suorsa, Marjaana; Ceci, Luigi R; Aro, Eva-Mari; Jansson, Stefan

    2013-01-01

    Light-harvesting complex II (LHCII) contains three highly homologous chlorophyll-a/b-binding proteins (Lhcb1, Lhcb2 and Lhcb3), which can be assembled into both homo- and heterotrimers. Lhcb1 and Lhcb2 are reversibly phosphorylated by the action of STN7 kinase and PPH1/TAP38 phosphatase in the so-called state-transition process. We have developed antibodies that are specific for the phosphorylated forms of Lhcb1 and Lhcb2. We found that Lhcb2 is more rapidly phosphorylated than Lhcb1: 10 sec of ‘state 2 light’ results in Lhcb2 phosphorylation to 30% of the maximum level. Phosphorylated and non-phosphorylated forms of the proteins showed no difference in electrophoretic mobility and dephosphorylation kinetics did not differ between the two proteins. In state 2, most of the phosphorylated forms of Lhcb1 and Lhcb2 were present in super- and mega-complexes that comprised both photosystem (PS)I and PSII, and the state 2-specific PSI–LHCII complex was highly enriched in the phosphorylated forms of Lhcb2. Our results imply distinct and specific roles for Lhcb1 and Lhcb2 in the regulation of photosynthetic light harvesting. PMID:23888908

  12. The PCIe-based readout system for the LHCb experiment

    NASA Astrophysics Data System (ADS)

    Cachemiche, J. P.; Duval, P. Y.; Hachon, F.; Le Gac, R.; Réthoré, F.

    2016-02-01

    The LHCb experiment is designed to study differences between particles and anti-particles as well as very rare decays in the beauty and charm sector at the LHC. The detector will be upgraded in 2019 in order to significantly increase its efficiency, by removing the first-level hardware trigger. The upgrade experiment will implement a trigger-less readout system in which all the data from every LHC bunch-crossing are transported to the computing farm over 12000 optical links without hardware filtering. The event building and event selection are carried out entirely in the farm. Another original feature of the system is that data transmitted through these fibres arrive directly to computers through a specially designed PCIe card called PCIe40. The same board handles the data acquisition flow and the distribution of fast and slow controls to the detector front-end electronics. It embeds one of the most powerful FPGAs currently available on the market with 1.2 million logic cells. The board has a bandwidth of 480 Gbits/s in both input and output over optical links and 100 Gbits/s over the PCI Express bus to the CPU. We will present how data circulate through the board and in the PC server for achieving the event building. We will focus on specific issues regarding the design of such a board with a very large FPGA, in particular in terms of power supply dimensioning and thermal simulations. The features of the board will be detailed and we will finally present the first performance measurements.

  13. PACIFIC: A 64-channel ASIC for scintillating fiber tracking in LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Gascon, D.; Chanal, H.; Comerma, A.; Gomez, S.; Han, X.; Mazorra, J.; Mauricio, J.; Pillet, N.; Yengui, F.; Vandaele, R.

    2015-04-01

    The LHCb detector will be upgraded during the next LHC shutdown in 2018/19 [1]. The tracker system will have a major overhaul. Its components will be replaced with new technologies in order to cope with the increased hit occupancy and radiation environment. Here we describe a detector made of scintillating fibers read out by silicon photomultipliers (SiPM), with a view to its application for this upgrade. This technology has been shown to achieve high efficiency and spatial resolution, but its integration within a LHCb experiment presents new challenges. This article gives an overview of the R&D status of the low-Power ASIC for the sCIntillating FIbres traCker (PACIFIC) chip implemented in a 130 nm CMOS technology. The PACIFIC chip is a 64-channel ASIC which can be connected to a SiPM without the need of any external component. It includes analog signal processing and digitization. The first stage is a current conveyor followed by a tunable fast shaper (≈10 ns) and a gated integrator. The digitization is performed using a 3 threshold non-linear flash ADC operating at 40 MHz. The PACIFIC chip has the ability to cope with different SiPM suppliers with a power consumption below 8 mW per channel and it is radiation-tolerant. Lastly, simulation and test results show the proper read out of the SiPMs with the PACIFIC chip.

  14. Machine Learning and Parallelism in the Reconstruction of LHCb and its Upgrade

    NASA Astrophysics Data System (ADS)

    De Cian, Michel

    2016-11-01

    The LHCb detector at the LHC is a general purpose detector in the forward region with a focus on reconstructing decays of c- and b-hadrons. For Run II of the LHC, a new trigger strategy with a real-time reconstruction, alignment and calibration was employed. This was made possible by implementing an offline-like track reconstruction in the high level trigger. However, the ever increasing need for a higher throughput and the move to parallelism in the CPU architectures in the last years necessitated the use of vectorization techniques to achieve the desired speed and a more extensive use of machine learning to veto bad events early on. This document discusses selected improvements in computationally expensive parts of the track reconstruction, like the Kalman filter, as well as an improved approach to get rid of fake tracks using fast machine learning techniques. In the last part, a short overview of the track reconstruction challenges for the upgrade of LHCb, is given. Running a fully software-based trigger, a large gain in speed in the reconstruction has to be achieved to cope with the 40 MHz bunch-crossing rate. Two possible approaches for techniques exploiting massive parallelization are discussed.

  15. Rare beauty and charm decays at LHCb

    NASA Astrophysics Data System (ADS)

    Albrecht, Johannes

    2013-05-01

    Rare heavy flavor decays are an ideal place to search for the effects of potential new particles that modify the decay rates or the Lorentz structure of the decay vertices. The LHCb experiment, a dedicated heavy flavour experiment at the LHC at CERN. It has recorded the worlds largest sample of heavy meson and lepton decays. The status of the rare decay analyses with 1 fb-1 of √s = 7 TeV and 1.1 fb-1 of √s = 8 TeV of pp-collisions collected by the LHCb experiment in 2011 and 2012 is reviewed. The worlds most precise measurements of the angular structure of B0 → K*0μ+μ- and B+ → K+μ+μ- decays is discussed, as well as the isospin asymmetry measurement in B → K(*)μ+μ- decays. The first evidence for the very rare decay Bs0 → µ+µ- is presented together with the most stringent upper exclusion limits on the branching fraction of decays of B0, D0 and Ks0 mesons into two muons. This note finishes with the discussion of searches for lepton number and lepton flavor violating τ decays.

  16. Optimization of detectors for the ILC

    NASA Astrophysics Data System (ADS)

    Suehara, Taikan; ILD Group; SID Group

    2016-04-01

    International Linear Collider (ILC) is a next-generation e+e- linear collider to explore Higgs, Beyond-Standard-Models, top and electroweak particles with great precision. We are optimizing our two detectors, International Large Detector (ILD) and Silicon Detector (SiD) to maximize the physics reach expected in ILC with reasonable detector cost and good reliability. The optimization study on vertex detectors, main trackers and calorimeters is underway. We aim to conclude the optimization to establish final designs in a few years, to finish detector TDR and proposal in reply to expected ;green sign; of the ILC project.

  17. The Silicon Detector (SiD) And Linear Collider Detector R&D in Asia And North America

    SciTech Connect

    Brau, J.E.; Breidenbach, M.; Fujii, Y.; /KEK, Tsukuba

    2005-08-11

    In Asia and North America research and development on a linear collider detector has followed complementary paths to that in Europe. Among the developments in the US has been the conception of a detector built around silicon tracking, which relies heavily on a pixel (CCD) vertex detector, and employs a silicon tungsten calorimeter. Since this detector is quite different from the TESLA detector, we describe it here, along with some of the sub-system specific R&D in these regions.

  18. Loop-quantum-gravity vertex amplitude.

    PubMed

    Engle, Jonathan; Pereira, Roberto; Rovelli, Carlo

    2007-10-19

    Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the most popular of these, the Barrett-Crane model, does not have the good boundary state space and there are indications that it fails to yield good low-energy n-point functions. We present an alternative dynamics that can be derived as a quantization of a Regge discretization of Euclidean general relativity, where second class constraints are imposed weakly. Its state space matches the SO(3) loop gravity one and it yields an SO(4)-covariant vertex amplitude for Euclidean loop gravity.

  19. Hadron Spectroscopy, exotics and BC + physics at LHCb

    NASA Astrophysics Data System (ADS)

    Dey, Biplab

    2016-11-01

    The LHCb experiment is designed to study properties and decays of heavy flavored hadrons produced from pp collisions at the LHC. During Run 1, it has recorded the world's largest data sample of beauty and charm hadrons, enabling precision spectroscopy studies of such particles. Several important results obtained by LHCb, such as the discovery of the first pentaquark states and the first unambiguous determination of the Zc (4430) - as an exotic state, have dramatically increased the interest in spectroscopy of heavy hadrons. An overview of the latest LHCb results on the subject, including the discovery of four strange exotic states decaying as X → J/ψϕ, is presented. LHCb has also made significant contributions to the field of BC + physics, the lowest bound state of the heavy flavor ̅b and c quarks. A synopsis of the latest results is given.

  20. Complete LQG propagator: Difficulties with the Barrett-Crane vertex

    SciTech Connect

    Alesci, Emanuele; Rovelli, Carlo

    2007-11-15

    Some components of the graviton two-point function have been recently computed in the context of loop quantum gravity, using the spinfoam Barrett-Crane vertex. We complete the calculation of the remaining components. We find that, under our assumptions, the Barrett-Crane vertex does not yield the correct long-distance limit. We argue that the problem is general and can be traced to the intertwiner independence of the Barrett-Crane vertex, and therefore to the well-known mismatch between the Barrett-Crane formalism and the standard canonical spin networks. In another paper we illustrate the asymptotic behavior of a vertex amplitude that can correct this difficulty.

  1. LHCb pentaquarks in constituent quark models

    NASA Astrophysics Data System (ADS)

    Ortega, P. G.; Entem, D. R.; Fernández, F.

    2017-01-01

    The recently discovered Pc(4380) + and Pc(4450) + states at LHCb have masses close to the D bar Σc* and Dbar*Σc thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The Pc(4380) + and Pc(4450) + are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the D bar Σc* and Dbar*Σc channels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the D bar Σc and Dbar*Σc* thresholds.

  2. The Neuro-Z-Vertex Trigger of the Belle II Experiment

    NASA Astrophysics Data System (ADS)

    Skambraks, Sebastian; Neuhaus, Sara; Kiesling, Christian

    2016-11-01

    A neural network z vertex trigger is planned for the upcoming Belle II detector at the SuperKEKB collider. This neural algorithm is based on a single track 3D parameter estimation using only hit and drift time information from the central drift chamber. Due to the high luminosity (L = 8 × 1035 cm-2 s-1) Belle II will have to face high levels of beam induced background, making a z vertex reconstruction at the first level trigger mandatory. Using the neural z vertex algorithm, the requirements of the standard track trigger can be strongly relaxed. By this, the trigger efficiencies, especially for low multiplicity events, e.g. τ pair production, can be significantly increased. This contribution presents the foreseen neural network trigger setup and the preceding 2D track finder. Special focus is put on the proposal and evaluation of a possible 3D upgrade of the 2D track finder. Additionally, details are given on a dedicated setup for the upcoming cosmic ray test.

  3. Large-pT production of D mesons at the LHCb in the parton Reggeization approach

    NASA Astrophysics Data System (ADS)

    Karpishkov, A. V.; Saleev, V. A.; Shipilova, A. V.

    2016-12-01

    The production of D mesons in proton-proton collisions at the LHCb detector is studied. We consider the single production of D0/D¯0, D±, D*±, and Ds± mesons and correlation spectra in the production of D D ¯ and D D pairs at the √{S }=7 TeV and √{S }=13 TeV . In case of the single D -meson production we calculate differential cross sections over transverse momentum pT while in the pair D D ¯ , D D -meson production the cross sections are calculated over the azimuthal angle difference Δ φ , rapidity difference Δ y , invariant mass of the pair M and over the pT of the one meson from a pair. The cross sections are obtained at the leading order of the parton Reggeization approach using Kimber-Martin-Ryskin unintegrated parton distribution functions in a proton. To describe the D -meson production we use universal scale-dependent c -quark and gluon fragmentation functions fitted to e+e- annihilation data from CERN LEP1. Our predictions find a good agreement with the LHCb Collaboration data within uncertainties and without free parameters.

  4. Status of the Mu3e detector

    NASA Astrophysics Data System (ADS)

    Wiedner, D.

    2017-06-01

    Mu3e is an experiment searching for charged lepton flavour violation in the decay μ+ → e+e-e+. Decay vertex position, decay time and particle momenta have to be precisely measured in order to reject both accidental and physics background. A silicon pixel tracker based on 50 μm thin High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) in a 1 T magnetic field provides precise vertex and momentum information. A scintillating fibre detector and a scintillating tile detector provide sub-nanosecond time information. The status of the Mu3e detector is presented, summarizing the development of HV-MAPS chips, the pixel detector modules as well as the timing detectors.

  5. Packing Vertex Data into Hardware-Decompressible Textures.

    PubMed

    Kwan, Kin Chung; Xu, Xuemiao; Wan, Liang; Wong, Tien-Tsin; Pang, Wai-Man

    2017-04-18

    Most graphics hardware features memory to store textures and vertex data for rendering. However, because of the irreversible trend of increasing complexity of scenes, rendering a scene can easily reach the limit of memory resources. Thus, vertex data are preferably compressed, with a requirement that they can be decompressed during rendering. In this paper, we present a novel method to exploit existing hardware texture compression circuits to facilitate the decompression of vertex data in graphics processing unit (GPUs). This built-in hardware allows real-time, random-order decoding of data. However, vertex data must be packed into textures, and careless packing arrangements can easily disrupt data coherence. Hence, we propose an optimization approach for the best vertex data permutation that minimizes compression error. All of these result in fast and high-quality vertex data decompression for real-time rendering. To further improve the visual quality, we introduce vertex clustering to reduce the dynamic range of data during quantization. Our experiments demonstrate the effectiveness of our method for various vertex data of 3D models during rendering with the advantages of a minimized memory footprint and high frame rate.

  6. Twisted vertex algebras, bicharacter construction and boson-fermion correspondences

    NASA Astrophysics Data System (ADS)

    Anguelova, Iana I.

    2013-12-01

    The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras.

  7. Twisted vertex algebras, bicharacter construction and boson-fermion correspondences

    SciTech Connect

    Anguelova, Iana I.

    2013-12-15

    The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras.

  8. Weight Representations of Admissible Affine Vertex Algebras

    NASA Astrophysics Data System (ADS)

    Arakawa, Tomoyuki; Futorny, Vyacheslav; Ramirez, Luis Enrique

    2017-08-01

    For an admissible affine vertex algebra {V_k{(\\mathfrak{g})}} of type A, we describe a new family of relaxed highest weight representations of {V_k{(\\mathfrak{g})}}. They are simple quotients of representations of the affine Kac-Moody algebra {\\widehat{\\mathfrak{g}}} induced from the following {\\mathfrak{g}}-modules: (1) generic Gelfand-Tsetlin modules in the principal nilpotent orbit, in particular all such modules induced from {\\mathfrak{sl}_2}; (2) all Gelfand-Tsetlin modules in the principal nilpotent orbit that are induced from {\\mathfrak{sl}_3}; (3) all simple Gelfand-Tsetlin modules over {\\mathfrak{sl}_3}. This in particular gives the classification of all simple positive energy weight representations of {V_k{(\\mathfrak{g})}} with finite dimensional weight spaces for {\\mathfrak{g}=\\mathfrak{sl}_3}.

  9. Evaluation of new spin foam vertex amplitudes

    NASA Astrophysics Data System (ADS)

    Khavkine, Igor

    2009-06-01

    The Christensen-Egan algorithm is extended and generalized to efficiently evaluate new spin foam vertex amplitudes proposed by Engle, Pereira and Rovelli and Freidel and Krasnov, with or without (factored) boundary states. A concrete pragmatic proposal is made for comparing the different models using uniform methodologies, applicable to the behavior of large spin asymptotics and of expectation values of specific semiclassical observables. The asymptotics of the new models exhibit non-oscillatory, power-law decay similar to that of the Barrett-Crane model, though with different exponents. Also, an analysis of the semiclassical wave packet propagation problem indicates that the Magliaro, Rovelli and Perini's conjecture of good semiclassical behavior of the new models does not hold for generic factored states, which neglect spin-spin correlations.

  10. Quarkonium decays: Testing the 3-gluon vertex

    NASA Astrophysics Data System (ADS)

    Koller, K.; Streng, K. H.; Walsh, T. F.; Zerwas, P. M.

    1981-12-01

    We study the 3-jet decays of S- and P-wave quarkonia with C=+. If observed, some of these will offer a way of seeing the 3G vertex of QCD via 1S 0, 3P 0, 3P 2(Q overlineQ) → GGG + Gq overlineq → 3 jets. (As is well-known, cancellations reduce 3P1( Q overlineQ)→ GGG.) We elaborate in detail the S-wave decay, as it is expected to show all the characteristic features of orthoquarkonium decays into 4 jets, 3S 1(Q overlineQ) → GGGG + GGq overlineq → 4 jets, which we will comment upon. These quarkonium decays offer a very clear signal for QCD as a non-abelian local gauge field theory with color-charged gluons.

  11. Artificial Spin-Ice and Vertex Models

    NASA Astrophysics Data System (ADS)

    Cugliandolo, Leticia F.

    2017-01-01

    In classical and quantum frustrated magnets the interactions in combination with the lattice structure impede the spins to order in optimal configurations at zero temperature. The theoretical interest in their classical realisations has been boosted by the artificial manufacture of materials with these properties, that are of flexible design. This note summarises work on the use of vertex models to study bidimensional spin-ices samples, done in collaboration with R. A. Borzi, M. V. Ferreyra, L. Foini, G. Gonnella, S. A. Grigera, P. Guruciaga, D. Levis, A. Pelizzola and M. Tarzia, in recent years. It is an invited contribution to a J. Stat. Mech. special issue dedicated to the memory of Leo P. Kadanoff.

  12. Vertex Separators for Partitioning a Graph

    PubMed Central

    Evrendilek, Cem

    2008-01-01

    Finite Element Method (FEM) is a well known technique extensively studied for spatial and temporal modeling of environmental processes, weather prediction computations, and intelligent signal processing for wireless sensors. The need for huge computational power arising in such applications to simulate physical phenomenon correctly mandates the use of massively parallel computers to distribute the workload evenly. In this study, a novel heuristic algorithm called Line Graph Bisection which partitions a graph via vertex separators so as to balance the workload amongst the processors and to minimize the communication overhead is proposed. The proposed algorithm is proved to be computationally feasible and makes cost-effective parallel implementations possible to speed up the solution process. PMID:27879727

  13. Artificial Spin-Ice and Vertex Models

    NASA Astrophysics Data System (ADS)

    Cugliandolo, Leticia F.

    2017-05-01

    In classical and quantum frustrated magnets the interactions in combination with the lattice structure impede the spins to order in optimal configurations at zero temperature. The theoretical interest in their classical realisations has been boosted by the artificial manufacture of materials with these properties, that are of flexible design. This note summarises work on the use of vertex models to study bidimensional spin-ices samples, done in collaboration with R. A. Borzi, M. V. Ferreyra, L. Foini, G. Gonnella, S. A. Grigera, P. Guruciaga, D. Levis, A. Pelizzola and M. Tarzia, in recent years. It is an invited contribution to a J. Stat. Mech. special issue dedicated to the memory of Leo P. Kadanoff.

  14. Compton scattering vertex for massive scalar QED

    SciTech Connect

    Bashir, A.; Concha-Sanchez, Y.; Delbourgo, R.; Tejeda-Yeomans, M. E.

    2009-08-15

    We investigate the Compton scattering vertex of charged scalars and photons in scalar quantum electrodynamics (SQED). We carry out its nonperturbative construction consistent with Ward-Fradkin-Green-Takahashi identity which relates 3-point vertices to the 4-point ones. There is an undetermined part which is transverse to one or both the external photons, and needs to be evaluated through perturbation theory. We present in detail how the transverse part at the 1-loop order can be evaluated for completely general kinematics of momenta involved in covariant gauges and dimensions. This involves the calculation of genuine 4-point functions with three massive propagators, the most nontrivial integrals reported in this paper. We also discuss possible applications of our results.

  15. A generic firmware core to drive the Front-End GBT-SCAs for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Alessio, F.; Caplan, C.; Gaspar, C.; Jacobsson, R.; Wyllie, K.

    2015-02-01

    The LHCb experiment has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity. The entire Front-End electronics will be upgraded in order to cope with higher sub-detector occupancy, higher data rate and to work in a complete trigger-less fashion. In this paper, we describe a novel way to transmit slow control information to the Front-End electronics, by profiting from bidirectional optical connections and the GBT and GBT-SCA chipset capabilities. The implementation and preliminary validation tests are shown as well.

  16. The Light-Harvesting Chlorophyll a/b Binding Proteins Lhcb1 and Lhcb2 Play Complementary Roles during State Transitions in Arabidopsis[C][W][OPEN

    PubMed Central

    Pietrzykowska, Malgorzata; Suorsa, Marjaana; Semchonok, Dmitry A.; Tikkanen, Mikko; Boekema, Egbert J.; Aro, Eva-Mari

    2014-01-01

    Photosynthetic light harvesting in plants is regulated by phosphorylation-driven state transitions: functional redistributions of the major trimeric light-harvesting complex II (LHCII) to balance the relative excitation of photosystem I and photosystem II. State transitions are driven by reversible LHCII phosphorylation by the STN7 kinase and PPH1/TAP38 phosphatase. LHCII trimers are composed of Lhcb1, Lhcb2, and Lhcb3 proteins in various trimeric configurations. Here, we show that despite their nearly identical amino acid composition, the functional roles of Lhcb1 and Lhcb2 are different but complementary. Arabidopsis thaliana plants lacking only Lhcb2 contain thylakoid protein complexes similar to wild-type plants, where Lhcb2 has been replaced by Lhcb1. However, these do not perform state transitions, so phosphorylation of Lhcb2 seems to be a critical step. In contrast, plants lacking Lhcb1 had a more profound antenna remodeling due to a decrease in the amount of LHCII trimers influencing thylakoid membrane structure and, more indirectly, state transitions. Although state transitions are also found in green algae, the detailed architecture of the extant seed plant light-harvesting antenna can now be dated back to a time after the divergence of the bryophyte and spermatophyte lineages, but before the split of the angiosperm and gymnosperm lineages more than 300 million years ago. PMID:25194026

  17. NRQCD Confronts LHCb Data on Quarkonium Production within Jets

    NASA Astrophysics Data System (ADS)

    Bain, Reggie; Makris, Yiannis; Mehen, Thomas; Dai, Lin; Leibovich, Adam K.

    2017-07-01

    We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, z (J /ψ ), carried by the J /ψ within a jet. LHCb data are compared with analytic calculations using the fragmenting jet function (FJF) formalism for studying J /ψ in jets. Logarithms in the FJFs are resummed using Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution. We also convolve hard QCD partonic cross sections, showered with pythia, with leading order nonrelativistic quantum chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the z (J /ψ ) distribution that was shown to be poorly described by default pythia simulations in the LHCb paper. We compare our predictions for the J /ψ distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default pythia regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement.

  18. 8-channel prototype of SALT readout ASIC for Upstream Tracker in the upgraded LHCb experiment

    NASA Astrophysics Data System (ADS)

    Abellan Beteta, C.; Bugiel, S.; Dasgupta, R.; Firlej, M.; Fiutowski, T.; Idzik, M.; Kane, C.; Moron, J.; Swientek, K.; Wang, J.

    2017-02-01

    SALT is a new 128-channel readout ASIC for silicon strip detectors in the upgraded Upstream Tracker of the LHCb experiment. It will extract and digitise analogue signals from the sensor, perform digital processing and transmit serial output data. SALT is designed in CMOS 130 nm process and uses a novel architecture comprising of an analogue front-end and an ultra-low power (<0.5 mW) fast (40 MSps) sampling 6-bit ADC in each channel. An 8-channel prototype (SALT8), comprising all important functionalities was designed, fabricated and tested. A full 128-channel version was also submitted. The design and test results of the SALT8 prototype are presented showing its full functionality.

  19. From J/ψ to LHCb pentaquarks

    NASA Astrophysics Data System (ADS)

    Fernandez, F.; Ortega, P. G.; Entem, D. R.; Segovia, J.

    2016-09-01

    The two exotic $P_c^+(4380)$ and $P_c^+(4450)$ discovered in $2015$ by the LHCb Collaboration, together with the four resonances $X(4140)$, $X(4274)$, $X(4500)$ and $X(4700)$, reported in $2016$ by the same collaboration, are described in a constituent quark model which has been able to explain the properties of charmonium states from the $J/\\psi$ to the $X(3872)$. Using this model we found a $\\bar D\\Sigma_c^*$ bound state with $J^P=\\frac{3}{2}^-$ that may be identified with the $P_c^+(4380)$. In the $\\bar D^*\\Sigma_c$ channel we found three possible candidates for the $P_c^+(4450)$ with $J^P=\\frac{1}{2}^-$, $\\frac{3}{2}^-$ and $\\frac{3}{2}^+$ with almost degenerated energies. The $X(4140)$ resonance appears as a cusp in the $J/\\psi\\phi$ channel due to the near coincidence of the $D_{s}^{\\pm}D_{s}^{\\ast\\pm}$ and $J/\\psi\\phi$ mass thresholds. The remaining three $X(4274)$, $X(4500)$ and $X(4700)$ resonances appear as conventional charmonium states with quantum numbers $3^{3}P_{1}$, $4^{3}P_{0}$ and $5^{3}P_{0}$, respectively; and whose masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds.

  20. Locking mechanisms in degree-4 vertex origami structures

    NASA Astrophysics Data System (ADS)

    Fang, Hongbin; Li, Suyi; Xu, Jian; Wang, K. W.

    2016-04-01

    Origami has emerged as a potential tool for the design of mechanical metamaterials and metastructures whose novel properties originate from their crease patterns. Most of the attention in origami engineering has focused on the wellknown Miura-Ori, a folded tessellation that is flat-foldable for folded sheet and stacked blocks. This study advances the state of the art and expands the research field to investigate generic degree-4 vertex (4-vertex) origami, with a focus on facet-binding. In order to understand how facet-binding attributes to the mechanical properties of 4-vertex origami structures, geometries of the 4-vertex origami cells are analyzed and analytically expressed. Through repeating and stacking 4-vertex cells, origami sheets and stacked origami blocks can be constructed. Geometry analyses discover four mechanisms that will lead to the self-locking of 4-vertex origami cells, sheets, and stacked blocks: in-cell facet-binding, inlayer facet-binding, inter-layer facet binding, and in-layer and inter-layer facet-bindings. These mechanisms and the predicted self-locking phenomena are verified through 3D simulations and prototype experiments. Finally, this paper briefly introduces the unusual mechanical properties caused by the locking of 4-vertex origami structures. The research reported in this paper could foster a new breed of self-locking structures with various engineering applications.

  1. First-year experience with the BaBar silicon vertex tracker

    NASA Astrophysics Data System (ADS)

    Bozzi, C.; Carassiti, V.; Cotta Ramusino, A.; Dittongo, S.; Folegani, M.; Piemontese, L.; Abbott, B. K.; Breon, A. B.; Clark, A. R.; Dow, S.; Fan, Q.; Goozen, F.; Hernikl, C.; Karcher, A.; Kerth, L. T.; Kipnis, I.; Kluth, S.; Lynch, G.; Levi, M.; Luft, P.; Luo, L.; Nyman, M.; Pedrali-Noy, M.; Roe, N. A.; Zizka, G.; Roberts, D.; Schieck, J.; Barni, D.; Brenna, E.; Defendi, I.; Forti, A.; Giugni, D.; Lanni, F.; Palombo, F.; Vaniev, V.; Leona, A.; Mandelli, E.; Manfredi, P. F.; Perazzo, A.; Re, V.; Angelini, C.; Batignani, G.; Bettarini, S.; Bondioli, M.; Bosi, F.; Calderini, G.; Carpinelli, M.; Forti, F.; Gagliardi, D.; Giorgi, M. A.; Lusiani, A.; Mammini, P.; Morganti, M.; Morsani, F.; Neri, N.; Paoloni, E.; Profeti, A.; Rama, M.; Rampino, G.; Rizzo, G.; Sandrelli, F.; Simi, G.; Triggiani, G.; Tritto, S.; Vitale, R.; Walsh, J.; Burchat, P.; Cheng, C.; Kirkby, D.; Meyer, T.; Roat, C.; Bona, M.; Bianchi, F.; Daudo, F.; Di Girolamo, B.; Gamba, D.; Giraudo, G.; Grosso, P.; Romero, A.; Smol, A.; Trapani, P.; Zanin, D.; Bosisio, L.; Della Ricca, G.; Rashevskaia, I.; Lanceri, L.; Pompili, A.; Poropat, P.; Prest, M.; Rastelli, C.; Vallazza, E.; Vuagnin, G.; Hast, C.; Potter, E. P.; Sharma, V.; Burke, S.; Callahan, D.; Campagnari, C.; Dahmes, B.; Eppich, A.; Hale, D.; Hall, K.; Hart, P.; Kuznetsova, N.; Kyre, S.; Levy, S.; Long, O.; May, J.; Richman, J.; Verkerke, W.; Witherell, M.; Beringer, J.; Eisner, A. M.; Frey, A.; Grillo, A.; Grothe, M.; Johnson, R.; Kroeger, W.; Lockman, W.; Pulliam, T.; Rowe, W.; Schmitz, R.; Seiden, A.; Spencer, E.; Turri, M.; Walkowiak, W.; Wilder, M.; Charles, E.; Elmer, P.; Nielsen, J.; Orejudos, W.; Scott, I.; Zobernig, H.

