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Sample records for hadron electron collider

  1. Future Electron-Hadron Colliders

    SciTech Connect

    Litvinenko, V.

    2010-05-23

    Outstanding research potential of electron-hadron colliders (EHC) was clearly demonstrated by first - and the only - electron-proton collider HERA (DESY, Germany). Physics data from HERA revealed new previously unknown facets of Quantum Chromo-Dynamics (QCD). EHC is an ultimate microscope probing QCD in its natural environment, i.e. inside the hadrons. In contrast with hadrons, electrons are elementary particles with known initial state. Hence, scattering electrons from hadrons provides a clearest pass to their secrets. It turns EHC into an ultimate machine for high precision QCD studies and opens access to rich physics with a great discovery potential: solving proton spin puzzle, observing gluon saturation or physics beyond standard model. Access to this physics requires high-energy high-luminosity EHCs and a wide reach in the center-of-mass (CM) energies. This paper gives a brief overview of four proposed electron-hadron colliders: ENC at GSI (Darmstadt, Germany), ELIC/MEIC at TJNAF (Newport News, VA, USA), eRHIC at BNL (Upton, NY, USA) and LHeC at CERN (Geneva, Switzerland). Future electron-hadron colliders promise to deliver very rich physics not only in the quantity but also in the precision. They are aiming at very high luminosity two-to-four orders of magnitude beyond the luminosity demonstrated by the very successful HERA. While ENC and LHeC are on opposite side of the energy spectrum, eRHIC and ELIC are competing for becoming an electron-ion collider (EIC) in the U.S. Administrations of BNL and Jlab, in concert with US DoE office of Nuclear Physics, work on the strategy for down-selecting between eRHIC and ELIC. The ENC, EIC and LHeC QCD physics programs to a large degree are complimentary to each other and to the LHC physics. In last decade, an Electron Ion Collider (EIC) collaboration held about 25 collaboration meetings to develop physics program for EIC with CM energy {approx}100 GeV. One of these meetings was held at GSI, where ENC topic was in the

  2. A large hadron electron collider at CERN

    DOE PAGES

    Abelleira Fernandez, J. L.

    2015-04-06

    This document provides a brief overview of the recently published report on the design of the Large Hadron Electron Collider (LHeC), which comprises its physics programme, accelerator physics, technology and main detector concepts. The LHeC exploits and develops challenging, though principally existing, accelerator and detector technologies. This summary is complemented by brief illustrations of some of the highlights of the physics programme, which relies on a vastly extended kinematic range, luminosity and unprecedented precision in deep inelastic scattering. Illustrations are provided regarding high precision QCD, new physics (Higgs, SUSY) and eletron-ion physics. The LHeC is designed to run synchronously withmore » the LHC in the twenties and to achieve an integrated luminosity of O(100)fb–1. It will become the cleanest high resolution microscope of mankind and will substantially extend as well as complement the investigation of the physics of the TeV energy scale, which has been enabled by the LHC.« less

  3. A large hadron electron collider at CERN

    SciTech Connect

    Abelleira Fernandez, J. L.

    2015-04-06

    This document provides a brief overview of the recently published report on the design of the Large Hadron Electron Collider (LHeC), which comprises its physics programme, accelerator physics, technology and main detector concepts. The LHeC exploits and develops challenging, though principally existing, accelerator and detector technologies. This summary is complemented by brief illustrations of some of the highlights of the physics programme, which relies on a vastly extended kinematic range, luminosity and unprecedented precision in deep inelastic scattering. Illustrations are provided regarding high precision QCD, new physics (Higgs, SUSY) and eletron-ion physics. The LHeC is designed to run synchronously with the LHC in the twenties and to achieve an integrated luminosity of O(100)fb–1. It will become the cleanest high resolution microscope of mankind and will substantially extend as well as complement the investigation of the physics of the TeV energy scale, which has been enabled by the LHC.

  4. Electron Lenses for the Large Hadron Collider

    SciTech Connect

    Stancari, Giulio; Valishev, Alexander; Bruce, Roderik; Redaelli, Stefano; Rossi, Adriana; Salvachua, Belen

    2014-07-01

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. This project is moving towards a technical design in 2014, with the goal to build the devices in 2015-2017, after resuming LHC operations and re-assessing needs and requirements at 6.5 TeV. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles.

  5. Top quark FCNC couplings at future circular hadron electron colliders

    NASA Astrophysics Data System (ADS)

    Denizli, H.; Senol, A.; Yilmaz, A.; Cakir, I. Turk; Karadeniz, H.; Cakir, O.

    2017-07-01

    A study of single top quark production via flavor changing neutral current interactions at t q γ vertices is performed at the future circular hadron electron collider. The signal cross sections for the processes e-p →e-W±q +X and e-p →e-W±b q +X in the collision of an electron beam with energy Ee=60 GeV and a proton beam with energy Ep=50 TeV are calculated. In the analysis, the invariant mass distributions of three jets reconstructing top quark mass, requiring one b-tagged jet and two other jets reconstructing the W mass are used to count signal and background events after all selection cuts. The upper limits on the anomalous flavor changing neutral current t q γ couplings are found to be λq<0.01 at the future circular hadron electron collider for Lint=100 fb-1 with the fast simulation of detector effects. Signal significance depending on the couplings λq is analyzed and an enhanced sensitivity is found to the branching ratio BR (t →q γ ) at the future circular hadron electron collider when compared to the current experimental results.

  6. High luminosity electron-hadron collider eRHIC

    SciTech Connect

    Ptitsyn, V.; Aschenauer, E.; Bai, M.; Beebe-Wang, J.; Belomestnykh, S.; Ben-Zvi, I.; Blaskiewicz, M..; Calaga, R.; Chang, X.; Fedotov, A.; Gassner, D.; Hammons, L.; Hahn, H.; Hammons, L.; He, P.; Hao, Y.; Jackson, W.; Jain, A.; Johnson, E.C.; Kayran, D.; Kewisch, J.; Litvinenko, V.N.; Luo, Y.; Mahler, G.; McIntyre, G.; Meng, W.; Minty, M.; Parker, B.; Pikin, A.; Rao, T.; Roser, T.; Skaritka, J.; Sheehy, B.; Skaritka, J.; Tepikian, S.; Than, Y.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; Wang, G.; Webb, S.; Wu, Q.; Xu, W.; Pozdeyev, E.; Tsentalovich, E.

    2011-03-28

    We present the design of a future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC. We plan on adding 20 (potentially 30) GeV energy recovery linacs to accelerate and to collide polarized and unpolarized electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 10{sup 34} cm{sup -2} s{sup -1} can be achieved in eRHIC using the low-beta interaction region with a 10 mrad crab crossing. We report on the progress of important eRHIC R&D such as the high-current polarized electron source, the coherent electron cooling, ERL test facility and the compact magnets for recirculation passes. A natural staging scenario of step-by-step increases of the electron beam energy by building-up of eRHIC's SRF linacs is presented.

  7. Design of the large hadron electron collider interaction region

    NASA Astrophysics Data System (ADS)

    Cruz-Alaniz, E.; Newton, D.; Tomás, R.; Korostelev, M.

    2015-11-01

    The large hadron electron collider (LHeC) is a proposed upgrade of the Large Hadron Collider (LHC) within the high luminosity LHC (HL-LHC) project, to provide electron-nucleon collisions and explore a new regime of energy and luminosity for deep inelastic scattering. The design of an interaction region for any collider is always a challenging task given that the beams are brought into crossing with the smallest beam sizes in a region where there are tight detector constraints. In this case integrating the LHeC into the existing HL-LHC lattice, to allow simultaneous proton-proton and electron-proton collisions, increases the difficulty of the task. A nominal design was presented in the the LHeC conceptual design report in 2012 featuring an optical configuration that focuses one of the proton beams of the LHC to β*=10 cm in the LHeC interaction point to reach the desired luminosity of L =1033 cm-2 s-1 . This value is achieved with the aid of a new inner triplet of quadrupoles at a distance L*=10 m from the interaction point. However the chromatic beta beating was found intolerable regarding machine protection issues. An advanced chromatic correction scheme was required. This paper explores the feasibility of the extension of a novel optical technique called the achromatic telescopic squeezing scheme and the flexibility of the interaction region design, in order to find the optimal solution that would produce the highest luminosity while controlling the chromaticity, minimizing the synchrotron radiation power and maintaining the dynamic aperture required for stability.

  8. Updated electron-cloud simulation results for the Large Hadron Collider (LHC)

    SciTech Connect

    Furman, M. A.; Pivi, M.

    2001-06-26

    This paper presents new simulation results for the power deposition from the electron cloud in the beam screen of the Large Hadron Collider (LHC). We pay particular attention to the sensitivity of the results to certain low-energy parameters of the secondary electron (SE)emission. Most of these parameters, which constitute an input to the simulation program, are extracted from recent measurements at CERN and SLAC.

  9. Hadron collider physics

    SciTech Connect

    Pondrom, L.

    1991-10-03

    An introduction to the techniques of analysis of hadron collider events is presented in the context of the quark-parton model. Production and decay of W and Z intermediate vector bosons are used as examples. The structure of the Electroweak theory is outlined. Three simple FORTRAN programs are introduced, to illustrate Monte Carlo calculation techniques. 25 refs.

  10. Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

    SciTech Connect

    Stancari, Giulio; Previtali, Valentina; Valishev, Alexander; Bruce, Roderik; Redaelli, Stefano; Rossi, Adriana; Salvachua Ferrando, Belen

    2014-06-26

    Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.

  11. The ERL-based Design of Electron-Hadron Collider eRHIC

    SciTech Connect

    Ptitsyn, Vadim

    2016-06-01

    Recent developments of the ERL-based design of future high-luminosity electron-hadron collider eRHIC focused on balancing technological risks present in the design versus the design cost. As a result a lower risk design has been adopted at moderate cost increase. The modifications include a change of the main linac RF frequency, reduced number of SRF cavity types and modified electron spin transport using a spin rotator. A luminosity-staged approach is being explored with a Nominal design ($L \\sim 10^{33} {\\rm cm}^2 {\\rm s}^{-1}$) that employs reduced electron current and could possibly be based on classical electron cooling, and then with the Ultimate design ($L \\gt 10^{34} {\\rm cm}^{-2} {\\rm s}^{-1}$) that uses higher electron current and an innovative cooling technique (CeC). The paper describes the recent design modifications, and presents the full status of the eRHIC ERL-based design.

  12. Measuring CP nature of top-Higgs couplings at the future Large Hadron electron Collider

    NASA Astrophysics Data System (ADS)

    Coleppa, Baradhwaj; Kumar, Mukesh; Kumar, Satendra; Mellado, Bruce

    2017-07-01

    We investigate the sensitivity of top-Higgs coupling by considering the associated vertex as CP phase (ζt) dependent through the process pe- → t bar hνe in the future Large Hadron electron Collider. In particular the decay modes are taken to be h → b b bar and t bar → leptonic mode. Several distinct ζt dependent features are demonstrated by considering observables like cross sections, top-quark polarisation, rapidity difference between h and t bar and different angular asymmetries. Luminosity (L) dependent exclusion limits are obtained for ζt by considering significance based on fiducial cross sections at different σ-levels. For electron and proton beam-energies of 60 GeV and 7 TeV respectively, at L = 100 fb-1, the regions above π / 5 <ζt ≤ π are excluded at 2σ confidence level, which reflects better sensitivity expected at the Large Hadron Collider. With appropriate error fitting methodology we find that the accuracy of SM top-Higgs coupling could be measured to be κ = 1.00 ± 0.17 (0.08) at √{ s} = 1.3 (1.8) TeV for an ultimate L = 1ab-1.

  13. Physics at future hadron colliders

    SciTech Connect

    U. Baur et al.

    2002-12-23

    We discuss the physics opportunities and detector challenges at future hadron colliders. As guidelines for energies and luminosities we use the proposed luminosity and/or energy upgrade of the LHC (SLHC), and the Fermilab design of a Very Large Hadron Collider (VLHC). We illustrate the physics capabilities of future hadron colliders for a variety of new physics scenarios (supersymmetry, strong electroweak symmetry breaking, new gauge bosons, compositeness and extra dimensions). We also investigate the prospects of doing precision Higgs physics studies at such a machine, and list selected Standard Model physics rates.

  14. Hadron collider physics at UCR

    SciTech Connect

    Kernan, A.; Shen, B.C.

    1997-07-01

    This paper describes the research work in high energy physics by the group at the University of California, Riverside. Work has been divided between hadron collider physics and e{sup +}-e{sup {minus}} collider physics, and theoretical work. The hadron effort has been heavily involved in the startup activities of the D-Zero detector, commissioning and ongoing redesign. The lepton collider work has included work on TPC/2{gamma} at PEP and the OPAL detector at LEP, as well as efforts on hadron machines.

  15. The high luminosity interaction region for a ring-ring Large Hadron Electron Collider

    NASA Astrophysics Data System (ADS)

    Appleby, R. B.; Thompson, L.; Holzer, B.; Fitterer, M.; Bernard, N.; Kostka, P.

    2013-12-01

    The Large Hadron Electron Collider (LHeC) project is a proposal for high luminosity TeV-scale electron-proton (ep) collisions at the LHC. The LHeC Conceptual Design Report presented an early overview of the machine, including an electron linac solution and a solution involving a 60 GeV electron storage ring. Here we present a new complete solution for the collision insertion of this electron ring, incorporating all constraints including those imposed by the LHC and, for the first time, proving the feasibility of ep collisions at a luminosity of ˜1033 cm-2s-1 in the LHC era. The solution presented offers high luminosity while maintaining the large detector coverage required by the particle physics programme. This negates the earlier need for two separate interaction region designs, one optimized for high luminosity at the cost of detector coverage, and the other for lower luminosity but higher coverage. Synchrotron radiation emission is also a major factor in electron accelerator design, and studies are presented showing the feasibility of the design in this regard. The design is found to be technically viable, solving the problem of TeV-scale, high luminosity and high coverage ep collisions at a ring-ring LHeC.

  16. FEL-based coherent electron cooling for high-energy hadron colliders

    SciTech Connect

    Litvinenko,V.N.; Derbenev, Y.S.

    2008-06-23

    Cooling intense high-energy hadron beams is a major challenge in modern accelerator physics. Synchrotron radiation is too feeble and two common methods--stochastic and electron cooling--are not efficient in providing significant cooling for high energy, high intensity proton colliders. In this paper they discuss a practical scheme of Coherent Electron Cooling (CeC), which promises short cooling times (below one hour) for intense proton beams in RHIC at 250 GeV or in LHC at 7 TeV. A possibility of CeC using various microwave instabilities was discussed since 1980s. In this paper, they present first evaluation of specific CeC scheme based on capabilities of present-day accelerator technology, ERLs, and high-gain Free-Electron lasers (FELs). They discuss the principles, the main limitations of this scheme and present some predictions for Coherent Electron Cooling in RHIC and the LHC operating with ions or protons, summarized in Table 1.

  17. Precision measurements of W and Z boson production and their decays to electrons at hadron colliders

    SciTech Connect

    Ehlers, Jans Hermann

    2006-01-01

    For many measurements at hadron colliders, such as cross sections and branching ratios, the uncertainty of the integrated luminosity is an important contribution to the error of the final result. In 1997, the ETH Zurich group proposed a new approach to determine the integrated luminosity via a counting measurement of the W and Z bosons through their decays to leptons. In this thesis this proposal has been applied on real data as well as on simulation for a future experiment.

  18. B physics at hadron colliders

    SciTech Connect

    Butler, J.N.; /Fermilab

    2005-09-01

    This paper discusses the physics opportunity and challenges for doing high precision B physics experiments at hadron colliders. It describes how these challenges have been addressed by the two currently operating experiments, CDF and D0, and how they are addressed by three experiments, ATLAS, CMS, and LHCb, at the LHC.

  19. The very large hadron collider

    SciTech Connect

    1998-09-01

    This paper reviews the purposes to be served by a very large hadron collider and the organization and coordination of efforts to bring it about. There is some discussion of magnet requirements and R&D and the suitability of the Fermilab site.

  20. Recent results from hadron colliders

    SciTech Connect

    Frisch, H.J. )

    1990-12-10

    This is a summary of some of the many recent results from the CERN and Fermilab colliders, presented for an audience of nuclear, medium-energy, and elementary particle physicists. The topics are jets and QCD at very high energies, precision measurements of electroweak parameters, the remarkably heavy top quark, and new results on the detection of the large flux of B mesons produced at these machines. A summary and some comments on the bright prospects for the future of hadron colliders conclude the talk. 39 refs., 44 figs., 3 tabs.

  1. Soviet Hadron Collider

    NASA Astrophysics Data System (ADS)

    Kotchetkov, Dmitri

    2017-01-01

    Rapid growth of the high energy physics program in the USSR during 1960s-1970s culminated with a decision to build the Accelerating and Storage Complex (UNK) to carry out fixed target and colliding beam experiments. The UNK was to have three rings. One ring was to be built with conventional magnets to accelerate protons up to the energy of 600 GeV. The other two rings were to be made from superconducting magnets, each ring was supposed to accelerate protons up to the energy of 3 TeV. The accelerating rings were to be placed in an underground tunnel with a circumference of 21 km. As a 3 x 3 TeV collider, the UNK would make proton-proton collisions with a luminosity of 4 x 1034 cm-1s-1. Institute for High Energy Physics in Protvino was a project leading institution and a site of the UNK. Accelerator and detector research and development studies were commenced in the second half of 1970s. State Committee for Utilization of Atomic Energy of the USSR approved the project in 1980, and the construction of the UNK started in 1983. Political turmoil in the Soviet Union during late 1980s and early 1990s resulted in disintegration of the USSR and subsequent collapse of the Russian economy. As a result of drastic reduction of funding for the UNK, in 1993 the project was restructured to be a 600 GeV fixed target accelerator only. While the ring tunnel and proton injection line were completed by 1995, and 70% of all magnets and associated accelerator equipment were fabricated, lack of Russian federal funding for high energy physics halted the project at the end of 1990s.

  2. State of hadron collider physics

    SciTech Connect

    Grannis, P.D. |

    1993-12-01

    The 9th Topical Workshop on Proton-Antiproton Collider Physics in Tsukuba Japan demonstrated clearly the enormous breadth of physics accessible in hadron cowders. Although no significant chinks were reported in the armor of the Standard Model, new results presented in this meeting have expanded our knowledge of the electroweak and strong interactions and have extended the searches for non-standard phenomena significantly. Much of the new data reported came from the CDF and D0 experiments at the Fermilab cowder. Superb operation of the Tevatron during the 1992-1993 Run and significant advances on the detector fronts -- in particular, the emergence of the new D0 detector as a productive physics instrument in its first outing and the addition of the CDF silicon vertex detector -- enabled much of this advance. It is noteworthy however that physics from the CERN collider experiments UA1 and UA4 continued to make a large impact at this meeting. In addition, very interesting summary talks were given on new results from HERA, cosmic ray experiments, on super-hadron collider physics, and on e{sup +}e{sup {minus}} experiments at LEP and TRISTAN. These summaries are reported in elsewhere in this volume.

  3. LHC: The Large Hadron Collider

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The Large Hadron Collider (or LHC) is the world’s most powerful particle accelerator. In 2012, scientists used data taken by it to discover the Higgs boson, before pausing operations for upgrades and improvements. In the spring of 2015, the LHC will return to operations with 163% the energy it had before and with three times as many collisions per second. It’s essentially a new and improved version of itself. In this video, Fermilab’s Dr. Don Lincoln explains both some of the absolutely amazing scientific and engineering properties of this modern scientific wonder.

  4. LHC: The Large Hadron Collider

    SciTech Connect

    Lincoln, Don

    2015-03-04

    The Large Hadron Collider (or LHC) is the world’s most powerful particle accelerator. In 2012, scientists used data taken by it to discover the Higgs boson, before pausing operations for upgrades and improvements. In the spring of 2015, the LHC will return to operations with 163% the energy it had before and with three times as many collisions per second. It’s essentially a new and improved version of itself. In this video, Fermilab’s Dr. Don Lincoln explains both some of the absolutely amazing scientific and engineering properties of this modern scientific wonder.

  5. Very large hadron collider (VLHC)

    SciTech Connect

    1998-09-01

    A VLHC informal study group started to come together at Fermilab in the fall of 1995 and at the 1996 Snowmass Study the parameters of this machine took form. The VLHC as now conceived would be a 100 TeV hadron collider. It would use the Fermilab Main Injector (now nearing completion) to inject protons at 150 GeV into a new 3 TeV Booster and then into a superconducting pp collider ring producing 100 TeV c.m. interactions. A luminosity of {approximately}10{sup 34} cm{sup -2}s{sup -1} is planned. Our plans were presented to the Subpanel on the Planning for the Future of US High- Energy Physics (the successor to the Drell committee) and in February 1998 their report stated ``The Subpanel recommends an expanded program of R&D on cost reduction strategies, enabling technologies, and accelerator physics issues for a VLHC. These efforts should be coordinated across laboratory and university groups with the aim of identifying design concepts for an economically and technically viable facility`` The coordination has been started with the inclusion of physicists from Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL), and Cornell University. Clearly, this collaboration must expanded internationally as well as nationally. The phrase ``economically and technically viable facility`` presents the real challenge.

  6. Electron reconstruction and electroweak processes as tools to achieve precision measurements at a hadron collider: From CDF to CMS

    SciTech Connect

    Giolo-Nicollerat, Anne-Sylvie

    2004-01-01

    Precision measurements are an important aspect of hadron colliders physics program. This thesis describes a method, together with a first application, of how to achieve and use precision measurements at the LHC. The idea is to use refernce processes to control the detector systematics and to constrain the theoretical predictions.

  7. Exotic hadron bound state production at hadron colliders

    NASA Astrophysics Data System (ADS)

    Jin, Yi; Li, Shi-Yuan; Liu, Yan-Rui; Meng, Lu; Si, Zong-Guo; Zhang, Xiao-Feng

    2017-08-01

    The non-relativistic wave function framework is applied to study the production and decay of exotic hadrons, which can be effectively described as bound states of other hadrons. Employing the factorized formulation, with the help of event generators, we investigate the production of exotic hadrons in multiproduction processes at high energy hadron colliders. This study provides crucial information for the measurements of the relevant exotic hadrons. Supported by Natural Science Foundation of Shandong Province (ZR2014AM016, ZR2016AM16) and National Natural Science Foundation of China (11275115, 11325525, 11635009)

  8. Physics of very high energy hadron-hadron colliders

    SciTech Connect

    Hinchliffe, I.

    1986-09-01

    A review is given of the physics accessible at a very high energy hadron-hadron collider. Emphasis is placed on the reliability of the predicted rates, and upon the energy and luminosity required to explore new physics options. 38 refs., 19 figs.

  9. The Very Large Hadron Collider: The farthest energy frontier

    SciTech Connect

    Barletta, William A.

    2001-06-21

    The Very Large Hadron Collider (or Eloisatron) represents what may well be the final step on the energy frontier of accelerator-based high energy physics. While an extremely high luminosity proton collider at 100-200 TeV center of mass energy can probably be built in one step with LHC technology, that machine would cost more than what is presently politically acceptable. This talk summarizes the strategies of collider design including staged deployment, comparison with electron-positron colliders, opportunities for major innovation, and the technical challenges of reducing costs to manageable proportions. It also presents the priorities for relevant R and D for the next few years.

  10. Optimizing integrated luminosity of future hadron colliders

    NASA Astrophysics Data System (ADS)

    Benedikt, Michael; Schulte, Daniel; Zimmermann, Frank

    2015-10-01

    The integrated luminosity, a key figure of merit for any particle-physics collider, is closely linked to the peak luminosity and to the beam lifetime. The instantaneous peak luminosity of a collider is constrained by a number of boundary conditions, such as the available beam current, the maximum beam-beam tune shift with acceptable beam stability and reasonable luminosity lifetime (i.e., the empirical "beam-beam limit"), or the event pileup in the physics detectors. The beam lifetime at high-luminosity hadron colliders is largely determined by particle burn off in the collisions. In future highest-energy circular colliders synchrotron radiation provides a natural damping mechanism, which can be exploited for maximizing the integrated luminosity. In this article, we derive analytical expressions describing the optimized integrated luminosity, the corresponding optimum store length, and the time evolution of relevant beam parameters, without or with radiation damping, while respecting a fixed maximum value for the total beam-beam tune shift or for the event pileup in the detector. Our results are illustrated by examples for the proton-proton luminosity of the existing Large Hadron Collider (LHC) at its design parameters, of the High-Luminosity Large Hadron Collider (HL-LHC), and of the Future Circular Collider (FCC-hh).

  11. Forward physics of hadronic colliders

    NASA Astrophysics Data System (ADS)

    Ivanov, I. P.

    2013-12-01

    These lectures were given at the Baikal Summer School on Physics of Elementary Particles and Astrophysics in July 2012. They can be viewed as a concise introduction to hadronic diffraction, to the physics of the Pomeron and related topics.

  12. Top quark studies at hadron colliders

    SciTech Connect

    Sinervo, P.K.

    1997-01-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

  13. The Large Hadron Collider, a personal recollection

    NASA Astrophysics Data System (ADS)

    Evans, Lyndon

    2014-03-01

    The construction of the Large Hadron Collider (LHC) has been a massive endeavor spanning almost 30 years from conception to commissioning. Building the machine with the highest possible energy (7 TeV) in the existing LEP tunnel of 27 km circumference and with a tunnel diameter of only 3.8 m has required considerable innovation. The first was the development of an idea first proposed by Bob Palmer at Brookhaven National Laboratory in 1978, where the two rings are integrated into a single magnetic structure. This compact 2-in-1 structure was essential for the LHC due to both the limited space available in the existing Large Electron-Positron collider tunnel and the cost. The second innovation was the bold move to use superfluid helium cooling on a massive scale, which was imposed by the need to achieve a high (8.3 T) magnetic field using an affordable Nb-Ti superconductor. In this article, no attempt is made to give a comprehensive review of the machine design. This can be found in the LHC Design Report [1], which gives a detailed description of the machine as it was built and comprehensive references. A more popular description of the LHC and its detectors can be found in [2]. Instead, this is a more personal account of the project from approval to commissioning, describing some of the main technologies and some of the trials and tribulations encountered in bringing this truly remarkable machine alive.

  14. Black Holes and the Large Hadron Collider

    ERIC Educational Resources Information Center

    Roy, Arunava

    2011-01-01

    The European Center for Nuclear Research or CERN's Large Hadron Collider (LHC) has caught our attention partly due to the film "Angels and Demons." In the movie, an antimatter bomb attack on the Vatican is foiled by the protagonist. Perhaps just as controversial is the formation of mini black holes (BHs). Recently, the American Physical Society…

  15. Black Holes and the Large Hadron Collider

    ERIC Educational Resources Information Center

    Roy, Arunava

    2011-01-01

    The European Center for Nuclear Research or CERN's Large Hadron Collider (LHC) has caught our attention partly due to the film "Angels and Demons." In the movie, an antimatter bomb attack on the Vatican is foiled by the protagonist. Perhaps just as controversial is the formation of mini black holes (BHs). Recently, the American Physical Society…

  16. Fourth Annual Large Hadron Collider Physics

    NASA Astrophysics Data System (ADS)

    The fourth annual Large Hadron Collider Physics (LHCP2016) conference will be held in Lund, Sweden, in the period of June 13-18, 2016. The conference is hosted by Lund University. The LHCP conference series has emerged in 2013 as a successful result of fusion of two international conferences, Physics at Large Hadron Collider Conference and Hadron Collider Physics Symposium. The program will be devoted to a detailed review of the latest experimental and theoretical results on collider physics, particularly the first results of the LHC Run II, and discussions on further research directions within the high energy particle physics community, both in theory and experiment. The main goal of the conference is to provide intense and lively discussions between experimenters and theorists in such research areas as the Standard Model Physics and Beyond, the Higgs Boson, Supersymmetry, Heavy Quark Physics and Heavy Ion Physics as well as to share a recent progress in the high luminosity upgrades and future colliders developments. Chairpersons: Gregorio Bernardi (LPNHE-Paris CNRS/IN2P3), Guenakh Mitselmakher (University of Florida (US)), Leif Lönnblad (Lund University (SE)), Torsten Akesson (Lund University (SE)) Editorial Board Johan Bijnens (Lund University) Andreas Hoecker (CERN) Jim Olsen (Princeton University)

  17. The Large Hadron Collider: Redefining High Energy

    SciTech Connect

    Demers, Sarah

    2007-06-19

    Particle physicists have a description of the forces of nature known as the Standard Model that has successfully withstood decades of testing at laboratories around the world. Though the Standard Model is powerful, it is not complete. Important details like the masses of particles are not explained well, and realities as fundamental as gravity, dark matter, and dark energy are left out altogether. I will discuss gaps in the model and why there is hope that some puzzles will be solved by probing high energies with the Large Hadron Collider. Beginning next year, this machine will accelerate protons to record energies, hurling them around a 27 kilometer ring before colliding them 40 million times per second. Detectors the size of five-story buildings will record the debris of these collisions. The new energy frontier made accessible by the Large Hadron Collider will allow thousands of physicists to explore nature's fundamental forces and particles from a fantastic vantage point.

  18. The future of the Large Hadron Collider and CERN.

    PubMed

    Heuer, Rolf-Dieter

    2012-02-28

    This paper presents the Large Hadron Collider (LHC) and its current scientific programme and outlines options for high-energy colliders at the energy frontier for the years to come. The immediate plans include the exploitation of the LHC at its design luminosity and energy, as well as upgrades to the LHC and its injectors. This may be followed by a linear electron-positron collider, based on the technology being developed by the Compact Linear Collider and the International Linear Collider collaborations, or by a high-energy electron-proton machine. This contribution describes the past, present and future directions, all of which have a unique value to add to experimental particle physics, and concludes by outlining key messages for the way forward.

  19. Cross sections at hadron colliders

    SciTech Connect

    Paige, F.E.

    1982-01-01

    The predicted cross sections are given for new Z'/sup 0/ bosons, for the Drell-Yan continuum of ..mu../sup +/..mu../sup -/ pairs, for high p/sub T/ hadron jets, for high p/sub T/ single photons, and for the associated production of heavy quarks. These processes have been selected not to cover the most interesting physics, but to provide a representative selection of cross sections for which to compare various energies and luminosities.

  20. Hadron colliders (SSC/LHC)

    SciTech Connect

    Chao, A.W.; Palmer, R.B. |; Evans, L.; Gareyte, J.; Siemann, R.H.

    1992-12-31

    The nominal SSC and LHC designs should operate conservatively at luminosities up to 10{sup 33} cm{sup {minus}2} s{sup {minus}1}. This luminosity is dictated by the event rates that can be handled by the detectors. However, this limit is event dependent (e.g. it does not take much of a detector to detect the event pp {yields} elephant; all one needs is extremely high luminosity). As such, it is useful to explore the possibility of going beyond the 10{sup 33} cm{sup {minus}2} s{sup {minus}1} level. Such exploration will also improve the accelerator physics understanding of pp collider designs. If the detector limitations are removed, the first accelerator limits occur when the luminosity is at the level of 10{sup 34} cm{sup {minus}2}s{sup {minus}1}. These accelerator limits will first be reviewed. The authors will then continue on to explore even higher luminosity as the ultimate limit of pp colliders. Accelerator technologies needed to achieve this ultimate luminosity as well as the R and D needed to reach it are discussed.