    2001-11-01

    Within its first year of operation, the BaBar Silicon Vertex Tracker (SVT) has accomplished its primary design goal, measuring the z vertex coordinate with sufficient accuracy as to allow the measurement of the time-dependent CP asymmetry in the neutral B-meson system. The SVT consists of five layers of double-sided, AC-coupled silicon-strip detectors of 300 μm thickness with a readout strip pitch of 50-210 μm and a stereo angle of 90° between the strips on the two sides. Detector alignment and performance with respect to spatial resolution and efficiency in the reconstruction of single hits are discussed. In the day-to-day operation of the SVT, radiation damage and protection issues were of primary concern. The SVT is equipped with a dedicated system (SVTRAD) for radiation monitoring and protection, using reverse-biased photodiodes. The evolution of the SVTRAD thresholds on the tolerated radiation level is described. Results on the first-year radiation exposure as measured with the SVTRAD system and on the so far accumulated damage are presented. The implications of test-irradiation results and possible future PEP-II luminosity upgrades on the radiation limited lifetime of the SVT are discussed.

  2. Quark-gluon vertex model and lattice-QCD data

    SciTech Connect

    Bhagwat, M.S.; Tandy, P.C.

    2004-11-01

    A model for the dressed-quark-gluon vertex, at zero gluon momentum, is formed from a nonperturbative extension of the two Feynman diagrams that contribute at one loop in perturbation theory. The required input is an existing ladder-rainbow model Bethe-Salpeter kernel from an approach based on the Dyson-Schwinger equations; no new parameters are introduced. The model includes an Ansatz for the triple-gluon vertex. Two of the three vertex amplitudes from the model provide a pointwise description of the recent quenched-lattice-QCD data. An estimate of the effects of quenching is made.

  3. Quark-gluon vertex in arbitrary gauge and dimension

    NASA Astrophysics Data System (ADS)

    Davydychev, A. I.; Osland, P.; Saks, L.

    2001-01-01

    One-loop off-shell contributions to the quark-gluon vertex are calculated, in an arbitrary covariant gauge and in arbitrary space-time dimension, including quark-mass effects. It is shown how one can get results for all on-shell limits of interest directly from the off-shell expressions. In order to demonstrate that the Ward-Slavnov-Taylor identity for the quark-gluon vertex is satisfied, we have also calculated the corresponding one-loop contribution involving the quark-quark-ghost-ghost vertex.

  4. Superstring vertex operators in type IIB matrix model

    SciTech Connect

    Kitazawa, Yoshihisa; Nagaoka, Satoshi

    2008-06-15

    We clarify the relation between the vertex operators in type IIB matrix model and superstring. Green-Schwarz light-cone closed superstring theory is obtained from IIB matrix model on two-dimensional noncommutative backgrounds. Superstring vertex operators should be reproduced from those of IIB matrix model through this connection. Indeed, we confirm that supergravity vertex operators in IIB matrix model on the two-dimensional backgrounds reduce to those in superstring theory. Noncommutativity plays an important role in our identification. Through this correspondence, we can reproduce superstring scattering amplitudes from IIB matrix model.

  5. The formation of a yield-surface vertex in rock

    SciTech Connect

    Olsson, W.A.

    1992-01-01

    Microstructural models of deformation of polycrystalline materials suggest that inelastic deformation leads to the formation of a corner or vertex at the current load point. This vertex can cause the response to non-proportional loading to be more compliant than predicted by the smooth yield-surface idealization. Combined compression-torsion experiments on Tennessee marble indicate that a vertex forms during inelastic flow. An important implication is that strain localization by bifurcation occurs earlier than predicted by bifurcation analysis using isotropic hardening.

  6. LHCb Results on Penta(tetra)-Quark Search

    NASA Astrophysics Data System (ADS)

    Kucharczyk, Marcin

    The LHCb experiment is designed to study the properties and decays of heavy flavored hadrons produced in pp collisions at the LHC. The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed, such as the discovery of the first charmonium pentaquark states in the J/ψp system or the confirmation of resonant nature of the Z(4430)- mesonic state. LHCb has also made significant contributions to determination of the quantum numbers for the X(3872) state and to exclude the existence of the X(5568) tetraquark candidate. The LHCb results described in the present document have dramatically increased the interest on spectroscopy of heavy hadrons.

  7. Revision of the LHCb limit on Majorana neutrinos

    NASA Astrophysics Data System (ADS)

    Shuve, Brian; Peskin, Michael E.

    2016-12-01

    We revisit the recent limits from LHCb on a Majorana neutrino N in the mass range 250-5000 MeV [1 R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett. 112, 131802 (2014)., 10.1103/PhysRevLett.112.131802]. These limits are among the best currently available, and they will be improved soon by the addition of data from Run 2 of the LHC. LHCb presented a model-independent constraint on the rate of like-sign leptonic decays, and then derived a constraint on the mixing angle Vμ 4 based on a theoretical model for the B decay width to N and the N lifetime. The model used is unfortunately unsound. We revise the conclusions of the paper based on a decay model similar to the one used for the τ lepton and provide formulas useful for future analyses.

  8. Searching supersymmetry at the LHCb with displaced vertices

    SciTech Connect

    Campos, F. de; Eboli, O. J. P.; Magro, M. B.; Restrepo, D.

    2009-03-01

    Supersymmetric theories with bilinear R-parity violation can give rise to the observed neutrino masses and mixings. One important feature of such models is that the lightest supersymmetric particle might have a sufficiently large lifetime to produce detached vertices. Working in the framework of supergravity models, we analyze the potential of the LHCb experiment to search for supersymmetric models exhibiting bilinear R-parity violation. We show that the LHCb experiment can probe a large fraction of the m{sub 0} x m{sub 1/2}, being able to explore gluino masses up to 1.3 TeV. The LHCb discover potential for these kinds of models is similar to the ATLAS and CMS ones in the low luminosity phase of operation of the LHC.

  9. LHCb Build and Deployment Infrastructure for run 2

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Couturier, B.

    2015-12-01

    After the successful run 1 of the LHC, the LHCb Core software team has taken advantage of the long shutdown to consolidate and improve its build and deployment infrastructure. Several of the related projects have already been presented like the build system using Jenkins, as well as the LHCb Performance and Regression testing infrastructure. Some components are completely new, like the Software Configuration Database (using the Graph DB Neo4j), or the new packaging installation using RPM packages. Furthermore all those parts are integrated to allow easier and quicker releases of the LHCb Software stack, therefore reducing the risk of operational errors. Integration and Regression tests are also now easier to implement, allowing to improve further the software checks.

  10. Revision of the LHCb limit on Majorana neutrinos

    SciTech Connect

    Shuve, Brian; Peskin, Michael E.

    2016-12-16

    We revisit the recent limits from LHCb on a Majorana neutrino N in the mass range 250–5000 MeV [R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett. 112, 131802 (2014).]. These limits are among the best currently available, and they will be improved soon by the addition of data from Run 2 of the LHC. LHCb presented a model-independent constraint on the rate of like-sign leptonic decays, and then derived a constraint on the mixing angle V μ 4 based on a theoretical model for the B decay width to N and the N lifetime. The model used is unfortunately unsound. We revise the conclusions of the paper based on a decay model similar to the one used for the τ lepton and provide formulas useful for future analyses.

  11. The ALPHA - detector: Module Production and Assembly

    NASA Astrophysics Data System (ADS)

    Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jonsell, S.; JØrgensen, L. V.; Kurchaninov, L.; Madsen, N.; McKenna, J. T. K.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sampson, J.; Sarid, E.; Seddon, D.; Seif el Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; Thornhill, J.; Wells, D.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2012-01-01

    ALPHA is one of the experiments situated at CERN's Antiproton Decelerator (AD). A Silicon Vertex Detector (SVD) is placed to surround the ALPHA atom trap. The main purpose of the SVD is to detect and locate antiproton annihilation events by means of the emitted charged pions. The SVD system is presented with special focus given to the design, fabrication and performance of the modules.

  12. Vertex micromagnetic energy in artificial square ice

    NASA Astrophysics Data System (ADS)

    Perrin, Yann; Canals, Benjamin; Rougemaille, Nicolas

    2016-10-01

    Artificial arrays of interacting magnetic elements provide an uncharted arena in which the physics of magnetic frustration and magnetic monopoles can be observed in real space and in real time. These systems offer the formidable opportunity to investigate a wide range of collective magnetic phenomena with a lab-on-chip approach and to explore various theoretical predictions from spin models. Here, we study artificial square ice systems numerically and use micromagnetic simulations to understand how the geometrical parameters of the individual magnetic elements affect the energy levels of an isolated square vertex. More specifically, we address the question of whether the celebrated square ice model could be made relevant for artificial square ice systems. Our work reveals that tuning the geometry alone should not allow the experimental realization of the square ice model when using nanomagnets coupled through the magnetostatic interaction. However, low-aspect ratios combined with small gaps separating neighboring magnetic elements of moderated thickness might permit approaching the ideal case where the degeneracy of the ice rule states is recovered.

  13. Ghost story. II. The midpoint ghost vertex

    NASA Astrophysics Data System (ADS)

    Bonora, L.; Maccaferri, C.; Santos, R. J. Scherer; Tolla, D. D.

    2009-11-01

    We construct the ghost number 9 three strings vertex for OSFT in the natural normal ordering. We find two versions, one with a ghost insertion at z = i and a twist-conjugate one with insertion at z = -i. For this reason we call them midpoint vertices. We show that the relevant Neumann matrices commute among themselves and with the matrix G representing the operator K1. We analyze the spectrum of the latter and find that beside a continuous spectrum there is a (so far ignored) discrete one. We are able to write spectral formulas for all the Neumann matrices involved and clarify the important role of the integration contour over the continuous spectrum. We then pass to examine the (ghost) wedge states. We compute the discrete and continuous eigenvalues of the corresponding Neumann matrices and show that they satisfy the appropriate recursion relations. Using these results we show that the formulas for our vertices correctly define the star product in that, starting from the data of two ghost number 0 wedge states, they allow us to reconstruct a ghost number 3 state which is the expected wedge state with the ghost insertion at the midpoint, according to the star recursion relation.

  14. Dynamical Vertex Approximation for the Hubbard Model

    NASA Astrophysics Data System (ADS)

    Toschi, Alessandro

    A full understanding of correlated electron systems in the physically relevant situations of three and two dimensions represents a challenge for the contemporary condensed matter theory. However, in the last years considerable progress has been achieved by means of increasingly more powerful quantum many-body algorithms, applied to the basic model for correlated electrons, the Hubbard Hamiltonian. Here, I will review the physics emerging from studies performed with the dynamical vertex approximation, which includes diagrammatic corrections to the local description of the dynamical mean field theory (DMFT). In particular, I will first discuss the phase diagram in three dimensions with a special focus on the commensurate and incommensurate magnetic phases, their (quantum) critical properties, and the impact of fluctuations on electronic lifetimes and spectral functions. In two dimensions, the effects of non-local fluctuations beyond DMFT grow enormously, determining the appearance of a low-temperature insulating behavior for all values of the interaction in the unfrustrated model: Here the prototypical features of the Mott-Hubbard metal-insulator transition, as well as the existence of magnetically ordered phases, are completely overwhelmed by antiferromagnetic fluctuations of exponentially large extension, in accordance with the Mermin-Wagner theorem. Eventually, by a fluctuation diagnostics analysis of cluster DMFT self-energies, the same magnetic fluctuations are identified as responsible for the pseudogap regime in the holed-doped frustrated case, with important implications for the theoretical modeling of the cuprate physics.

  15. Linear Time Vertex Partitioning on Massive Graphs.

    PubMed

    Mell, Peter; Harang, Richard; Gueye, Assane

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity.

  16. Linear Time Vertex Partitioning on Massive Graphs

    PubMed Central

    Mell, Peter; Harang, Richard; Gueye, Assane

    2016-01-01

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity. PMID:27336059

  17. The D0 detector upgrade

    SciTech Connect

    Bross, A.D.

    1995-02-01

    The Fermilab collider program is undergoing a major upgrade of both the accelerator complex and the two detectors. Operation of the Tevatron at luminosities upwards of ten time that currently provided will occur in early 1999 after the commissioning of the new Fermilab Main Injector. The D0 upgrade program has been established to deliver a detector that will meet the challenges of this environment. A new magnetic tracker consisting of a superconducting solenoid, a silicon vertex detector, a scintillating fiber central tracker, and a central preshower detector will replace the current central tracking and transition radiation chambers. We present the design and performance capabilities of these new systems and describe results from physics simulations that demonstrate the physics reach of the upgraded detector.

  18. Efficient variants of the vertex space domain decomposition algorithm

    SciTech Connect

    Chan, T.F.; Shao, J.P. . Dept. of Mathematics); Mathew, T.P. . Dept. of Mathematics)

    1994-11-01

    Several variants of the vertex space algorithm of Smith for two-dimensional elliptic problems are described. The vertex space algorithm is a domain decomposition method based on nonoverlapping subregions, in which the reduced Schur complement system on the interface is solved using a generalized block Jacobi-type preconditioner, with the blocks corresponding to the vertex space, edges, and a coarse grid. Two kinds of approximations are considered for the edge and vertex space subblocks, one based on Fourier approximation, and another based on an algebraic probing technique in which sparse approximations to these subblocks are computed. The motivation is to improve the efficiency of the algorithm without sacrificing the optimal convergence rate. Numerical and theoretical results on the performance of these algorithms, including variants of an algorithm of Bramble, Pasciak, and Schatz are presented.

  19. Vertex models: from cell mechanics to tissue morphogenesis.

    PubMed

    Alt, Silvanus; Ganguly, Poulami; Salbreux, Guillaume

    2017-05-19

    Tissue morphogenesis requires the collective, coordinated motion and deformation of a large number of cells. Vertex model simulations for tissue mechanics have been developed to bridge the scales between force generation at the cellular level and tissue deformation and flows. We review here various formulations of vertex models that have been proposed for describing tissues in two and three dimensions. We discuss a generic formulation using a virtual work differential, and we review applications of vertex models to biological morphogenetic processes. We also highlight recent efforts to obtain continuum theories of tissue mechanics, which are effective, coarse-grained descriptions of vertex models.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'.

  20. Vertex models: from cell mechanics to tissue morphogenesis

    PubMed Central

    Alt, Silvanus; Ganguly, Poulami

    2017-01-01

    Tissue morphogenesis requires the collective, coordinated motion and deformation of a large number of cells. Vertex model simulations for tissue mechanics have been developed to bridge the scales between force generation at the cellular level and tissue deformation and flows. We review here various formulations of vertex models that have been proposed for describing tissues in two and three dimensions. We discuss a generic formulation using a virtual work differential, and we review applications of vertex models to biological morphogenetic processes. We also highlight recent efforts to obtain continuum theories of tissue mechanics, which are effective, coarse-grained descriptions of vertex models. This article is part of the themed issue ‘Systems morphodynamics: understanding the development of tissue hardware’. PMID:28348254

  1. Virtualization for the LHCb Online system

    NASA Astrophysics Data System (ADS)

    Bonaccorsi, Enrico; Brarda, Loic; Moine, Gary; Neufeld, Niko

    2011-12-01

    Virtualization has long been advertised by the IT-industry as a way to cut down cost, optimise resource usage and manage the complexity in large data-centers. The great number and the huge heterogeneity of hardware, both industrial and custom-made, has up to now led to reluctance in the adoption of virtualization in the IT infrastructure of large experiment installations. Our experience in the LHCb experiment has shown that virtualization improves the availability and the manageability of the whole system. We have done an evaluation of available hypervisors / virtualization solutions and find that the Microsoft HV technology provides a high level of maturity and flexibility for our purpose. We present the results of these comparison tests, describing in detail, the architecture of our virtualization infrastructure with a special emphasis on the security for services visible to the outside world. Security is achieved by a sophisticated combination of VLANs, firewalls and virtual routing - the cost and benefits of this solution are analysed. We have adapted our cluster management tools, notably Quattor, for the needs of virtual machines and this allows us to migrate smoothly services on physical machines to the virtualized infrastructure. The procedures for migration will also be described. In the final part of the document we describe our recent R&D activities aiming to replacing the SAN-backend for the virtualization by a cheaper iSCSI solution - this will allow to move all servers and related services to the virtualized infrastructure, excepting the ones doing hardware control via non-commodity PCI plugin cards.

  2. Physics performance of the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Tsuno, S.

    2017-01-01

    In preparation for LHC Run-2 the ATLAS detector introduced a new pixel detector, the Insertable B-Layer (IBL). This detector is located between the beampipe and what was the innermost pixel layer. The tracking and vertex reconstruction are significantly improved and good performance is expected in high level objects such a b-quark jet tagging. This in turn, leads to better physics results. This note summarizes the impact of the IBL detector on physics results, especially focusing on the analyses using b-quark jets throughout 2016 summer physics program.

  3. D bar Σc* and Dbar*Σc interactions and the LHCb hidden-charmed pentaquarks

    NASA Astrophysics Data System (ADS)

    He, Jun

    2016-02-01

    Very recently, two hidden-charmed resonances Pc (4380) and Pc (4450) consistent with pentaquark states were observed at the LHCb detector. The two Pc states locate just below the D bar Σc* and Dbar*Σc thresholds with mass of gaps about 5 and 15 MeV, respectively. Inspired by this fact we perform a dynamical investigation about the D bar Σc* (2520) and Dbar*Σc (2455) interactions which are described by the meson exchanges. A bound state which carries spin-parity JP = 3 /2- is produced from the D bar Σc* (2520) interaction, which is consistent with the Pc (4380) observed at the LHCb detector. From the D*Σc (2455) interaction, a bound state with 5 /2+ is produced, which can be related to the Pc (4450). The results suggest that the Pc (4380) and Pc (4450) are good candidates of D bar Σc* (2520) and Dbar*Σc (2455) molecular states, respectively.

  4. Hessian and graviton propagator of the proper vertex

    NASA Astrophysics Data System (ADS)

    Chaharsough Shirazi, Atousa; Engle, Jonathan; Vilensky, Ilya

    2016-10-01

    The proper spin-foam vertex amplitude is obtained from the EPRL vertex by projecting out all but a single gravitational sector, in order to achieve correct semi-classical behavior. In this paper we calculate the gravitational two-point function predicted by the proper spin-foam vertex to lowest order in the vertex expansion. We find the same answer as in the EPRL case in the ‘continuum spectrum’ limit, so that the theory is consistent with the predictions of linearized gravity in the regime of small curvature. The method for calculating the two-point function is similar to that used in prior works: we cast it in terms of an action integral and use stationary phase methods. Thus, the calculation of the Hessian matrix plays a key role. Once the Hessian is calculated, it is used not only to calculate the two-point function, but also to calculate the coefficient appearing in the semi-classical limit of the proper vertex amplitude itself. This coefficient is the effective discrete ‘measure factor’ encoded in the spin-foam model. Through a non-trivial cancellation of different factors, we find that this coefficient is the same as the coefficient in front of the term in the asymptotics of the EPRL vertex corresponding to the selected gravitational sector.

  5. Anomalous pseudoscalar-photon vertex in and out of equilibrium

    SciTech Connect

    Kumar, S. Prem; Boyanovsky, Daniel; Vega, Hector J. de

    2000-03-15

    The anomalous pseudoscalar-photon vertex is studied in real time in and out of equilibrium in a constituent quark model. The goal is to understand the in-medium modifications of this vertex, exploring the possibility of enhanced isospin breaking by electromagnetic effects as well as the formation of neutral pion condensates in a rapid chiral phase transition in peripheral, ultrarelativistic heavy-ion collisions. In equilibrium the effective vertex is afflicted by infrared and pinch singularities that require hard thermal loop and width corrections of the quark propagator. The resumed effective equilibrium vertex vanishes near the chiral transition in the chiral limit. In a strongly out of equilibrium chiral phase transition we find that the chiral condensate drastically modifies the quark propagators and the effective vertex. The ensuing dynamics for the neutral pion results in a potential enhancement of isospin breaking and the formation of {pi}{sup 0} condensates. While the anomaly equation and the axial Ward identity are not modified by the medium in or out of equilibrium, the effective real-time pseudoscalar-photon vertex is sensitive to low energy physics. (c) 2000 The American Physical Society.

  6. The Belle detector

    NASA Astrophysics Data System (ADS)

    Abashian, A.; Gotow, K.; Morgan, N.; Piilonen, L.; Schrenk, S.; Abe, K.; Adachi, I.; Alexander, J. P.; Aoki, K.; Behari, S.; Doi, Y.; Enomoto, R.; Fujii, H.; Fujita, Y.; Funahashi, Y.; Haba, J.; Hamasaki, H.; Haruyama, T.; Hayashi, K.; Higashi, Y.; Hitomi, N.; Igarashi, S.; Igarashi, Y.; Iijima, T.; Ikeda, Hirokazu; Ikeda, Hitomi; Itoh, R.; Iwai, M.; Iwasaki, H.; Iwasaki, Y.; Joo, K. K.; Kasami, K.; Katayama, N.; Kawai, M.; Kichimi, H.; Kobayashi, T.; Koike, S.; Kondo, Y.; Lee, M. H.; Makida, Y.; Manabe, A.; Matsuda, T.; Murakami, T.; Nagayama, S.; Nakao, M.; Nozaki, T.; Ogawa, K.; Ohkubo, R.; Ohnishi, Y.; Ozaki, H.; Sagawa, H.; Saito, M.; Sakai, Y.; Sasaki, T.; Sato, N.; Sumiyoshi, T.; Suzuki, J.; Suzuki, J. I.; Suzuki, S.; Takasaki, F.; Tamai, K.; Tanaka, M.; Tatomi, T.; Tsuboyama, T.; Tsukada, K.; Tsukamoto, T.; Uehara, S.; Ujiie, N.; Uno, S.; Yabsley, B.; Yamada, Y.; Yamaguchi, H.; Yamaoka, H.; Yamaoka, Y.; Yamauchi, M.; Yoshimura, Y.; Zhao, H.; Abe, R.; Iwai, G.; Kawasaki, T.; Miyata, H.; Shimada, K.; Takahashi, S.; Tamura, N.; Abe, K.; Hanada, H.; Nagamine, T.; Nakajima, M.; Nakajima, T.; Narita, S.; Sanpei, M.; Takayama, T.; Ueki, M.; Yamaga, M.; Yamaguchi, A.; Ahn, B. S.; Kang, J. S.; Kim, Hyunwoo; Park, C. W.; Park, H.; Ahn, H. S.; Jang, H. K.; Kim, C. H.; Kim, S. K.; Lee, S. H.; Park, C. S.; Won, E.; Aihara, H.; Higuchi, T.; Kawai, H.; Matsubara, T.; Nakadaira, T.; Tajima, H.; Tanaka, J.; Tomura, T.; Yokoyama, M.; Akatsu, M.; Fujimoto, K.; Hirose, M.; Inami, K.; Ishikawa, A.; Itami, S.; Kani, T.; Matsumoto, T.; Nagai, I.; Okabe, T.; Oshima, T.; Senyo, K.; Sugi, A.; Sugiyama, A.; Suitoh, S.; Suzuki, S.; Tomoto, M.; Yoshida, K.; Akhmetshin, R.; Chang, P.; Chao, Y.; Chen, Y. Q.; Hou, W. S.; Hsu, S. C.; Huang, H. C.; Huang, T. J.; Lee, M. C.; Lu, R. S.; Peng, J. C.; Peng, K. C.; Sahu, S.; Sung, H. F.; Tsai, K. L.; Ueno, K.; Wang, C. C.; Wang, M. Z.; Alimonti, G.; Browder, T. E.; Casey, B. C. K.; Fang, F.; Guler, H.; Jones, M.; Li, Y.; Olsen, S. L.; Peters, M.; Rodriguez, J. L.; Rosen, M.; Swain, S.; Trabelsi, K.; Varner, G.; Yamamoto, H.; Zheng, Y. H.; An, Q.; Chen, H. F.; Wang, Y. F.; Xu, Z. Z.; Ye, S. W.; Zhang, Z. P.; Asai, M.; Asano, Y.; Mori, S.; Stanič, S.; Tsujita, Y.; Zhang, J.; Žontar, D.; Aso, T.; Aulchenko, V.; Beiline, D.; Bondar, A.; Dneprovsky, L.; Eidelman, S.; Garmash, A.; Kuzmin, A.; Romanov, L.; Root, N.; Shwartz, B.; Sidorov, A.; Sidorov, V.; Usov, Y.; Zhilich, V.; Bakich, A. M.; Peak, L. S.; Varvell, K. E.; Banas, E.; Bozek, A.; Jalocha, P.; Kapusta, P.; Natkaniec, Z.; Ostrowicz, W.; Palka, H.; Rozanka, M.; Rybicki, K.; Behera, P. K.; Mohapatra, A.; Satapathy, M.; Chang, Y. H.; Chen, H. S.; Dong, L. Y.; Li, J.; Liu, H. M.; Mao, Z. P.; Yu, C. X.; Zhang, C. C.; Zhang, S. Q.; Zhao, Z. G.; Zheng, Z. P.; Cheon, B. G.; Choi, Y.; Kim, D. W.; Nam, J. W.; Chidzik, S.; Korotuschenko, K.; Leonidopoulos, C.; Liu, T.; Marlow, D.; Mindas, C.; Prebys, E.; Rabberman, R.; Sands, W.; Wixted, R.; Choi, S.; Dragic, J.; Everton, C. W.; Gordon, A.; Hastings, N. C.; Heenan, E. M.; Moffitt, L. C.; Moloney, G. R.; Moorhead, G. F.; Sevior, M. E.; Taylor, G. N.; Tovey, S. N.; Drutskoy, A.; Kagan, R.; Pakhlov, P.; Semenov, S.; Fukunaga, C.; Suda, R.; Fukushima, M.; Goriletsky, V. I.; Grinyov, B. V.; Lyubinsky, V. R.; Panova, A. I.; Shakhova, K. V.; Shpilinskaya, L. I.; Vinograd, E. L.; Zaslavsky, B. G.; Guo, R. S.; Haitani, F.; Hoshi, Y.; Neichi, K.; Hara, K.; Hara, T.; Hazumi, M.; Hojo, T.; Jackson, D.; Miyake, H.; Nagashima, Y.; Ryuko, J.; Sumisawa, K.; Takita, M.; Yamanaka, T.; Hayashii, H.; Miyabayashi, K.; Noguchi, S.; Hikita, S.; Hirano, H.; Hoshina, K.; Mamada, H.; Nitoh, O.; Okazaki, N.; Yokoyama, T.; Ishino, H.; Ichizawa, S.; Hirai, T.; Kakuno, H.; Kaneko, J.; Nakamura, T.; Ohshima, Y.; Watanabe, Y.; Yanaka, S.; Inoue, Y.; Nakano, E.; Takahashi, T.; Teramoto, Y.; Kang, J. H.; Kim, H. J.; Kim, Heejong; Kwon, Y.-J.; Kawai, H.; Kurihara, E.; Ooba, T.; Suzuki, K.; Unno, Y.; Kawamura, N.; Yuta, H.; Kinoshita, K.; Satpathy, A.; Kobayashi, S.; Kuniya, T.; Murakami, A.; Tsukamoto, T.; Kumar, S.; Singh, J.; Lange, J.; Stock, R.; Matsumoto, S.; Watanabe, M.; Matsuo, H.; Nishida, S.; Nomura, T.; Sakamoto, H.; Sasao, N.; Ushiroda, Y.; Nagasaka, Y.; Tanaka, Y.; Ogawa, S.; Shibuya, H.; Hanagaki, K.; Okuno, S.; Shen, D. Z.; Yan, D. S.; Yin, Z. W.; Tan, N.; Wang, C. H.; Yamaki, T.; Yamashita, Y.