  1. Collins Asymmetry at Hadron Colliders

    SciTech Connect

    Yuan, Feng

    2008-01-17

    We study the Collins effect in the azimuthal asymmetricdistribution of hadrons inside a high energy jet in the single transversepolarized proton proton scattering. From the detailed analysis ofone-gluon and two-gluon exchange diagrams contributions, the Collinsfunction is found the same as that in the semi-inclusive deep inelasticscattering and e+e- annihilations. The eikonal propagators in thesediagrams do not contribute to the phase needed for the Collins-typesingle spin asymmetry, and the universality is derived as a result of theWard identity. We argue that this conclusion depends on the momentum flowof the exchanged gluon and the kinematic constraints in the fragmentationprocess, and is generic and model-independent.

  2. Slepton Pair Production at Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Fuks, B.

    2007-04-01

    In R-parity conserving supersymmetric models, sleptons are produced in pairs at hadron colliders. We show that measurements of the longitudinal single-spin asymmetry at possible polarization upgrades of existing colliders allow for a direct extraction of the slepton mixing angle. A calculation of the transverse-momentum spectrum shows the importance of resummed contributions at next-to-leading logarithmic accuracy in the small and intermediate transverse-momentum regions and little dependence on unphysical scales and non-perturbative contributions.

  3. Quark-Hadron Duality in Electron Scattering

    SciTech Connect

    W. Melnitchouk

    2000-09-01

    Quark-hadron duality addresses some of the most fundamental issues in strong interaction physics, in particular the nature of the transition from the perturbative to non-perturbative regions of QCD. I summarize recent developments in quark-hadron duality in lepton-hadron scattering, and outline how duality can be studied at future high-luminosity facilities such as Jefferson Lab at 12 GeV, or an electron-hadron collider such as EPIC.

  4. Really large hadron collider working group summary

    SciTech Connect

    Dugan, G.; Limon, P.; Syphers, M.

    1996-12-01

    A summary is presented of preliminary studies of three 100 TeV center-of-mass hadron colliders made with magnets of different field strengths, 1.8T, 9.5T and 12.6T. Descriptions of the machines, and some of the major and most challenging subsystems, are presented, along with parameter lists and the major issues for future study.

  5. The Tevatron Hadron Collider: A short history

    SciTech Connect

    Tollestrup, A.V.

    1994-11-01

    The subject of this presentation was intended to cover the history of hadron colliders. However this broad topic is probably better left to historians. I will cover a much smaller portion of this subject and specialize my subject to the history of the Tevatron. As we will see, the Tevatron project is tightly entwined with the progress in collider technology. It occupies a unique place among accelerators in that it was the first to make use of superconducting magnets and indeed the basic design now forms a template for all machines using this technology. It was spawned in an incredibly productive era when new ideas were being generated almost monthly and it has matured into our highest energy collider complete with two large detectors that provide the major facility in the US for probing high Pt physics for the coming decade.

  6. String resonances at hadron colliders

    NASA Astrophysics Data System (ADS)

    Anchordoqui, Luis A.; Antoniadis, Ignatios; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lüst, Dieter; Stojkovic, Dejan; Taylor, Tomasz R.

    2014-09-01

    We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale Ms is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (integrated luminosity =3000 fb-1) with a center-of-mass energy of √s =14 TeV and at potential future pp colliders, HE-LHC and VLHC, operating at √s =33 and 100 TeV, respectively (with the same integrated luminosity). In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and γ +jet are completely independent of the details of compactification and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV) lowest massive Regge excitations are open to discovery at the ≥5σ in dijet (γ +jet) HL-LHC data. We also show that for n=1 the dijet discovery potential at HE-LHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signal-to-noise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states (including decays into massless particles and a massive n=1 and a massless particle), where we rely on factorization and conformal field theory techniques. Helicity wave functions of arbitrary higher spin massive bosons are also constructed. We demonstrate that for string scales Ms≲10.5 TeV (Ms≲28 TeV) detection of n =2 Regge recurrences at HE-LHC (VLHC) would become the smoking gun for D

  7. Beyond the Large Hadron Collider: A First Look at Cryogenics for CERN Future Circular Colliders

    NASA Astrophysics Data System (ADS)

    Lebrun, Philippe; Tavian, Laurent

    Following the first experimental discoveries at the Large Hadron Collider (LHC) and the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. The study, conducted with the collaborative participation of interested institutes world-wide, considers several options for very high energy hadron-hadron, electron-positron and hadron-electron colliders to be installed in a quasi-circular underground tunnel in the Geneva basin, with a circumference of 80 km to 100 km. All these machines would make intensive use of advanced superconducting devices, i.e. high-field bending and focusing magnets and/or accelerating RF cavities, thus requiring large helium cryogenic systems operating at 4.5 K or below. Based on preliminary sets of parameters and layouts for the particle colliders under study, we discuss the main challenges of their cryogenic systems and present first estimates of the cryogenic refrigeration capacities required, with emphasis on the qualitative and quantitative steps to be accomplished with respect to the present state-of-the-art.

  8. Single and multiple intrabeam scattering in hadron colliders

    SciTech Connect

    Lebedev, V.; /Fermilab

    2005-01-01

    Single and multiple intra-beam scattering are usually considered separately. Such separation works well for electron-positron colliders but usually yields only coarse description in the case of hadron colliders. Boltzmann type integro-differential equation is used to describe evolution of longitudinal distribution due to IBS. The finite size of the longitudinal potential well, its non-linearity and x-y coupling are taken into account. The model predictions for longitudinal and transverse distributions are compared to the experimental measurements.

  9. Signatures for Majorana neutrinos at hadron colliders.

    PubMed

    Han, Tao; Zhang, Bin

    2006-10-27

    The Majorana nature of neutrinos may only be experimentally verified via lepton-number violating processes involving charged leptons. We explore the Delta L = 2 like-sign dilepton production at hadron colliders to search for signals of Majorana neutrinos. We find significant sensitivity for resonant production of a Majorana neutrino in the mass range of 10-80 GeV at the current run of the Tevatron with 2 fb(-1) integrated luminosity and in the range of 10-400 GeV at the CERN LHC with 100 fb(-1).

  10. Black Holes and the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Roy, Arunava

    2011-12-01

    The European Center for Nuclear Research or CERN's Large Hadron Collider (LHC) has caught our attention partly due to the film ``Angels and Demons.'' In the movie, an antimatter bomb attack on the Vatican is foiled by the protagonist. Perhaps just as controversial is the formation of mini black holes (BHs). Recently, the American Physical Society1 website featured an article on BH formation at the LHC.2 This article examines some aspects of mini BHs and explores the possibility of their detection at the LHC.

  11. The Large Hadron Collider and Grid computing.

    PubMed

    Geddes, Neil

    2012-02-28

    We present a brief history of the beginnings, development and achievements of the worldwide Large Hadron Collider Computing Grid (wLCG). The wLCG is a huge international endeavour, which is itself embedded within, and directly influences, a much broader computing and information technology landscape. It is often impossible to identify true cause and effect, and they may appear very different from the different perspectives (e.g. information technology industry or academic researcher). This account is no different. It represents a personal view of the developments over the last two decades and is therefore inevitably biased towards those things in which the author has been personally involved.

  12. Resummed Results for Hadron Collider Observables

    NASA Astrophysics Data System (ADS)

    McAslan, Heather

    2016-07-01

    Event shapes are invaluable QCD tools for theoretical calculations and experimental measurements. We revise the definition of these observables in e+e- annihilation and in hadron collisions, and give a review of the state-of-the-art results for their resummation. Then we detail how recent work on the re-summation of event shapes in electron-positron annihilation can provide us with the tools to extend resummation of generic hadronic event shapes to NNLL accuracy. We match our findings to fixed-order results at NNLO accuracy, showing the sizeable effects of resummation in the relevant regions of phase space.

  13. Illuminating new electroweak states at hadron colliders

    SciTech Connect

    Ismail, Ahmed; Izaguirre, Eder; Shuve, Brian

    2016-07-01

    In this paper, we propose a novel powerful strategy to perform searches for new electroweak states. Uncolored electroweak states appear in generic extensions of the Standard Model (SM) and yet are challenging to discover at hadron colliders. This problem is particularly acute when the lightest state in the electroweak multiplet is neutral and all multiplet components are approximately degenerate. In this scenario, production of the charged fields of the multiplet is followed by decay into nearly invisible states; if this decay occurs promptly, the only way to infer the presence of the reaction is through its missing energy signature. Our proposal relies on emission of photon radiation from the new charged states as a means of discriminating the signal from SM backgrounds. Lastly, we demonstrate its broad applicability by studying two examples: a pure Higgsino doublet and an electroweak quintuplet field.

  14. Illuminating new electroweak states at hadron colliders

    DOE PAGES

    Ismail, Ahmed; Izaguirre, Eder; Shuve, Brian

    2016-07-01

    In this paper, we propose a novel powerful strategy to perform searches for new electroweak states. Uncolored electroweak states appear in generic extensions of the Standard Model (SM) and yet are challenging to discover at hadron colliders. This problem is particularly acute when the lightest state in the electroweak multiplet is neutral and all multiplet components are approximately degenerate. In this scenario, production of the charged fields of the multiplet is followed by decay into nearly invisible states; if this decay occurs promptly, the only way to infer the presence of the reaction is through its missing energy signature. Ourmore » proposal relies on emission of photon radiation from the new charged states as a means of discriminating the signal from SM backgrounds. Lastly, we demonstrate its broad applicability by studying two examples: a pure Higgsino doublet and an electroweak quintuplet field.« less

  15. Large Hadron Collider momentum calibration and accuracy

    NASA Astrophysics Data System (ADS)

    Todesco, E.; Wenninger, J.

    2017-08-01

    As a result of the excellent quality of the Large Hadron Collider (LHC) experimental detectors and the accurate calibration of the luminosity at the LHC, uncertainties on the LHC beam energy may contribute significantly to the measurement errors on certain observables unless the relative uncertainty is well below 1%. Direct measurements of the beam energy using the revolution frequency difference of proton and lead beams combined with the magnetic model errors are used to provide the energy uncertainty of the LHC beams. Above injection energy the relative uncertainty on the beam energy is determined to be ±0.1 %. The energy values as reconstructed and distributed online to the LHC experiments do not require any correction above injection energy. At injection a correction of +0.31 GeV /c must be applied to the online energy values.

  16. QCD and jets at hadron colliders

    NASA Astrophysics Data System (ADS)

    Sapeta, Sebastian

    2016-07-01

    We review various aspects of jet physics in the context of hadron colliders. We start by discussing the definitions and properties of jets and recent development in this area. We then consider the question of factorization for processes with jets, in particular for cases in which jets are produced in special configurations, like for example in the region of forward rapidities. We review numerous perturbative methods for calculating predictions for jet processes, including the fixed-order calculations as well as various matching and merging techniques. We also discuss the questions related to non-perturbative effects and the role they play in precision jet studies. We describe the status of calculations for processes with jet vetoes and we also elaborate on production of jets in forward direction. Throughout the article, we present selected comparisons between state-of-the-art theoretical predictions and the data from the LHC.

  17. Illuminating new electroweak states at hadron colliders

    SciTech Connect

    Ismail, Ahmed; Izaguirre, Eder; Shuve, Brian

    2016-07-01

    In this paper, we propose a novel powerful strategy to perform searches for new electroweak states. Uncolored electroweak states appear in generic extensions of the Standard Model (SM) and yet are challenging to discover at hadron colliders. This problem is particularly acute when the lightest state in the electroweak multiplet is neutral and all multiplet components are approximately degenerate. In this scenario, production of the charged fields of the multiplet is followed by decay into nearly invisible states; if this decay occurs promptly, the only way to infer the presence of the reaction is through its missing energy signature. Our proposal relies on emission of photon radiation from the new charged states as a means of discriminating the signal from SM backgrounds. Lastly, we demonstrate its broad applicability by studying two examples: a pure Higgsino doublet and an electroweak quintuplet field.

  18. Big Science and the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Giudice, Gian Francesco

    2012-03-01

    The Large Hadron Collider (LHC), the particle accelerator operating at CERN, is probably the most complex and ambitious scientific project ever accomplished by humanity. The sheer size of the enterprise, in terms of financial and human resources, naturally raises the question whether society should support such costly basic-research programs. I address this question by first reviewing the process that led to the emergence of Big Science and the role of large projects in the development of science and technology. I then compare the methodologies of Small and Big Science, emphasizing their mutual linkage. Finally, after examining the cost of Big Science projects, I highlight several general aspects of their beneficial implications for society.

  19. A feedback microprocessor for hadron colliders

    SciTech Connect

    Herrup, D.A.; Chapman, L.; Franck, A.; Groves, T.; Lublinsky, B.

    1992-12-01

    A feedback microprocessor has been built for the TEVATRON. It has been constructed to be applicable to hadron colliders in general. Its inputs are realtime accelerator measurements, data describing the state of the TEVATRON, and ramp tables. The microprocessor software includes a finite state machine. Each state corresponds to a specific TEVATRON operation and has a state-specific TEVATRON model. Transitions between states are initiated by the global TEVATRON clock. Each state includes a cyclic routine which is called periodically and where all calculations are performed. The output corrections are inserted onto a fast TEVATRON-wide link from which the power supplies will read the realtime corrections. We also store all of the input data and output corrections in a set of buffers which can easily be retrieved for diagnostic analysis. In this paper we will describe this device and its use to control the TEVATRON tunes as well as other possible applications.

  20. Illuminating new electroweak states at hadron colliders

    NASA Astrophysics Data System (ADS)

    Ismail, Ahmed; Izaguirre, Eder; Shuve, Brian

    2016-07-01

    In this paper, we propose a novel powerful strategy to perform searches for new electroweak states. Uncolored electroweak states appear in generic extensions of the Standard Model (SM) and yet are challenging to discover at hadron colliders. This problem is particularly acute when the lightest state in the electroweak multiplet is neutral and all multiplet components are approximately degenerate. In this scenario, production of the charged fields of the multiplet is followed by decay into nearly invisible states; if this decay occurs promptly, the only way to infer the presence of the reaction is through its missing energy signature. Our proposal relies on emission of photon radiation from the new charged states as a means of discriminating the signal from SM backgrounds. We demonstrate its broad applicability by studying two examples: a pure Higgsino doublet and an electroweak quintuplet field.

  1. Development of Large Area Gas Electron Multiplier Detector and Its Application to a Digital Hadron Calorimeter for Future Collider Experiments

    SciTech Connect

    Yu, Jaehoon; White, Andrew

    2014-09-25

    The UTA High Energy Physics Group conducted generic detector development based on large area, very thin and high sensitivity gas detector using gas electron multiplier (GEM) technology. This is in preparation for a use as a sensitive medium for sampling calorimeters in future collider experiments at the Energy Frontier as well as part of the tracking detector in Intensity Frontier experiments. We also have been monitoring the long term behavior of one of the prototype detectors (30cmx30cm) read out by the SLAC-developed 13-bit KPiX analog chip over three years and have made presentations of results at various APS meetings. While the important next step was the development of large area (1m x 1m) GEM planes, we also have looked into opportunities of applying this technology to precision tracking detectors to significantly improve the performance of the Range Stack detector for CP violation experiments and to provide an amplification layer for the liquid Argon Time Projection Chamber in the LBNE experiment. We have jointly developed 33cmx100cm large GEM foils with the CERN gas detector development group to construct 33cm x100cm unit chambers. Three of these unit chambers will be put together to form a 1m x 1m detector plane. Following characterization of one 33cmx100cm unit chamber prototype, a total of five 1m x 1m planes will be constructed and inserted into an existing 1m3 RPC DHCAL stack to test the performance of the new GEM DHCAL in particle beams. The large area GEM detector we planned to develop in this proposal not only gives an important option to DHCAL for future collider experiments but also the potential to expand its use to Intensity Frontier and Cosmic Frontier experiments as high efficiency, high amplification anode planes for liquid Argon time projection chambers. Finally, thanks to its sensitivity to X-rays and other neutral radiations and its light-weight characteristics, the large area GEM has a great potential for the use in medical imaging and

  2. Prospects for heavy flavor physics at hadron colliders

    SciTech Connect

    Butler, J.N.