    2002-02-01

    The Belle detector was designed and constructed to carry out quantitative studies of rare B-meson decay modes with very small branching fractions using an asymmetric e +e - collider operating at the ϒ(4S) resonance, the KEK-B-factory. Such studies require data samples containing ˜10 7 B-meson decays. The Belle detector is configured around a 1.5 T superconducting solenoid and iron structure surrounding the KEK-B beams at the Tsukuba interaction region. B-meson decay vertices are measured by a silicon vertex detector situated just outside of a cylindrical beryllium beam pipe. Charged particle tracking is performed by a wire drift chamber (CDC). Particle identification is provided by d E/d x measurements in CDC, aerogel threshold Cherenkov counter and time-of-flight counter placed radially outside of CDC. Electromagnetic showers are detected in an array of CsI( Tl) crystals located inside the solenoid coil. Muons and K L mesons are identified by arrays of resistive plate counters interspersed in the iron yoke. The detector covers the θ region extending from 17° to 150°. The part of the uncovered small-angle region is instrumented with a pair of BGO crystal arrays placed on the surfaces of the QCS cryostats in the forward and backward directions. Details of the design and development works of the detector subsystems, which include trigger, data acquisition and computer systems, are described. Results of performance of the detector subsystems are also presented.

  7. Overview of LHCb results on beauty and charm spectroscopy

    NASA Astrophysics Data System (ADS)

    Palano, Antimo

    2016-11-01

    We present a summary of new experimental results from LHCb experiment on the status of the charm spectroscopy using inclusive approaches and Dalitz plot analyses of B and Bs decays. We also summarize latest results on the spectroscopy of heavy baryons.

  8. Onia and onia-like states at LHCb

    NASA Astrophysics Data System (ADS)

    Passaleva, Giovanni

    2014-06-01

    We present recent LHCb results of studies on the production of J/ψ and χc charmonium states, of Υ bottomonia and on J/ψ polarization in proton-proton collisions at √s. Results on J/ψ production in proton-lead collisions are also presented.

  9. Integration of Cloud resources in the LHCb Distributed Computing

    NASA Astrophysics Data System (ADS)

    Úbeda García, Mario; Méndez Muñoz, Víctor; Stagni, Federico; Cabarrou, Baptiste; Rauschmayr, Nathalie; Charpentier, Philippe; Closier, Joel

    2014-06-01

    This contribution describes how Cloud resources have been integrated in the LHCb Distributed Computing. LHCb is using its specific Dirac extension (LHCbDirac) as an interware for its Distributed Computing. So far, it was seamlessly integrating Grid resources and Computer clusters. The cloud extension of DIRAC (VMDIRAC) allows the integration of Cloud computing infrastructures. It is able to interact with multiple types of infrastructures in commercial and institutional clouds, supported by multiple interfaces (Amazon EC2, OpenNebula, OpenStack and CloudStack) - instantiates, monitors and manages Virtual Machines running on this aggregation of Cloud resources. Moreover, specifications for institutional Cloud resources proposed by Worldwide LHC Computing Grid (WLCG), mainly by the High Energy Physics Unix Information Exchange (HEPiX) group, have been taken into account. Several initiatives and computing resource providers in the eScience environment have already deployed IaaS in production during 2013. Keeping this on mind, pros and cons of a cloud based infrasctructure have been studied in contrast with the current setup. As a result, this work addresses four different use cases which represent a major improvement on several levels of our infrastructure. We describe the solution implemented by LHCb for the contextualisation of the VMs based on the idea of Cloud Site. We report on operational experience of using in production several institutional Cloud resources that are thus becoming integral part of the LHCb Distributed Computing resources. Furthermore, we describe as well the gradual migration of our Service Infrastructure towards a fully distributed architecture following the Service as a Service (SaaS) model.

  10. Design and construction of a Vertex Chamber and measurement of the average B-Hadron lifetime

    SciTech Connect

    Nelson, H.N.

    1987-10-01

    Four parameters describe the mixing of the three quark generations in the Standard Model of the weak charged current interaction. These four parameters are experimental inputs to the model. A measurement of the mean lifetime of hadrons containing b-quarks, or B-Hadrons, constrains the magnitudes of two of these parameters. Measurement of the B-Hadron lifetime requires a device that can measure the locations of the stable particles that result from B-Hadron decay. This device must function reliably in an inaccessible location, and survive high radiation levels. We describe the design and construction of such a device, a gaseous drift chamber. Tubes of 6.9 mm diameter, having aluminized mylar walls of 100 ..mu..m thickness are utilized in this Vertex Chamber. It achieves a spatial resolution of 45 ..mu..m, and a resolution in extrapolation to the B-Hadron decay location of 87 ..mu..m. Its inner layer is 4.6 cm from e/sup +/e/sup -/ colliding beams. The Vertex Chamber is situated within the MAC detector at PEP. We have analyzed botht he 94 pb/sup -1/ of integrated luminosity accumulated at ..sqrt..s = 29 GeV with the Vertex Chamber in place as well as the 210 pb/sup -1/ accumulated previously. We require a lepton with large momentum transverse to the event thrust axis to obtain a sample of events enriched in B-Hadron decays. The distribution of signed impact parameters of all tracks in these events is used to measure the B-Hadron flight distance, and hence lifetime. 106 refs., 79 figs., 20 tabs.

  11. Students' Understanding of the Concept of Vertex of Quadratic Functions in Relation to Their Personal Meaning of the Concept of Vertex

    ERIC Educational Resources Information Center

    Childers, Annie Burns; Vidakovic, Draga

    2014-01-01

    This paper explores sixty-six students' personal meaning and interpretation of the vertex of a quadratic function in relation to their understanding of quadratic functions in two different representations, algebraic and word problem. Several categories emerged from students' personal meaning of the vertex including vertex as maximum or minimum…

  12. Students' Understanding of the Concept of Vertex of Quadratic Functions in Relation to Their Personal Meaning of the Concept of Vertex

    ERIC Educational Resources Information Center

    Childers, Annie Burns; Vidakovic, Draga

    2014-01-01

    This paper explores sixty-six students' personal meaning and interpretation of the vertex of a quadratic function in relation to their understanding of quadratic functions in two different representations, algebraic and word problem. Several categories emerged from students' personal meaning of the vertex including vertex as maximum or minimum…

  13. VERTEX: manganese transport through oxygen minima

    NASA Astrophysics Data System (ADS)

    Martin, John H.; Knauer, George A.

    1984-01-01

    Manganese transport through a well-developed oxygen minimum was studied off central Mexico (18°N, 108°W) in October-November 1981 as part of the VERTEX (Vertical Transport and Exchange) research program. Refractory, leachable and dissolved Mn fractions associated with particulates caught in traps set at eight depths (120-1950 m) were analyzed. Particles entering the oxygen minimum had relatively large Mn loads; however, as the particulates sank further into the minimum, total Mn fluxes steadily decreased from 190 nmol m -2 day -1 at 120 m to 36 nmol m -2 day -1 at 400 m. Manganese fluxes then steadily increased in the remaining 800-1950 m, reaching rates of up to 230 nmol m -2 day -1 at 1950 m. Manganese concentrations were also measured in the water column. Dissolved Mn levels < 3.0 nmol kg -1 were consistently observed within the 150-600 m depth interval. In contrast, suspended particulate leachable Mn amounts were especially low at those depths, and never exceeded 0.04 nmol kg -1. The combined water column and particle trap data clearly indicate that Mn is released from particles as they sink through the oxygen minimum. Rate-of-change estimates based on trap flux data yield regeneration rates of up to 0.44 nmol kg -1 yr -1 in the upper oxygen minimum (120-200 m). However, only 30% of the dissolved Mn in the oxygen minimum appears to be from sinking particulate regeneration; the other 70% probably results from continental-slope-release-horizontal-transport processes. Dissolved Mn scavenges back onto particles as oxygen levels begin to increase with depth. Scavenging rates ranging from -0.03 to -0.09 nmol kg -1 yr -1 were observed at depths from 700 to 1950 m. These scavenging rates result in Mn residence times of 16-19 years, and scavenging rate constants on the order of 0.057 yr -1. Manganese removal via scavenging on sinking particles below the oxygen minimum is balanced by Mn released along continental boundaries and transported horizontally via advective

  14. Central FPGA-based destination and load control in the LHCb MHz event readout

    NASA Astrophysics Data System (ADS)

    Jacobsson, R.

    2012-10-01

    The readout strategy of the LHCb experiment is based on complete event readout at 1 MHz. A set of 320 sub-detector readout boards transmit event fragments at total rate of 24.6 MHz at a bandwidth usage of up to 70 GB/s over a commercial switching network based on Gigabit Ethernet to a distributed event building and high-level trigger processing farm with 1470 individual multi-core computer nodes. In the original specifications, the readout was based on a pure push protocol. This paper describes the proposal, implementation, and experience of a non-conventional mixture of a push and a pull protocol, akin to credit-based flow control. An FPGA-based central master module, partly operating at the LHC bunch clock frequency of 40.08 MHz and partly at a double clock speed, is in charge of the entire trigger and readout control from the front-end electronics up to the high-level trigger farm. One FPGA is dedicated to controlling the event fragment packing in the readout boards, the assignment of the farm node destination for each event, and controls the farm load based on an asynchronous pull mechanism from each farm node. This dynamic readout scheme relies on generic event requests and the concept of node credit allowing load control and trigger rate regulation as a function of the global farm load. It also allows the vital task of fast central monitoring and automatic recovery in-flight of failing nodes while maintaining dead-time and event loss at a minimum. This paper demonstrates the strength and suitability of implementing this real-time task for a very large distributed system in an FPGA where no random delays are introduced, and where extreme reliability and accurate event accounting are fundamental requirements. It was in use during the entire commissioning phase of LHCb and has been in faultless operation during the first two years of physics luminosity data taking.

  15. Hessian and graviton propagator of the proper vertex

    NASA Astrophysics Data System (ADS)

    Chaharsough Shirazi, Atousa; Engle, Jonathan; Vilenskiy, Ilya

    2015-04-01

    The proper spin-foam vertex amplitude was obtained from the EPRL vertex by projecting out all but a single gravitational sector, in order to enable correct semi-classical behavior. In this paper we calculate the gravitational two-point function predicted by the proper spin-foam vertex to lowest order in the vertex expansion. We find the same answer as in the EPRL case, so that the theory is consistent with the predictions of linearized gravity in the regime of small curvature. The method for calculating the two-point function is again to cast it in terms of an action integral and to use stationary phase methods. Thus, the calculation of the Hessian matrix plays a key role. Once the Hessian is calculated, it is used not only to calculate the two-point function, but also to calculate the coefficient appearing in the semi-classical limit of the proper vertex amplitude itself. This coefficient can be thought of as the effective discrete ``measure factor'' encoded in the spin-foam model.

  16. Genus Ranges of 4-Regular Rigid Vertex Graphs.

    PubMed

    Buck, Dorothy; Dolzhenko, Egor; Jonoska, Nataša; Saito, Masahico; Valencia, Karin

    2015-01-01

    A rigid vertex of a graph is one that has a prescribed cyclic order of its incident edges. We study orientable genus ranges of 4-regular rigid vertex graphs. The (orientable) genus range is a set of genera values over all orientable surfaces into which a graph is embedded cellularly, and the embeddings of rigid vertex graphs are required to preserve the prescribed cyclic order of incident edges at every vertex. The genus ranges of 4-regular rigid vertex graphs are sets of consecutive integers, and we address two questions: which intervals of integers appear as genus ranges of such graphs, and what types of graphs realize a given genus range. For graphs with 2n vertices (n > 1), we prove that all intervals [a, b] for all a < b ≤ n, and singletons [h, h] for some h ≤ n, are realized as genus ranges. For graphs with 2n - 1 vertices (n ≥ 1), we prove that all intervals [a, b] for all a < b ≤ n except [0, n], and [h, h] for some h ≤ n, are realized as genus ranges. We also provide constructions of graphs that realize these ranges.

  17. Genus Ranges of 4-Regular Rigid Vertex Graphs

    PubMed Central

    Buck, Dorothy; Dolzhenko, Egor; Jonoska, Nataša; Saito, Masahico; Valencia, Karin

    2016-01-01

    A rigid vertex of a graph is one that has a prescribed cyclic order of its incident edges. We study orientable genus ranges of 4-regular rigid vertex graphs. The (orientable) genus range is a set of genera values over all orientable surfaces into which a graph is embedded cellularly, and the embeddings of rigid vertex graphs are required to preserve the prescribed cyclic order of incident edges at every vertex. The genus ranges of 4-regular rigid vertex graphs are sets of consecutive integers, and we address two questions: which intervals of integers appear as genus ranges of such graphs, and what types of graphs realize a given genus range. For graphs with 2n vertices (n > 1), we prove that all intervals [a, b] for all a < b ≤ n, and singletons [h, h] for some h ≤ n, are realized as genus ranges. For graphs with 2n − 1 vertices (n ≥ 1), we prove that all intervals [a, b] for all a < b ≤ n except [0, n], and [h, h] for some h ≤ n, are realized as genus ranges. We also provide constructions of graphs that realize these ranges. PMID:27807395

  18. Online Data Reduction using Track and Vertex Reconstruction on GPUs for the Mu3e Experiment

    NASA Astrophysics Data System (ADS)

    vom Bruch, Dorothea

    2017-08-01

    The Mu3e experiment searches for the lepton flavour violating decay μ+ → e+e-e+, aiming to achieve a sensitivity of 2 · 10-15 in its first phase and ultimately aspiring to a final sensitivity of 10-16. During the first phase of the experiment, a muon rate of ˜ 108 μ/s will be available, resulting in a data rate of ˜ 80 Gbit/s. The trigger-less readout system is based on optical links and switching FPGAs sending the complete detector data for a time slice to one node of the filter farm. A full online reconstruction is necessary to reduce the data rate to a manageable amount to be written to disk. Graphics processing units (GPUs) are used to fit tracks with a non-iterative 3D tracking algorithm for multiple scattering dominated resolution. In addition, a three track vertex selection is performed by calculating the vertex position from the intersections of the tracks. Together with kinematic cuts, this allows for a reduction of the output data rate to below 100MB/s using 12 DAQ PCs.

  19. A two-level fanout system for the CDF silicon vertex tracker

    SciTech Connect

    A. Bardi et al.

    2001-11-02

    The Fanout system is part of the Silicon Vertex Tracker, a new trigger processor designed to reconstruct charged particle trajectories at Level 2 of the CDF trigger, with a latency of 10 {micro}s and an event rate up to 100 kHz. The core of SVT is organized as 12 identical slices, which process in parallel the data from the 12 independent azimuthal wedges of the Silicon Vertex Detector (SVXII). Each SVT slice links the digitized pulse heights found within one SVXII wedge to the tracks reconstructed by the Level 1 fast track finder (XFT) in the corresponding 30{sup o} angular region of the Central Outer Tracker. Since the XFT tracks are transmitted to SVT as a single data stream, their distribution to the proper SVT slices requires dedicated fanout logic. The Fanout system has been implemented as a multi-board project running on a common 20 MHz clock. Track fanout is performed in two steps by one ''Fanout A'' and two ''Fanout B'' boards. The architecture, design, and implementation of this system are described.

  20. Plethystic vertex operators and boson-fermion correspondences

    NASA Astrophysics Data System (ADS)

    Fauser, Bertfried; Jarvis, Peter D.; King, Ronald C.

    2016-10-01

    We study the algebraic properties of plethystic vertex operators, introduced in (2010 J. Phys. A: Math. Theor. 43 405202), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape π. Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each π, the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms.

  1. Arrow-arrow correlations for the six-vertex model.

    PubMed

    Falco, P

    2013-09-01

    The six-vertex model on a square lattice is "exactly solvable" because an exact formula for the free energy can be obtained by the Bethe ansatz. However, exact formulas for the correlations of local bulk observables, such as the orientation of the arrow at a given edge, are, in general, not available. In this Rapid Communication, we consider the isotropic "zero-field" six-vertex model at small Δ. We derive the long-distance asymptotic formula of arrow-arrow correlations, which display power law decays with one anomalous exponent. Our method is based on an interacting fermion representation of the six-vertex model and does not use any information obtained from the exact solution.

  2. Three-dimensional vertex model for simulating multicellular morphogenesis

    PubMed Central

    Okuda, Satoru; Inoue, Yasuhiro; Adachi, Taiji

    2015-01-01

    During morphogenesis, various cellular activities are spatiotemporally coordinated on the protein regulatory background to construct the complicated, three-dimensional (3D) structures of organs. Computational simulations using 3D vertex models have been the focus of efforts to approach the mechanisms underlying 3D multicellular constructions, such as dynamics of the 3D monolayer or multilayer cell sheet like epithelia as well as the 3D compacted cell aggregate, including dynamic changes in layer structures. 3D vertex models enable the quantitative simulation of multicellular morphogenesis on the basis of single-cell mechanics, with complete control of various cellular activities such as cell contraction, growth, rearrangement, division, and death. This review describes the general use of the 3D vertex model, along with its applications to several simplified problems of developmental phenomena. PMID:27493850

  3. A GPU algorithm for minimum vertex cover problems

    NASA Astrophysics Data System (ADS)

    Toume, Kouta; Kinjo, Daiki; Nakamura, Morikazu

    2014-10-01

    The minimum vertex cover problem is one of the fundamental problems in graph theory and is known to be NP-hard. For data mining in large-scale structured systems, we proposes a GPU algorithm for the minimum vertex cover problem. The algorithm is designed to derive sufficient parallelism of the problem for the GPU architecture and also to arrange data on the device memory for efficient coalesced accessing. Through the experimental evaluation, we demonstrate that our GPU algorithm is quite faster than CPU programs and the speedup becomes much evident when the graph size is enlarged.

  4. q-vertex operator from 5D Nekrasov function

    NASA Astrophysics Data System (ADS)

    Itoyama, H.; Oota, T.; Yoshioka, R.

    2016-08-01

    The five-dimensional AGT correspondence implies the connection between the q-deformed Virasoro block and the 5d Nekrasov partition function. In this paper, we determine a q-deformation of the four-point block in the Coulomb gas representation from the 5d Nekrasov function, and obtain an expression of the q-deformed vertex operator. If we use only one kind of the q-vertex operators, one of the insertion points of them must be modified in order to hold the 2d/5d correspondence.

  5. The Virasoro vertex algebra and factorization algebras on Riemann surfaces

    NASA Astrophysics Data System (ADS)

    Williams, Brian

    2017-08-01

    This paper focuses on the connection of holomorphic two-dimensional factorization algebras and vertex algebras which has been made precise in the forthcoming book of Costello-Gwilliam. We provide a construction of the Virasoro vertex algebra starting from a local Lie algebra on the complex plane. Moreover, we discuss an extension of this factorization algebra to a factorization algebra on the category of Riemann surfaces. The factorization homology of this factorization algebra is computed as the correlation functions. We provide an example of how the Virasoro factorization algebra implements conformal symmetry of the beta-gamma system using the method of effective BV quantization.

  6. Simulations of silicon vertex tracker for star experiment at RHIC

    SciTech Connect

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W.; Liko, D.; Cramer, J.; Prindle, D.; Trainor, T.; Braithwaite, W.

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  7. Direct Measurement of Ab and Ac Using Vertex/Kaon Charge Tags at SLD

    SciTech Connect

    Abe, K.

    2004-10-13

    Exploiting the manipulation of the SLC electron-beam polarization, we present precise direct measurements of the parity violation parameters A{sub c} and A{sub b} in the Z boson-c quark and Z boson-b quark coupling. Quark/antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLD CCD vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-98 sample of 400,000 Z decays, produced with an average beam polarization of 73.4%, we find A{sub c} = 0.673 {+-} 0.029(stat.) {+-} 0.023(syst.) and A{sub b} = 0.919 {+-} 0.018(stat.) {+-} 0.017(syst.).

  8. Prediction of least-scattered photons traversing turbid medium: a vertex/propagator model

    NASA Astrophysics Data System (ADS)

    Wang, Ruikang K.; Wilson, Michael J.

    2000-04-01

    The least scattered photons that arrive at a detector through the highly scattering tissues have the potential for imaging internal structures, functions and status with high imaging resolution. In contrast optical diffusing tomography is based on the use of the late arriving photons, which have been diffusely scattered, leading to very low imaging resolution. A good model of the early arriving photons, i.e. the least scattered photons may have a significant impact on the development of imaging algorithms and the further understanding of imaging mechanisms within current high resolution optical imaging techniques. This paper describes a vertex/propagator approach, which attempts to find the probabilities for least scattered photons traversing a scattering medium, based on analytical expressions for photon histories. The basic mathematical derivations for the model are outlined, and the results are discussed and found to be in very good agreement with those from the Monte-Carlo simulations.

  9. Vertex/propagator model for least-scattered photons traversing a turbid medium.

    PubMed

    Wang, R K; Wilson, M

    2001-01-01

    The least-scattered photons that arrive at a detector through highly scattering tissues have the potential to image internal structures, functions, and status with high imaging resolution. In contrast, optical diffusing tomography is based on the use of the late-arriving photons, which have been diffusely scattered, leading to very low imaging resolution. A good model of the early-arriving photons, i.e., the least-scattered photons, may have a significant effect on the development of imaging algorithms and a further understanding of imaging mechanisms within current high-resolution optical-imaging techniques. We describe a vertex/propagator approach that attempts to find the probabilities for least-scattered photons traversing a scattering medium, based on analytical expressions for photon histories. The basic mathematical derivations for the model are outlined, and the results are discussed and found to be in very good agreement with those from the Monte Carlo simulations.

  10. A PCIe Gen3 based readout for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Bellato, M.; Collazuol, G.; D'Antone, I.; Durante, P.; Galli, D.; Jost, B.; Lax, I.; Liu, G.; Marconi, U.; Neufeld, N.; Schwemmer, R.; Vagnoni, V.

    2014-06-01

    The architecture of the data acquisition system foreseen for the LHCb upgrade, to be installed by 2018, is devised to readout events trigger-less, synchronously with the LHC bunch crossing rate at 40 MHz. Within this approach the readout boards act as a bridge between the front-end electronics and the High Level Trigger (HLT) computing farm. The baseline design for the LHCb readout is an ATCA board requiring dedicated crates. A local area standard network protocol is implemented in the on-board FPGAs to read out the data. The alternative solution proposed here consists in building the readout boards as PCIe peripherals of the event-builder servers. The main architectural advantage is that protocol and link-technology of the event-builder can be left open until very late, to profit from the most cost-effective industry technology available at the time of the LHC LS2.

  11. Search for New Physics in rare decays at LHCb

    NASA Astrophysics Data System (ADS)

    Albrecht, Johannes

    2013-08-01

    Rare heavy flavor decays provide stringent tests of the Standard Model of particle physics and allow to test for possible new Physics scenarios. The LHCb experiment at CERN is the ideal place for these searches as it has recorded the worlds largest sample of beauty mesons. The status of the rare decay analyses with 1 fb of √{s}=7 TeV of pp-collisions collected by the LHCb experiment in 2011 is reviewed. The worlds most precise measurements of the angular structure of B0→K*0μ+μ- decays is discussed, as well as the isospin asymmetry measurement in B→Kμ+μ- decays. The most stringent upper exclusion limit on the branching fraction of Bs0→μ+μ- decays is shown, as well as searches for lepton number and lepton flavor violating processes.

  12. Measurement of the B± lifetime and top quark identification using secondary vertex b-tagging

    SciTech Connect

    Schwartzman, Ariel G.

    2004-01-01

    This dissertation presents a preliminary measurement of the B± lifetime through the full reconstruction of its decay chain, and the identification of top quark production in the electron plus jets channel using the displaced vertex b-tagging method. Its main contribution is the development, implementation and optimization of the Kalman filter algorithm for vertex reconstruction, and of the displaced vertex technique for tagging jets arising from b quark fragmentation, both of which have now become part of the standard D0 reconstruction package. These two algorithms fully exploit the new state-of-the-art tracking detectors, recently installed as part of the Run 2 D0 upgrade project. The analysis is based on data collected during Run 2a at the Fermilab Tevatron p$\\bar{p}$ Hadron Collider up to April 2003, corresponding to an integrated luminosity of 60 pb-1. The measured B meson lifetime of τ = 1.57 ± 0.18 ps is in agreement with the current world average, with a competitive level of precision expected when the full data sample becomes available.

  13. b -flavour tagging in pp collisions at LHCb

    NASA Astrophysics Data System (ADS)

    Battista, V.; LHCb Collaboration

    2017-07-01

    Measurements of CP violation and flavour oscillations of neutral B mesons require the knowledge of the meson flavour at the production time. Flavour-tagging algorithms in the LHCb experiment allow to perform such measurements with very high precision. Recent examples include the determination of the CKM angles 2β and 2βs . The details of these flavour-tagging algorithms are presented, together with their performances.

  14. Neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight.

    PubMed

    Yang, Q; Wen, S W; Chen, Y; Krewski, D; Fung Kee Fung, K; Walker, M

    2006-01-01

    To assess the risk of neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight. Data from a historical cohort study based on a twin registry in the US (1995-1997) were used. Multivariate logistic regression was used to control for maternal age, race, marital status, cigarette smoking during pregnancy, parity, medical complications, gestational age, and other confounders. A total of 86 041 vertex-vertex second twins were classified into two groups: second twins delivered by cesarean section after cesarean delivery of first twin (C-C) (43.0%), second twins whose co-twins delivered vaginally (V-X) (57.0%). In infants of birth weight>or=2500 g group, the risks of noncongenital anomaly-related death (adjusted odds ratio (aOR): 4.64, 95% confidence interval (95% CI): 1.90, 13.92), low Apgar score (aOR: 2.39, 95% CI: 1.43, 4.14), and ventilation use (aOR: 1.31, 95% CI: 1.18, 1.47) were higher in the V-X group compared with the C-C group. No asphyxia-related neonatal deaths occurred in C-C group, whereas the incidence of this death was 0.04% in the V-X group. The risks of neonatal mortality and morbidity are increased in vertex-vertex second twins with birth weight>or=2500 g whose co-twins delivered vaginally compared with second twins delivered by cesarean section after cesarean delivery of first twin.

  15. Prototype system for proton beam range measurement based on gamma electron vertex imaging

    NASA Astrophysics Data System (ADS)

    Lee, Han Rim; Kim, Sung Hun; Park, Jong Hoon; Jung, Won Gyun; Lim, Hansang; Kim, Chan Hyeong

    2017-06-01

    In proton therapy, for both therapeutic effectiveness and patient safety, it is very important to accurately measure the proton dose distribution, especially the range of the proton beam. For this purpose, recently we proposed a new imaging method named gamma electron vertex imaging (GEVI), in which the prompt gammas emitting from the nuclear reactions of the proton beam in the patient are converted to electrons, and then the converted electrons are tracked to determine the vertices of the prompt gammas, thereby producing a 2D image of the vertices. In the present study, we developed a prototype GEVI system, including dedicated signal processing and data acquisition systems, which consists of a beryllium plate (= electron converter) to convert the prompt gammas to electrons, two double-sided silicon strip detectors (= hodoscopes) to determine the trajectories of those converted electrons, and a plastic scintillation detector (= calorimeter) to measure their kinetic energies. The system uses triple coincidence logic and multiple energy windows to select only the events from prompt gammas. The detectors of the prototype GEVI system were evaluated for electronic noise level, energy resolution, and time resolution. Finally, the imaging capability of the GEVI system was tested by imaging a 90Sr beta source, a 60Co gamma source, and a 45-MeV proton beam in a PMMA phantom. The overall results of the present study generally show that the prototype GEVI system can image the vertices of the prompt gammas produced by the proton nuclear interactions.

  16. DIRAC3 - the new generation of the LHCb grid software

    NASA Astrophysics Data System (ADS)

    Tsaregorodtsev, A.; Brook, N.; Casajus Ramo, A.; Charpentier, Ph; Closier, J.; Cowan, G.; Graciani Diaz, R.; Lanciotti, E.; Mathe, Z.; Nandakumar, R.; Paterson, S.; Romanovsky, V.; Santinelli, R.; Sapunov, M.; Smith, A. C.; Seco Miguelez, M.; Zhelezov, A.

    2010-04-01

    DIRAC, the LHCb community Grid solution, was considerably reengineered in order to meet all the requirements for processing the data coming from the LHCb experiment. It is covering all the tasks starting with raw data transportation from the experiment area to the grid storage, data processing up to the final user analysis. The reengineered DIRAC3 version of the system includes a fully grid security compliant framework for building service oriented distributed systems; complete Pilot Job framework for creating efficient workload management systems; several subsystems to manage high level operations like data production and distribution management. The user interfaces of the DIRAC3 system providing rich command line and scripting tools are complemented by a full-featured Web portal providing users with a secure access to all the details of the system status and ongoing activities. We will present an overview of the DIRAC3 architecture, new innovative features and the achieved performance. Extending DIRAC3 to manage computing resources beyond the WLCG grid will be discussed. Experience with using DIRAC3 by other user communities than LHCb and in other application domains than High Energy Physics will be shown to demonstrate the general-purpose nature of the system.

  17. Comparative Investigation of Shared Filesystems for the LHCb Online Cluster

    NASA Astrophysics Data System (ADS)

    Vijay Kartik, S.; Neufeld, Niko

    2012-12-01

    This paper describes the investigative study undertaken to evaluate shared filesystem performance and suitability in the LHCb Online environment. Particular focus is given to the measurements and field tests designed and performed on an in-house OpenAFS setup; related comparisons with NFSv4 and GPFS (a clustered filesystem from IBM) are presented. The motivation for the investigation and the test setup arises from the need to serve common user-space like home directories, experiment software and control areas, and clustered log areas. Since the operational requirements on such user-space are stringent in terms of read-write operations (in frequency and access speed) and unobtrusive data relocation, test results are presented with emphasis on file-level performance, stability and “high-availability” of the shared filesystems. Use cases specific to the experiment operation in LHCb, including the specific handling of shared filesystems served to a cluster of 1500 diskless nodes, are described. Issues of prematurely expiring authenticated sessions are explicitly addressed, keeping in mind long-running analysis jobs on the Online cluster. In addition, quantitative test results are also presented with alternatives including NFSv4. Comparative measurements of filesystem performance benchmarks are presented, which are seen to be used as reference for decisions on potential migration of the current storage solution deployed in the LHCb online cluster.

  18. The BABAR Detector

    SciTech Connect

    Luth, Vera G

    2001-05-18

    BABAR, the detector for the SLAC PEP-II asymmetric e{sup +}e{sup -} B Factory operating at the {Upsilon}(4S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagentic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

  19. Detectors and experiments

    NASA Astrophysics Data System (ADS)

    Hauptman, John

    2016-11-01

    The talks in the Program and the Conference parallel sessions make clear that high quality pixel vertex chambers are presently well developed and with continuing improvements (M. Caccia,1 X. Sun,2 M. Stanitzki,3 J. Qian4); that there are at least two major tracking chambers that are well studied, a TPC and silicon-strip chambers (H. Qi,5,6 C. Young,7,8 A. de Roeck9,10); that the energy measurement of photons and electrons is generally very good (H. Yang,11 S. Franchino12); and, that the last remaining detector that has not yet achieved the high precision required for good e+e- physics is the hadronic calorimeter for the measurement of jets, most importantly, jets from the decays of W and Z to quarks (S. Lee,13,14 M. Cascella,15 A. de Roeck16). The relationship of the detectors to physics and the overall design of detectors was addressed and questioned (Y. Gao,17 M. Ruan,18 G. Tonelli,19 H. Zhu,20 M. Mangano,21 C. Quigg22) in addition to precision time measurements in detectors (C. Tully23).

  20. Symmetric point quartic gluon vertex and momentum subtraction

    NASA Astrophysics Data System (ADS)

    Gracey, J. A.

    2014-07-01

    We compute the full one loop correction to the quartic vertex of QCD at the fully symmetric point. This allows us to define a new momentum subtraction (MOM) scheme in the class of schemes introduced by Celmaster and Gonsalves. Hence using properties of the renormalization group equation, the two loop renormalization group functions for this scheme are given.

  1. A Cohomology Theory of Grading-Restricted Vertex Algebras

    NASA Astrophysics Data System (ADS)

    Huang, Yi-Zhi

    2014-04-01

    We introduce a cohomology theory of grading-restricted vertex algebras. To construct the correct cohomologies, we consider linear maps from tensor powers of a grading-restricted vertex algebra to "rational functions valued in the algebraic completion of a module for the algebra," instead of linear maps from tensor powers of the algebra to a module for the algebra. One subtle complication arising from such functions is that we have to carefully address the issue of convergence when we compose these linear maps with vertex operators. In particular, for each , we have an inverse system of nth cohomologies and an additional nth cohomology of a grading-restricted vertex algebra V with coefficients in a V-module W such that is isomorphic to the inverse limit of the inverse system . In the case of n = 2, there is an additional second cohomology denoted by which will be shown in a sequel to the present paper to correspond to what we call square-zero extensions of V and to first order deformations of V when W = V.

  2. The role of geometry in 4-vertex origami mechanics

    NASA Astrophysics Data System (ADS)

    Waitukaitis, Scott; Dieleman, Peter; van Hecke, Martin

    Origami offers an interesting design platform metamaterials because it strongly couples mechanics with geometry. Even so, most research carried out so far has been limited to one or two particular patterns. I will discuss the full geometrical space of the most common origami building block, the 4-vertex, and show how exotic geometries can have dramatic effects on the mechanics.

  3. Self-locking degree-4 vertex origami structures.

    PubMed

    Fang, Hongbin; Li, Suyi; Wang, K W

    2016-11-01

    A generic degree-4 vertex (4-vertex) origami possesses one continuous degree-of-freedom for rigid folding, and this folding process can be stopped when two of its facets bind together. Such facet-binding will induce self-locking so that the overall structure stays at a pre-specified configuration without additional locking elements or actuators. Self-locking offers many promising properties, such as programmable deformation ranges and piecewise stiffness jumps, that could significantly advance many adaptive structural systems. However, despite its excellent potential, the origami self-locking features have not been well studied, understood, and used. To advance the state of the art, this research conducts a comprehensive investigation on the principles of achieving and harnessing self-locking in 4-vertex origami structures. Especially, for the first time, this study expands the 4-vertex structure construction from single-component to dual-component designs and investigates their self-locking behaviours. By exploiting various tessellation designs, this research discovers that the dual-component designs offer the origami structures with extraordinary attributes that the single-component structures do not have, which include the existence of flat-folded locking planes, programmable locking points and deformability. Finally, proof-of-concept experiments investigate how self-locking can effectively induce piecewise stiffness jumps. The results of this research provide new scientific knowledge and a systematic framework for the design, analysis and utilization of self-locking origami structures for many potential engineering applications.

  4. Network Unfolding Map by Vertex-Edge Dynamics Modeling.

    PubMed

    Verri, Filipe Alves Neto; Urio, Paulo Roberto; Zhao, Liang

    2016-11-29

    The emergence of collective dynamics in neural networks is a mechanism of the animal and human brain for information processing. In this paper, we develop a computational technique using distributed processing elements in a complex network, which are called particles, to solve semisupervised learning problems. Three actions govern the particles' dynamics: generation, walking, and absorption. Labeled vertices generate new particles that compete against rival particles for edge domination. Active particles randomly walk in the network until they are absorbed by either a rival vertex or an edge currently dominated by rival particles. The result from the model evolution consists of sets of edges arranged by the label dominance. Each set tends to form a connected subnetwork to represent a data class. Although the intrinsic dynamics of the model is a stochastic one, we prove that there exists a deterministic version with largely reduced computational complexity; specifically, with linear growth. Furthermore, the edge domination process corresponds to an unfolding map in such way that edges "stretch" and "shrink" according to the vertex-edge dynamics. Consequently, the unfolding effect summarizes the relevant relationships between vertices and the uncovered data classes. The proposed model captures important details of connectivity patterns over the vertex-edge dynamics evolution, in contrast to the previous approaches, which focused on only vertex or only edge dynamics. Computer simulations reveal that the new model can identify nonlinear features in both real and artificial data, including boundaries between distinct classes and overlapping structures of data.

  5. Spin glass approach to the feedback vertex set problem

    NASA Astrophysics Data System (ADS)

    Zhou, Hai-Jun

    2013-11-01

    A feedback vertex set (FVS) of an undirected graph is a set of vertices that contains at least one vertex of each cycle of the graph. The feedback vertex set problem consists of constructing a FVS of size less than a certain given value. This combinatorial optimization problem has many practical applications, but it is in the nondeterministic polynomial-complete class of worst-case computational complexity. In this paper we define a spin glass model for the FVS problem and then study this model on the ensemble of finite-connectivity random graphs. In our model the global cycle constraints are represented through the local constraints on all the edges of the graph, and they are then treated by distributed message-passing procedures such as belief propagation. Our belief propagation-guided decimation algorithm can construct nearly optimal feedback vertex sets for single random graph instances and regular lattices. We also design a spin glass model for the FVS problem on a directed graph. Our work will be very useful for identifying the set of vertices that contribute most significantly to the dynamical complexity of a large networked system.

  6. AN ONLINE LONGITUDINAL VERTEX AND BUNCH SPECTRUM MONITOR FOR RHIC.

    SciTech Connect

    VAN ZEIJTS,J.

    2004-07-05

    The longitudinal bunch profile acquisition system at RHIC was recently upgraded to allow on-line measurements of the bunch spectrum, and collision vertex location and shape. The system allows monitoring the evolution of these properties along the ramp, at transition and rebucketing, and at store conditions. We describe some of the hardware and software changes, and show some applications of the system.

  7. A neural network z-vertex trigger for Belle II

    NASA Astrophysics Data System (ADS)

    Neuhaus, S.; Skambraks, S.; Abudinen, F.; Chen, Y.; Feindt, M.; Frühwirth, R.; Heck, M.; Kiesling, C.; Knoll, A.; Paul, S.; Schieck, J.

    2015-05-01

    We present the concept of a track trigger for the Belle II experiment, based on a neural network approach, that is able to reconstruct the z (longitudinal) position of the event vertex within the latency of the first level trigger. The trigger will thus be able to suppress a large fraction of the dominating background from events outside of the interaction region. The trigger uses the drift time information of the hits from the Central Drift Chamber (CDC) of Belle II within narrow cones in polar and azimuthal angle as well as in transverse momentum (sectors), and estimates the z-vertex without explicit track reconstruction. The preprocessing for the track trigger is based on the track information provided by the standard CDC trigger. It takes input from the 2D (r — φ) track finder, adds information from the stereo wires of the CDC, and finds the appropriate sectors in the CDC for each track in a given event. Within each sector, the z-vertex of the associated track is estimated by a specialized neural network, with a continuous output corresponding to the scaled z-vertex. The input values for the neural network are calculated from the wire hits of the CDC.

  8. Tests of track segment and vertex finding with neural networks

    SciTech Connect

    Denby, B.; Lessner, E. ); Lindsey, C.S. )

    1990-04-01

    Feed forward neural networks have been trained, using back-propagation, to find the slopes of simulated track segments in a straw chamber and to find the vertex of tracks from both simulated and real events in a more conventional drift chamber geometry. Network architectures, training, and performance are presented. 12 refs., 7 figs.

  9. Self-locking degree-4 vertex origami structures

    NASA Astrophysics Data System (ADS)

    Fang, Hongbin; Li, Suyi; Wang, K. W.

    2016-11-01

    A generic degree-4 vertex (4-vertex) origami possesses one continuous degree-of-freedom for rigid folding, and this folding process can be stopped when two of its facets bind together. Such facet-binding will induce self-locking so that the overall structure stays at a pre-specified configuration without additional locking elements or actuators. Self-locking offers many promising properties, such as programmable deformation ranges and piecewise stiffness jumps, that could significantly advance many adaptive structural systems. However, despite its excellent potential, the origami self-locking features have not been well studied, understood, and used. To advance the state of the art, this research conducts a comprehensive investigation on the principles of achieving and harnessing self-locking in 4-vertex origami structures. Especially, for the first time, this study expands the 4-vertex structure construction from single-component to dual-component designs and investigates their self-locking behaviours. By exploiting various tessellation designs, this research discovers that the dual-component designs offer the origami structures with extraordinary attributes that the single-component structures do not have, which include the existence of flat-folded locking planes, programmable locking points and deformability. Finally, proof-of-concept experiments investigate how self-locking can effectively induce piecewise stiffness jumps. The results of this research provide new scientific knowledge and a systematic framework for the design, analysis and utilization of self-locking origami structures for many potential engineering applications.

  10. Conservation laws, vertex corrections, and screening in Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Maiti, Saurabh; Chubukov, Andrey V.; Hirschfeld, P. J.

    2017-07-01

    We present a microscopic theory for the Raman response of a clean multiband superconductor, with emphasis on the effects of vertex corrections and long-range Coulomb interaction. The measured Raman intensity, R (Ω ) , is proportional to the imaginary part of the fully renormalized particle-hole correlator with Raman form factors γ (k ⃗) . In a BCS superconductor, a bare Raman bubble is nonzero for any γ (k ⃗) and diverges at Ω =2 Δmax , where Δmax is the largest gap along the Fermi surface. However, for γ (k ⃗) = constant, the full R (Ω ) is expected to vanish due to particle number conservation. It was sometimes stated that this vanishing is due to the singular screening by long-range Coulomb interaction. In our general approach, we show diagrammatically that this vanishing actually holds due to vertex corrections from the same short-range interaction that gives rise to superconductivity. We further argue that long-range Coulomb interaction does not affect the Raman signal for any γ (k ⃗) . We argue that vertex corrections eliminate the divergence at 2 Δmax . We also argue that vertex corrections give rise to sharp peaks in R (Ω ) at Ω <2 Δmin (the minimum gap along the Fermi surface), when Ω coincides with the frequency of one of the collective modes in a superconductor, e.g., Leggett and Bardasis-Schrieffer modes in the particle-particle channel, and an excitonic mode in the particle-hole channel.

  11. Integrability of Limit Shapes of the Six Vertex Model

    NASA Astrophysics Data System (ADS)

    Reshetikhin, Nicolai; Sridhar, Ananth

    2017-09-01

    The main result of this paper is the construction of infinitely many conserved quantities (corresponding to commuting transfer-matrices) for the limit shape equation for the six vertex model on a cylinder. This suggests that the limit shape equation is an integrable PDE with gradient constraints. At the free fermionic point this equation becomes the complex Burgers equation.

  12. Jobs masonry in LHCb with elastic Grid Jobs

    NASA Astrophysics Data System (ADS)

    Stagni, F.; Charpentier, Ph

    2015-12-01

    In any distributed computing infrastructure, a job is normally forbidden to run for an indefinite amount of time. This limitation is implemented using different technologies, the most common one being the CPU time limit implemented by batch queues. It is therefore important to have a good estimate of how much CPU work a job will require: otherwise, it might be killed by the batch system, or by whatever system is controlling the jobs’ execution. In many modern interwares, the jobs are actually executed by pilot jobs, that can use the whole available time in running multiple consecutive jobs. If at some point the available time in a pilot is too short for the execution of any job, it should be released, while it could have been used efficiently by a shorter job. Within LHCbDIRAC, the LHCb extension of the DIRAC interware, we developed a simple way to fully exploit computing capabilities available to a pilot, even for resources with limited time capabilities, by adding elasticity to production MonteCarlo (MC) simulation jobs. With our approach, independently of the time available, LHCbDIRAC will always have the possibility to execute a MC job, whose length will be adapted to the available amount of time: therefore the same job, running on different computing resources with different time limits, will produce different amounts of events. The decision on the number of events to be produced is made just in time at the start of the job, when the capabilities of the resource are known. In order to know how many events a MC job will be instructed to produce, LHCbDIRAC simply requires three values: the CPU-work per event for that type of job, the power of the machine it is running on, and the time left for the job before being killed. Knowing these values, we can estimate the number of events the job will be able to simulate with the available CPU time. This paper will demonstrate that, using this simple but effective solution, LHCb manages to make a more efficient use of

  13. Empty versus filled polyhedra: 11 vertex bare germanium clusters.

    PubMed

    Uţă, Matei-Maria; King, Robert Bruce

    2014-04-01

    The structures and energetics of centered 10-vertex Ge@Ge₁₀(z) (z = -4, -2, 0, +2, +4) clusters have been investigated by density functional theory (DFT) for comparison with the previously studied isomeric empty 11-vertex Ge₁₁(z) clusters. For the cationic species (z = +2, +4) such centered Ge@Ge₁₀(z) structures are shown to be energetically competitive (within ∼1 kcal mol⁻¹) to the lowest energy isomeric empty Ge₁₁(z) structures. These Ge@Ge₁₀(z) structures can be derived from the lowest energy empty 10-vertex Ge₁₀(z-4) structures by inserting a Ge⁴⁺ ion in the center. The outer 10-vertex polyhedron in the lowest energy Ge@Ge₁₀²⁺ dication structure is the most spherical D(4d) bicapped square antiprism, which is also the lowest energy structure of the empty Ge₁₀²⁻ dianion, as expected from the Wade-Mingos skeletal electron counting rules. For the tetracationic Ge₁₁⁴⁺ /Ge@Ge₁₀⁴⁺ system the lowest energy centered Ge@Ge₁₀⁴⁺ structure can be obtained by inserting a Ge⁴⁺ ion in the center of a C(3v) deltahedral empty Ge10 cluster. Centered 10-vertex polyhedral Ge@Ge₁₀(z) structures were also found for the neutral (z = 0) and dianionic (z = -2) systems but at significantly higher energies than the lowest energy isomeric empty Ge₁₁(z) structures.

  14. Proposed proper Engle-Pereira-Rovelli-Livine vertex amplitude

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan

    2013-04-01

    As established in a prior work of the author, the linear simplicity constraints used in the construction of the so-called “new” spin-foam models mix three of the five sectors of Plebanski theory as well as two dynamical orientations, and this is the reason for multiple terms in the asymptotics of the Engle-Pereira-Rovelli-Livine vertex amplitude as calculated by Barrett et al. Specifically, the term equal to the usual exponential of i times the Regge action corresponds to configurations either in sector (II+) with positive orientation or sector (II-) with negative orientation. The presence of the other terms beyond this cause problems in the semiclassical limit of the spin-foam model when considering multiple 4-simplices due to the fact that the different terms for different 4-simplices mix in the semiclassical limit, leading in general to a non-Regge action and hence non-Regge and nongravitational configurations persisting in the semiclassical limit. To correct this problem, we propose to modify the vertex so its asymptotics include only the one term of the form eiSRegge. To do this, an explicit classical discrete condition is derived that isolates the desired gravitational sector corresponding to this one term. This condition is quantized and used to modify the vertex amplitude, yielding what we call the “proper Engle-Pereira-Rovelli-Livine vertex amplitude.” This vertex still depends only on standard SU(2) spin-network data on the boundary, is SU(2) gauge-invariant, and is linear in the boundary state, as required. In addition, the asymptotics now consist in the single desired term of the form eiSRegge, and all degenerate configurations are exponentially suppressed. A natural generalization to the Lorentzian signature is also presented.

  15. A quantum hybrid with a thin antenna at the vertex of a wedge

    NASA Astrophysics Data System (ADS)

    Carlone, Raffaele; Posilicano, Andrea

    2017-03-01

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a "hybrid surface" consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex.

  16. Silicon pixel-detector R&D for CLIC

    NASA Astrophysics Data System (ADS)

    Nürnberg, A.

    2016-11-01

    The physics aims at the future CLIC high-energy linear e+e- collider set very high precision requirements on the performance of the vertex and tracking detectors. Moreover, these detectors have to be well adapted to the experimental conditions, such as the time structure of the collisions and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of a few μm, ultra-low mass (~ 0.2%X0 per layer for the vertex region and ~ 1%X0 per layer for the outer tracker), very low power dissipation (compatible with air-flow cooling in the inner vertex region) and pulsed power operation, complemented with ~ 10 ns time stamping capabilities. A highly granular all-silicon vertex and tracking detector system is under development, following an integrated approach addressing simultaneously the physics requirements and engineering constraints. For the vertex-detector region, hybrid pixel detectors with small pitch (25 μm) and analog readout are explored. For the outer tracking region, both hybrid concepts and fully integrated CMOS sensors are under consideration. The feasibility of ultra-thin sensor layers is validated with Timepix3 readout ASICs bump bonded to active edge planar sensors with 50 μm to 150 μm thickness. Prototypes of CLICpix readout ASICs implemented in 6525 nm CMOS technology with 25 μm pixel pitch have been produced. Hybridisation concepts have been developed for interconnecting these chips either through capacitive coupling to active HV-CMOS sensors or through bump-bonding to planar sensors. Recent R&D achievements include results from beam tests with all types of hybrid assemblies. Simulations based on Geant4 and TCAD are used to validate the experimental results and to assess and optimise the performance of various detector designs.

  17. Detector Developments for the High Luminosity LHC Era (3/4)

    ScienceCinema

    None

    2016-07-12

    Tracking Detectors - Part I. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

  18. Detector Developments for the High Luminosity LHC Era (4/4)

    ScienceCinema

    None

    2016-07-12

    Tracking Detectors - Part II. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

  19. Detector Developments for the High Luminosity LHC Era (4/4)

    SciTech Connect

    2010-09-22

    Tracking Detectors - Part II. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

  20. Detector Developments for the High Luminosity LHC Era (3/4)

    SciTech Connect

    2010-09-22

    Tracking Detectors - Part I. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

  1. Small-Scale Readout Systems Prototype for the STAR PIXEL Detector

    SciTech Connect

    Szelezniak, Michal A.; Besson, Auguste; Colledani, Claude; Dorokhov, Andrei; Dulinski, Wojciech; Greiner, Leo C.; Himmi, Abdelkader; Hu, Christine; Matis, Howard S.; Ritter, Hans Georg; Rose, Andrew; Shabetai, Alexandre; Stezelberger, Thorsten; Sun, Xiangming; Thomas, Jim H.; Valin, Isabelle; Vu, Chinh Q.; Wieman, Howard H.; Winter, Marc

    2008-10-01

    A prototype readout system for the STAR PIXEL detector in the Heavy Flavor Tracker (HFT) vertex detector upgrade is presented. The PIXEL detector is a Monolithic Active Pixel Sensor (MAPS) based silicon pixel vertex detector fabricated in a commercial CMOS process that integrates the detector and front-end electronics layers in one silicon die. Two generations ofMAPS prototypes designed specifically for the PIXEL are discussed. We have constructed a prototype telescope system consisting of three small MAPS sensors arranged in three parallel and coaxial planes with a readout system based on the readout architecture for PIXEL. This proposed readout architecture is simple and scales to the size required to readout the final detector. The real-time hit finding algorithm necessary for data rate reduction in the 400 million pixel detector is described, and aspects of the PIXEL system integration into the existing STAR framework are addressed. The complete system has been recently tested and shown to be fully functional.

  2. Physics benchmarks for the Belle II pixel detector

    NASA Astrophysics Data System (ADS)

    Li Gioi, L.

    2015-03-01

    SuperKEKB, the massive upgrade of the asymmetric electron positron collider KEKB in Tsukuba, Japan, aims at an integrated luminosity in excess of 50 ab-1. It will deliver an instantaneous luminosity of 8 ṡ 1035 cm-2s-1, which is 40 times higher than the world record set by KEKB. At this high luminosity, a large increase of the background relative to the previous KEKB machine is expected. This and the more demanding physics rate ask for an entirely new tracking system. The expected increase of background would in fact create an unacceptable high occupancy for a silicon strip detector, making an efficient tracks reconstruction and vertexing impossible. The solution for Belle II is a pixel detector which intrinsically provides three dimensional space points. The new two layers silicon pixel vertex detector, based on DEPFET technology, will be mounted directly on the beam pipe. It will provide an accurate measurement of the tracks position in order to precisely reconstruct the decay vertex of the short living particles.In this paper we will discuss the physics performance of the Belle II pixel vertex detector which will be essential for the precise measurement of the CP parameters in various B and D decay modes.

  3. Heavy flavor production in CDF II detector

    SciTech Connect

    Gorelov, Igor V.; /New Mexico U.

    2006-01-01

    For data collected with the CDF Run II detector, measurements of the charm and bottom production cross-sections are presented. The results are based both on large samples of fully reconstructed hadron decay products of charm and bottom made available by the tracking triggers and on a calorimeter jet triggered sample tagged by the presence of a secondary vertex. The experimental data are compared with theoretical predictions from recent next-to-leading order (NLO) QCD calculations.

  4. Measurement of C P violation in B → J/ ψ KS0 decays at LHCb

    NASA Astrophysics Data System (ADS)

    Meier, F.; LHCb Collaboration

    2016-07-01

    Analysing a data sample corresponding to an integrated luminosity of 3 fb-1 of pp collisions collected by the LHCb detector at the LHC CP violation in B0→J/ψK0S and B0s→J/ψK0S is measured. The results S(B0→J/ψK0S) = -0.038 ± 0.035 {(stat)} ± 0.020 {(syst)} are consistent with the current world averages and with the Standard Model expectations. In B0s→J/ψK0s the results A_{ΔΓ(B0s→J/ψK0s) = 0.49 ±^{0.77}_{0.65} {(stat)} ± 0.06 {(syst)}, S(B0s→J/ψK0s) = -0.08 ± 0.40 {(stat)} ± 0.08 {(syst)}, C(B0s→J/ψK0s) = - 0.28 ± 0.41 {(stat)} ± 0.08 {(syst)} reflect the first determination of these C P observables paving a new way towards the control of penguin pollutions in the determination of sin 2β.

  5. Phosphorylation of the Light-Harvesting Complex II Isoform Lhcb2 Is Central to State Transitions1[OPEN

    PubMed Central

    Cariti, Federica; Fucile, Geoffrey; Goldschmidt-Clermont, Michel

    2015-01-01

    Light-harvesting complex II (LHCII) is a crucial component of the photosynthetic machinery, with central roles in light capture and acclimation to changing light. The association of an LHCII trimer with PSI in the PSI-LHCII supercomplex is strictly dependent on LHCII phosphorylation mediated by the kinase STATE TRANSITION7, and is directly related to the light acclimation process called state transitions. In Arabidopsis (Arabidopsis thaliana), the LHCII trimers contain isoforms that belong to three classes: Lhcb1, Lhcb2, and Lhcb3. Only Lhcb1 and Lhcb2 can be phosphorylated in the N-terminal region. Here, we present an improved Phos-tag-based method to determine the absolute extent of phosphorylation of Lhcb1 and Lhcb2. Both classes show very similar phosphorylation kinetics during state transition. Nevertheless, only Lhcb2 is extensively phosphorylated (>98%) in PSI-LHCII, whereas phosphorylated Lhcb1 is largely excluded from this supercomplex. Both isoforms are phosphorylated to different extents in other photosystem supercomplexes and in different domains of the thylakoid membranes. The data imply that, despite their high sequence similarity, differential phosphorylation of Lhcb1 and Lhcb2 plays contrasting roles in light acclimation of photosynthesis. PMID:26438789

  6. Vertex amplitudes in spin foam loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Craig, David

    2016-03-01

    We discuss properties of the vertex expansion for homogeneous, isotropic loop quantum cosmological models sourced by a massless, minimally coupled scalar field, which in this model plays the role of an internal matter ``clock''. We show that the vertex expansion, first written down by Ashtekar, Campiglia and Henderson, must be thought of as a short-time expansion in the sense that the amplitude for volume transitions is constrained both by the order of the expansion and by the elapsed scalar field. To calculate the amplitude for significant volume changes or between large differences in the value of the scalar field requires the expansion be evaluated to very high order. This contribution describes work in collaboration with P. Singh.

  7. An unenumerative DNA computing model for vertex coloring problem.

    PubMed

    Xu, Jin; Qiang, Xiaoli; Yang, Yan; Wang, Baoju; Yang, Dongliang; Luo, Liang; Pan, Linqiang; Wang, Shudong

    2011-06-01

    The solution space exponential explosion caused by the enumeration of the candidate solutions maybe is the biggest obstacle in DNA computing. In the paper, a new unenumerative DNA computing model for graph vertex coloring problem is presented based on two techniques: 1) ordering the vertex sequence for a given graph in such a way that any two consecutive labeled vertices i and i+1 should be adjacent in the graph as much as possible; 2) reducing the number of encodings representing colors according to the construture of the given graph. A graph with 12 vertices without triangles is solved and its initial solution space includes only 283 DNA strands, which is 0.0532 of 3(12) (the worst complexity).

  8. On the zero crossing of the three-gluon vertex

    NASA Astrophysics Data System (ADS)

    Athenodorou, A.; Binosi, D.; Boucaud, Ph.; De Soto, F.; Papavassiliou, J.; Rodríguez-Quintero, J.; Zafeiropoulos, S.

    2016-10-01

    We report on new results on the infrared behavior of the three-gluon vertex in quenched Quantum Chromodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as 'zero crossing', the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev-Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger-Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.

  9. 3-state Hamiltonians associated to solvable 33-vertex models

    NASA Astrophysics Data System (ADS)

    Crampé, N.; Frappat, L.; Ragoucy, E.; Vanicat, M.