    1997-09-01

    The role of hadron colliders in the observation and study of CP violation in B decays is discussed. We show that hadron collider experiments can play a significant role in the early studies of these phenomena and will play an increasingly dominant role as the effort turns towards difficult to measure decays, especially those of the B{sub s} meson, and sensitive searches for rare decays and subtle deviations from Standard Model predictions. We conclude with a discussion of the relative merits of hadron collider detectors with `forward` vs `central` rapidity coverage.

  3. Higgs boson production at hadron colliders: Signal and background processes

    SciTech Connect

    David Rainwater; Michael Spira; Dieter Zeppenfeld

    2004-01-12

    We review the theoretical status of signal and background calculations for Higgs boson production at hadron colliders. Particular emphasis is given to missing NLO results, which will play a crucial role for the Tevatron and the LHC.

  4. The ATLAS Experiment at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    ATLAS Collaboration; Aad, G.; Abat, E.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B. A.; Abolins, M.; Abramowicz, H.; Acerbi, E.; Acharya, B. S.; Achenbach, R.; Ackers, M.; Adams, D. L.; Adamyan, F.; Addy, T. N.; Aderholz, M.; Adorisio, C.; Adragna, P.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Aielli, G.; Åkesson, P. F.; Åkesson, T. P. A.; Akimov, A. V.; Alam, S. M.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alimonti, G.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Aloisio, A.; Alonso, J.; Alves, R.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amaral, S. P.; Ambrosini, G.; Ambrosio, G.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amram, N.; Anastopoulos, C.; Anderson, B.; Anderson, K. J.; Anderssen, E. C.; Andreazza, A.; Andrei, V.; Andricek, L.; Andrieux, M.-L.; Anduaga, X. S.; Anghinolfi, F.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Apsimon, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arguin, J.-F.; Arik, E.; Arik, M.; Arms, K. E.; Armstrong, S. R.; Arnaud, M.; Arnault, C.; Artamonov, A.; Asai, S.; Ask, S.; Åsman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Athar, B.; Atkinson, T.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aulchenko, V. M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, A.; Ay, C.; Azuelos, G.; Baccaglioni, G.; Bacci, C.; Bachacou, H.; Bachas, K.; Bachy, G.; Badescu, E.; Bagnaia, P.; Bailey, D. C.; Baines, J. T.; Baker, O. K.; Ballester, F.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S. P.; Baranov, S.; Barashkou, A.; Barberio, E. L.; Barberis, D.; Barbier, G.; Barclay, P.; Bardin, D. Y.; Bargassa, P.; Barillari, T.; Barisonzi, M.; Barnett, B. M.; Barnett, R. M.; Baron, S.; Baroncelli, A.; Barone, M.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Barriuso Poy, A.; Barros, N.; Bartheld, V.; Bartko, H.; Bartoldus, R.; Basiladze, S.; Bastos, J.; Batchelor, L. E.; Bates, R. L.; Batley, J. R.; Batraneanu, S.; Battistin, M.; Battistoni, G.; Batusov, V.; Bauer, F.; Bauss, B.; Baynham, D. E.; Bazalova, M.; Bazan, A.; Beauchemin, P. H.; Beaugiraud, B.; Beccherle, R. B.; Beck, G. A.; Beck, H. P.; Becks, K. H.; Bedajanek, I.; Beddall, A. J.; Beddall, A.; Bednár, P.; Bednyakov, V. A.; Bee, C.; Behar Harpaz, S.; Belanger, G. A. N.; Belanger-Champagne, C.; Belhorma, B.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellachia, F.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Beltramello, O.; Belymam, A.; Ben Ami, S.; Ben Moshe, M.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benes, J.; Benhammou, Y.; Benincasa, G. P.; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas, E.; Berger, N.; Berghaus, F.; Berglund, S.; Bergsma, F.; Beringer, J.; Bernabéu, J.; Bernardet, K.; Berriaud, C.; Berry, T.; Bertelsen, H.; Bertin, A.; Bertinelli, F.; Bertolucci, S.; Besson, N.; Beteille, A.; Bethke, S.; Bialas, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieri, M.; Biglietti, M.; Bilokon, H.; Binder, M.; Binet, S.; Bingefors, N.; Bingul, A.; Bini, C.; Biscarat, C.; Bischof, R.; Bischofberger, M.; Bitadze, A.; Bizzell, J. P.; Black, K. M.; Blair, R. E.; Blaising, J. J.; Blanch, O.; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Boaretto, C.; Bobbink, G. J.; Bocci, A.; Bocian, D.; Bock, R.; Boehm, M.; Boek, J.; Bogaerts, J. A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bondarenko, V. G.; Bonino, R.; Bonis, J.; Bonivento, W.; Bonneau, P.; Boonekamp, M.; Boorman, G.; Boosten, M.; Booth, C. N.; Booth, P. S. L.; Booth, P.; Booth, J. R. A.; Borer, K.; Borisov, A.; Borjanovic, I.; Bos, K.; Boscherini, D.; Bosi, F.; Bosman, M.; Bosteels, M.; Botchev, B.; Boterenbrood, H.; Botterill, D.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Boutemeur, M.; Bouzakis, K.; Boyd, G. R.; Boyd, J.; Boyer, B. H.; Boyko, I. R.; Bozhko, N. I.; Braccini, S.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, O.; Bratzler, U.; Braun, H. M.; Bravo, S.; Brawn, I. P.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Brett, N. D.; Breugnon, P.; Bright-Thomas, P. G.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Broklova, Z.; Bromberg, C.; Brooijmans, G.; Brouwer, G.; Broz, J.; Brubaker, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Buchanan, N. J.; Buchholz, P.; Budagov, I. A.; Büscher, V.; Bugge, L.; Buira-Clark, D.; Buis, E. J.; Bujor, F.; Buran, T.; Burckhart, H.; Burckhart-Chromek, D.; Burdin, S.; Burns, R.; Busato, E.; Buskop, J. J. F.; Buszello, K. P.; Butin, F.; Butler, J. M.; Buttar, C. M.; Butterworth, J.; Butterworth, J. M.; Byatt, T.; Cabrera Urbán, S.; Cabruja Casas, E.; Caccia, M.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calderón Terol, D.; Callahan, J.; Caloba, L. P.; Caloi, R.; Calvet, D.; Camard, A.; Camarena, F.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Cammin, J.; Campabadal Segura, F.; Campana, S.; Canale, V.; Cantero, J.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Caprio, M.; Caracinha, D.; Caramarcu, C.; Carcagno, Y.; Cardarelli, R.; Cardeira, C.; Cardiel Sas, L.; Cardini, A.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carpentieri, C.; Carr, F. S.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Cascella, M.; Caso, C.; Castelo, J.; Castillo Gimenez, V.; Castro, N.; Castrovillari, F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caughron, S.; Cauz, D.; Cavallari, A.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerna, C.; Cernoch, C.; Cerqueira, A. S.; Cerri, A.; Cerutti, F.; Cervetto, M.; Cetin, S. A.; Cevenini, F.; Chalifour, M.; Chamizo llatas, M.; Chan, A.; Chapman, J. W.; Charlton, D. G.; Charron, S.; Chekulaev, S. V.; Chelkov, G. A.; Chen, H.; Chen, L.; Chen, T.; Chen, X.; Cheng, S.; Cheng, T. L.; Cheplakov, A.; Chepurnov, V. F.; Cherkaoui El Moursli, R.; Chesneanu, D.; Cheu, E.; Chevalier, L.; Chevalley, J. L.; Chevallier, F.; Chiarella, V.; Chiefari, G.; Chikovani, L.; Chilingarov, A.; Chiodini, G.; Chouridou, S.; Chren, D.; Christiansen, T.; Christidi, I. A.; Christov, A.; Chu, M. L.; Chudoba, J.; Chuguev, A. G.; Ciapetti, G.; Cicalini, E.; Ciftci, A. K.; Cindro, V.; Ciobotaru, M. D.; Ciocio, A.; Cirilli, M.; Citterio, M.; Ciubancan, M.; Civera, J. V.; Clark, A.; Cleland, W.; Clemens, J. C.; Clement, B. C.; Clément, C.; Clements, D.; Clifft, R. W.; Cobal, M.; Coccaro, A.; Cochran, J.; Coco, R.; Coe, P.; Coelli, S.; Cogneras, E.; Cojocaru, C. D.; Colas, J.; Colijn, A. P.; Collard, C.; Collins-Tooth, C.; Collot, J.; Coluccia, R.; Comune, G.; Conde Muiño, P.; Coniavitis, E.; Consonni, M.; Constantinescu, S.; Conta, C.; Conventi, F. A.; Cook, J.; Cooke, M.; Cooper-Smith, N. J.; Cornelissen, T.; Corradi, M.; Correard, S.; Corso-Radu, A.; Coss, J.; Costa, G.; Costa, M. J.; Costanzo, D.; Costin, T.; Coura Torres, R.; Courneyea, L.; Couyoumtzelis, C.; Cowan, G.; Cox, B. E.; Cox, J.; Cragg, D. A.; Cranmer, K.; Cranshaw, J.; Cristinziani, M.; Crosetti, G.; Cuenca Almenar, C.; Cuneo, S.; Cunha, A.; Curatolo, M.; Curtis, C. J.; Cwetanski, P.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; Da Rocha Gesualdi Mello, A.; Da Silva, P. V. M.; Da Silva, R.; Dabrowski, W.; Dael, A.; Dahlhoff, A.; Dai, T.; Dallapiccola, C.; Dallison, S. J.; Dalmau, J.; Daly, C. H.; Dam, M.; Damazio, D.; Dameri, M.; Danielsen, K. M.; Danielsson, H. O.; Dankers, R.; Dannheim, D.; Darbo, G.; Dargent, P.; Daum, C.; Dauvergne, J. P.; David, M.; Davidek, T.; Davidson, N.; Davidson, R.; Dawson, I.; Dawson, J. W.; Daya, R. K.; De, K.; de Asmundis, R.; de Boer, R.; DeCastro, S.; DeGroot, N.; de Jong, P.; de La Broise, X.; DeLa Cruz-Burelo, E.; DeLa Taille, C.; DeLotto, B.; DeOliveira Branco, M.; DePedis, D.; de Saintignon, P.; DeSalvo, A.; DeSanctis, U.; DeSanto, A.; DeVivie DeRegie, J. B.; DeZorzi, G.; Dean, S.; Dedes, G.; Dedovich, D. V.; Defay, P. O.; Degele, R.; Dehchar, M.; Deile, M.; DelPapa, C.; DelPeso, J.; DelPrete, T.; Delagnes, E.; Delebecque, P.; Dell'Acqua, A.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P. A.; Deluca Silberberg, C.; Demers, S.; Demichev, M.; Demierre, P.; Demirköz, B.; Deng, W.; Denisov, S. P.; Dennis, C.; Densham, C. J.; Dentan, M.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K. K.; Dewhurst, A.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Girolamo, A.; Di Girolamo, B.; Di Luise, S.; Di Mattia, A.; Di Simone, A.; Diaz Gomez, M. M.; Diehl, E. B.; Dietl, H.; Dietrich, J.; Dietsche, W.; Diglio, S.; Dima, M.; Dindar, K.; Dinkespiler, B.; Dionisi, C.; Dipanjan, R.; Dita, P.; Dita, S.; Dittus, F.; Dixon, S. D.; Djama, F.; Djilkibaev, R.; Djobava, T.; do Vale, M. A. B.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Dogan, O. B.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B. A.; Domingo, E.; Donega, M.; Dopke, J.; Dorfan, D. E.; Dorholt, O.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M. T.; Dowell, J. D.; Doyle, A. T.; Drake, G.; Drakoulakos, D.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Drohan, J. G.; Dubbert, J.; Dubbs, T.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dührssen, M.; Dür, H.; Duerdoth, I. P.; Duffin, S.; Duflot, L.; Dufour, M.-A.; Dumont Dayot, N.; Duran Yildiz, H.; Durand, D.; Dushkin, A.; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Díez Cornell, S.; Düren, M.; Ebenstein, W. L.; Eckert, S.; Eckweiler, S.; Eerola, P.; Efthymiopoulos, I.; Egede, U.; Egorov, K.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; Eklund, L. M.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engström, M.; Ennes, P.; Epp, B.; Eppig, A.; Epshteyn, V. S.; Ereditato, A.; Eremin, V.; Eriksson, D.; Ermoline, I.; Ernwein, J.; Errede, D.; Errede, S.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Esteves, F.; Etienne, F.; Etienvre, A. I.; Etzion, E.; Evans, H.; Evdokimov, V. N.; Evtoukhovitch, P.; Eyring, A.; Fabbri, L.; Fabjan, C. W.; Fabre, C.; Faccioli, P.; Facius, K.; Fadeyev, V.; Fakhrutdinov, R. M.; Falciano, S.; Falleau, I.; Falou, A. C.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farrell, J.; Farthouat, P.; Fasching, D.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Fawzi, F.; Fayard, L.; Fayette, F.; Febbraro, R.; Fedin, O. L.; Fedorko, I.; Feld, L.; Feldman, G.; Feligioni, L.; Feng, C.; Feng, E. J.; Fent, J.; Fenyuk, A. B.; Ferencei, J.; Ferguson, D.; Ferland, J.; Fernando, W.; Ferrag, S.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferrer, A.; Ferrer, M. L.; Ferrere, D.; Ferretti, C.; Ferro, F.; Fiascaris, M.; Fichet, S.; Fiedler, F.; Filimonov, V.; Filipčič, A.; Filippas, A.; Filthaut, F.; Fincke-Keeler, M.; Finocchiaro, G.; Fiorini, L.; Firan, A.; Fischer, P.; Fisher, M. J.; Fisher, S. M.; Flaminio, V.; Flammer, J.; Flechl, M.; Fleck, I.; Flegel, W.; Fleischmann, P.; Fleischmann, S.; Fleta Corral, C. M.; Fleuret, F.; Flick, T.; Flix, J.; Flores Castillo, L. R.; Flowerdew, M. J.; Föhlisch, F.; Fokitis, M.; Fonseca Martin, T. M.; Fopma, J.; Forbush, D. A.; Formica, A.; Foster, J. M.; Fournier, D.; Foussat, A.; Fowler, A. J.; Fox, H.; Francavilla, P.; Francis, D.; Franz, S.; Fraser, J. T.; Fraternali, M.; Fratianni, S.; Freestone, J.; French, R. S.; Fritsch, K.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fulachier, J.; Fullana Torregrosa, E.; Fuster, J.; Gabaldon, C.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, E. J.; Gallas, M. V.; Gallop, B. J.; Gan, K. K.; Gannaway, F. C.; Gao, Y. S.; Gapienko, V. A.; Gaponenko, A.; Garciá, C.; Garcia-Sciveres, M.; Garcìa Navarro, J. E.; Garde, V.; Gardner, R. W.; Garelli, N.; Garitaonandia, H.; Garonne, V. G.; Garvey, J.; Gatti, C.; Gaudio, G.; Gaumer, O.; Gautard, V.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gayde, J.-C.; Gazis, E. N.; Gazo, E.; Gee, C. N. P.; Geich-Gimbel, C.; Gellerstedt, K.; Gemme, C.; Genest, M. H.; Gentile, S.; George, M. A.; George, S.; Gerlach, P.; Gernizky, Y.; Geweniger, C.; Ghazlane, H.; Ghete, V. M.; Ghez, P.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giakoumopoulou, V.; Giangiobbe, V.; Gianotti, F.; Gibbard, B.; Gibson, A.; Gibson, M. D.; Gibson, S. M.; Gieraltowski, G. F.; Gil Botella, I.; Gilbert, L. M.; Gilchriese, M.; Gildemeister, O.; Gilewsky, V.; Gillman, A. R.; Gingrich, D. M.; Ginzburg, J.; Giokaris, N.; Giordani, M. P.; Girard, C. G.; Giraud, P. F.; Girtler, P.; Giugni, D.; Giusti, P.; Gjelsten, B. K.; Glasman, C.; Glazov, A.; Glitza, K. W.; Glonti, G. L.; Gnanvo, K. G.; Godlewski, J.; Göpfert, T.; Gössling, C.; Göttfert, T.; Goldfarb, S.; Goldin, D.; Goldschmidt, N.; Golling, T.; Gollub, N. P.; Golonka, P. J.; Golovnia, S. N.; Gomes, A.; Gomes, J.; Gonçalo, R.; Gongadze, A.; Gonidec, A.; Gonzalez, S.; González de la Hoz, S.; González Millán, V.; Gonzalez Silva, M. L.; Gonzalez-Pineiro, B.; González-Sevilla, S.; Goodrick, M. J.; Goodson, J. J.; Goossens, L.; Gorbounov, P. A.; Gordeev, A.; Gordon, H.; Gorelov, I.; Gorfine, G.