    2016-09-01

    Using the nested coordinate Bethe ansatz, we study 3-state Hamiltonians with 33 non-vanishing entries, or 33-vertex models, where only one global charge with degenerate eigenvalues exists and each site possesses three internal degrees of freedom. In the context of Markovian processes, they correspond to diffusing particles with two possible internal states which may be exchanged during the diffusion (transmutation). The first step of the nested coordinate Bethe ansatz is performed providing the eigenvalues in terms of rapidities. We give the constraints ensuring the consistency of the computations. These rapidities also satisfy Bethe equations involving 4 × 4 R-matrices, solutions of the Yang-Baxter equation which implies new constraints on the models. We solve them allowing us to list all the solvable 33-vertex models.

  10. Vertex topological indices and tree expressions, generalizations of continued fractions

    PubMed Central

    2010-01-01

    We expand on the work of Hosoya to describe a generalization of continued fractions called “tree expressions.” Each rooted tree will be shown to correspond to a unique tree expression which can be evaluated as a rational number (not necessarily in lowest terms) whose numerator is equal to the Hosoya index of the entire tree and whose denominator is equal to the tree with the root deleted. In the development, we use Z(G) to define a natural candidate ζ(G, v) for a “vertex topological index” which is a value applied to each vertex of a graph, rather than a value assigned to the graph overall. Finally, we generalize the notion of tree expression to “labeled tree expressions” that correspond to labeled trees and show that such expressions can be evaluated as quotients of determinants of matrices that resemble adjacency matrices. PMID:20490285

  11. Six-vertex model and Schramm-Loewner evolution

    NASA Astrophysics Data System (ADS)

    Kenyon, Richard; Miller, Jason; Sheffield, Scott; Wilson, David B.

    2017-05-01

    Square ice is a statistical mechanics model for two-dimensional ice, widely believed to have a conformally invariant scaling limit. We associate a Peano (space-filling) curve to a square ice configuration, and more generally to a so-called six-vertex model configuration, and argue that its scaling limit is a space-filling version of the random fractal curve SL E κ, Schramm-Loewner evolution with parameter κ , where 4 <κ ≤12 +8 √{2 } . For square ice, κ =12 . At the "free-fermion point" of the six-vertex model, κ =8 +4 √{3 } . These unusual values lie outside the classical interval 2 ≤κ ≤8 .

  12. Worldline calculation of the three-gluon vertex

    SciTech Connect

    Ahmadiniaz, N.; Schubert, C.

    2012-10-23

    The three-gluon vertex is a basic object of interest in nonabelian gauge theory. At the one-loop level, it has been calculated and analyzed by a number of authors. Here we use the worldline formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in terms of field strength tensors. We verify its equivalence with previously obtained representations, and explain the relation of its structure to the low-energy effective action. The sum rule found by Binger and Brodsky for the scalar, spinor and gluon loop contributions in the present approach relates to worldline supersymmetry.

  13. Prospects for studying penguin decays in LHCb experiments

    SciTech Connect

    Barsuk, S. Ya. Pakhlova, G. V. Belyaev, I. M.

    2006-04-15

    Investigation of loop penguin decays of beauty hadrons seems promising in testing the predictions of the Standard Model of electroweak and strong interactions and in seeking new phenomena beyond the Standard Model. The possibility of studying the radiative penguin decays B{sup 0} {sup {yields}} K*{sup 0}{gamma}, B{sup 0}{sub s} {sup {yields}} {phi}{gamma}, and B{sup 0} {sup {yields}} {omega}{gamma} and the gluonic penguin decays B{sup 0} {sup {yields}} {phi}K{sup 0}{sub S} and B{sup 0}{sub s} {sup {yields}} {phi}{phi} in LHCb experiments is discussed.

  14. Study of Lepton Flavor Universality in Semileptonic decays with LHCb

    NASA Astrophysics Data System (ADS)

    Hamilton, Brian; LHCb Collaboration

    2017-01-01

    Semileptonic b-hadron decays to tau leptons provide a powerful probe for a class of new physics models that may have Higgs-like non-universal couplings to the charged leptons. Recent improvements in the measured decay rates in these channels hint at an excess relative to the expected rates in Standard Model calculations. A new development in this area is the emergence of hadron collider measurements with different systematics and backgrounds providing complimentary probes of the same or similar processes. We present the latest progress in these measurements using the LHCb 7 and 8 TeV datasets. National Science Foundation.

  15. A Review of Recent Results on Quarkonium Production at LHCb

    NASA Astrophysics Data System (ADS)

    Pepe Altarelli, Monica

    2014-04-01

    A selection of LHCb results is presented on the production of heavy quarkonium states in pp collisions, including results on J/ψ and ϓ production at √s = 8 TeV, the measurement of prompt J/ψ polarisation, the production of χc mesons from converted photons, exclusive charmonium production, double J/ψ production, as well as recent results on J/ψ production in proton-lead collisions at √sNN = 5 TeV.

  16. 100 Gbps PCI-Express readout for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Durante, P.; Neufeld, N.; Schwemmer, R.; Balbi, G.; Marconi, U.

    2015-04-01

    We present a new data acquisition system under development for the next upgrade of the LHCb experiment at CERN. We focus in particular on the design of a new generation of readout boards, the PCIe40, and on the viability of PCI-Express as an interconnect technology for high speed readout. We show throughput measurements across the PCI-Express bus, on Altera Stratix 5 devices, using a DMA mechanism and different synchronization schemes between the FPGA and the readout unit. Finally we discuss hardware and software design considerations necessary to achieve a data throughput of 100 Gbps in the final readout board.

  17. Measurements of the LHCb software stack on the ARM architecture

    NASA Astrophysics Data System (ADS)

    Vijay Kartik, S.; Couturier, Ben; Clemencic, Marco; Neufeld, Niko

    2014-06-01

    The ARM architecture is a power-efficient design that is used in most processors in mobile devices all around the world today since they provide reasonable compute performance per watt. The current LHCb software stack is designed (and thus expected) to build and run on machines with the x86/x86_64 architecture. This paper outlines the process of measuring the performance of the LHCb software stack on the ARM architecture - specifically, the ARMv7 architecture on Cortex-A9 processors from NVIDIA and on full-fledged ARM servers with chipsets from Calxeda - and makes comparisons with the performance on x86_64 architectures on the Intel Xeon L5520/X5650 and AMD Opteron 6272. The paper emphasises the aspects of performance per core with respect to the power drawn by the compute nodes for the given performance - this ensures a fair real-world comparison with much more 'powerful' Intel/AMD processors. The comparisons of these real workloads in the context of LHCb are also complemented with the standard synthetic benchmarks HEPSPEC and Coremark. The pitfalls and solutions for the non-trivial task of porting the source code to build for the ARMv7 instruction set are presented. The specific changes in the build process needed for ARM-specific portions of the software stack are described, to serve as pointers for further attempts taken up by other groups in this direction. Cases where architecture-specific tweaks at the assembler lever (both in ROOT and the LHCb software stack) were needed for a successful compile are detailed - these cases are good indicators of where/how the software stack as well as the build system can be made more portable and multi-arch friendly. The experience gained from the tasks described in this paper are intended to i) assist in making an informed choice about ARM-based server solutions as a feasible low-power alternative to the current compute nodes, and ii) revisit the software design and build system for portability and generic improvements.

  18. Antihydrogen annihilation reconstruction with the ALPHA silicon detector

    NASA Astrophysics Data System (ADS)

    Andresen, G. B.; Ashkezari, M. D.; Bertsche, W.; Bowe, P. D.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Hayano, R. S.; Humphries, A. J.; Hydomako, R.; Jonsell, S.; Jørgensen, L. V.; Kurchaninov, L.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Sarid, E.; Seif El Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Yamazaki, Y.; Alpha Collaboration

    2012-08-01

    The ALPHA experiment has succeeded in trapping antihydrogen, a major milestone on the road to spectroscopic comparisons of antihydrogen with hydrogen. An annihilation vertex detector, which determines the time and position of antiproton annihilations, has been central to this achievement. This detector, an array of double-sided silicon microstrip detector modules arranged in three concentric cylindrical tiers, is sensitive to the passage of charged particles resulting from antiproton annihilation. This article describes the method used to reconstruct the annihilation location and to distinguish the annihilation signal from the cosmic ray background. Recent experimental results using this detector are outlined.

  19. Duality, gauged supergravities and vertex operators in string theory

    NASA Astrophysics Data System (ADS)

    Langham, Michael Charles

    2000-10-01

    We first examine a conjectured S-duality between the type IIA on R6 × K3 and the Heterotic string on R6 × T4, and compare their perturbative spectra. The partition function of type II strings on R6 × K3, in the orbifold limit, is computed as a modular invariant sum of spin structures or sectors, required by perturbative unitarity. Secondly, we analyze type II strings on R6 × W4, where W4 is associated with the tube metric conformal field theory, given by the degrees of freedom transverse to the Neveu- Schwarz fivebrane solution. The tube metric generates partition functions and perturbative spectra of string theories in six space-time dimensions, associated with the modular invariants of the level k affine SU(2) Kac-Moody algebra. We then study maximally supersymmetric gauged supergravities; i.e. low-energy limits of superstrings and M theory in anti-deSitter space times a sphere (AdSxS). We show how the gauge symmetry representation of the massless particle content of gauged supergravities can be derived from symmetric subgroups to be carried by string theory vertex operators in these compactified models. Lastly, for a non-maximally supersymmetric case, type IIB in AdS3 × S 3 background with NS-NS flux, we calculate explicit vertex operators using the Berkovits-Vafa-Witten formalism. From these, with suitable field definitions, the linearized field equations for six-dimensional supergravity and a tensor multiplet on AdS3 × S3 are recovered. We also discuss the three dimensional massless degrees of freedom that survive the S3 Kaluza-Klein compactification and show how our vertex operators are related to the vertex operators introduced by Giveon, Kutasov, and Seiberg.

  20. Nucleon contribution to the neutrino electromagnetic vertex in matter

    SciTech Connect

    DOlivo, J.C.; Nieves, J.F.

    1997-11-01

    We calculate the nucleon contribution to the electromagnetic vertex of a neutrino in a background of particles, including the effect of the anomalous magnetic moment of the nucleons. Explicit formulas for the form factors are given in various physical limits of practical interest. Several applications of the results are mentioned, including the effect of an external magnetic field on the dispersion relation of a neutrino in matter. {copyright} {ital 1997} {ital The American Physical Society}

  1. String loop corrections from fusion of handles and vertex operators

    NASA Astrophysics Data System (ADS)

    Ooguri, H.; Sakai, N.

    1987-10-01

    Handle operators are introduced to describe nonlinear sigma models on higher genus surfaces by an operator formalism. Operator product expansions (fusions) among handle and vertex operators provide new sources of conformal symmetry breakings. Through the renormalization group equations, string-loop corrected equations of motion without one-particle reducible parts are derived to one-loop order. Work supported in part by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture (No. 61540200).

  2. Edge union of networks on the same vertex set

    NASA Astrophysics Data System (ADS)

    Loe, Chuan Wen; Jeldtoft Jensen, Henrik

    2013-06-01

    Random network generators such as Erdős-Rényi, Watts-Strogatz and Barabási-Albert models are used as models to study real-world networks. Let G1(V, E1) and G2(V, E2) be two such networks on the same vertex set V. This paper studies the degree distribution and clustering coefficient of the resultant networks, G(V, E1∪E2).

  3. Organization mechanism and counting algorithm on vertex-cover solutions

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Zhang, Renquan; Niu, Baolong; Guo, Binghui; Zheng, Zhiming

    2015-04-01

    Counting the solution number of combinational optimization problems is an important topic in the study of computational complexity, which is concerned with Vertex-Cover in this paper. First, we investigate organizations of Vertex-Cover solution spaces by the underlying connectivity of unfrozen vertices and provide facts on the global and local environment. Then, a Vertex-Cover Solution Number Counting Algorithm is proposed and its complexity analysis is provided, the results of which fit very well with the simulations and have a better performance than those by 1-RSB in the neighborhood of c = e for random graphs. Based on the algorithm, variation and fluctuation on the solution number the statistics are studied to reveal the evolution mechanism of the solution numbers. Furthermore, the marginal probability distributions on the solution space are investigated on both the random graph and scale-free graph to illustrate the different evolution characteristics of their solution spaces. Thus, doing solution number counting based on the graph expression of the solution space should be an alternative and meaningful way to study the hardness of NP-complete and #P-complete problems and the appropriate algorithm design can help to achieve better approximations of solving combinational optimization problems and the corresponding counting problems.

  4. Automatically generated algorithms for the vertex coloring problem.

    PubMed

    Contreras Bolton, Carlos; Gatica, Gustavo; Parada, Víctor

    2013-01-01

    The vertex coloring problem is a classical problem in combinatorial optimization that consists of assigning a color to each vertex of a graph such that no adjacent vertices share the same color, minimizing the number of colors used. Despite the various practical applications that exist for this problem, its NP-hardness still represents a computational challenge. Some of the best computational results obtained for this problem are consequences of hybridizing the various known heuristics. Automatically revising the space constituted by combining these techniques to find the most adequate combination has received less attention. In this paper, we propose exploring the heuristics space for the vertex coloring problem using evolutionary algorithms. We automatically generate three new algorithms by combining elementary heuristics. To evaluate the new algorithms, a computational experiment was performed that allowed comparing them numerically with existing heuristics. The obtained algorithms present an average 29.97% relative error, while four other heuristics selected from the literature present a 59.73% error, considering 29 of the more difficult instances in the DIMACS benchmark.

  5. Automatically Generated Algorithms for the Vertex Coloring Problem

    PubMed Central

    Contreras Bolton, Carlos; Gatica, Gustavo; Parada, Víctor

    2013-01-01

    The vertex coloring problem is a classical problem in combinatorial optimization that consists of assigning a color to each vertex of a graph such that no adjacent vertices share the same color, minimizing the number of colors used. Despite the various practical applications that exist for this problem, its NP-hardness still represents a computational challenge. Some of the best computational results obtained for this problem are consequences of hybridizing the various known heuristics. Automatically revising the space constituted by combining these techniques to find the most adequate combination has received less attention. In this paper, we propose exploring the heuristics space for the vertex coloring problem using evolutionary algorithms. We automatically generate three new algorithms by combining elementary heuristics. To evaluate the new algorithms, a computational experiment was performed that allowed comparing them numerically with existing heuristics. The obtained algorithms present an average 29.97% relative error, while four other heuristics selected from the literature present a 59.73% error, considering 29 of the more difficult instances in the DIMACS benchmark. PMID:23516506

  6. DEPFET detectors for future electron-positron colliders

    NASA Astrophysics Data System (ADS)

    Marinas, C.

    2015-11-01

    The DEPFET Collaboration develops highly granular, ultra-thin pixel detectors for outstanding vertex reconstruction at future electron-positron collider experiments. A DEPFET sensor, by the integration of a field effect transistor on a fully depleted silicon bulk, provides simultaneous position sensitive detector capabilities and in pixel amplification. The characterization of the latest DEPFET prototypes has proven that a adequate signal-to-noise ratio and excellent single point resolution can be achieved for a sensor thickness of 50 micrometers. The close to final auxiliary ASICs have been produced and found to operate a DEPFET pixel detector of the latest generation with the required read-out speed. A complete detector concept is being developed for the Belle II experiment at the new Japanese super flavor factory. DEPFET is not only the technology of choice for the Belle II vertex detector, but also a prime candidate for the ILC. Therefore, in this contribution, the status of DEPFET R&D project is reviewed in the light of the requirements of the vertex detector at a future electron-positron collider.

  7. Disk storage management for LHCb based on Data Popularity estimator

    NASA Astrophysics Data System (ADS)

    Hushchyn, Mikhail; Charpentier, Philippe; Ustyuzhanin, Andrey

    2015-12-01

    This paper presents an algorithm providing recommendations for optimizing the LHCb data storage. The LHCb data storage system is a hybrid system. All datasets are kept as archives on magnetic tapes. The most popular datasets are kept on disks. The algorithm takes the dataset usage history and metadata (size, type, configuration etc.) to generate a recommendation report. This article presents how we use machine learning algorithms to predict future data popularity. Using these predictions it is possible to estimate which datasets should be removed from disk. We use regression algorithms and time series analysis to find the optimal number of replicas for datasets that are kept on disk. Based on the data popularity and the number of replicas optimization, the algorithm minimizes a loss function to find the optimal data distribution. The loss function represents all requirements for data distribution in the data storage system. We demonstrate how our algorithm helps to save disk space and to reduce waiting times for jobs using this data.

  8. More lepton flavor violating observables for LHCb's run 2

    NASA Astrophysics Data System (ADS)

    Guadagnoli, Diego; Melikhov, Dmitri; Reboud, Méril

    2016-09-01

    The RK measurement by LHCb suggests non-standard lepton non-universality (LNU) to occur in b → sℓ+ℓ- transitions, with effects in muons rather than electrons. A number of other measurements of b → sℓ+ℓ- transitions by LHCb and B-factories display disagreement with the SM predictions and, remarkably, these discrepancies are consistent in magnitude and sign with the RK effect. Non-standard LNU suggests non-standard lepton flavor violation (LFV) as well, for example in B → Kℓℓ‧ and Bs → ℓℓ‧. There are good reasons to expect that the new effects may be larger for generations closer to the third one. In this case, the Bs → μe decay may be the most difficult to reach experimentally. We propose and study in detail the radiative counterpart of this decay, namely Bs → μeγ, whereby the chiral-suppression factor is replaced by a factor of order α / π. A measurement of this mode would be sensitive to the same physics as the purely leptonic LFV decay and, depending on experimental efficiencies, it may be more accessible. A realistic expectation is a factor of two improvement in statistics for either of the Bd,s modes.

  9. LHCb experience with running jobs in virtual machines

    NASA Astrophysics Data System (ADS)

    McNab, A.; Stagni, F.; Luzzi, C.

    2015-12-01

    The LHCb experiment has been running production jobs in virtual machines since 2013 as part of its DIRAC-based infrastructure. We describe the architecture of these virtual machines and the steps taken to replicate the WLCG worker node environment expected by user and production jobs. This relies on the uCernVM system for providing root images for virtual machines. We use the CernVM-FS distributed filesystem to supply the root partition files, the LHCb software stack, and the bootstrapping scripts necessary to configure the virtual machines for us. Using this approach, we have been able to minimise the amount of contextualisation which must be provided by the virtual machine managers. We explain the process by which the virtual machine is able to receive payload jobs submitted to DIRAC by users and production managers, and how this differs from payloads executed within conventional DIRAC pilot jobs on batch queue based sites. We describe our operational experiences in running production on VM based sites managed using Vcycle/OpenStack, Vac, and HTCondor Vacuum. Finally we show how our use of these resources is monitored using Ganglia and DIRAC.

  10. The LHCb Data Acquisition and High Level Trigger Processing Architecture

    NASA Astrophysics Data System (ADS)

    Frank, M.; Gaspar, C.; Jost, B.; Neufeld, N.

    2015-12-01

    The LHCb experiment at the LHC accelerator at CERN collects collisions of particle bunches at 40 MHz. After a first level of hardware trigger with an output rate of 1 MHz, the physically interesting collisions are selected by running dedicated trigger algorithms in the High Level Trigger (HLT) computing farm. This farm consists of up to roughly 25000 CPU cores in roughly 1750 physical nodes each equipped with up to 4 TB local storage space. This work describes the LHCb online system with an emphasis on the developments implemented during the current long shutdown (LS1). We will elaborate the architecture to treble the available CPU power of the HLT farm and the technicalities to determine and verify precise calibration and alignment constants which are fed to the HLT event selection procedure. We will describe how the constants are fed into a two stage HLT event selection facility using extensively the local disk buffering capabilities on the worker nodes. With the installed disk buffers, the CPU resources can be used during periods of up to ten days without beams. These periods in the past accounted to more than 70% of the total time.

  11. PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT.

    SciTech Connect

    AKIBA,Y.

    2004-03-30

    We propose the construction of a Silicon Vertex Tracker (VTX) for the PHENIX experiment at RHIC. The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometers. Our prime motivation is to provide precision measurements of heavy-quark production (charm and beauty) in A+A, p(d)+A, and polarized p+p collisions. These are key measurements for the future RHIC program, both for the heavy ion program as it moves from the discovery phase towards detailed investigation of the properties of the dense nuclear medium created in heavy ion collisions, and for the exploration of the nucleon spin-structure functions. In addition, the VTX will also considerably improve other measurements with PHENIX. The main physics topics addressed by the VTX are: (1) Hot and dense strongly interacting matter--Potential enhancement of charm production; Open beauty production; Flavor dependence of jet quenching and QCD energy loss; Accurate charm reference for quarkonium; Thermal dilepton radiation; High p{sub T} phenomena with light flavors above 10-15 GeV/c in p{sub T}; and Upsilon spectroscopy in the e{sup +}e{sup -} decay channel. (2) Gluon spin structure of the nucleon--{Delta}G/G with charm; {Delta}G/G with beauty; and x dependence of {Delta}G/G with {gamma}-jet correlations. (3) Nucleon structure in nuclei--Gluon shadowing over broad x-range. With the present PHENIX detector, heavy-quark production has been measured indirectly through the observation of single electrons. These measurements are inherently limited in accuracy by systematic uncertainties resulting from the large electron background from Dalitz decays and photon conversions. In particular, the statistical nature of the analysis does not allow for a model-independent separation of the charm and beauty contributions. The VTX detector will provide vertex tracking with a resolution of <50 {micro}m over a large coverage both in rapidity (|{eta}| < 1.2) and in azimuthal angle ({Delta}{phi} {approx

  12. Final Report for the UNIVERSITY-BASED DETECTOR RESEARCH AND DEVELOPMENT FOR THE INTERNATIONAL LINEAR COLLIDER

    SciTech Connect

    Brau, James E

    2013-04-22

    The U.S Linear Collider Detector R&D program, supported by the DOE and NSF umbrella grants to the University of Oregon, made significant advances on many critical aspects of the ILC detector program. Progress advanced on vertex detector sensor development, silicon and TPC tracking, calorimetry on candidate technologies, and muon detection, as well as on beamline measurements of luminosity, energy, and polarization.

  13. Status and future plans for the Mark II detector at SLAC

    SciTech Connect

    Perl, M.L.

    1983-04-01

    In this brief talk, I report on three subjects. First the present status of PEP, where there has been a very large increase in the luminosity in the past five months. Next, the present status of the Mark II detector, whose secondary vertex detector constitutes a very important part of the physics which our collaboration is doing at PEP. Finally, I review the design of the upgraded Mark II Detector which will be used at the Stanford Linear Collider (SLC).

  14. Operational experience with the ALICE pixel detector

    NASA Astrophysics Data System (ADS)

    Mastroserio, A.

    2017-01-01

    The Silicon Pixel Detector (SPD) constitutes the two innermost layers of the Inner Tracking System of the ALICE experiment and it is the closest detector to the interaction point. As a vertex detector, it has the unique feature of generating a trigger signal that contributes to the L0 trigger of the ALICE experiment. The SPD started collecting data since the very first pp collisions at LHC in 2009 and since then it has taken part in all pp, Pb-Pb and p-Pb data taking campaigns. This contribution will present the main features of the SPD, the detector performance and the operational experience, including calibration and optimization activities from Run 1 to Run 2.

  15. Sensor Development and Readout Prototyping for the STAR Pixel Detector

    SciTech Connect

    Greiner, L.; Anderssen, E.; Matis, H.S.; Ritter, H.G.; Stezelberger, T.; Szelezniak, M.; Sun, X.; Vu, C.; Wieman, H.

    2009-01-14

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

  16. cellGPU: Massively parallel simulations of dynamic vertex models

    NASA Astrophysics Data System (ADS)

    Sussman, Daniel M.

    2017-10-01

    Vertex models represent confluent tissue by polygonal or polyhedral tilings of space, with the individual cells interacting via force laws that depend on both the geometry of the cells and the topology of the tessellation. This dependence on the connectivity of the cellular network introduces several complications to performing molecular-dynamics-like simulations of vertex models, and in particular makes parallelizing the simulations difficult. cellGPU addresses this difficulty and lays the foundation for massively parallelized, GPU-based simulations of these models. This article discusses its implementation for a pair of two-dimensional models, and compares the typical performance that can be expected between running cellGPU entirely on the CPU versus its performance when running on a range of commercial and server-grade graphics cards. By implementing the calculation of topological changes and forces on cells in a highly parallelizable fashion, cellGPU enables researchers to simulate time- and length-scales previously inaccessible via existing single-threaded CPU implementations. Program Files doi:http://dx.doi.org/10.17632/6j2cj29t3r.1 Licensing provisions: MIT Programming language: CUDA/C++ Nature of problem: Simulations of off-lattice "vertex models" of cells, in which the interaction forces depend on both the geometry and the topology of the cellular aggregate. Solution method: Highly parallelized GPU-accelerated dynamical simulations in which the force calculations and the topological features can be handled on either the CPU or GPU. Additional comments: The code is hosted at https://gitlab.com/dmsussman/cellGPU, with documentation additionally maintained at http://dmsussman.gitlab.io/cellGPUdocumentation

  17. A brief review of measurements of electroweak bosons at the LHCb experiment in LHC Run 1

    NASA Astrophysics Data System (ADS)

    Barter, William

    2016-09-01

    The LHCb experiment is one of four major experiments at the large hadron collider (LHC). Despite being designed for the study of beauty and charm particles, it has made important contributions in other areas, such as the production and decay of W and Z bosons. Such measurements can be used to study and constrain parton distribution functions (PDFs), as well as to test perturbative quantum chromodynamics (QCD) in hard scattering processes. The angular structure of Z boson decays to leptons can also be studied and used to measure the weak mixing angle. The phase-space probed by LHCb is particularly sensitive to this quantity, and the LHCb measurement using the dimuon final state is currently the most precise determination of sin2𝜃 eff.lept. at the LHC. LHCb measurements made using data collected during the first period of LHC operations (LHC Run 1) are discussed in this review. The paper also considers the potential impact of related future measurements.

  18. The eight-vertex model with quasi-periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Niccoli, G.; Terras, V.

    2016-01-01

    We study the inhomogeneous eight-vertex model (or equivalently the XYZ Heisenberg spin-1/2 chain) with all kinds of integrable quasi-periodic boundary conditions: periodic, {σ }x-twisted, {σ }y-twisted or {σ }z-twisted. We show that in all these cases but the periodic one with an even number of sites {N}, the transfer matrix of the model is related, by the vertex-IRF transformation, to the transfer matrix of the dynamical six-vertex model with antiperiodic boundary conditions, which we have recently solved by means of Sklyanin's separation of variables approach. We show moreover that, in all the twisted cases, the vertex-IRF transformation is bijective. This allows us to completely characterize, from our previous results on the antiperiodic dynamical six-vertex model, the twisted eight-vertex transfer matrix spectrum (proving that it is simple) and eigenstates. We also consider the periodic case for {N} odd. In this case we can define two independent vertex-IRF transformations, both not bijective, and by using them we show that the eight-vertex transfer matrix spectrum is doubly degenerate, and that it can, as well as the corresponding eigenstates, also be completely characterized in terms of the spectrum and eigenstates of the dynamical six-vertex antiperiodic transfer matrix. In all these cases we can adapt to the eight-vertex case the reformulations of the dynamical six-vertex transfer matrix spectrum and eigenstates that had been obtained by T-Q functional equations, where the Q-functions are elliptic polynomials with twist-dependent quasi-periods. Such reformulations enable one to characterize the eight-vertex transfer matrix spectrum by the solutions of some Bethe-type equations, and to rewrite the corresponding eigenstates as the multiple action of some operators on a pseudo-vacuum state, in a similar way as in the algebraic Bethe ansatz framework.

  19. Multijet decays of quarkonia: Testing the three-gluon vertex

    NASA Astrophysics Data System (ADS)

    Koller, K.; Streng, K. H.; Walsh, T. F.; Zerwas, P. M.

    1982-10-01

    We study the 4-jet and photon plus 3-jet decays of orthoquarkonia, 3S1( Q overlineQ)→ GGGG+ GGq overlineq→4 jets, 3S1( Q overlineQ→γ GGG+γ Gq overlineq→γ+3 jets. We show that the characteristic features of the jet distributions in the final state are determined by the 3-gluon vertex of quantum chromodynamics. These decays of a heavy quarkonium resonance (toponium) will offer clear signals for the gluons' self-coupling which can establish QCD as a local non-abelian gauge theory.