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Gorokhov, S. A.; Gorski, B. T.; Goryachev, S. V.; Goryachev, V. N.; Gosselink, M.; Gostkin, M. I.; Gouanère, M.; Gough Eschrich, I.; Goujdami, D.; Goulette, M.; Gousakov, I.; Gouveia, J.; Gowdy, S.; Goy, C.; Grabowska-Bold, I.; Grabski, V.; Grafström, P.; Grah, C.; Grahn, K.-J.; Grancagnolo, F.; Grancagnolo, S.; Grassmann, H.; Gratchev, V.; Gray, H. M.; Graziani, E.; Green, B.; Greenall, A.; Greenfield, D.; Greenwood, D.; Gregor, I. M.; Grewal, A.; Griesmayer, E.; Grigalashvili, N.; Grigson, C.; Grillo, A. A.; Grimaldi, F.; Grimm, K.; Gris, P. L. Y.; Grishkevich, Y.; Groenstege, H.; Groer, L. S.; Grognuz, J.; Groh, M.; Gross, E.; Grosse-Knetter, J.; Grothe, M. E. M.; Grudzinski, J.; Gruse, C.; Gruwe, M.; Grybel, K.; Grybos, P.; Gschwendtner, E. M.; Guarino, V. J.; Guicheney, C. J.; Guilhem, G.; Guillemin, T.; Gunther, J.; Guo, B.; Gupta, A.; Gurriana, L.; Gushchin, V. N.; Gutierrez, P.; Guy, L.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haas, S.; Haber, C.; Haboubi, G.; Hackenburg, R.; Hadash, E.; Hadavand, H. K.; Haeberli, C.; Härtel, R.; Haggerty, R.; Hahn, F.; Haider, S.; Hajduk, Z.; Hakimi, M.; Hakobyan, H.; Hakobyan, H.; Haller, J.; Hallewell, G. D.; Hallgren, B.; Hamacher, K.; Hamilton, A.; Han, H.; Han, L.; Hanagaki, K.; Hance, M.; Hanke, P.; Hansen, C. J.; Hansen, F. H.; Hansen, J. R.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hansl-Kozanecka, T.; Hanson, G.; Hansson, P.; Hara, K.; Harder, S.; Harel, A.; Harenberg, T.; Harper, R.; Hart, J. C.; Hart, R. G. G.; Hartjes, F.; Hartman, N.; Haruyama, T.; Harvey, A.; Hasegawa, Y.; Hashemi, K.; Hassani, S.; Hatch, M.; Hatley, R. W.; Haubold, T. G.; Hauff, D.; Haug, F.; Haug, S.; Hauschild, M.; Hauser, R.; Hauviller, C.; Havranek, M.; Hawes, B. M.; Hawkings, R. J.; Hawkins, D.; Hayler, T.; Hayward, H. S.; Haywood, S. J.; Hazen, E.; He, M.; He, Y. P.; Head, S. J.; Hedberg, V.; Heelan, L.; Heinemann, F. E. W.; Heldmann, M.; Hellman, S.; Helsens, C.; Henderson, R. C. W.; Hendriks, P. J.; Henriques Correia, A. M.; Henrot-Versille, S.; Henry-Couannier, F.; Henß, T.; Herten, G.; Hertenberger, R.; Hervas, L.; Hess, M.; Hessey, N. P.; Hicheur, A.; Hidvegi, A.; Higón-Rodriguez, E.; Hill, D.; Hill, J.; Hill, J. C.; Hill, N.; Hillier, S. J.; Hinchliffe, I.; Hindson, D.; Hinkelbein, C.; Hodges, T. A.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoffman, J.; Hoffmann, A. E.; Hoffmann, D.; Hoffmann, H. F.; Holder, M.; Hollins, T. I.; Hollyman, G.; Holmes, A.; Holmgren, S. O.; Holt, R.; Holtom, E.; Holy, T.; Homer, R. J.; Homma, Y.; Homola, P.; Honerbach, W.; Honma, A.; Hooton, I.; Horazdovsky, T.; Horn, C.; Horvat, S.; Hostachy, J.-Y.; Hott, T.; Hou, S.; Houlden, M. A.; Hoummada, A.; Hover, J.; Howell, D. F.; Hrivnac, J.; Hruska, I.; Hryn'ova, T.; Huang, G. S.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, B. T.; Hughes, E.; Hughes, G.; Hughes-Jones, R. E.; Hulsbergen, W.; Hurst, P.; Hurwitz, M.; Huse, T.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Ibbotson, M.; Ibragimov, I.; Ichimiya, R.; Iconomidou-Fayard, L.; Idarraga, J.; Idzik, M.; Iengo, P.; Iglesias Escudero, M. C.; Igonkina, O.; Ikegami, Y.; Ikeno, M.; Ilchenko, Y.; Ilyushenka, Y.; Imbault, D.; Imbert, P.; Imhaeuser, M.; Imori, M.; Ince, T.; Inigo-Golfin, J.; Inoue, K.; Ioannou, P.; Iodice, M.; Ionescu, G.; Ishii, K.; Ishino, M.; Ishizawa, Y.; Ishmukhametov, R.; Issever, C.; Ito, H.; Ivashin, A. V.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jackson, J.; Jackson, J. N.; Jaekel, M.; Jagielski, S.; Jahoda, M.; Jain, V.; Jakobs, K.; Jakubek, J.; Jansen, E.; Jansweijer, P. P. M.; Jared, R. C.; Jarlskog, G.; Jarp, S.; Jarron, P.; Jelen, K.; Jen-La Plante, I.; Jenni, P.; Jeremie, A.; Jez, P.; Jézéquel, S.; Jiang, Y.; Jin, G.; Jin, S.; Jinnouchi, O.; Joffe, D.; Johansen, L. G.; Johansen, M.; Johansson, K. E.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, M.; Jones, R.; Jones, R. W. L.; Jones, T. W.; Jones, T. J.; Jones, A.; Jonsson, O.; Joo, K. K.; Joos, D.; Joos, M.; Joram, C.; Jorgensen, S.; Joseph, J.; Jovanovic, P.; Junnarkar, S. S.; Juranek, V.; Jussel, P.; Kabachenko, V. V.; Kabana, S.; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagawa, S.; Kaiser, S.; Kajomovitz, E.; Kakurin, S.; Kalinovskaya, L. V.; Kama, S.; Kambara, H.; Kanaya, N.; Kandasamy, A.; Kandasamy, S.; Kaneda, M.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kapliy, A.; Kaplon, J.; Karagounis, M.; Karagoz Unel, M.; Karr, K.; Karst, P.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kasmi, A.; Kass, R. D.; Kastanas, A.; Kataoka, M.; Kataoka, Y.; Katsoufis, E.; Katunin, S.; Kawagoe, K.; Kawai, M.; Kawamoto, T.; Kayumov, F.; Kazanin, V. A.; Kazarinov, M. Y.; Kazarov, A.; Kazi, S. I.; Keates, J. R.; Keeler, R.; Keener, P. T.; Kehoe, R.; Keil, M.; Kekelidze, G. D.; Kelly, M.; Kennedy, J.; Kenyon, M.; Kepka, O.; Kerschen, N.; Kerševan, B. P.; Kersten, S.; Ketterer, C.; Khakzad, M.; Khalilzade, F.; Khandanyan, H.; Khanov, A.; Kharchenko, D.; Khodinov, A.; Kholodenko, A. G.; Khomich, A.; Khomutnikov, V. P.; Khoriauli, G.; Khovanskiy, N.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kieft, G.; Kierstead, J. A.; Kilvington, G.; Kim, H.; Kim, H.; Kim, S. H.; Kind, P.; King, B. T.; Kirk, J.; Kirsch, G. P.; Kirsch, L. E.; Kiryunin, A. E.; Kisielewska, D.; Kisielewski, B.; Kittelmann, T.; Kiver, A. M.; Kiyamura, H.; Kladiva, E.; Klaiber-Lodewigs, J.; Kleinknecht, K.; Klier, A.; Klimentov, A.; Kline, C. R.; Klingenberg, R.; Klinkby, E. B.; Klioutchnikova, T.; Klok, P. F.; Klous, S.; Kluge, E.-E.; Kluit, P.; Klute, M.; Kluth, S.; Knecht, N. K.; Kneringer, E.; Knezo, E.; Knobloch, J.; Ko, B. R.; Kobayashi, T.; Kobel, M.; Kodys, P.; König, A. C.; König, S.; Köpke, L.; Koetsveld, F.; Koffas, T.; Koffeman, E.; Kohout, Z.; Kohriki, T.; Kokott, T.; Kolachev, G. M.; Kolanoski, H.; Kolesnikov, V.; Koletsou, I.; Kollefrath, M.; Kolos, S.; Kolya, S. D.; Komar, A. A.; Komaragiri, J. R.; Kondo, T.; Kondo, Y.; Kondratyeva, N. V.; Kono, T.; Kononov, A. I.; Konoplich, R.; Konovalov, S. P.; Konstantinidis, N.; Kootz, A.; Koperny, S.; Kopikov, S. V.; Korcyl, K.; Kordas, K.; Koreshev, V.; Korn, A.; Korolkov, I.; Korotkov, V. A.; Korsmo, H.; Kortner, O.; Kostrikov, M. E.; Kostyukhin, V. V.; Kotamäki, M. J.; Kotchetkov, D.; Kotov, S.; Kotov, V. M.; Kotov, K. Y.; Kourkoumelis, C.; Koutsman, A.; Kovalenko, S.; Kowalewski, R.; Kowalski, H.; Kowalski, T. Z.; Kozanecki, W.; Kozhin, A. S.; Kral, V.; Kramarenko, V.; Kramberger, G.; Kramer, A.; Krasel, O.; Krasny, M. W.; Krasznahorkay, A.; Krepouri, A.; Krieger, P.; Krivkova, P.; Krobath, G.; Kroha, H.; Krstic, J.; Kruchonak, U.; Krüger, H.; Kruger, K.; Krumshteyn, Z. V.; Kubik, P.; Kubischta, W.; Kubota, T.; Kudin, L. G.; Kudlaty, J.; Kugel, A.; Kuhl, T.; Kuhn, D.; Kukhtin, V.; Kulchitsky, Y.; Kundu, N.; Kupco, A.; Kupper, M.; Kurashige, H.; Kurchaninov, L. L.; Kurochkin, Y. A.; Kus, V.; Kuykendall, W.; Kuzhir, P.; Kuznetsova, E. K.; Kvasnicka, O.; Kwee, R.; La Marra, D.; La Rosa, M.; La Rotonda, L.; Labarga, L.; Labbe, J. A.; Lacasta, C.; Lacava, F.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lamanna, E.; Lambacher, M.; Lambert, F.; Lampl, W.; Lancon, E.; Landgraf, U.; Landon, M. P. J.; Landsman, H.; Langstaff, R. R.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Lapin, V. V.; Laplace, S.; Laporte, J. F.; Lara, V.; Lari, T.; Larionov, A. V.; Lasseur, C.; Lau, W.; Laurelli, P.; Lavorato, A.; Lavrijsen, W.; Lazarev, A. B.; LeBihan, A.-C.; LeDortz, O.; LeManer, C.; LeVine, M.; Leahu, L.; Leahu, M.; Lebel, C.; Lechowski, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, H.; Lee, J. S. H.; Lee, S. C.; Lefebvre, M.; Lefevre, R. P.; Legendre, M.; Leger, A.; LeGeyt, B. C.; Leggett, C.; Lehmacher, M.; Lehmann Miotto, G.; Lehto, M.; Leitner, R.; Lelas, D.; Lellouch, D.; Leltchouk, M.; Lendermann, V.; Leney, K. J. C.; Lenz, T.; Lenzen, G.; Lepidis, J.; Leroy, C.; Lessard, J.-R.; Lesser, J.; Lester, C. G.; Letheren, M.; Fook Cheong, A. Leung; Levêque, J.; Levin, D.; Levinson, L. J.; Levitski, M. S.; Lewandowska, M.; Leyton, M.; Li, J.; Li, W.; Liabline, M.; Liang, Z.; Liang, Z.; Liberti, B.; Lichard, P.; Liebig, W.; Lifshitz, R.; Liko, D.; Lim, H.; Limper, M.; Lin, S. C.; Lindahl, A.; Linde, F.; Lindquist, L.; Lindsay, S. W.; Linhart, V.; Lintern, A. J.; Liolios, A.; Lipniacka, A.; Liss, T. M.; Lissauer, A.; List, J.; Litke, A. M.; Liu, S.; Liu, T.; Liu, Y.; Livan, M.; Lleres, A.; Llosá Llácer, G.; Lloyd, S. L.; Lobkowicz, F.; Loch, P.; Lockman, W. S.; Loddenkoetter, T.; Loebinger, F. K.; Loginov, A.; Loh, C. W.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Loken, J.; Lokwitz, S.; Long, M. C.; Lopes, L.; Lopez Mateos, D.; Losty, M. J.; Lou, X.; Loureiro, K. F.; Lovas, L.; Love, J.; Lowe, A.; Lozano Fantoba, M.; Lu, F.; Lu, J.; Lu, L.; Lubatti, H. J.; Lucas, S.; Luci, C.; Lucotte, A.; Ludwig, A.; Ludwig, I.; Ludwig, J.; Luehring, F.; Lüke, D.; Luijckx, G.; Luisa, L.; Lumb, D.; Luminari, L.; Lund, E.; Lund-Jensen, B.; Lundberg, B.; Lundquist, J.; Lupi, A.; Lupu, N.; Lutz, G.; Lynn, D.; Lynn, J.; Lys, J.; Lysan, V.; Lytken, E.; López-Amengual, J. M.; Ma, H.; Ma, L. L.; Maaß en, M.; Maccarrone, G.; Mace, G. G. R.; Macina, D.; Mackeprang, R.; Macpherson, A.; MacQueen, D.; Macwaters, C.; Madaras, R. J.; Mader, W. F.; Maenner, R.; Maeno, T.; Mättig, P.; Mättig, S.; Magrath, C. A.; Mahalalel, Y.; Mahboubi, K.; Mahout, G.; Maidantchik, C.; Maio, A.; Mair, G. M.; Mair, K.; Makida, Y.; Makowiecki, D.; Malecki, P.; Maleev, V. P.; Malek, F.; Malon, D.; Maltezos, S.; Malychev, V.; Malyukov, S.; Mambelli, M.; Mameghani, R.; Mamuzic, J.; Manabe, A.; Manara, A.; Manca, G.; Mandelli, L.; Mandić, I.; Mandl, M.; Maneira, J.; Maneira, M.; Mangeard, P. S.; Mangin-Brinet, M.; Manjavidze, I. D.; Mann, W. A.; Manolopoulos, S.; Manousakis-Katsikakis, A.; Mansoulie, B.; Manz, A.; Mapelli, A.; Mapelli, L.; March, L.; Marchand, J. F.; Marchesotti, M.; Marcisovsky, M.; Marin, A.; Marques, C. N.; Marroquim, F.; Marshall, R.; Marshall, Z.; Martens, F. K.; Garcia, S. Marti i.; Martin, A. J.; Martin, B.; Martin, B.; Martin, F. F.; Martin, J. P.; Martin, Ph; Martinez, G.; Martínez Lacambra, C.; Martinez Outschoorn, V.; Martini, A.; Martins, J.; Maruyama, T.; Marzano, F.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Maß, M.; Massa, I.; Massaro, G.; Massol, N.; Mathes, M.; Matheson, J.; Matricon, P.; Matsumoto, H.; Matsunaga, H.; Maugain, J. M.; Maxfield, S. J.; May, E. N.; Mayer, J. K.; Mayri, C.; Mazini, R.; Mazzanti, M.; Mazzanti, P.; Mazzoni, E.; Mazzucato, F.; McKee, S. P.; McCarthy, R. L.; McCormick, C.; McCubbin, N. A.; McDonald, J.; McFarlane, K. W.; McGarvie, S.; McGlone, H.; McLaren, R. A.; McMahon, S. J.; McMahon, T. R.; McMahon, T. J.; McPherson, R. A.; Mechtel, M.; Meder-Marouelli, D.; Medinnis, M.; Meera-Lebbai, R.; Meessen, C.; Mehdiyev, R.; Mehta, A.; Meier, K.; Meinhard, H.; Meinhardt, J.; Meirosu, C.; Meisel, F.; Melamed-Katz, A.; Mellado Garcia, B. R.; Mendes Jorge, P.; Mendez, P.; Menke, S.; Menot, C.; Meoni, E.; Merkl, D.; Merola, L.; Meroni, C.; Merritt, F. S.; Messmer, I.; Metcalfe, J.; Meuser, S.; Meyer, J.-P.; Meyer, T. C.; Meyer, W. T.; Mialkovski, V.; Michelotto, M.; Micu, L.; Middleton, R.; Miele, P.; Migliaccio, A.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikestikova, M.; Mikulec, B.; Mikuž, M.; Miller, D. W.; Miller, R. J.; Miller, W.; Milosavljevic, M.; Milstead, D. A.; Mima, S.; Minaenko, A. A.; Minano, M.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Mir, L. M.; Mirabelli, G.; Miralles Verge, L.; Misawa, S.; Miscetti, S.; Misiejuk, A.; Mitra, A.; Mitrofanov, G. Y.; Mitsou, V. A.; Miyagawa, P. S.; Miyazaki, Y.; Mjörnmark, J. U.; Mkrtchyan, S.; Mladenov, D.; Moa, T.; Moch, M.; Mochizuki, A.; Mockett, P.; Modesto, P.; Moed, S.; Mönig, K.; Möser, N.; Mohn, B.; Mohr, W.; Mohrdieck-Möck, S.; Moisseev, A. M.; Moles Valls, R. M.; Molina-Perez, J.; Moll, A.; Moloney, G.; Mommsen, R.; Moneta, L.; Monnier, E.; Montarou, G.; Montesano, S.; Monticelli, F.; Moore, R. W.; Moore, T. B.; Moorhead, G. F.; Moraes, A.; Morel, J.; Moreno, A.; Moreno, D.; Morettini, P.; Morgan, D.; Morii, M.; Morin, J.; Morley, A. K.; Mornacchi, G.; Morone, M.-C.; Morozov, S. V.; Morris, E. J.; Morris, J.; Morrissey, M. C.; Moser, H. G.; Mosidze, M.; Moszczynski, A.; Mouraviev, S. V.; Mouthuy, T.; Moye, T. H.; Moyse, E. J. W.; Mueller, J.; Müller, M.; Muijs, A.; Muller, T. R.; Munar, A.; Munday, D. J.; Murakami, K.; Murillo Garcia, R.; Murray, W. J.; Myagkov, A. G.; Myska, M.; Nagai, K.; Nagai, Y.; Nagano, K.; Nagasaka, Y.; Nairz, A. M.; Naito, D.; Nakamura, K.; Nakamura, Y.; Nakano, I.; Nanava, G.; Napier, A.; Nassiakou, M.; Nasteva, I.; Nation, N. R.; Naumann, T.; Nauyock, F.; Nderitu, S. K.; Neal, H. A.; Nebot, E.; Nechaeva, P.; Neganov, A.; Negri, A.; Negroni, S.; Nelson, C.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Nesterov, S. Y.; Neukermans, L.; Nevski, P.; Newcomer, F. M.; Nichols, A.; Nicholson, C.; Nicholson, R.; Nickerson, R. B.; Nicolaidou, R.; Nicoletti, G.; Nicquevert, B.; Niculescu, M.; Nielsen, J.; Niinikoski, T.; Niinimaki, M. J.; Nikitin, N.; Nikolaev, K.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, H.; Nilsson, B. S.; Nilsson, P.; Nisati, A.; Nisius, R.; Nodulman, L. J.; Nomachi, M.; Nomoto, H.; Noppe, J.-M.; Nordberg, M.; Norniella Francisco, O.; Norton, P. R.; Novakova, J.; Nowak, M.; Nozaki, M.; Nunes, R.; Nunes Hanninger, G.; Nunnemann, T.; Nyman, T.; O'Connor, P.; O'Neale, S. W.; O'Neil, D. C.; O'Neill, M.