  20. Anomalous ω-Z-γ vertex from hidden local symmetry

    NASA Astrophysics Data System (ADS)

    Harada, Masayasu; Matsuzaki, Shinya; Yamawaki, Koichi

    2011-08-01

    We formulate the general form of the ω-Z-γ vertex in the framework based on the hidden local symmetry, which arises from the gauge-invariant terms for intrinsic parity-odd part of the effective action. Those terms are given as the homogeneous part of the general solution (having free parameters) to the Wess-Zumino anomaly equation and hence are not determined by the anomaly, in sharp contrast to the Harvey-Hill-Hill (HHH) action where the relevant vertex is claimed to be uniquely determined by the anomaly. We show that, even in the framework that HHH was based on, the ω-Z-γ vertex is actually not determined by the anomaly but by the homogeneous (anomaly-free) part of the general solution to the Wess-Zumino anomaly equation having free parameters in the same way as in the hidden local symmetry formulation: The HHH action is just a particular choice of the free parameters in the general solution. We further show that the ω-Z-γ vertex related to the neutrino (ν)-nucleon (N) scattering cross section σ(νN→νN(N')γ) is determined not by the anomaly but by the anomaly-free part of the general solution having free parameters. Nevertheless, we find that the cross section σ(νN→νN(N')γ) is related through the Ward-Takahashi identity to Γ(ω→π0γ) which has the same parameter dependence as that of σ(νN→νN(N')γ) and hence the ratio σ(νN→νN(N')γ)/Γ(ω→π0γ) is fixed independently of these free parameters. Other set of the free parameters of the general solution can be fixed to make the best fit of the ω→π0l+l- process, which substantially differs from the HHH action. This gives a prediction of the cross section σ(νN→νN(N')γ*(l+l-)) to be tested at ν-N collision experiments in the future.

  1. Vertex Operators Arising from Jacobi-Trudi Identities

    NASA Astrophysics Data System (ADS)

    Jing, Naihuan; Rozhkovskaya, Natasha

    2016-09-01

    We give an interpretation of the boson-fermion correspondence as a direct consequence of the Jacobi-Trudi identity. This viewpoint enables us to construct from a generalized version of the Jacobi-Trudi identity the action of a Clifford algebra on the polynomial algebras that arrive as analogues of the algebra of symmetric functions. A generalized Giambelli identity is also proved to follow from that identity. As applications, we obtain explicit formulas for vertex operators corresponding to characters of the classical Lie algebras, shifted Schur functions, and generalized Schur symmetric functions associated to linear recurrence relations.

  2. Reconstruction of low-momentum protons with the Fine-Grained Detector of the T2K experiment

    NASA Astrophysics Data System (ADS)

    Zalipska, Joanna; T2K Collaboration

    2017-09-01

    Low-momentum protons are important in the searches for neutrino interactions with correlated pairs of nucleons, 2p-2h. An attempt using the T2K 0ff-axis near detector data was made to use vertex activity (energy deposited near the vertex of the neutrino interaction) to search for a signature of such low-momentum particles. The analysis is based on extracting a signal of non-reconstructed particles expected to be associated to the vertex activity, which is later used by a neural network to detect the presence of the low-momentum proton in the interaction.

  3. Three-point vertex functions in Yang-Mills Theory and QCD in Landau gauge

    NASA Astrophysics Data System (ADS)

    Blum, Adrian L.; Alkofer, Reinhard; Huber, Markus Q.; Windisch, Andreas

    2017-03-01

    Solutions for the three-gluon and quark-gluon vertices from Dyson-Schwinger equations and the three-particle irreducible formalism are discussed. Dynamical quarks ("unquenching") change the three-gluon vertex via the quark-triangle diagrams which themselves include fully dressed quark-gluon vertex functions. On the other hand, the quark-swordfish diagram is, at least with the model used for the two-quark-two-gluon vertex employed here, of minor importance. For the leading tensor structure of the threegluon vertex the "unquenching" effect can be summarized for the nonperturbative part as a shift of the related dressing function towards the infrared.

  4. Radiation hard programmable delay line for LHCb calorimeter upgrade

    NASA Astrophysics Data System (ADS)

    Mauricio, J.; Gascón, D.; Vilasís, X.; Picatoste, E.; Machefert, F.; Lefrancois, J.; Duarte, O.; Beigbeder, C.

    2014-01-01

    This paper describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with less than 5 ps jitter and 23 ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end analog signal processing ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35 μm technology.

  5. Identification of beauty and charm quark jets at LHCb

    NASA Astrophysics Data System (ADS)

    The LHCb Collaboration

    2015-06-01

    Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select b- and c-quark jets is measured using data recorded by LHCb from proton-proton collisions at √s = 7 TeV in 2011 and at √s = 8 TeV in 2012. The efficiency for identifying a b(c) jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum pT > 20GeV and pseudorapidity 2.2 < η < 4.2. The dependence of the performance on the pT and η of the jet is also measured.

  6. A History-based Estimation for LHCb job requirements

    NASA Astrophysics Data System (ADS)

    Rauschmayr, Nathalie

    2015-12-01

    The main goal of a Workload Management System (WMS) is to find and allocate resources for the given tasks. The more and better job information the WMS receives, the easier will be to accomplish its task, which directly translates into higher utilization of resources. Traditionally, the information associated with each job, like expected runtime, is defined beforehand by the Production Manager in best case and fixed arbitrary values by default. In the case of LHCb's Workload Management System no mechanisms are provided which automate the estimation of job requirements. As a result, much more CPU time is normally requested than actually needed. Particularly, in the context of multicore jobs this presents a major problem, since single- and multicore jobs shall share the same resources. Consequently, grid sites need to rely on estimations given by the VOs in order to not decrease the utilization of their worker nodes when making multicore job slots available. The main reason for going to multicore jobs is the reduction of the overall memory footprint. Therefore, it also needs to be studied how memory consumption of jobs can be estimated. A detailed workload analysis of past LHCb jobs is presented. It includes a study of job features and their correlation with runtime and memory consumption. Following the features, a supervised learning algorithm is developed based on a history based prediction. The aim is to learn over time how jobs’ runtime and memory evolve influenced due to changes in experiment conditions and software versions. It will be shown that estimation can be notably improved if experiment conditions are taken into account.

  7. Natural constraints on the gluon-quark vertex

    NASA Astrophysics Data System (ADS)

    Binosi, Daniele; Chang, Lei; Papavassiliou, Joannis; Qin, Si-Xue; Roberts, Craig D.

    2017-02-01

    In principle, the strong-interaction sector of the standard model is characterized by a unique renormalization-group-invariant (RGI) running interaction and a unique form for the dressed-gluon-quark vertex, Γμ; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansätze for Γμ. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Evidently, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansätze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.

  8. Quark-gluon vertex: A perturbation theory primer and beyond

    NASA Astrophysics Data System (ADS)

    Bermudez, R.; Albino, L.; Gutiérrez-Guerrero, L. X.; Tejeda-Yeomans, M. E.; Bashir, A.

    2017-02-01

    There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in quantum chromodynamics, leading to the observed spectrum and properties of hadrons. Both the lattice and the Schwinger-Dyson communities have begun to calculate these form factors in various kinematical regimes of momenta involved. A natural consistency check for these studies is that they should match onto the perturbative predictions in the ultraviolet, where nonperturbative effects mellow down. In this article, we carry out a numerical analysis of the one-loop result for all the form factors of the quark-gluon vertex. Interestingly, even the one-loop results qualitatively encode most of the infrared enhancement features expected of their nonperturbative counter parts. We analyze various kinematical configurations of momenta: symmetric, on shell, and asymptotic. The on-shell limit enables us to compute anomalous chromomagnetic moment of quarks. The asymptotic results have implications for the multiplicative renormalizability of the quark propagator and its connection with the Landau-Khalatnikov-Fradkin transformations, allowing us to analyze and compare various Ansätze proposed so far.

  9. Vertex epidural hematoma: An analysis of a large series

    PubMed Central

    Ramesh, Vengalathur Ganesan; Kodeeswaran, Marappan; Deiveegan, Kunjithapatham; Sundar, Venkataraman; Sriram, Kuchalambal

    2017-01-01

    Context: Vertex epidural hematoma (VEDH) is uncommon. A high index of suspicion is required to suspect and diagnose this condition, and the surgical management is a challenge to neurosurgeons. There are only isolated case reports or small series of VEDH in the literature. Aims: We have tried to analyze a large series of VEDH seen in our institute. Settings and Design: Retrospective observational study. Subjects and Methods: This is an analysis of case records of patients with VEDH during 17 years period from 1995 to 2012. Statistical Analysis Used: Nil. Results: Twenty nine cases of VEDH encountered over a period of 17 years have been analyzed, including 26 males and 3 females. Majority were due to road accidents. Headache, papilledema and lower limb weakness have been the major presenting features in these cases. The diagnosis was by direct coronal computerized tomography (CT) scan in most of them. Majority were managed conservatively with observation and serial imaging. Four patients who had large VEDH with altered sensorium were managed surgically. The source of bleeding was mainly from superior sagittal sinus. Conclusions: VEDH has to be suspected when a patient presents with impact over the vertex and features of raised intracranial pressure. Direct coronal CT or magnetic resonance imaging is useful in the diagnosis. Surgery is required when the patient develops progressive deterioration in sensorium and/or with the hematoma volume more than 30 ml. The present series of 29 cases is the largest reported so far. PMID:28484524

  10. Commissioning of the control and data acquisition electronics for the CDF Silicon Vertex Detector

    SciTech Connect

    Tkaczyk, S.M.; Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R. ); Bailey, M.W.; Kruse, M.C. ); Castro, A. )

    1991-11-01

    The SVX data acquisition system includes three components: a Fastbus Sequencer, an SVX Rabbit Crate Controller and a Digitizer. These modules are integrated into the CDF DAQ system and operate the readout chips. The results of the extensive functional tests of the SVX modules are reported. We discuss the stability of the Sequencers, systematic differences between them and methods of synchronization with the Tevatron beam crossings. The Digitizer ADC calibration procedure run on the microsequencer is described. The microsequencer code used for data taking and SVX chip calibration modes is described. Measurements of the SVX data scan time are discussed.

  11. Commissioning of the control and data acquisition electronics for the CDF Silicon Vertex Detector

    SciTech Connect

    Tkaczyk, S.M.; Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.; Bailey, M.W.; Kruse, M.C.; Castro, A.

    1991-11-01

    The SVX data acquisition system includes three components: a Fastbus Sequencer, an SVX Rabbit Crate Controller and a Digitizer. These modules are integrated into the CDF DAQ system and operate the readout chips. The results of the extensive functional tests of the SVX modules are reported. We discuss the stability of the Sequencers, systematic differences between them and methods of synchronization with the Tevatron beam crossings. The Digitizer ADC calibration procedure run on the microsequencer is described. The microsequencer code used for data taking and SVX chip calibration modes is described. Measurements of the SVX data scan time are discussed.

  12. The STAR Heavy Flavor Tracker PXL detector readout electronics

    NASA Astrophysics Data System (ADS)

    Schambach, J.; Contin, G.; Greiner, L.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.

    2016-01-01

    The Heavy Flavor Tracker (HFT) is a recently installed micro-vertex detector upgrade to the STAR experiment at RHIC, consisting of three subsystems with various technologies of silicon sensors arranged in 4 concentric cylinders. The two innermost layers of the HFT close to the beam pipe, the Pixel ("PXL") subsystem, employ CMOS Monolithic Active Pixel Sensor (MAPS) technology that integrate the sensor, front-end electronics, and zero-suppression circuitry in one silicon die. This paper presents selected characteristics of the PXL detector part of the HFT and the hardware, firmware and software associated with the readout system for this detector.

  13. Development of vertexing and lifetime triggers and a study of Bs mixing using hadronic decays at D0

    SciTech Connect

    Barnes, Christopher P.

    2005-03-01

    The D0 detector underwent a major upgrade to maximize its ability to fully exploit Run II at the Fermilab Tevatron, the world's highest energy collider. The upgrade included a completely new central tracking system with an outer scintillating fiber tracker and an inner silicon vertex detector all within a 2T superconducting solenoid. This thesis describes the development of high level trigger algorithms including vertexing, impact parameter significance and invariant mass, that utilize tracks from these detectors. One of the main physics goals of Run II is the observation of Bs oscillations. This measurement, which cannot be performed at the B factories, will significantly constrain the ''unitarity triangle'' associated with Cp violation and so probe the Standard Model of particle physics. Furthermore this is an interesting measurement as the study of mixing in meson systems has a long history for revealing new physics. The second part of this thesis presents a study of the hadronic decay Bs → Dsπ. This important mode provides the best proper time resolution for Bs mixing and is reconstructed for the first time at D0. Projections on the sensitivity to Bs oscillations are then presented.

  14. The cylindrical GEM detector of the KLOE-2 experiment

    NASA Astrophysics Data System (ADS)

    Bencivenni, G.; Branchini, P.; Ciambrone, P.; Czerwinski, E.; De Lucia, E.; Di Cicco, A.; Domenici, D.; Felici, G.; Fermani, P.; Morello, G.

    2017-07-01

    The KLOE-2 experiment started its data taking campaign in November 2014 with an upgraded tracking system at the DAΦNE electron-positron collider at the Frascati National Laboratory of INFN. The new tracking device, the Inner Tracker, operated together with the KLOE-2 Drift Chamber, has been installed to improve track and vertex reconstruction capabilities of the experimental apparatus. The Inner Tracker is a cylindrical GEM detector composed of four cylindrical triple-GEM detectors, each provided with an X-V strips-pads stereo readout. Although GEM detectors are already used in high energy physics experiments, this device is considered a frontier detector due to its fully-cylindrical geometry: KLOE-2 is the first experiment benefiting of this novel detector technology. Alignment and calibration of this detector will be presented together with its operating performance and reconstruction capabilities.

  15. Recent developments on the STAR detector system at RHIC

    SciTech Connect

    Wieman, H.; Adams, D.L.; Added, N.

    1997-12-01

    The STAR detector system is designed to provide tracking, momentum analysis and particle identification for many of the mid-rapidity charged particles produced in collisions at the RHIC collider. A silicon vertex detector (SVT) provides three layers of tracking near the interaction point. This is followed by the main time projection chamber (TPC), which continues tracking out to 200 cm radial distance from the interaction region. The detector design also includes an electromagnetic calorimeter, various trigger detectors, and radial TPCs in the forward region. The entire system is enclosed in a 0.5 T solenoid magnet. A progress report is given for the various components of the STAR detector system. The authors report on the recent developments in the detector proto-typing and construction, with an emphasis on the main TPC, recent TPC cosmic ray testing and shipping to Brookhaven National Laboratory.

  16. Search for massive long-lived particles decaying semileptonically in the LHCb detector.

    PubMed

    Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Betancourt, C; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Chamont, D; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Aguiar Francisco, O; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Funk, W; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Gándara, M Grabalosa; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, H; Hulsbergen, W; Humair, T; Hushchyn, M; Hussain, N; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kosmyntseva, A; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, T; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Muster, B; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Soares Lavra, L; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Viemann, H; Vilasis-Cardona, X; Vitti, M; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yao, Y; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhu, X; Zhukov, V; Zucchelli, S

    2017-01-01

    A search is presented for massive long-lived particles decaying into a muon and two quarks. The dataset consists of proton-proton interactions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 1 and 2[Formula: see text], respectively. The analysis is performed assuming a set of production mechanisms with simple topologies, including the production of a Higgs-like particle decaying into two long-lived particles. The mass range from 20 to 80 [Formula: see text] and lifetimes from 5 to 100[Formula: see text] are explored. Results are also interpreted in terms of neutralino production in different R-Parity violating supersymmetric models, with masses in the 23-198 GeV/[Formula: see text] range. No excess above the background expectation is observed and upper limits are set on the production cross-section for various points in the parameter space of theoretical models.

  17. Search for massive long-lived particles decaying semileptonically in the LHCb detector

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Archilli, F.; d'Argent, P.; Arnau Romeu, J.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Babuschkin, I.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Baszczyk, M.; Batozskaya, V.; Batsukh, B.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Betancourt, C.; Betti, F.; Bettler, M.-O.; van Beuzekom, M.; Bezshyiko, Ia.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bitadze, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bonivento, W.; Bordyuzhin, I.; Borgheresi, A.; Borghi, S.; Borisyak, M.; Borsato, M.; Bossu, F.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D. H.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Chamont, D.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chobanova, V.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombs, G.; Coquereau, S.; Corti, G.; Corvo, M.; Costa Sobral, C. M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Da Cunha Marinho, F.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Serio, M.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Demmer, M.; Dendek, A.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Dijkstra, H.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Déléage, N.; Easo, S.; Ebert, M.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fay, R.; Fazzini, D.; Ferguson, D.; Fernandez Prieto, A.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fini, R. A.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Franco Lima, V.; Frank, M.; Frei, C.; Fu, J.; Funk, W.; Furfaro, E.; Färber, C.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Martin, L. M.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorelov, I. V.; Gotti, C.; Gándara, M. Grabalosa; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Griffith, P.; Grillo, L.; Gruberg Cazon, B. R.; Grünberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Göbel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hatch, M.; He, J.; Head, T.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hombach, C.; Hopchev, H.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hussain, N.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jiang, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Koliiev, S.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kosmyntseva, A.; Kozachuk, A.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Leflat, A.; Lefrançois, J.; Lefèvre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, T.; Li, Y.; Likhomanenko, T.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Manning, P.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Mogini, A.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Mulder, M.; Mussini, M.; Muster, B.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, T. D.; Nguyen-Mau, C.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Oldeman, R.; Onderwater, C. J. G.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parker, W.; Parkes, C.; Passaleva, G.; Pastore, A.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Popov, A.; Popov, D.; Popovici, B.; Poslavskii, S.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Ratnikov, F.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Rogozhnikov, A.; Roiser, S.; Rollings, A.; Romanovskiy, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Rudolph, M. S.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schellenberg, M.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubert, K.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Simone, S.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Soares Lavra, l.; Sokoloff, M. D.; Soler, F. J. P.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stemmle, S.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, E.; van Tilburg, J.; Tilley, M. J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Toriello, F.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valassi, A.; Valat, S.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Vernet, M.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Viemann, H.; Vilasis-Cardona, X.; Vitti, M.; Volkov, V.; Vollhardt, A.; Voneki, B.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Vázquez Sierra, C.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Wark, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wyllie, K.; Xie, Y.; Xing, Z.; Xu, Z.; Yang, Z.; Yao, Y.; Yin, H.; Yu, J.; Yuan, X.; Yushchenko, O.; Zarebski, K. A.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhang, Y.; Zhelezov, A.; Zheng, Y.; Zhu, X.; Zhukov, V.; Zucchelli, S.

    2017-04-01

    A search is presented for massive long-lived particles decaying into a muon and two quarks. The dataset consists of proton-proton interactions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 1 and 2 fb^{-1}, respectively. The analysis is performed assuming a set of production mechanisms with simple topologies, including the production of a Higgs-like particle decaying into two long-lived particles. The mass range from 20 to 80 {GeV}/c^2 and lifetimes from 5 to 100{ {ps}} are explored. Results are also interpreted in terms of neutralino production in different R-Parity violating supersymmetric models, with masses in the 23-198 GeV/c^2 range. No excess above the background expectation is observed and upper limits are set on the production cross-section for various points in the parameter space of theoretical models.

  18. The B AB AR detector

    NASA Astrophysics Data System (ADS)

    Aubert, B.; Bazan, A.; Boucham, A.; Boutigny, D.; De Bonis, I.; Favier, J.; Gaillard, J.-M.; Jeremie, A.; Karyotakis, Y.; Le Flour, T.; Lees, J. P.; Lieunard, S.; Petitpas, P.; Robbe, P.; Tisserand, V.; Zachariadou, K.; Palano, A.; Chen, G. P.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Reinertsen, P. L.; Stugu, B.; Abbott, B.; Abrams, G. S.; Amerman, L.; Borgland, A. W.; Breon, A. B.; Brown, D. N.; Button-Shafer, J.; Clark, A. R.; Dardin, S.; Day, C.; Dow, S. F.; Fan, Q.; Gaponenko, I.; Gill, M. S.; Goozen, F. R.; Gowdy, S. J.; Gritsan, A.; Groysman, Y.; Hernikl, C.; Jacobsen, R. G.; Jared, R. C.; Kadel, R. W.; Kadyk, J.; Karcher, A.; Kerth, L. T.; Kipnis, I.; Kluth, S.; Kral, J. F.; Lafever, R.; LeClerc, C.; Levi, M. E.; Lewis, S. A.; Lionberger, C.; Liu, T.; Long, M.; Luo, L.; Lynch, G.; Luft, P.; Mandelli, E.; Marino, M.; Marks, K.; Matuk, C.; Meyer, A. B.; Minor, R.; Mokhtarani, A.; Momayezi, M.; Nyman, M.; Oddone, P. J.; Ohnemus, J.; Oshatz, D.; Patton, S.; Pedrali-Noy, M.; Perazzo, A.; Peters, C.; Pope, W.; Pripstein, M.; Quarrie, D. R.; Rasson, J. E.; Roe, N. A.; Romosan, A.; Ronan, M. T.; Shelkov, V. G.; Stone, R.; Strother, P. D.; Telnov, A. V.; von der Lippe, H.; Weber, T. F.; Wenzel, W. A.; Zizka, G.; Bright-Thomas, P. G.; Hawkes, C. M.; Kirk, A.; Knowles, D. J.; O'Neale, S. W.; Watson, A. T.; Watson, N. K.; Deppermann, T.; Koch, H.; Krug, J.; Kunze, M.; Lewandowski, B.; Peters, K.; Schmuecker, H.; Steinke, M.; Andress, J. C.; Barlow, N. R.; Bhimji, W.; Chevalier, N.; Clark, P. J.; Cottingham, W. N.; De Groot, N.; Dyce, N.; Foster, B.; Mass, A.; McFall, J. D.; Wallom, D.; Wilson, F. F.; Abe, K.; Hearty, C.; McKenna, J. A.; Thiessen, D.; Camanzi, B.; Harrison, T. J.; McKemey, A. K.; Tinslay, J.; Antohin, E. I.; Blinov, V. E.; Bukin, A. D.; Bukin, D. A.; Buzykaev, A. R.; Dubrovin, M. S.; Golubev, V. B.; Ivanchenko, V. N.; Kolachev, G. M.; Korol, A. A.; Kravchenko, E. A.; Mikhailov, S. F.; Onuchin, A. P.; Salnikov, A. A.; Serednyakov, S. I.; Skovpen, Yu. I.; Telnov, V. I.; Yushkov, A. N.; Booth, J.; Lankford, A. J.; Mandelkern, M.; Pier, S.; Stoker, D. P.; Zioulas, G.; Ahsan, A.; Arisaka, K.; Buchanan, C.; Chun, S.; Faccini, R.; MacFarlane, D. B.; Prell, S. A.; Rahatlou, Sh.; Raven, G.; Sharma, V.; Burke, S.; Callahan, D.; Campagnari, C.; Dahmes, B.; Hale, D.; Hart, P. A.; Kuznetsova, N.; Kyre, S.; Levy, S. L.; Long, O.; Lu, A.; May, J.; Richman, J. D.; Verkerke, W.; Witherell, M.; Yellin, S.; Beringer, J.; DeWitt, J.; Dorfan, D. E.; Eisner, A. M.; Frey, A.; Grillo, A. A.; Grothe, M.; Heusch, C. A.; Johnson, R. P.; Kroeger, W.; Lockman, W. S.; Pulliam, T.; Rowe, W.; Sadrozinski, H.; Schalk, T.; Schmitz, R. E.; Schumm, B. A.; Seiden, A.; Spencer, E. N.; Turri, M.; Walkowiak, W.; Wilder, M.; Williams, D. C.; Chen, E.; Dubois-Felsmann, G. P.; Dvoretskii, A.; Hanson, J. E.; Hitlin, D. G.; Kolomensky, Yu. G.; Metzler, S.; Oyang, J.; Porter, F. C.; Ryd, A.; Samuel, A.; Weaver, M.; Yang, S.; Zhu, R. Y.; Devmal, S.; Geld, T. L.; Jayatilleke, S.; Jayatilleke, S. M.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P.; Broomer, B.; Erdos, E.; Fahey, S.; Ford, W. T.; Gaede, F.; van Hoek, W. C.; Johnson, D. R.; Michael, A. K.; Nauenberg, U.; Olivas, A.; Park, H.; Rankin, P.; Roy, J.; Sen, S.; Smith, J. G.; Wagner, D. L.; Blouw, J.; Harton, J. L.; Krishnamurthy, M.; Soffer, A.; Toki, W. H.; Warner, D. W.; Wilson, R. J.; Zhang, J.; Brandt, T.; Brose, J.; Dahlinger, G.; Dickopp, M.; Dubitzky, R. S.; Eckstein, P.; Futterschneider, H.; Kocian, M. L.; Krause, R.; Müller-Pfefferkorn, R.; Schubert, K. R.; Schwierz, R.; Spaan, B.; Wilden, L.; Behr, L.; Bernard, D.; Bonneaud, G. R.; Brochard, F.; Cohen-Tanugi, J.; Ferrag, S.; Fouque, G.; Gastaldi, F.; Matricon, P.; Mora de Freitas, P.; Renard, C.; Roussot, E.; T'Jampens, S.; Thiebaux, C.; Vasileiadis, G.; Verderi, M.; Anjomshoaa, A.; Bernet, R.; Di Lodovico, F.; Muheim, F.; Playfer, S.; Swain, J. E.; Falbo, M.; Bozzi, C.; Dittongo, S.; Folegani, M.; Piemontese, L.; Ramusino, A. C.; Treadwell, E.; Anulli, F.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Falciai, D.; Finocchiaro, G.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Xie, Y.; Zallo, A.; Bagnasco, S.; Buzzo, A.; Contri, R.; Crosetti, G.; Fabbricatore, P.; Farinon, S.; Lo Vetere, M.; Macri, M.; Minutoli, S.; Monge, M. R.; Musenich, R.; Pallavicini, M.; Parodi, R.; Passaggio, S.; Pastore, F. C.; Patrignani, C.; Pia, M. G.; Priano, C.; Robutti, E.; Santroni, A.; Bartoldus, R.; Dignan, T.; Hamilton, R.; Mallik, U.; Cochran, J.; Crawley, H. B.; Fischer, P. A.; Lamsa, J.; McKay, R.; Meyer, W. T.; Rosenberg, E. I.; Albert, J. N.; Beigbeder, C.; Benkebil, M.; Breton, D.; Cizeron, R.; Du, S.; Grosdidier, G.; Hast, C.; Höcker, A.; Lacker, H. M.; LePeltier, V.; Lutz, A. M.; Plaszczynski, S.; Schune, M. H.; Trincaz-Duvoid, S.; Truong, K.; Valassi, A.; Wormser, G.; Alford, O.; Behne, D.; Bionta, R. M.; Bowman, J.; Brigljević, V.; Brooks, A.; Dacosta, V. A.; Fackler, O.; Fujino, D.; Harper, M.; Lange, D. J.; Mugge, M.; O'Connor, T. G.; Olson, H.; Ott, L.; Parker, E.; Pedrotti, B.; Roeben, M.; Shi, X.; van Bibber, K.; Wenaus, T. J.; Wright, D. M.; Wuest, C. R.; Yamamoto, B.; Carroll, M.; Cooke, P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; George, M.; Kay, M.; McMahon, S.; Muir, A.; Payne, D. J.; Sloane, R. J.; Sutcliffe, P.; Touramanis, C.; Aspinwall, M. L.; Bowerman, D. A.; Dauncey, P. D.; Eschrich, I.; Gunawardane, N. J. W.; Martin, R.; Nash, J. A.; Price, D. R.; Sanders, P.; Smith, D.; Azzopardi, D. E.; Back, J. J.; Dixon, P.; Harrison, P. F.; Newman-Coburn, D.; Potter, R. J. L.; Shorthouse, H. W.; Williams, M. I.; Vidal, P. B.; Cowan, G.; George, S.; Green, M. G.; Kurup, A.; Marker, C. E.; McGrath, P.; McMahon, T. R.; Salvatore, F.; Scott, I.; Vaitsas, G.; Brown, D.; Davis, C. L.; Li, Y.; Pavlovich, J.; Allison, J.; Barlow, R. J.; Boyd, J. T.; Fullwood, J.; Jackson, F.; Khan, A.; Lafferty, G. D.; Savvas, N.; Simopoulos, E. T.; Thompson, R. J.; Weatherall, J. H.; Bard, R.; Dallapiccola, C.; Farbin, A.; Jawahery, A.; Lillard, V.; Olsen, J.; Roberts, D. A.; Schieck, J. R.; Blaylock, G.; Flood, K. T.; Hertzbach, S. S.; Kofler, R.; Lin, C. S.; Willocq, S.; Wittlin, J.; Brau, B.; Cowan, R.; Taylor, F.; Yamamoto, R. K.; Britton, D. I.; Fernholz, R.; Houde, M.; Milek, M.; Patel, P. M.; Trischuk, J.; Lanni, F.; Palombo, F.; Bauer, J. M.; Booke, M.; Cremaldi, L.; Kroeger, R.; Reep, M.; Reidy, J.; Sanders, D. A.; Summers, D. J.; Arguin, J. F.; Beaulieu, M.; Martin, J. P.; Nief, J. Y.; Seitz, R.; Taras, P.; Woch, A.; Zacek, V.; Nicholson, H.; Sutton, C. S.; Cartaro, C.; Cavallo, N.; De Nardo, G.; Fabozzi, F.; Gatto, C.; Lista, L.; Piccolo, D.; Sciacca, C.; Cason, N. M.; LoSecco, J. M.; Alsmiller, J. R. G.; Gabriel, T. A.; Handler, T.; Heck, J.; Iwasaki, M.; Sinev, N. B.; Caracciolo, R.; Colecchia, F.; Dal Corso, F.; Galeazzi, F.; Marzolla, M.; Michelon, G.; Morandin, M.; Posocco, M.; Rotondo, M.; Santi, S.; Simonetto, F.; Stroili, R.; Torassa, E.; Voci, C.; Bailly, P.; Benayoun, M.; Briand, H.; Chauveau, J.; David, P.; De la Vaissière, C.; Del Buono, L.; Genat, J.-F.; Hamon, O.; Leruste, Ph.; Le Diberder, F.; Lebbolo, H.; Lory, J.; Martin, L.; Martinez-Vidal, F.; Roos, L.; Stark, J.; Versillé, S.; Zhang, B.; Manfredi, P. F.; Ratti, L.; Re, V.; Speziali, V.; Frank, E. D.; Gladney, L.; Guo, Q. H.; Panetta, J. H.; Angelini, C.; Batignani, G.; Bettarini, S.; Bondioli, M.; Bosi, F.; Carpinelli, M.; Forti, F.; Gaddi, A.; Gagliardi, D.; Giorgi, M. A.; Lusiani, A.; Mammini, P.; Morganti, M.; Morsani, F.; Neri, N.; Profeti, A.; Paoloni, E.; Raffaelli, F.; Rama, M.; Rizzo, G.; Sandrelli, F.; Simi, G.; Triggiani, G.; Haire, M.; Judd, D.; Paick, K.; Turnbull, L.; Wagoner, D. E.; Albert, J.; Bula, C.; Kelsey, M. H.; Lu, C.; McDonald, K. T.; Miftakov, V.; Sands, B.; Schaffner, S. F.; Smith, A. J. S.; Tumanov, A.; Varnes, E. W.; Bronzini, F.; Buccheri, A.; Bulfon, C.; Cavoto, G.; del Re, D.; Ferrarotto, F.; Ferroni, F.; Fratini, K.; Lamanna, E.; Leonardi, E.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Safai Tehrani, F.; Serra, M.; Voena, C.; Waldi, R.; Jacques, P. F.; Kalelkar, M.; Plano, R. J.; Adye, T.; Claxton, B.; Dowdell, J.; Egede, U.; Franek, B.; Galagedera, S.; Geddes, N. I.; Gopal, G. P.; Kay, J.; Lidbury, J.; Madani, S.; Metcalfe, S.; Metcalfe, S.; Markey, G.; Olley, P.; Watt, M.; Xella, S. M.; Aleksan, R.; Besson, P.; Bourgeois, P.; Convert, P.; De Domenico, G.; de Lesquen, A.; Emery, S.; Gaidot, A.; Ganzhur, S. F.; Georgette, Z.; Gosset, L.; Graffin, P.; Hamel de Monchenault, G.; Hervé, S.; Karolak, M.; Kozanecki, W.; Langer, M.; London, G. W.; Marques, V.; Mayer, B.; Micout, P.; Mols, J. P.; Mouly, J. P.; Penichot, Y.; Rolquin, J.; Serfass, B.; Toussaint, J. C.; Usseglio, M.; Vasseur, G.; Yeche, C.; Zito, M.; Copty, N.; Purohit, M. V.; Yumiceva, F. X.; Adam, I.; Adesanya, A.; Anthony, P. L.; Aston, D.; Bartelt, J.; Becla, J.; Bell, R.; Bloom, E.; Boeheim, C. T.; Boyarski, A. M.; Boyce, R. F.; Briggs, D.; Bulos, F.; Burgess, W.; Byers, B.; Calderini, G.; Chestnut, R.; Claus, R.; Convery, M. R.; Coombes, R.; Cottrell, L.; Coupal, D. P.; Coward, D. H.; Craddock, W. W.; DeBarger, S.; DeStaebler, H.; Dorfan, J.; Doser, M.; Dunwoodie, W.; Dusatko, J. E.; Ecklund, S.; Fieguth, T. H.; Freytag, D. R.; Glanzman, T.; Godfrey, G. L.; Haller, G.; Hanushevsky, A.; Harris, J.; Hasan, A.; Hee, C.; Himel, T.; Huffer, M. E.; Hung, T.; Innes, W. R.; Jessop, C. P.; Kawahara, H.; Keller, L.; King, M. E.; Klaisner, L.; Krebs, H. J.; Langenegger, U.; Langeveld, W.; Leith, D. W. G. S.; Louie, S. K.; Luitz, S.; Luth, V.; Lynch, H. L.; McDonald, J.; Manzin, G.; Marsiske, H.; Mattison, T.; McCulloch, M.; McDougald, M.; McShurley, D.; Menke, S.; Messner, R.; Metcalfe, S.; Morii, M.; Mount, R.; Muller, D. R.; Nelson, D.; Nordby, M.; O'Grady, C. P.; Olavson, L.; Olsen, J.; O'Neill, F. G.; Oxoby, G.; Paolucci, P.; Pavel, T.; Perl, J.; Pertsova, M.; Petrak, S.; Putallaz, G.; Raines, P. E.; Ratcliff, B. N.; Reif, R.; Robertson, S. H.; Rochester, L. S.; Roodman, A.; Russel, J. J.; Sapozhnikov, L.; Saxton, O. H.; Schietinger, T.; Schindler, R. H.; Schwiening, J.; Sciolla, G.; Seeman, J. T.; Serbo, V. V.; Shapiro, S.; Skarpass, K., Sr.; Snyder, A.; Soderstrom, E.; Soha, A.; Spanier, S. M.; Stahl, A.; Stiles, P.; Su, D.; Sullivan, M. K.; Talby, M.; Tanaka, H. A.; Va'vra, J.; Wagner, S. R.; Wang, R.; Weber, T.; Weinstein, A. J. R.; White, J. L.; Wienands, U.; Wisniewski, W. J.; Young, C. C.; Yu, N.; Burchat, P. R.; Cheng, C. H.; Kirkby, D.; Meyer, T. I.; Roat, C.; Henderson, R.; Khan, N.; Berridge, S.; Bugg, W.; Cohn, H.; Hart, E.; Weidemann, A. W.; Benninger, T.; Izen, J. M.; Kitayama, I.; Lou, X. C.; Turcotte, M.; Bianchi, F.; Bona, M.; Daudo, F.; Di Girolamo, B.; Gamba, D.; Grosso, P.; Smol, A.; Trapani, P. P.; Zanin, D.; Bosisio, L.; Della Ricca, G.; Lanceri, L.; Pompili, A.; Poropat, P.; Prest, M.; Rashevskaia, I.; Vallazza, E.; Vuagnin, G.; Panvini, R. S.; Brown, C.; De Silva, A.; Kowalewski, R.; Pitman, D.; Roney, J. M.; Band, H. R.; Charles, E.; Dasu, S.; Elmer, P.; Johnson, J. R.; Nielsen, J.; Orejudos, W.; Pan, Y.; Prepost, R.; Scott, I. J.; Walsh, J.; Wu, S. L.; Yu, Z.; Zobernig, H.; Moore, T. B.; Neal, H.