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermaier, M.; Oberson, P.; Ochi, A.; Ockenfels, W.; Odaka, S.; Odenthal, I.; Odino, G. A.; Ogren, H.; Oh, S. H.; Ohshima, T.; Ohshita, H.; Okawa, H.; Olcese, M.; Olchevski, A. G.; Oliver, C.; Oliver, J.; Olivo Gomez, M.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onea, A.; Onofre, A.; Oram, C. J.; Ordonez, G.; Oreglia, M. J.; Orellana, F.; Oren, Y.; Orestano, D.; Orlov, I. O.; Orr, R. S.; Orsini, F.; Osborne, L. S.; Osculati, B.; Osuna, C.; Otec, R.; Othegraven, R.; Ottewell, B.; Ould-Saada, F.; Ouraou, A.; Ouyang, Q.; Øye, O. K.; Ozcan, V. E.; Ozone, K.; Ozturk, N.; Pacheco Pages, A.; Padhi, S.; Padilla Aranda, C.; Paganis, E.; Paige, F.; Pailler, P. M.; Pajchel, K.; Palestini, S.; Palla, J.; Pallin, D.; Palmer, M. J.; Pan, Y. B.; Panikashvili, N.; Panin, V. N.; Panitkin, S.; Pantea, D.; Panuskova, M.; Paolone, V.; Paoloni, A.; Papadopoulos, I.; Papadopoulou, T.; Park, I.; Park, W.; Parker, M. A.; Parker, S.; Parkman, C.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passardi, G.; Passeri, A.; Passmore, M. S.; Pastore, F.; Pastore, Fr; Pataraia, S.; Pate, D.; Pater, J. R.; Patricelli, S.; Pauly, T.; Pauna, E.; Peak, L. S.; Peeters, S. J. M.; Peez, M.; Pei, E.; Peleganchuk, S. V.; Pellegrini, G.; Pengo, R.; Pequenao, J.; Perantoni, M.; Perazzo, A.; Pereira, A.; Perepelkin, E.; Perera, V. J. O.; Perez Codina, E.; Perez Reale, V.; Peric, I.; Perini, L.; Pernegger, H.; Perrin, E.; Perrino, R.; Perrodo, P.; Perrot, G.; Perus, P.; Peshekhonov, V. D.; Petereit, E.; Petersen, J.; Petersen, T. C.; Petit, P. J. F.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petti, R.; Pezzetti, M.; Pfeifer, B.; Phan, A.; Phillips, A. W.; Phillips, P. W.; Piacquadio, G.; Piccinini, M.; Pickford, A.; Piegaia, R.; Pier, S.; Pilcher, J. E.; Pilkington, A. D.; Pimenta Dos Santos, M. A.; Pina, J.; Pinfold, J. L.; Ping, J.; Pinhão, J.; Pinto, B.; Pirotte, O.; Placakyte, R.; Placci, A.; Plamondon, M.; Plano, W. G.; Pleier, M.-A.; Pleskach, A. V.; Podkladkin, S.; Podlyski, F.; Poffenberger, P.; Poggioli, L.; Pohl, M.; Polak, I.; Polesello, G.; Policicchio, A.; Polini, A.; Polychronakos, V.; Pomarede, D. M.; Pommès, K.; Ponsot, P.; Pontecorvo, L.; Pope, B. G.; Popescu, R.; Popovic, D. S.; Poppleton, A.; Popule, J.; Portell Bueso, X.; Posch, C.; Pospelov, G. E.; Pospichal, P.; Pospisil, S.; Postranecky, M.; Potrap, I. N.; Potter, C. J.; Poulard, G.; Pousada, A.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Prast, J.; Prat, S.; Prata, M.; Pravahan, R.; Preda, T.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L. E.; Price, M. J.; Prichard, P. M.; Prieur, D.; Primavera, M.; Primor, D.; Prokofiev, K.; Prosso, E.; Proudfoot, J.; Przysiezniak, H.; Puigdengoles, C.; Purdham, J.; Purohit, M.; Puzo, P.; Pylaev, A. N.; Pylypchenko, Y.; Qi, M.; Qian, J.; Qian, W.; Qian, Z.; Qing, D.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Rabbers, J. J.; Radeka, V.; Rafi, J. M.; Ragusa, F.; Rahimi, A. M.; Rahm, D.; Raine, C.; Raith, B.; Rajagopalan, S.; Rajek, S.; Rammer, H.; Ramstedt, M.; Rangod, S.; Ratoff, P. N.; Raufer, T.; Rauscher, F.; Rauter, E.; Raymond, M.; Reads, A. L.; Rebuzzi, D.; Redlinger, G. R.; Reeves, K.; Rehak, M.; Reichold, A.; Reinherz-Aronis, E.; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z.; Renaudin-Crepe, S. R. C.; Renkel, P.; Rensch, B.; Rescia, S.; Rescigno, M.; Resconi, S.; Resende, B.; Rewiersma, P.; Rey, J.; Rey-Campagnolle, M.; Rezaie, E.; Reznicek, P.; Richards, R. A.; Richer, J.-P.; Richter, R. H.; Richter, R.; Richter-Was, E.; Ridel, M.; Riegler, W.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rios, R. R.; Riu Dachs, I.; Rivline, M.; Rivoltella, G.; Rizatdinova, F.; Robertson, S. H.; Robichaud-Veronneau, A.; Robins, S.; Robinson, D.; Robson, A.; Rochford, J. H.; Roda, C.; Rodier, S.; Roe, S.; Røhne, O.; Rohrbach, F.; Roldán, J.; Rolli, S.; Romance, J. B.; Romaniouk, A.; Romanov, V. M.; Romeo, G.; Roos, L.; Ros, E.; Rosati, S.; Rosenbaum, F.; Rosenbaum, G. A.; Rosenberg, E. I.; Rosselet, L.; Rossi, L. P.; Rossi, L.; Rotaru, M.; Rothberg, J.; Rottländer, I.; Rousseau, D.; Rozanov, A.; Rozen, Y.; Ruber, R.; Ruckert, B.; Rudolph, G.; Rühr, F.; Ruggieri, F.; Ruggiero, G.; Ruiz, H.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rusakovich, N. A.; Rust, D. R.; Rutherfoord, J. P.; Ruwiedel, C.; Ryabov, Y. F.; Ryadovikov, V.; Ryan, P.; Rybkine, G.; da Costa, J. Sá; Saavedra, A. F.; Saboumazrag, S.; F-W Sadrozinski, H.; Sadykov, R.; Sakamoto, H.; Sala, P.; Salamon, A.; Saleem, M.; Salihagic, D.; Salt, J.; Saltó Bauza, O.; Salvachúa Ferrando, B. M.; Salvatore, D.; Salzburger, A.; Sampsonidis, D.; Samset, B. H.; Sánchez Sánchez, C. A.; Sanchis Lozano, M. A.; Sanchis Peris, E.; Sandaker, H.; Sander, H. G.; Sandhoff, M.; Sandvoss, S.; Sankey, D. P. C.; Sanny, B.; Sansone, S.; Sansoni, A.; Santamarina Rios, C.; Santander, J.; Santi, L.; Santoni, C.; Santonico, R.; Santos, J.; Sapinski, M.; Saraiva, J. G.; Sarri, F.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, D.; Sauvage, G.; Savard, P.; Savine, A. Y.; Savinov, V.; Savoy-Navarro, A.; Savva, P.; Saxon, D. H.; Says, L. P.; Sbarra, C.; Sbrissa, E.; Sbrizzi, A.; Scannicchio, D. A.; Schaarschmidt, J.; Schacht, P.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schaller, M.; Schamov, A. G.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Scherzer, M. I.; Schiavi, C.; Schick, H.; Schieck, J.; Schieferdecker, P.; Schioppa, M.; Schlager, G.; Schlenker, S.; Schlereth, J. L.; Schmid, P.; Schmidt, M. P.; Schmitt, C.; Schmitt, K.; Schmitz, M.; Schmücker, H.; Schoerner, T.; Scholte, R. C.; Schott, M.; Schouten, D.; Schram, M.; Schricker, A.; Schroff, D.; Schuh, S.; Schuijlenburg, H. W.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.-C.; Schumacher, J.; Schumacher, M.; Schune, Ph; Schwartzman, A.; Schweiger, D.; Schwemling, Ph; Schwick, C.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W. G.; Secker, H.; Sedykh, E.; Seguin-Moreau, N.; Segura, E.; Seidel, S. C.; Seiden, A.; Seixas, J. M.; Sekhniaidze, G.; Seliverstov, D. M.; Selldén, B.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M. E.; Sexton, K. A.; Sfyrla, A.; Shah, T. P.; Shan, L.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaver, L.; Shaw, C.; Shears, T. G.; Sherwood, P.; Shibata, A.; Shield, P.; Shilov, S.; Shimojima, M.; Shin, T.; Shiyakova, M.; Shmeleva, A.; Shoa, M.; Shochet, M. J.; Shupe, M. A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siebel, M.; Siegrist, J.; Sijacki, D.; Silva, J.; Silverstein, S. B.; Simak, V.; Simic, Lj; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sipica, V.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S.; Sjölin, J.; Skubic, P.; Skvorodnev, N.; Slattery, P.; Slavicek, T.; Sliwa, K.; Sloan, T. J.; Sloper, J.; Smakhtin, V.; Small, A.; Smirnov, S. Yu; Smirnov, Y.; Smirnova, L.; Smirnova, O.; Smith, N. A.; Smith, B. C.; Smith, D. S.; Smith, J.; Smith, K. M.; Smith, B.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snow, S. W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Soares, S.; Sobie, R.; Sodomka, J.; Söderberg, M.; Soffer, A.; Solans, C. A.; Solar, M.; Sole, D.; Solfaroli Camillocci, E.; Solodkov, A. A.; Solov'yanov, O. V.; Soloviev, I.; Soluk, R.; Sondericker, J.; Sopko, V.; Sopko, B.; Sorbi, M.; Soret Medel, J.; Sosebee, M.; Sosnovtsev, V. V.; Sospedra Suay, L.; Soukharev, A.; Soukup, J.; Spagnolo, S.; Spano, F.; Speckmayer, P.; Spegel, M.; Spencer, E.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spogli, L.; Spousta, M.; Sprachmann, G.; Spurlock, B.; St. Denis, R. D.; Stahl, T.; Staley, R. J.; Stamen, R.; Stancu, S. N.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stapnes, S.; Starchenko, E. A.; Staroba, P.; Stastny, J.; Staude, A.; Stavina, P.; Stavrianakou, M.; Stavropoulos, G.; Stefanidis, E.; Steffens, J. L.; Stekl, I.; Stelzer, H. J.; Stenzel, H.; Stewart, G.; Stewart, T. D.; Stiller, W.; Stockmanns, T.; Stodulski, M.; Stonjek, S.; Stradling, A.; Straessner, A.; Strandberg, J.; Strandlie, A.; Strauss, M.; Strickland, V.; Striegel, D.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Strong, J. A.; Stroynowski, R.; Stugu, B.; Stumer, I.; Su, D.; Subramania, S.; Suchkov, S. I.; Sugaya, Y.; Sugimoto, T.; Suk, M.; Sulin, V. V.; Sultanov, S.; Sun, Z.; Sundal, B.; Sushkov, S.; Susinno, G.; Sutcliffe, P.; Sutton, M. R.; Sviridov, Yu M.; Sykora, I.; Szczygiel, R. R.; Szeless, B.; Szymocha, T.; Sánchez, J.; Ta, D.; Taboada Gameiro, S.; Tadel, M.; Tafirout, R.; Taga, A.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M. C.; Tanaka, J.; Tanaka, K.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tappern, G. P.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tarrant, J.; Tartarelli, G.; Tas, P.; Tasevsky, M.; Tayalati, Y.; Taylor, F. E.; Taylor, G.; Taylor, G. N.; Taylor, R. P.; Tcherniatine, V.; Tegenfeldt, F.; Teixeira-Dias, P.; Ten Kate, H.; Teng, P. K.; Ter-Antonyan, R.; Terada, S.; Terron, J.; Terwort, M.; Teuscher, R. J.; Tevlin, C. M.; Thadome, J.; Thion, J.; Thioye, M.; Thomas, A.; Thomas, J. P.; Thomas, T. L.; Thomas, E.; Thompson, R. J.; Thompson, A. S.; Thun, R. P.; Tic, T.; Tikhomirov, V. O.; Tikhonov, Y. A.; Timm, S.; Timmermans, C. J. W. P.; Tipton, P.; Tique Aires Viegas, F. J.; Tisserant, S.; Titov, M.; Tobias, J.; Tocut, V. M.; Toczek, B.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tomasek, L.; Tomasek, M.; Tomasz, F.; Tomoto, M.; Tompkins, D.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N. D.; Torrence, E.; Torres Pais, J. G.; Toth, J.; Touchard, F.; Tovey, D. R.; Tovey, S. N.; Towndrow, E. F.; Trefzger, T.; Treichel, M.; Treis, J.; Tremblet, L.; Tribanek, W.; Tricoli, A.; Trigger, I. M.; Trilling, G.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trka, Z.; Trocmé, B.; Troncon, C.; C-L Tseng, J.; Tsiafis, I.; Tsiareshka, P. V.; Tsipolitis, G.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Turala, M.; Turk Cakir, I.; Turlay, E.; Tuts, P. M.; Twomey, M. S.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzamarioudaki, E.; Tzanakos, G.; Ueda, I.; Uhrmacher, M.; Ukegawa, F.; Ullán Comes, M.; Unal, G.; Underwood, D. G.; Undrus, A.; Unel, G.; Unno, Y.; Urkovsky, E.; Usai, G.; Usov, Y.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valero, A.; Valkar, S.; Valls Ferrer, J. A.; Van der Bij, H.; van der Graaf, H.; van der Kraaij, E.; Van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Van Berg, R.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vannucci, F.; Varanda, M.; Varela Rodriguez, F.; Vari, R.; Varnes, E. W.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vassilakopoulos, V. I.; Vassilieva, L.; Vataga, E.; Vaz, L.; Vazeille, F.; Vedrine, P.; Vegni, G.; Veillet, J. J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, S.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vertogardov, L.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Viehhauser, G. H. A.; Vigeolas, E.; Villa, M.; Villani, E. G.; Villate, J.; Villella, I.; Vilucchi, E.; Vincent, P.; Vincke, H.; Vincter, M. G.; Vinogradov, V. B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vivarelli, I.; Vives, R.; Vives Vaques, F.; Vlachos, S.; Vogt, H.; Vokac, P.; Vollmer, C. F.; Volpi, M.; Volpini, G.; von Boehn-Buchholz, R.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorozhtsov, A. S.; Vorozhtsov, S. B.; Vos, M.; Voss, K. C.; Voss, R.; Vossebeld, J. H.; Vovenko, A. S.; Vranjes, N.; Vrba, V.; Vreeswijk, M.; Anh, T. Vu; Vuaridel, B.; Vudragovic, M.; Vuillemin, V.; Vuillermet, R.; Wänanen, A.; Wahlen, H.; Walbersloh, J.; Walker, R.; Walkowiak, W.; Wall, R.; Wallny, R. S.; Walsh, S.; Wang, C.; Wang, J. C.; Wappler, F.; Warburton, A.; Ward, C. P.; Warner, G. P.; Warren, M.; Warsinsky, M.; Wastie, R.; Watkins, P. M.; Watson, A. T.; Watts, G.; Waugh, A. T.; Waugh, B. M.; Weaverdyck, C.; Webel, M.; Weber, G.; Weber, J.; Weber, M.; Weber, P.; Weidberg, A. R.; Weilhammer, P. M.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wellisch, H. P.; Wells, P. S.; Wemans, A.; Wen, M.; Wenaus, T.; Wendler, S.; Wengler, T.; Wenig, S.; Wermes, N.; Werneke, P.; Werner, P.; Werthenbach, U.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; White, S.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiesmann, M.; Wiesmann, M.; Wijnen, T.; Wildauer, A.; Wilhelm, I.; Wilkens, H. G.; Williams, H. H.; Willis, W.; Willocq, S.; Wilmut, I.; Wilson, J. A.; Wilson, A.; Wingerter-Seez, I.; Winton, L.; Witzeling, W.; Wlodek, T.; Woehrling, E.; Wolter, M. W.; Wolters, H.; Wosiek, B.; Wotschack, J.; Woudstra, M. J.; Wright, C.; Wu, S. L.; Wu, X.; Wuestenfeld, J.; Wunstorf, R.; Xella-Hansen, S.; Xiang, A.; Xie, S.; Xie, Y.; Xu, G.; Xu, N.; Yamamoto, A.; Yamamoto, S.; Yamaoka, H.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, J. C.; Yang, S.; Yang, U. K.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yao, Y.; Yarradoddi, K.; Yasu, Y.; Ye, J.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, H.; Yoshida, R.; Young, C.; Youssef, S. P.; Yu, D.; Yu, J.; Yu, M.; Yu, X.; Yuan, J.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajac, J.; Zajacova, Z.; Zalite, A. Yu; Zalite, Yo K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zdrazil, M.; Zeitnitz, C.; Zeller, M.; Zema, P. F.; Zendler, C.; Zenin, A. V.; Zenis, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zhang, H.; Zhang, J.; Zheng, W.; Zhang, X.; Zhao, L.; Zhao, T.; Zhao, X.; Zhao, Z.; Zhelezko, A.; Zhemchugov, A.; Zheng, S.; Zhichao, L.; Zhou, B.; Zhou, N.; Zhou, S.; Zhou, Y.; Zhu, C. G.; Zhu, H. Z.; Zhuang, X. A.; Zhuravlov, V.; Zilka, B.; Zimin, N. I.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Zivkovic, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zoeller, M. M.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zychacek, V.