    2002-02-01

    B AB AR, the detector for the SLAC PEP-II asymmetric e +e - B Factory operating at the ϒ(4 S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by d E/d x measurements in the tracking detectors and by a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

  19. RADIATION DETECTOR

    DOEpatents

    Wilson, H.N.; Glass, F.M.

    1960-05-10

    A radiation detector of the type is described wherein a condenser is directly connected to the electrodes for the purpose of performing the dual function of a guard ring and to provide capacitance coupling for resetting the detector system.

  20. The scalar-photon 3-point vertex in massless quenched scalar QED

    NASA Astrophysics Data System (ADS)

    Concha-Sánchez, Y.; Gutiérrez-Guerrero, L. X.; Fernández-Rangel, L. A.

    2016-10-01

    Non perturbative studies of Schwinger-Dyson equations (SDEs) require their infinite, coupled tower to be truncated in order to reduce them to a practically solvable set. In this connection, a physically acceptable ansatz for the three point vertex is the most favorite choice. Scalar quantum electrodynamics (sQED) provides a simple and neat platform to address this problem. The most general form of the scalar-photon three point vertex can be expressed in terms of only two independent form factors, longitudinal and transverse. Ball and Chiu have demonstrated that the longitudinal vertex is fixed by requiring the Ward-Fradkin-Green- Takahashi identity (WFGTI), while the transverse vertex remains undetermined. In massless quenched sQED, we propose the transverse part of the non perturbative scalar-photon vertex.

  1. Quantum transport in strongly disordered crystals: Electrical conductivity with large negative vertex corrections

    NASA Astrophysics Data System (ADS)

    Janiš, Václav; Pokorný, Vladislav

    2012-12-01

    We propose a renormalization scheme of the Kubo formula for the electrical conductivity with multiple backscatterings contributing to the electron-hole irreducible vertex derived from the asymptotic limit to high spatial dimensions. We use this vertex to represent the two-particle Green function via a symmetrized Bethe-Salpeter equation in momentum space. We further utilize the dominance of a pole in the irreducible vertex to an approximate diagonalization of the Bethe-Salpeter equation and a non-perturbative representation of the electron-hole correlation function. The latter function is then used to derive a compact representation for the electrical conductivity at zero temperature without the necessity to evaluate separately the Drude term and vertex corrections. The electrical conductivity calculated in this way remains nonnegative also in the strongly disordered regime where the localization effects become significant and the negative vertex corrections in the standard Kubo formula overweight the Drude term.

  2. A vertex similarity index for better personalized recommendation

    NASA Astrophysics Data System (ADS)

    Chen, Ling-Jiao; Zhang, Zi-Ke; Liu, Jin-Hu; Gao, Jian; Zhou, Tao

    2017-01-01

    Recommender systems benefit us in tackling the problem of information overload by predicting our potential choices among diverse niche objects. So far, a variety of personalized recommendation algorithms have been proposed and most of them are based on similarities, such as collaborative filtering and mass diffusion. Here, we propose a novel vertex similarity index named CosRA, which combines advantages of both the cosine index and the resource-allocation (RA) index. By applying the CosRA index to real recommender systems including MovieLens, Netflix and RYM, we show that the CosRA-based method has better performance in accuracy, diversity and novelty than some benchmark methods. Moreover, the CosRA index is free of parameters, which is a significant advantage in real applications. Further experiments show that the introduction of two turnable parameters cannot remarkably improve the overall performance of the CosRA index.

  3. Emergent reduced dimensionality by vertex frustration in artificial spin ice

    SciTech Connect

    Gilbert, Ian; Lao, Yuyang; Carrasquillo, Isaac; O’Brien, Liam; Watts, Justin D.; Manno, Michael; Leighton, Chris; Scholl, Andreas; Nisoli, Cristiano; Schiffer, Peter

    2015-10-26

    Reducing the dimensionality of a physical system can have a profound effect on its properties, as in the ordering of low-dimensional magnetic materials, phonon dispersion in mercury chain salts, sliding phases, and the electronic states of graphene. Here we explore the emergence of quasi-one-dimensional behaviour in two-dimensional artificial spin ice, a class of lithographically fabricated nanomagnet arrays used to study geometrical frustration. We extend the implementation of artificial spin ice by fabricating a new array geometry, the so-called tetris lattice. We demonstrate that the ground state of the tetris lattice consists of alternating ordered and disordered bands of nanomagnetic moments. The disordered bands can be mapped onto an emergent thermal one-dimensional Ising model. Furthermore, we show that the level of degeneracy associated with these bands dictates the susceptibility of island moments to thermally induced reversals, thus establishing that vertex frustration can reduce the relevant dimensionality of physical behaviour in a magnetic system.

  4. Limits on anomalous contributions to the Wtb vertex

    NASA Astrophysics Data System (ADS)

    Pease, Christopher; Fiolhais, Miguel; Onofre, Antonio

    2017-01-01

    Recent LHC results on the measurements of the W-boson helicity fractions and single top quark production cross section at a center-of-mass energy of 13 TeV are combined in order to establish new limits on anomalous contributions to the Wtb vertex. The allowed regions for these limits are presented in three-dimensional graphics, for both real and imaginary components of the different anomalous couplings, allowing all the other anomalous couplings to vary at the same time. These results are combined with the prospected future measurement of the single top quark production cross section and W-boson helicity fractions at the LHC. When compared with the previous most precise limits, these results show a significant improvement, larger than 10%.

  5. Performance of the CLAS12 Silicon Vertex Tracker modules

    SciTech Connect

    Antonioli, Mary Ann; Boiarinov, Serguie; Bonneau, Peter R.; Elouadrhiri, Latifa; Eng, Brian J.; Gotra, Yuri N.; Kurbatov, Evgeny O.; Leffel, Mindy A.; Mandal, Saptarshi; McMullen, Marc E.; Merkin, Mikhail M.; Raydo, Benjamin J.; Teachey, Robert W,; Tucker, Ross J.; Ungaro, Maurizio; Yegneswaran, Amrit S.; Ziegler, Veronique

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  6. Cutaneous paraganglioma of the vertex in a child.

    PubMed

    Kim; Lee, Il Jae; Park, Myong Chul; Kim, Joo Hyoung; Lim, Hyoseob

    2012-07-01

    Paraganglioma is a neuroendocrine neoplasm that may develop at various body sites, including the head, neck, thorax, and abdomen. Approximately 85% of paragangliomas develop on the abdomen, 12% develop on the chest, and only 3% develop on the head and neck. These tumors are found in locations that parallel the sympathetic chain ganglion in the thoracolumbar regions and parasympathetic nervous system in craniosacral regions, and all head and neck paragangliomas arise from the parasympathetic nervous system. Although the skin has a rich neural network, it is devoid of ganglia. There has been only 1 report of a paraganglioma on the scalp of a child. We describe a 3-year-old child with a primary cutaneous paraganglioma of the vertex scalp and review the literature on paragangliomas.

  7. Performance of the CLAS12 Silicon Vertex Tracker modules

    NASA Astrophysics Data System (ADS)

    Antonioli, M. A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B.; Gotra, Y.; Kurbatov, E.; Leffel, M.; Mandal, S.; McMullen, M.; Merkin, M.; Raydo, B.; Teachey, W.; Tucker, R.; Ungaro, M.; Yegneswaran, A.; Ziegler, V.

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156 μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  8. Testing the RRPP vertex of effective Regge action

    NASA Astrophysics Data System (ADS)

    Kuraev, E. A.; Bytev, V. V.; Bakmaev, S.; Antonov, E. N.

    2008-06-01

    We discuss the possibility of checking the vertex with creation of two real gluons in collision of two reggeized ones (RRPP) which can reveal themselves in process of scalar meson production in high energy peripheral nucleon collisions. Numerical estimations of the cross section of a pair of charged pion production for the LHC facility give the value of an order of 10 mb. We also estimate the excess of production of positively charged muons (as a decay of pions) created by cosmic ray proton collisions with the atmosphere gas nuclei to be in reasonable agreement with modern data. The effects of higher orders which reveal themselves as a screening factor are considered in terms of impact parameter representation. We estimate the cross section of pion pair production in central region to fall faster than factorial σn ∼ 1 / (n2 n !).

  9. Vertex Sensitivity in the Schwinger-Dyson Equations of QCD

    SciTech Connect

    David J. Wilson, Michael R. Pennington

    2012-01-01

    The nonperturbative gluon and ghost propagators in Landau gauge QCD are obtained using the Schwinger-Dyson equation approach. The propagator equations are solved in Euclidean space using Landau gauge with a range of vertex inputs. Initially we solve for the ghost alone, using a model gluon input, which leads us to favour a finite ghost dressing in the nonperturbative region. In order to then solve the gluon and ghost equations simultaneously, we find that non-trivial vertices are required, particularly for the gluon propagator in the small momentum limit. We focus on the properties of a number vertices and how these differences influence the final solutions. The self-consistent solutions we obtain are all qualitatively similar and contain a mass-like term in the gluon propagator dressing in agreement with related studies, supporting the long-held proposal of Cornwall.

  10. Emergent reduced dimensionality by vertex frustration in artificial spin ice

    NASA Astrophysics Data System (ADS)

    Gilbert, Ian; Lao, Yuyang; Carrasquillo, Isaac; O'Brien, Liam; Watts, Justin D.; Manno, Michael; Leighton, Chris; Scholl, Andreas; Nisoli, Cristiano; Schiffer, Peter

    2016-02-01

    Reducing the dimensionality of a physical system can have a profound effect on its properties, as in the ordering of low-dimensional magnetic materials, phonon dispersion in mercury chain salts, sliding phases, and the electronic states of graphene. Here we explore the emergence of quasi-one-dimensional behaviour in two-dimensional artificial spin ice, a class of lithographically fabricated nanomagnet arrays used to study geometrical frustration. We extend the implementation of artificial spin ice by fabricating a new array geometry, the so-called tetris lattice. We demonstrate that the ground state of the tetris lattice consists of alternating ordered and disordered bands of nanomagnetic moments. The disordered bands can be mapped onto an emergent thermal one-dimensional Ising model. Furthermore, we show that the level of degeneracy associated with these bands dictates the susceptibility of island moments to thermally induced reversals, thus establishing that vertex frustration can reduce the relevant dimensionality of physical behaviour in a magnetic system.

  11. Photoabsorption off nuclei with self-consistent vertex corrections

    SciTech Connect

    Riek, F.; Lutz, M. F. M.; Korpa, C. L.

    2009-08-15

    We study photoproduction off nuclei based on a self-consistent and covariant many-body approach for the pion and isobar propagation in infinite nuclear matter. For the first time the t-channel exchange of an in-medium pion is evaluated in the presence of vertex correction effects consistently. In particular the interference pattern with the s-channel in-medium nucleon and isobar exchange contribution is considered. Electromagnetic gauge invariance is kept as a consequence of various Ward identities obeyed by the computation. Adjusting the set of Migdal parameters to the data set we predict an attractive mass shift for the isobar of about 50 MeV at nuclear saturation density.

  12. Small Vertex Cover Makes Petri Net Coverability and Boundedness Easier

    NASA Astrophysics Data System (ADS)

    Praveen, M.

    The coverability and boundedness problems for Petri nets are known to be Expspace-complete. Given a Petri net, we associate a graph with it. With the vertex cover number k of this graph and the maximum arc weight W as parameters, we show that coverability and boundedness are in ParaPspace. This means that these problems can be solved in space O(ef(k,W)poly(n)) where ef(k,W) is some exponential function and poly(n) is some polynomial in the size of the input. We then extend the ParaPspace result to model checking a logic that can express some generalizations of coverability and boundedness.

  13. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  14. Study for the LHCb upgrade read-out board

    NASA Astrophysics Data System (ADS)

    Cachemiche, J.-P.; Duval, P.-Y.; Hachon, F.; Le Gac, R.; Marin, F.

    2010-12-01

    The LHCb experiment envisages to upgrade its readout electronics in order to increase the readout rate from 1 MHz to 40 MHz. This electronics upgrade is very challenging, since readout boards will have to handle a higher number of serial links with an increased bandwidth. In addition, the new communication protocol (GBT) developed by the CERN micro-electronics group mixes data acquisition, slow control and clock distribution on the same link. To explore the feasibility of such a readout system, elementary building blocks have been studied. Their goals are multiple: understand signal integrity when using highly integrated high speed serial links running at 8 - 10 Gbits/s; test the implementation of the GBT protocol within FPGAs; understand advantages and limitations of commercial standard with a predefined interconnection topology; validate ideas on how to control easily such a system. We designed two boards compliant with the xTCA standard which meets an increasing interest in the physics community. The first one is a generic handling 32 high speed serial links. The second one is a communication switch allowing the generic boards to communicate together. In this paper, we present jitter measurements obtained at 8 Gbits/s on serial link. We describe the versatility of this architecture which can be tuned from basic acquisition systems to more high-end complex ones. Finally, we demonstrate the feasibility of a low cost scalable control system based on NIOS core embedded in FPGAs.

  15. Optimization of Large Scale HEP Data Analysis in LHCb

    NASA Astrophysics Data System (ADS)

    Remenska, Daniela; Aaij, Roel; Raven, Gerhard; Merk, Marcel; Templon, Jeff; Bril, Reinder J.; LHCb Collaboration

    2011-12-01

    Observation has lead to a conclusion that the physics analysis jobs run by LHCb physicists on a local computing farm (i.e. non-grid) require more efficient access to the data which resides on the Grid. Our experiments have shown that the I/O bound nature of the analysis jobs in combination with the latency due to the remote access protocols (e.g. rfio, dcap) cause a low CPU efficiency of these jobs. In addition to causing a low CPU efficiency, the remote access protocols give rise to high overhead (in terms of amount of data transferred). This paper gives an overview of the concept of pre-fetching and caching of input files in the proximity of the processing resources, which is exploited to cope with the I/O bound analysis jobs. The files are copied from Grid storage elements (using GridFTP), while concurrently performing computations, inspired from a similar idea used in the ATLAS experiment. The results illustrate that this file staging approach is relatively insensitive to the original location of the data, and a significant improvement can be achieved in terms of the CPU efficiency of an analysis job. Dealing with scalability of such a solution on the Grid environment is discussed briefly.

  16. γ Determination from TREE Decays (B → DK) with LHCb

    NASA Astrophysics Data System (ADS)

    van Tilburg, J.

    2008-12-01

    Direct measurements of the angle γ of the CKM unitarity triangle still have a relatively large uncertainty. B → DK decays provide a theoretically clean way of measuring γ, as they involve only tree diagrams. LHCb will measure γ using various methods. One method uses the B0s -> D∓ sK± decay, where CP violation can be measured from the time-dependent decay rates. The corresponding sensitivity on γ with 2 fb-1 of data is expected to be about 13°. Other methods use B → D0K decays, where the D0 and /line{D}0 decay into the same final state. With the ADS+GLW strategy the sensitivity ranges between 5-15° for the charged B decays and between 7-10° for the neutral B decays. With the Dalitz method the sensitivity is estimated to be 8° using charged B decays. Combining all methods a sensitivity on γ with 2 fb-1 of data is estimated to be roughly 5°.

  17. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    SciTech Connect

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

    2007-04-15

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region.

  18. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    SciTech Connect

    Hrayr Matevosyan; Anthony Thomas; Peter Tandy

    2007-04-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. With the more consistent vertex used here, the error in ladder-rainbow truncation for vector mesons is never more than 10% as the current quark mass is varied from the u/d region to the b region.

  19. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    NASA Astrophysics Data System (ADS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

    2007-04-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region.

  20. Characterizing general scale-free networks by vertex-degree sequences

    NASA Astrophysics Data System (ADS)

    Xiao, Wenjun; Lai, Zhengwen; Chen, Guanrong

    2015-11-01

    Many complex networks possess a scale-free vertex-degree distribution in a power-law form of c k-γ , where k is the vertex-degree variable and c and γ are constants. To better understand the mechanism of the power-law formation in scale-free networks, it is important to understand and analyze their vertex-degree sequences. We had shown before that, for a scale-free network of size N , if its vertex-degree sequence is k1 vertex degrees in the network, and if its power exponent satisfies γ>1 , then the length l of the vertex-degree sequence is of order log N . In the present paper, we further study complex networks with a more general vertex-degree distribution, not restricted to the power-law, and prove that the same conclusion holds as well. In addition, we verify the new result by real data from a large number of real-world examples. We finally discuss some potential applications of the new finding in various fields of science, technology, and society.

  1. Characterizing general scale-free networks by vertex-degree sequences.

    PubMed

    Xiao, Wenjun; Lai, Zhengwen; Chen, Guanrong

    2015-11-01

    Many complex networks possess a scale-free vertex-degree distribution in a power-law form of ck(-γ), where k is the vertex-degree variable and c and γ are constants. To better understand the mechanism of the power-law formation in scale-free networks, it is important to understand and analyze their vertex-degree sequences. We had shown before that, for a scale-free network of size N, if its vertex-degree sequence is k1 vertex degrees in the network, and if its power exponent satisfies γ>1, then the length l of the vertex-degree sequence is of order log N. In the present paper, we further study complex networks with a more general vertex-degree distribution, not restricted to the power-law, and prove that the same conclusion holds as well. In addition, we verify the new result by real data from a large number of real-world examples. We finally discuss some potential applications of the new finding in various fields of science, technology, and society.

  2. Overview of the data acquisition electronics system design for the SLAC Linear Collider Detector (SLD)

    SciTech Connect

    Larsen, R.S.

    1985-09-01

    The SLD Detector will contain five major electronics subsystems: Vertex, Drift, Liquid Argon Calorimeter, Cerenkov Ring Imaging, and Warm Iron Calorimeter. To implement the approximately 170,000 channels of electronics, extensive miniaturization and heavy use of multiplexing techniques are required. Design criteria for each subsystem, overall system architecture, and the R and D program are described.

  3. Mcfast, a Parameterized Fast Monte Carlo for Detector Studies

    NASA Astrophysics Data System (ADS)

    Boehnlein, Amber S.

    McFast is a modularized and parameterized fast Monte Carlo program which is designed to generate physics analysis information for different detector configurations and subdetector designs. McFast is based on simple geometrical object definitions and includes hit generation, parameterized track generation, vertexing, a muon system, electromagnetic calorimetry, and trigger framework for physics studies. Auxiliary tools include a geometry editor, visualization, and an i/o system.

  4. Characteristics of magnetic shields for protection PMT in the LHCb hadron calorimeter

    NASA Astrophysics Data System (ADS)

    Dmitrenko, V. V.; Vlasik, K. F.; Grachev, V. M.; Muravyev-Smirnov, S. S.; Novikov, A. S.; Ulin, S. E.; Uteshev, Z. M.; Shustov, A. E.; Petrenko, D. V.; Chernysheva, I. V.; Lobova, E. I.; Nepochataya, O. E.

    2017-01-01

    CERN is preparing the new experiment aimed at the detection of weakly interacting massive long-lived particles. The experiment was called SHiP. The instrumental and technological solutions successfully used in experimental setups ATLAS, LHCb and others will be applied in experimental setup SHiP. One of these units is a hadrons calorimeter. It uses several thousands photomultiplier tubes (PMT) placed in protective magnetic shields because PMTs are located near strong permanent magnets. Taking into account that since the creation of the experimental setup LHCb has been passed more than 10 years and there are new manufacturing techniques of magnetic screens appeared, we investigate the characteristics of shielding screens used in the LHCb, and proposed the recommendations to magnetic screens’ designs for SHiP experiment.

  5. Vertex corrections and the Korringa ratio in strongly correlated electron materials

    NASA Astrophysics Data System (ADS)

    Yusuf, Eddy; Powell, B. J.; McKenzie, Ross H.

    2009-05-01

    We show that the Korringa ratio, associated with nuclear magnetic resonance in metals, is unity if vertex corrections to the dynamic spin susceptibility are negligible, the hyperfine coupling is momentum independent, and there exists an energy scale below which the density of states is constant. In the absence of vertex corrections we also find a Korringa behaviour for T1, the nuclear spin relaxation rate, i.e., 1/T_1\\propto T , and a temperature independent Knight shift. These results are independent of the form and magnitude of the self-energy (so far as is consistent with neglecting vertex corrections) and of the dimensionality of the system.

  6. The performance of diphoton primary vertex reconstruction methods in H → γγ+Met channel of ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Tomiwa, K. G.

    2017-09-01

    The search for new physics in the H → γγ+met relies on how well the missing transverse energy is reconstructed. The Met algorithm used by the ATLAS experiment in turns uses input variables like photon and jets which depend on the reconstruction of the primary vertex. This document presents the performance of di-photon vertex reconstruction algorithms (hardest vertex method and Neural Network method). Comparing the performance of these algorithms for the nominal Standard Model sample and the Beyond Standard Model sample, we see the overall performance of the Neural Network method of primary vertex selection performed better than the Hardest vertex method.