    2008-08-01

    The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

  5. Simulating graviton production at hadron colliders

    NASA Astrophysics Data System (ADS)

    de Aquino, Priscila; Hagiwara, Kaoru; Li, Qiang; Maltoni, Fabio

    2011-06-01

    Spin-2 particles and in particular gravitons are predicted in many new physics scenarios at the TeV scale. Depending on the details of models such new states might show up as a continuum, massless particles, or TeV scale resonances. Correspondingly, very different discovery signatures should be exploited, from the search of excesses in events with multi jets and large missing transverse energy, to resonances in weak boson or jet pair productions. We present a very general and flexible implementation in M ad-G raph/M adE vent of spin-2 particles interacting with the standard model particles via the energy momentum tensor, which encompasses all of the most popular TeV scale models featuring gravitons. By merging matrix elements with parton shower, we can generate inclusive samples of graviton + jets at the hadron colliders in several scenarios (ADD, zero-mass graviton and RS). We compare and validate our results against the corresponding next-to-leading order QCD calculations.

  6. Hadron collider limits on anomalous WWγ couplings

    NASA Astrophysics Data System (ADS)

    Barger, Kevin R.; Reno, M. H.

    1995-01-01

    A next-to-leading log calculation of the reactions pp and pp¯-->W+/-γX is presented including a triboson gauge coupling from non-standard-model contributions. The additional term arises by considering the standard model as a low energy effective theory. Two approaches are made for comparison. The first approach considers the triboson WWγ coupling as being uniquely fixed by tree level unitarity at high energies to its standard model form and, consequently, suppresses the non-standard-model contributions with form factors. The second approach is to ignore such considerations and calculate the contributions to non-standard-model triboson gauge couplings without such suppressions, using the first term in the momentum expansion of an effective chiral Lagrangian. It is found that at Fermilab Tevatron energies the two approaches do not differ much in quantitative results, while at large Hadron Collider (LHC) energies the two approaches give significantly different predictions for production rates. At the Tevatron and LHC, however, the sensitivity limits on the anomalous coupling of WWγ are too weak to usefully constrain parameters in the chiral Lagrangian.

  7. Computing and data handling requirements for SSC (Superconducting Super Collider) and LHC (Large Hadron Collider) experiments

    SciTech Connect

    Lankford, A.J.

    1990-05-01

    A number of issues for computing and data handling in the online in environment at future high-luminosity, high-energy colliders, such as the Superconducting Super Collider (SSC) and Large Hadron Collider (LHC), are outlined. Requirements for trigger processing, data acquisition, and online processing are discussed. Some aspects of possible solutions are sketched. 6 refs., 3 figs.

  8. Suppressing Electron Cloud in Future Linear Colliders

    SciTech Connect

    Pivi, M; Kirby, R.E.; Raubenheimer, T.O.; Le Pimpec, F.; /PSI, Villigen

    2005-05-27

    Any accelerator circulating positively charged beams can suffer from a build-up of an electron cloud (EC) in the beam pipe. The cloud develops through ionization of residual gases, synchrotron radiation and secondary electron emission and, when severe, can cause instability, emittance blow-up or loss of the circulating beam. The electron cloud is potentially a luminosity limiting effect for both the Large Hadron Collider (LHC) and the International Linear Collider (ILC). For the ILC positron damping ring, the development of the electron cloud must be suppressed. This paper discusses the state-of-the-art of the ongoing SLAC and international R&D program to study potential remedies.

  9. Tolerable systematic errors in Really Large Hadron Collider dipoles

    SciTech Connect

    Peggs, S.; Dell, F.

    1996-12-01

    Maximum allowable systematic harmonics for arc dipoles in a Really Large Hadron Collider are derived. The possibility of half cell lengths much greater than 100 meters is justified. A convenient analytical model evaluating horizontal tune shifts is developed, and tested against a sample high field collider.

  10. Light neutral C P -even Higgs boson within the next-to-minimal supersymmetric standard model at the Large Hadron Electron Collider

    NASA Astrophysics Data System (ADS)

    Das, Siba Prasad; Nowakowski, Marek

    2017-09-01

    We analyze the prospects of observing the light charge parity (C P )-even neutral Higgs bosons (h1) in their decays into b b ¯ quarks, in the neutral and charged current production processes e h1q and ν h1q at the upcoming Large Hadron Electron Collider (LHeC), with √{s }≈1.296 TeV . Assuming that the intermediate Higgs boson (h2 ) is Standard Model (SM)-like, we study the Higgs production within the framework of next-to-minimal supersymmetric Standard Model (NMSSM). We consider the constraints from dark-matter, sparticle masses, and the Higgs boson data. The signal in our analysis can be classified as three jets, with electron (missing energy) coming from the neutral (charged) current interaction. We demand that the number of b -tagged jets in the central rapidity region be greater or equal to two. The remaining jet is tagged in the forward regions. With this forward jet and two b -tagged jets in the central region, we reconstructed three jets invariant masses. Applying some lower limits on these invariant masses turns out to be an essential criterion to enhance the signal-to-background rates, with slightly different sets of kinematical selections in the two different channels. We consider almost all reducible and irreducible SM background processes. We find that the non-SM like Higgs boson, h1, would be accessible in some of the NMSSM benchmark points, at approximately the 0.4 σ (2.5 σ ) level in the e +3 j channel up to Higgs boson masses of 75 GeV, and in the ET +3 j channel could be discovered with the 1.7 σ (2.4 σ ) level up to Higgs boson masses of 88 GeV with 100 fb-1 of data in a simple cut-based (with optimization) selection. With ten times more data accumulation at the end of the LHeC run, and using optimization, one can have 5 σ discovery in the electron (missing energy) channel up to 85 (more than 90) GeV.

  11. Production of Electroweak Bosons at Hadron Colliders: Theoretical Aspects

    NASA Astrophysics Data System (ADS)

    Mangano, Michelangelo L.

    2016-10-01

    Since the W± and Z0 discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard Model.

  12. INTRA-BEAM SCATTERING SCALING FOR VERY LARGE HADRON COLLIDERS.

    SciTech Connect

    WEI,J.; PARZEN,G.

    2001-06-18

    For Very Large Hadron Colliders (VLHC), flat hadron beams [2] with their vertical emittance much smaller than their horizontal emittance are proposed to maximize the design luminosity. Emittance growth caused by intra-beam scattering (IBS) is a concern on the realization of such flat-beam conditions. Based on existing IBS formalism on beams of Gaussian distribution, we analytically derive [6] the IBS growth rate and determine the IBS limit on the aspect ratio for a flat beam.

  13. Jet Reconstruction and Spectroscopy at Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Bellettini, Giorgio

    2011-11-01

    Dear colleagues and friends, Major new particle discoveries were made in the past by exploring the mass spectrum of lepton pairs. These searches still have great potential. However, new particle searches are now being extended to masses larger than the W, Z mass. More and more decay channels open up and the branching ratios into lepton pairs are reduced. Also, physics may dictate that states with heavy bosons and quarks become dominant. Examples are the decay of top quarks, and the expected final states of the standard model Higgs boson. Supersymmetry in any of its wide spectrum of models predicts intrigued final states where jets are major observables. To reconstruct masses and to study the dynamics of these states one must exploit the energy-momentum four-vectors of jets. Past experiments at the CERN SPS collider, at HERA, at LEP and now at the Tevatron collider and at LHC, have studied how best to reconstruct hadron jets. However, originally the role of jets in searching for new physics was primarily to sense new parton contact interactions by means of increased large pt tails in inclusive jet spectra, or studying jet events with large missing Et, or measuring branching ratios into jets of different flavour. These studies did not require as accurate a measure of jet four-momenta as needed in new particle searches in multi-jets final states. Figure 1 Figure 1. W, Z associated production in CDF events with large Et, miss and 2 jets. Consider for example (figure 1) the mass spectrum of dijets in events with large missing Et recently measured by CDF [1]. Trigger and analysis cuts were chosen so as to favour production of heavy boson pairs, with decay of one Z boson into neutrinos tagging the event and another W or Z boson decaying into jets. Associated production of boson pairs is observed, but the dijet mass resolution does not allow the separation of W from Z. A broad agreement of the overall observed rate with expectation is found, but a comparative study of the

  14. TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS

    SciTech Connect

    Jabeen, Shabnam

    2013-10-20

    This review summarizes the recent results for top quark and Higgs boson measurements from experiments at Tevatron, a proton–antiproton collider at a center-of-mass energy of √ s =1 . 96 TeV, and the Large Hadron Collider, a proton–proton collider at a center- of-mass energy of √ s = 7 TeV. These results include the discovery of a Higgs-like boson and measurement of its various properties, and measurements in the top quark sector, e.g. top quark mass, spin, charge asymmetry and production of single top quark.