  7. Adjacent-vertex-distinguishing proper total colouring number of {\\bar{K}}_{m}\\vee {P}_{n}

    NASA Astrophysics Data System (ADS)

    Liu, Shunqin

    2017-08-01

    Coloring is a fundamental problem in scientific computation and engineering design. In recent years, a variety of colorings frequently appeared and solved many problems in production. For example, adjacent-vertex-distinguishing proper total coloring, adjacent-vertex-distinguishing proper edge coloring, smarandachely-adjacent-vertex-distinguishing proper edge coloring. It is an important also difficult problem to discuss the coloring numbers of a given graph class. And we focus on the adjacent-vertex-distinguishing proper total coloring numbers in this paper. We study the adjacent-vertex-distinguishing proper total coloring numbers of joint graphs {\\bar{K}}m\\vee {P}n.

  8. First observation of the decay B s 0 → K S 0 K ∗(892)0 at LHCb

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casanova Mohr, R.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garofoli, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Geraci, A.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Matthieu, K.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Ninci, D.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepp, I.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Simi, G.; Sirendi, M.; Skidmore, N.; Skillicorn, I.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Sterpka, F.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wiedner, D.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.

    2016-01-01

    A search for B ( s) 0 → K S 0 K ∗(892)0 decays is performed using pp collision data, corresponding to an integrated luminosity of 1 .0 fb-1, collected with the LHCb detector at a centre-of-mass energy of 7 TeV. The B s 0 → K S 0 K ∗(892)0 decay is observed for the first time, with a significance of 7.1 standard deviations. The branching fraction is measured to be B({B}_s^0to {overline{K}}^0{K}^{ast }{(892)}^0)+B({B}_s^0to {K}^0{overline{K}}^{ast }{(892)}^0)=(16.4± 3.4± 2.3)× 1{0}^{-6}, where the first uncertainty is statistical and the second is systematic. No evidence is found for the decay B 0 → K S 0 K ∗(892)0 and an upper limit is set on the branching fraction, B({B}^0to {overline{K}}^0{K}^{ast }{(892)}^0)+B({B}^0to {K}^0{overline{K}}^{ast }{(892)}^0)<0.96× 1{0}^{-6} , at 90 % confidence level. All results are consistent with Standard Model predictions. [Figure not available: see fulltext.

  9. Smoke Detector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the photo, Fire Chief Jay Stout of Safety Harbor, Florida, is explaining to young Richard Davis the workings of the Honeywell smoke and fire detector which probably saved Richard's life and that of his teen-age brother. Alerted by the detector's warning, the pair were able to escape their burning home. The detector in the Davis home was one of 1,500 installed in Safety Harbor residences in a cooperative program conducted by the city and Honeywell Inc.

  10. An Information System to Access Status Information of the LHCb Online

    NASA Astrophysics Data System (ADS)

    Frank, M.; Gaspar, C.

    2012-12-01

    The LHCb collaboration consists of roughly 700 physicists from 52 institutes and universities. Most of the collaborating physicists - including subdetector experts - are not permanently based at CERN. This paper describes the architecture used to publish data internal to the LHCb experiment control- and data acquisition system to the World Wide Web. Collaborators can access the online (sub-) system status and the system performance directly from the institute abroad, from home or from a smart phone without the need of direct access to the online computing infrastructure.

  11. Implementing a Domain Specific Language to configure and run LHCb Continuous Integration builds

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Couturier, B.

    2015-12-01

    The new LHCb nightly build system described at CHEP 2013 was limited by the use of JSON files for its configuration. JSON had been chosen as a temporary solution to maintain backward compatibility towards the old XML format by means of a translation function. Modern languages like Python leverage on meta-programming techniques to enable the development of Domain Specific Languages (DSLs). In this contribution we will present the advantages of such techniques and how they have been used to implement a DSL that can be used to both describe the configuration of the LHCb Nightly Builds and actually operate them.

  12. A vertex trigger based on cylindrical multiwire proportional chambers

    NASA Astrophysics Data System (ADS)

    Becker, J.; Bösiger, K.; Lindfeld, L.; Müller, K.; Robmann, P.; Schmitt, S.; Schmitz, C.; Steiner, S.; Straumann, U.; Szeker, K.; Truöl, P.; Urban, M.; Vollhardt, A.; Werner, N.; Baumeister, D.; Löchner, S.; Hildebrandt, M.

    2008-02-01

    This article describes the technical implementation and the performance of the z-vertex trigger (CIP2k), which is part of the H1-experiment at HERA. The HERA storage ring and collider was designed to investigate electron (and positron) proton scattering at a center-of-mass energy of 320 GeV. To improve the sensitivity for detecting non-standard model physics and other high momentum transfer phenomena, the HERA ring has been ungraded between 2000 and 2003 to increase the specific luminosity for the experiments. In order to cope with the increased event and background rate the experiments were upgraded, too. The CIP2k trigger system is based on a set of five cylindrical multiwire proportional chambers with cathode pad readout, and allows to distinguish between events induced by beam background and ep-interactions at the first trigger stage. The trigger decision is calculated dead-time free with a latency of 1.5 μs in parallel to the beam clock at 10.4 MHz. The trigger-logic is realized in large field programmable gate arrays (FPGA) using the hardware description language Verilog. The system is operational since October 2003. It suppresses background events with high efficiency and provides event timing information, as designed.

  13. Fast unmixing of multispectral optoacoustic data with vertex component analysis

    NASA Astrophysics Data System (ADS)

    Luís Deán-Ben, X.; Deliolanis, Nikolaos C.; Ntziachristos, Vasilis; Razansky, Daniel

    2014-07-01

    Multispectral optoacoustic tomography enhances the performance of single-wavelength imaging in terms of sensitivity and selectivity in the measurement of the biodistribution of specific chromophores, thus enabling functional and molecular imaging applications. Spectral unmixing algorithms are used to decompose multi-spectral optoacoustic data into a set of images representing distribution of each individual chromophoric component while the particular algorithm employed determines the sensitivity and speed of data visualization. Here we suggest using vertex component analysis (VCA), a method with demonstrated good performance in hyperspectral imaging, as a fast blind unmixing algorithm for multispectral optoacoustic tomography. The performance of the method is subsequently compared with a previously reported blind unmixing procedure in optoacoustic tomography based on a combination of principal component analysis (PCA) and independent component analysis (ICA). As in most practical cases the absorption spectrum of the imaged chromophores and contrast agents are known or can be determined using e.g. a spectrophotometer, we further investigate the so-called semi-blind approach, in which the a priori known spectral profiles are included in a modified version of the algorithm termed constrained VCA. The performance of this approach is also analysed in numerical simulations and experimental measurements. It has been determined that, while the standard version of the VCA algorithm can attain similar sensitivity to the PCA-ICA approach and have a robust and faster performance, using the a priori measured spectral information within the constrained VCA does not generally render improvements in detection sensitivity in experimental optoacoustic measurements.

  14. Emergent reduced dimensionality by vertex frustration in artificial spin ice

    DOE PAGES

    Gilbert, Ian; Lao, Yuyang; Carrasquillo, Isaac; ...

    2015-10-26

    Reducing the dimensionality of a physical system can have a profound effect on its properties, as in the ordering of low-dimensional magnetic materials, phonon dispersion in mercury chain salts, sliding phases, and the electronic states of graphene. Here we explore the emergence of quasi-one-dimensional behaviour in two-dimensional artificial spin ice, a class of lithographically fabricated nanomagnet arrays used to study geometrical frustration. We extend the implementation of artificial spin ice by fabricating a new array geometry, the so-called tetris lattice. We demonstrate that the ground state of the tetris lattice consists of alternating ordered and disordered bands of nanomagnetic moments.more » The disordered bands can be mapped onto an emergent thermal one-dimensional Ising model. Furthermore, we show that the level of degeneracy associated with these bands dictates the susceptibility of island moments to thermally induced reversals, thus establishing that vertex frustration can reduce the relevant dimensionality of physical behaviour in a magnetic system.« less

  15. A dynamic cellular vertex model of growing epithelial tissues

    NASA Astrophysics Data System (ADS)

    Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao

    2017-03-01

    Intercellular interactions play a significant role in a wide range of biological functions and processes at both the cellular and tissue scales, for example, embryogenesis, organogenesis, and cancer invasion. In this paper, a dynamic cellular vertex model is presented to study the morphomechanics of a growing epithelial monolayer. The regulating role of stresses in soft tissue growth is revealed. It is found that the cells originating from the same parent cell in the monolayer can orchestrate into clustering patterns as the tissue grows. Collective cell migration exhibits a feature of spatial correlation across multiple cells. Dynamic intercellular interactions can engender a variety of distinct tissue behaviors in a social context. Uniform cell proliferation may render high and heterogeneous residual compressive stresses, while stress-regulated proliferation can effectively release the stresses, reducing the stress heterogeneity in the tissue. The results highlight the critical role of mechanical factors in the growth and morphogenesis of epithelial tissues and help understand the development and invasion of epithelial tumors.

  16. A dynamic cellular vertex model of growing epithelial tissues

    NASA Astrophysics Data System (ADS)

    Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao

    2017-04-01

    Intercellular interactions play a significant role in a wide range of biological functions and processes at both the cellular and tissue scales, for example, embryogenesis, organogenesis, and cancer invasion. In this paper, a dynamic cellular vertex model is presented to study the morphomechanics of a growing epithelial monolayer. The regulating role of stresses in soft tissue growth is revealed. It is found that the cells originating from the same parent cell in the monolayer can orchestrate into clustering patterns as the tissue grows. Collective cell migration exhibits a feature of spatial correlation across multiple cells. Dynamic intercellular interactions can engender a variety of distinct tissue behaviors in a social context. Uniform cell proliferation may render high and heterogeneous residual compressive stresses, while stress-regulated proliferation can effectively release the stresses, reducing the stress heterogeneity in the tissue. The results highlight the critical role of mechanical factors in the growth and morphogenesis of epithelial tissues and help understand the development and invasion of epithelial tumors.

  17. A spin glass approach to the directed feedback vertex set problem

    NASA Astrophysics Data System (ADS)

    Zhou, Hai-Jun

    2016-07-01

    A directed graph (digraph) is formed by vertices and arcs (directed edges) from one vertex to another. A feedback vertex set (FVS) is a set of vertices that contains at least one vertex of every directed cycle in this digraph. The directed feedback vertex set problem aims at constructing a FVS of minimum cardinality. This is a fundamental cycle-constrained hard combinatorial optimization problem with wide practical applications. In this paper we construct a spin glass model for the directed FVS problem by converting the global cycle constraints into local arc constraints, and study this model through the replica-symmetric (RS) mean field theory of statistical physics. We then implement a belief propagation-guided decimation (BPD) algorithm for single digraph instances. The BPD algorithm slightly outperforms the simulated annealing algorithm on large random graph instances. The RS mean field results and algorithmic results can be further improved by working on a more restrictive (and more difficult) spin glass model.

  18. G-equivariant {phi}-coordinated quasi modules for quantum vertex algebras

    SciTech Connect

    Li, Haisheng

    2013-05-15

    This is a paper in a series to study quantum vertex algebras and their relations with various quantum algebras. In this paper, we introduce a notion of T-type quantum vertex algebra and a notion of G-equivariant {phi}-coordinated quasi module for a T-type quantum vertex algebra with an automorphism group G. We refine and extend several previous results and we obtain a commutator formula for G-equivariant {phi}-coordinated quasi modules. As an illustrating example, we study a special case of the deformed Virasoro algebra Vir{sub p,q} with q=-1, to which we associate a Clifford vertex superalgebra and its G-equivariant {phi}-coordinated quasi modules.

  19. Fire Detector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    An early warning fire detection sensor developed for NASA's Space Shuttle Orbiter is being evaluated as a possible hazard prevention system for mining operations. The incipient Fire Detector represents an advancement over commercially available smoke detectors in that it senses and signals the presence of a fire condition before the appearance of flame and smoke, offering an extra margin of safety.

  20. Metal Detectors.

    ERIC Educational Resources Information Center

    Harrington-Lueker, Donna

    1992-01-01

    Schools that count on metal detectors to stem the flow of weapons into the schools create a false sense of security. Recommendations include investing in personnel rather than hardware, cultivating the confidence of law-abiding students, and enforcing discipline. Metal detectors can be quite effective at afterschool events. (MLF)

  1. Vapor Detector

    NASA Technical Reports Server (NTRS)

    Waddell, H. M.; Garrard, G. C.; Houston, D. W.

    1982-01-01

    Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

  2. Vertex evoked potentials in a rating-scale detection task - Relation to signal probability

    NASA Technical Reports Server (NTRS)

    Squires, K. C.; Squires, N. K.; Hillyard, S. A.

    1975-01-01

    Results of vertex-evoked potential studies conducted to determine how decision confidence level and decision probability interact to determine P3 amplitude for both signal-present and signal-absent decisions. They support the contention that the form of the vertex-evoked response is closely correlated with the subject's psychophysical response regarding the presence or absence of a threshold-level signal.

  3. Big subsets with small boundaries in a graph with a vertex-transitive group of automorphisms

    NASA Astrophysics Data System (ADS)

    Seifter, N.; Trofimov, V. I.

    2017-02-01

    The theory of ends of finitely generated groups G and connected locally finite graphs Γ with vertex- transitive groups of automorphisms can be regarded as a theory of Boolean algebras of subsets of G or vertex set of Γ with finite boundaries (in the locally finite Cayley graph of G or in Γ respectively), considered modulo finite subsets. We develop a more general theory where infinite subsets with finite boundaries are replaced by certain `big' subsets with `small' boundaries.

  4. Hubble Space Telescope secondary mirror vertex radius/conic constant test

    NASA Technical Reports Server (NTRS)

    Parks, Robert

    1991-01-01

    The Hubble Space Telescope backup secondary mirror was tested to determine the vertex radius and conic constant. Three completely independent tests (to the same procedure) were performed. Similar measurements in the three tests were highly consistent. The values obtained for the vertex radius and conic constant were the nominal design values within the error bars associated with the tests. Visual examination of the interferometric data did not show any measurable zonal figure error in the secondary mirror.

  5. Non-Abelian Ball-Chiu vertex for arbitrary Euclidean momenta

    NASA Astrophysics Data System (ADS)

    Aguilar, A. C.; Cardona, J. C.; Ferreira, M. N.; Papavassiliou, J.

    2017-07-01

    We determine the non-Abelian version of the four nontransverse form factors of the quark-gluon vertex, using exact expressions derived from the Slavnov-Taylor identity that this vertex satisfies. In addition to the quark and ghost propagators, a key ingredient of the present approach is the quark-ghost scattering kernel, which is computed within the one-loop dressed approximation. The vertex form factors obtained from this procedure are evaluated for arbitrary Euclidean momenta, and display features not captured by the well-known Ball-Chiu vertex, deduced from the Abelian (ghost-free) Ward identity. Particularly interesting in this analysis is the so-called soft-gluon limit, which, unlike other kinematic configurations considered, is especially sensitive to the approximations employed for the vertex entering in the quark-ghost scattering kernel, and may even be affected by a subtle numerical instability. As an elementary application of the results obtained, we evaluate and compare certain renormalization-point-independent combinations, which contribute to the interaction kernels appearing in the standard quark gap and Bethe-Salpeter equations. In doing so, even though all form factors of the quark-gluon vertex, and in particular the transverse ones which are unconstrained by our procedure, enter nontrivially in the aforementioned kernels, only the contribution of a single form factor, corresponding to the classical (tree-level) tensor, will be considered.

  6. Constructing scalar-photon three point vertex in massless quenched scalar QED

    NASA Astrophysics Data System (ADS)

    Fernández-Rangel, L. Albino; Bashir, Adnan; Gutiérrez-Guerrero, L. X.; Concha-Sánchez, Y.

    2016-03-01

    Nonperturbative studies of Schwinger-Dyson equations require their infinite, coupled tower to be truncated in order to reduce them to a practically solvable set. In this connection, a physically acceptable Ansatz for the three point vertex is the most favorite choice. Scalar quantum electrodynamics (sQED) provides a simple and neat platform to address this problem. The most general form of the three point scalar-photon vertex can be expressed in terms of only two independent form factors, a longitudinal and a transverse one. Ball and Chiu have demonstrated that the longitudinal vertex is fixed by requiring the Ward-Fradkin-Green-Takahashi identity while the transverse vertex remains undetermined. In massless quenched sQED, we construct the transverse part of the nonperturbative scalar-photon vertex. This construction (i) ensures multiplicative renormalizability of the scalar propagator in keeping with the Landau-Khalatnikov-Fradkin transformations, (ii) has the same transformation properties as the bare vertex under charge conjugation, parity and time reversal, (iii) has no kinematic singularities and (iv) reproduces the one-loop asymptotic result in the weak coupling regime of the theory.

  7. Retroreflector for GRACE follow-on: Vertex vs. point of minimal coupling.

    PubMed

    Schütze, Daniel; Müller, Vitali; Stede, Gunnar; Sheard, Benjamin S; Heinzel, Gerhard; Danzmann, Karsten; Sutton, Andrew J; Shaddock, Daniel A

    2014-04-21

    The GRACE Follow-On mission will monitor fluctuations in Earth's geoid using, for the first time, a Laser Ranging Interferometer to measure intersatellite distance changes. We have investigated the coupling between spacecraft rotation and the intersatellite range measurement that is incurred due to manufacturing and assembly tolerances of the Triple Mirror Assembly (TMA), a precision retroreflector to ensure alignment between in- and outgoing laser beams. The three TMA mirror planes intersect in a virtual vertex to which satellite displacements are referenced. TMA manufacturing tolerances degrade this ideal vertex, however, a Point of Minimal Coupling (PMC) between spacecraft rotation and displacement exists. This paper presents the experimental location of the PMC under pitch and yaw rotations for a prototype TMA. Rotations are performed using a hexapod, while displacements are monitored with heterodyne laser interferometry to verify the PMC position. Additionally, the vertex of the three TMA mirror planes is measured using a Coordinate Measuring Machine and compared to the PMC position. In the pitch and yaw axes, the biggest deviation between TMA vertex and PMC was 50 ± 64 μm. Thus, within the measurement uncertainties, no difference between TMA vertex and PMC could be observed. This is a key piece of information for integration of the TMA into the spacecraft: It is sufficient to use the readily-available TMA vertex location to ensure minimal rotation-to-displacement coupling during the mission.

  8. Proceedings of the symposium on RHIC detector R&D

    SciTech Connect

    Makdisi, Y.; Stevens, A.J.

    1991-12-31

    This report contains papers on the following topics: Development of Analog Memories for RHIC Detector Front-end Electronic Systems; Monolithic Circuit Development for RHIC at Oak Ridge National Laboratory; Highly Integrated Electronics for the STAR TPC; Monolithic Readout Circuits for RHIC; New Methods for Trigger Electronics Development; Neurocomputing methods for Pattern Recognition in Nuclear Physics; The Development of a Silicon Multiplicity Detector System; The Vertex Detector for the Lepton/Photon Collaboration; Simulations of Silicon Vertex Tracker for STAR Experiment at RHIC; Calorimeter/Absorber Optimization for a RHIC Dimuon Experiment (RD-10 Project); Applications of the LAHET simulation Code to Relativistic Heavy Ion Detectors; Highly Segmented, High Resolution Time-of-Flight System; Research and Development on a Sub 100 Picosecond Time-of-Flight System Based on Silicon Avalance Diodes; Behavior of TPC`s in a High Particle Flux Environment; Generic R&D on Undoped Cesium Iodide and Lead Fluoride; and A Transition Radiation Detector for RHIC Featuring Accurate Tracking and dE/dx Particle Identification. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  9. Kali: The framework for fine calibration of the LHCb Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Belyaev, Ivan; Savrina, Daria; Graciani, Ricardo; Puig, Albert; LHCb Collaboration

    2011-12-01

    The precise calibration (at a level of below 1%) of the electromagnetic calorimeter (ECAL) of the LHCb experiment is an essential task for the fulfilment of the LHCb physics program. The final step of this task is performed with two calibration methods using the real data from the experimental setup. It is a very CPU-consuming procedure as both methods require processing of Script O(108) events which must be selected, reconstructed and analyzed. In this document we present the Kali framework developed within the LHCb software framework, which implements these two final calibration methods. It is integrated with Grid middleware and makes use of parallelism tools, such as python parallel processing modules, to provide an efficient way, both time and disk wise, for the final ECAL calibration. The results of the fine calibration with the very first data collected by the LHCb experiment will also be presented. With the use of the Kali framework it took only two days of processing and allowed to achieve a calibration accuracy of 2-2.5% for the different ECAL areas.

  10. CP Violation in b- and c-hadron decays at LHCb

    NASA Astrophysics Data System (ADS)

    Steinkamp, Olaf; LHCb Collaboration

    2017-07-01

    Testing the Standard Model of particle physics by precision measurements of CP violating observables in the decays of b and c hadrons has been one of the design goals of the LHCb experiment. World-leading measurements have been performed of the semileptonic asymmetry, {a}ssl, and of the mixing-induced CP-violating phase ϕs in the {B}s0{\\bar{B}}s0 system. The CKM angle γ is still the least known angle of the Unitarity Triangle, and the only one easily accessible using tree-level decays. A recent combination of LHCb measurements in various B → DK decay modes has yielded the most precise determination of γ from a single experiment to date. The LHCb experiment is collecting unprecedented samples of beauty baryons, allowing for the first time to study CP violating observables in their decays. A recent analysis provided the first evidence for CP violation in the beauty baryon sector. Finally, LHCb has the largest samples of charmed hadron decays collected by any experiment to date. These samples yield some of the world’s most sensitive searches for direct and indirect CP violation in the charm sector.

  11. VERTEX: Manganese transport with CaCO 3

    NASA Astrophysics Data System (ADS)

    Martin, John H.; Knauer, George A.

    1983-04-01

    Manganese transport was studied off central California in August and September 1981 as part of the VERTEX (Vertica l Transport and Exchange) research program. Refractory, leachable, and dissolved Mn fractions associated with particles caught in traps set at 11 depths (50 to 2000 m) were analyzed. Through intentional and unintentional CaCO 3 dissolution 'experiments', it was learned that the weakly leachable Mn was originally in association with the carbonate phase. Adsorption on surfaces rather than absorption in CaCO 3 matrices was indicated by the finding that Mn was not released in proportion to the CaCo 3 dissolved, instead it appeared to keep readsorbing to the dissolving surface. Ultimately, Mn went into solution when the particulate CaCO 3 was essentially depleted, suggesting that sufficient sites for adsorption were no longer available. Manganese fluxes with CaCO 3 were low near the surface (0.1 mg cm -2 ky -1), but increased rapidly in the 50 to 200-m depth interval, and then became more or less constant (1.3 mg cm -2 ky -1 for the remainder of the water column (300 to 2000 m). Rate-of-change estimates indicate that Mn is rapidly scavenged in near-surface waters (-130 ng 1 -1 y -1) and slowly regenerated at depth (2.7 ng 1 -1 y -1) in our near-shore study area. Residence times for dissolved Mn were estimated at 1.2 y for surface waters and 17 y at depth. The implications of Mn transport with CaCO 3 in relation to open-ocean sediment excess Mn are discussed.

  12. TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)

    SciTech Connect

    PHENIX EXPERIMENT; OBRIEN,E.; PAK, R.; DREES, K.A.

    2007-08-01

    The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the {upsilon}{prime} and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality.

  13. Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Titov, Maxim

    Since long time, the compelling scientific goals of future high-energy physics experiments were a driving factor in the development of advanced detector technologies. A true innovation in detector instrumentation concepts came in 1968, with the development of a fully parallel readout for a large array of sensing elements - the Multi-Wire Proportional Chamber (MWPC), which earned Georges Charpak a Nobel prize in physics in 1992. Since that time radiation detection and imaging with fast gaseous detectors, capable of economically covering large detection volumes with low mass budget, have been playing an important role in many fields of physics. Advances in photolithography and microprocessing techniques in the chip industry during the past decade triggered a major transition in the field of gas detectors from wire structures to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size limitations for many gas detector applications. The high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the next generation of colliders. The design of the new micro-pattern devices appears suitable for industrial production. Novel structures where MPGDs are directly coupled to the CMOS pixel readout represent an exciting field allowing timing and charge measurements as well as precise spatial information in 3D. Originally developed for the high-energy physics, MPGD applications have expanded to nuclear physics, photon detection, astroparticle and neutrino physics, neutron detection, and medical imaging.

  14. Coherent operation of detector systems and their readout electronics in a complex experiment control environment

    NASA Astrophysics Data System (ADS)

    Koestner, Stefan

    2009-09-01

    With the increasing size and degree of complexity of today's experiments in high energy physics the required amount of work and complexity to integrate a complete subdetector into an experiment control system is often underestimated. We report here on the layered software structure and protocols used by the LHCb experiment to control its detectors and readout boards. The experiment control system of LHCb is based on the commercial SCADA system PVSS II. Readout boards which are outside the radiation area are accessed via embedded credit card sized PCs which are connected to a large local area network. The SPECS protocol is used for control of the front end electronics. Finite state machines are introduced to facilitate the control of a large number of electronic devices and to model the whole experiment at the level of an expert system.

  15. A pressurized argon gas TPC as DUNE near detector

    NASA Astrophysics Data System (ADS)

    Martín-Albo, J.; DUNE Collaboration

    2017-09-01

    DUNE is a new international experiment for neutrino physics and nucleon decay searches. It will consist of two detectors, about 1300 km apart, exposed to a multi-megawatt neutrino beam that will be built at Fermilab. One of the two detectors will be installed several hundred meters downstream of the neutrino production point with the primary role of characterising the energy spectrum and composition of the beam as well as performing precision measurements of neutrino cross sections. For the design of this so-called near detector, the DUNE Collaboration is considering, among other technologies, a pressurized argon gas time projection chamber. Such a detector, thanks to its low density and low detection thresholds, would allow the detailed measurement in argon of nuclear effects at the neutrino interaction vertex, which are considered at present one of the most important sources of systematic uncertainty for neutrino oscillation measurements.

  16. Status and performance of the CDF Run II silicon detectors

    SciTech Connect

    Nielsen, Jason; /LBL, Berkeley

    2004-11-01

    In 2001, an upgraded silicon detector system was installed in the CDF II experiment on the Tevatron at Fermilab. The complete system consists of three silicon microstrip detectors: SVX II with five layers for precision tracking, Layer 00 with one beampipe-mounted layer for vertexing, and two Intermediate Silicon Layers located between SVX II and the main CDF II tracking chamber. Currently all detectors in the system are operating at or near design levels. The performance of the combined silicon system is excellent in the context of CDF tracking algorithms, and the first useful physics results from the innermost Layer 00 detector have been recently documented. Operational and monitoring efforts have also been strengthened to maintain silicon efficiency through the end of Run 2 at the Tevatron.

  17. MS Detectors

    SciTech Connect

    Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

    2005-11-01

    Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

  18. Diamond detectors for the TOTEM timing upgrade

    NASA Astrophysics Data System (ADS)

    Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bottigli, U.; Bozzo, M.; Broulím, P.; Buzzo, A.; Cafagna, F. S.; Catanesi, M. G.; Csanád, M.; Csörgő, T.; Deile, M.; De Leonardis, F.; D'Orazio, A.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Georgiev, V.; Giani, S.; Grzanka, L.; Guaragnella, C.; Hammerbauer, J.; Heino, J.; Karev, A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Lami, S.; Latino, G.; Lauhakangas, R.; Linhart, R.; Lokajíček, M. V.; Losurdo, L.; Lo Vetere, M.; Rodríguez, F. Lucas; Lucsanyi, D.; Macrí, M.; Mercadante, A.; Minafra, N.; Minutoli, S.; Naaranoja, T.; Nemes, F.; Niewiadomski, H.; Novak, T.; Oliveri, E.; Oljemark, F.; Oriunno, M.; Österberg, K.; Palazzi, P.; Paločko, L.; Passaro, V.; Peroutka, Z.; Petruzzelli, V.; Politi, T.; Procházka, J.; Prudenzano, F.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Royon, C.; Ruggiero, G.; Saarikko, H.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Welti, J.; Wyszkowski, P.; Zielinski, K.

    2017-03-01

    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC . The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.

  19. Diamond detectors for the TOTEM timing upgrade

    DOE PAGES

    Antchev, G.; Aspell, P.; Atanassov, I.; ...

    2017-03-09

    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC . The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision.more » This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. In conclusion, after introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.« less

  20. The specific localizations of phosphorylated Lhcb1 and Lhcb2 isoforms reveal the role of Lhcb2 in the formation of the PSI-LHCII supercomplex in Arabidopsis during state transitions.

    PubMed