  15. Higgs boson production and decay at hadron colliders

    NASA Astrophysics Data System (ADS)

    Spira, Michael

    2017-07-01

    Higgs physics at hadron colliders as the LHC is reviewed within the Standard Model (SM) and its minimal supersymmetric extension (MSSM) by summarizing the present state-of-the-art of theoretical predictions for the production cross sections and decay rates.

  16. Department of Energy assessment of the Large Hadron Collider

    SciTech Connect

    1996-06-01

    This report summarizes the conclusions of the committee that assessed the cost estimate for the Large Hadron Collider (LHC). This proton-proton collider will be built at CERN, the European Laboratory for Particle Physics near Geneva, Switzerland. The committee found the accelerator-project cost estimate of 2.3 billion in 1995 Swiss francs, or about $2 billion US, to be adequate and reasonable. The planned project completion date of 2005 also appears achievable, assuming the resources are available when needed. The cost estimate was made using established European accounting procedures. In particular, the cost estimate does not include R and D, prototyping and testing, spare parts, and most of the engineering labor. Also excluded are costs for decommissioning the Large Electron-Positron collider (LEP) that now occupies the tunnel, modifications to the injector system, the experimental areas, preoperations costs, and CERN manpower. All these items are assumed by CERN to be included in the normal annual operations budget rather than the construction budget. Finally, contingency is built into the base estimate, in contrast to Department of Energy (DOE) estimates that explicitly identify contingency. The committee`s charge, given by Dr. James F. Decker, Deputy Directory of the DOE Office of Energy Research, was to understand the basis for the LHC cost estimate, identify uncertainties, and judge the overall validity of the estimate, proposed schedule, and related issues. The committee met at CERN April 22--26, 1996. The assessment was based on the October 1995 LHC Conceptual Design Report or ``Yellow Book,`` cost estimates and formal presentations made by the CERN staff, site inspection, detailed discussions with LHC technical experts, and the committee members` considerable experience.

  17. High-brightness injectors for hadron colliders

    SciTech Connect

    Wangler, T.P.

    1990-01-01

    The counterrotating beams in collider rings consist of trains of beam bunches with N{sub B} particles per bunch, spaced a distance S{sub B} apart. When the bunches collide, the interaction rate is determined by the luminosity, which is defined as the interaction rate per unit cross section. For head-on collisions between cylindrical Gaussian beams moving at speed {beta}c, the luminosity is given by L = N{sub B}{sup 2}{beta}c/4{pi}{sigma}{sup 2}S{sub B}, where {sigma} is the rms beam size projected onto a transverse plane (the two transverse planes are assumed identical) at the interaction point. This beam size depends on the rms emittance of the beam and the focusing strength, which is a measure of the 2-D phase-space area in each transverse plane, and is defined in terms of the second moments of the beam distribution. Our convention is to use the rms normalized emittance, without factors of 4 or 6 that are sometimes used. The quantity {tilde {beta}} is the Courant-Synder betatron amplitude function at the interaction point, a characteristic of the focusing lattice and {gamma} is the relativistic Lorentz factor. Achieving high luminosity at a given energy, and at practical values of {tilde {beta}} and S{sub B}, requires a large value for the ratio N{sub B}{sup 2}/{var epsilon}{sub n}, which implies high intensity and small emittance. Thus, specification of the luminosity sets the requirements for beam intensity and emittance, and establishes the requirements on the performance of the injector to the collider ring. In general, for fixed N{sub B}, the luminosity can be increased if {var epsilon}{sub n} can be reduced. The minimum emittance of the collider is limited by the performance of the injector; consequently the design of the injector is of great importance for the ultimate performance of the collider.

  18. Microbunched electron cooling for high-energy hadron beams.

    PubMed

    Ratner, D

    2013-08-23

    Electron and stochastic cooling are proven methods for cooling low-energy hadron beams, but at present there is no way of cooling hadrons as they near the TeV scale. In the 1980s, Derbenev suggested that electron instabilities, such as free-electron lasers, could create collective space charge fields strong enough to correct the hadron energies. This Letter presents a variation on Derbenev's electron cooling scheme using the microbunching instability as the amplifier. The large bandwidth of the instability allows for faster cooling of high-density beams. A simple analytical model illustrates the cooling mechanism, and simulations show cooling rates for realistic parameters of the Large Hadron Collider.

  19. Deciphering the MSSM Higgs mass at future hadron colliders

    DOE PAGES

    Agrawal, Prateek; Fan, JiJi; Reece, Matthew; ...

    2017-06-06

    Here, future hadron colliders will have a remarkable capacity to discover massive new particles, but their capabilities for precision measurements of couplings that can reveal underlying mechanisms have received less study. In this work we study the capability of future hadron colliders to shed light on a precise, focused question: is the higgs mass of 125 GeV explained by the MSSM? If supersymmetry is realized near the TeV scale, a future hadron collider could produce huge numbers of gluinos and electroweakinos. We explore whether precision measurements of their properties could allow inference of the scalar masses and tan β withmore » sufficient accuracy to test whether physics beyond the MSSM is needed to explain the higgs mass. We also discuss dark matter direct detection and precision higgs physics as complementary probes of tan β. For concreteness, we focus on the mini-split regime of MSSM parameter space at a 100 TeV pp collider, with scalar masses ranging from 10s to about 1000 TeV.« less

  20. Deciphering the MSSM Higgs mass at future hadron colliders

    NASA Astrophysics Data System (ADS)

    Agrawal, Prateek; Fan, JiJi; Reece, Matthew; Xue, Wei

    2017-06-01

    Future hadron colliders will have a remarkable capacity to discover massive new particles, but their capabilities for precision measurements of couplings that can reveal underlying mechanisms have received less study. In this work we study the capability of future hadron colliders to shed light on a precise, focused question: is the higgs mass of 125 GeV explained by the MSSM? If supersymmetry is realized near the TeV scale, a future hadron collider could produce huge numbers of gluinos and electroweakinos. We explore whether precision measurements of their properties could allow inference of the scalar masses and tan β with sufficient accuracy to test whether physics beyond the MSSM is needed to explain the higgs mass. We also discuss dark matter direct detection and precision higgs physics as complementary probes of tan β. For concreteness, we focus on the mini-split regime of MSSM parameter space at a 100 TeV pp collider, with scalar masses ranging from 10s to about 1000 TeV.

  1. Collider Detector at Fermilab (CDF): Data from B Hadrons Research

    DOE Data Explorer

    The Collider Detector at Fermilab (CDF) is a Tevatron experiment at Fermilab. The Tevatron, a powerful particle accelerator, accelerates protons and antiprotons close to the speed of light, and then makes them collide head-on inside the CDF detector. The CDF detector is used to study the products of such collisions. The CDF Physics Group is organized into six working groups, each with a specific focus. The Bottom group studies the production and decay of B hadrons. Their public web page makes data and numerous figures available from both CDF Runs I and II.

  2. Searches for scalar and vector leptoquarks at future hadron colliders

    SciTech Connect

    Rizzo, T.G.

    1996-09-01

    The search reaches for both scalar(S) and vector(V) leptoquarks at future hadron colliders are summarized. In particular the authors evaluate the production cross sections of both leptoquark types at TeV33 and LHC as well as the proposed 60 and 200 TeV colliders through both quark-antiquark annihilation and gluon-gluon fusion: q{anti q},gg {r_arrow} SS,VV. Experiments at these machines should easily discover such particles if their masses are not in excess of the few TeV range.

  3. Tracking study of hadron collider boosters

    SciTech Connect

    Machida, S.; Bourianoff, G.; Huang, Y.; Mahale, N.

    1992-07-01

    A simulation code SIMPSONS (previously called 6D-TEASE T) of single- and multi-particle tracking has been developed for proton synchrotrons. The 6D phase space coordinates are calculated each time step including acceleration with an arbitrary ramping curve by integration of the rf phase. Space-charge effects are modelled by means of the Particle In Cell (PIC) method. We observed the transverse emittance growth around the injection energy of the Low Energy Booster (LEB) of the Superconducting Super Collider (SSC) with and without second harmonic rf cavities which reduce peak line density. We also employed the code to see the possible transverse emittance deterioration around the transition energy in the Medium Energy Booster (MEB) and to estimate the emittance dilution due to an injection error of the MEB.

  4. The Structure of Jets at Hadron Colliders

    SciTech Connect

    Larkoski, Andrew James

    2012-08-01

    Particle physics seeks to understand the interactions and properties of the fundamental particles. To gain understanding, there is an interplay between theory and experiment. Models are proposed to explain how particles behave and interact. These models make precise predictions that can be tested. Experiments are built and executed to measure the properties of these particles, providing necessary tests for the theories that attempt to explain the realm of fundamental particles. However, there is also another level of interaction between theory and experiment; the development of new experiments demands the study of how particles will behave with respect to the measured observables toward the goal of understanding the details and idiosyncrasies of the measurements very well. Only once these are well-modeled and understood can one be con dent that the data that are measured is trustworthy. The modeling and interpretation of the physics of a proton collider, such as the LHC, is the main topic of this thesis.

  5. Higgs Boson Searches at Hadron Colliders (1/4)

    ScienceCinema

    None

    2016-07-12

    In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and strategies to measured Higgs boson parameters and the investigation of alternative symmetry breaking scenarios are addressed.

  6. Learning to See at the Large Hadron Collider

    SciTech Connect

    Quigg, Chris

    2010-01-01

    The staged commissioning of the Large Hadron Collider presents an opportunity to map gross features of particle production over a significant energy range. I suggest a visual tool - event displays in (pseudo)rapidity-transverse-momentum space - as a scenic route that may help sharpen intuition, identify interesting classes of events for further investigation, and test expectations about the underlying event that accompanies large-transverse-momentum phenomena.

  7. Lattice optimization for a really large hadron collider (RLHC)

    SciTech Connect

    Peggs, S.; Dell, F.; Harrison, M.; Syphers, M.; Tepikian, S.

    1996-07-01

    Long arc cells would lead to major cost savings in a high field high T{sub c} hadron collider, operating in the regime of significant synchrotron radiation. Two such lattices, with half cell lengths of 110 and 260 m, are compared. Both allow flexible tuning, and have large dynamic apertures when dominated by chromatic sextupoles. Lattices with longer cells are much more sensitive to systematic magnet errors, which are expected to dominate.

  8. Discriminating Supersymmetry and Black Holes at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglia, Marco

    2008-04-01

    We assess the distinguishability between supersymmetry and black hole events at the Large Hadron Collider. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET. Our study, based on event shape variables, visible and missing momenta, and analysis of dilepton events, shows that supersymmetry and black hole events at the LHC can be easily discriminated.

  9. Synchrotron radiation issues in future hadron colliders

    SciTech Connect

    P. Bauer, C. Darve and I. Terechkine

    2002-11-21

    Hadron machines mostly use high field superconducting magnets operating at low temperatures. Therefore the issue of extracting a SR power heat load becomes more critical and costly. Conceptual solutions to the problem exist in the form of beam screens and photon stops. Cooled beam screens are more expensive in production and operation than photon stops, but they are, unlike photon stops, routinely used in existing machines. Photon stops are the most economical solution because the heat load is extracted at room temperature. They presently consider it most prudent to work with a combined beam screen and photon stop approach, in which the photon stop absorbs most of the SR power, and the beam screen serves only the vacuum purpose. Provided that the recently launched photon stop R and D [10] supports it, we would like to explore solutions with photon stops only. This would allow to reduce the magnet apertures to a certain extent with respect to those required to accommodate high SR power compliant beam screens and reduce cost. The possibility of magnet designs, which have larger vertical apertures where large cooling capillaries can be housed at no additional cost, would allow to soften this statement somewhat and should therefore be pursued as well.

  10. Disambiguating seesaw models using invariant mass variables at hadron colliders

    SciTech Connect

    Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

    2016-01-19

    Here, we propose ways to distinguish between different mechanisms behind the collider signals of TeV-scale seesaw models for neutrino masses using kinematic endpoints of invariant mass variables. We particularly focus on two classes of such models widely discussed in literature: (i) Standard Model extended by the addition of singlet neutrinos and (ii) Left-Right Symmetric Models. Relevant scenarios involving the same "smoking-gun" collider signature of dilepton plus dijet with no missing transverse energy differ from one another by their event topology, resulting in distinctive relationships among the kinematic endpoints to be used for discerning them at hadron colliders. Furthermore, these kinematic endpoints are readily translated to the mass parameters of the on-shell particles through simple analytic expressions which can be used for measuring the masses of the new particles. We also conducted a Monte Carlo simulation with detector effects in order to test the viability of the proposed strategy in a realistic environment. Finally, we discuss the future prospects of testing these scenarios at the $\\sqrt{s}$ = 14 and 100TeV hadron colliders.

  11. Disambiguating seesaw models using invariant mass variables at hadron colliders

    DOE PAGES

    Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

    2016-01-19

    Here, we propose ways to distinguish between different mechanisms behind the collider signals of TeV-scale seesaw models for neutrino masses using kinematic endpoints of invariant mass variables. We particularly focus on two classes of such models widely discussed in literature: (i) Standard Model extended by the addition of singlet neutrinos and (ii) Left-Right Symmetric Models. Relevant scenarios involving the same "smoking-gun" collider signature of dilepton plus dijet with no missing transverse energy differ from one another by their event topology, resulting in distinctive relationships among the kinematic endpoints to be used for discerning them at hadron colliders. Furthermore, these kinematic endpoints are readily translated to the mass parameters of the on-shell particles through simple analytic expressions which can be used for measuring the masses of the new particles. We also conducted a Monte Carlo simulation with detector effects in order to test the viability of the proposed strategy in a realistic environment. Finally, we discuss the future prospects of testing these scenarios at themore » $$\\sqrt{s}$$ = 14 and 100TeV hadron colliders.« less

  12. Disambiguating seesaw models using invariant mass variables at hadron colliders

    NASA Astrophysics Data System (ADS)

    Dev, P. S. Bhupal; Kim, Doojin; Mohapatra, Rabindra N.

    2016-01-01

    We propose ways to distinguish between different mechanisms behind the collider signals of TeV-scale seesaw models for neutrino masses using kinematic endpoints of invariant mass variables. We particularly focus on two classes of such models widely discussed in literature: (i) Standard Model extended by the addition of singlet neutrinos and (ii) Left-Right Symmetric Models. Relevant scenarios involving the same "smoking-gun" collider signature of dilepton plus dijet with no missing transverse energy differ from one another by their event topology, resulting in distinctive relationships among the kinematic endpoints to be used for discerning them at hadron colliders. These kinematic endpoints are readily translated to the mass parameters of the on-shell particles through simple analytic expressions which can be used for measuring the masses of the new particles. A Monte Carlo simulation with detector effects is conducted to test the viability of the proposed strategy in a realistic environment. Finally, we discuss the future prospects of testing these scenarios at the √{s}=14 and 100 TeV hadron colliders.

  13. Dark matter searches at the large hadron collider

    NASA Astrophysics Data System (ADS)

    Hoh, S. Y.; Komaragiri, J. R.; Wan Abdullah, W. A. T.

    2016-01-01

    Dark Matter is a hypothetical particle proposed to explain the missing matter expected from the cosmological observation. The motivation of Dark Matter is overwhelming however as it is mainly deduced from its gravitational interaction, for it does little to pinpoint what Dark Matter really is. In WIMPs Miracle, weakly interactive massive particle being the Dark Matter candidate is correctly producing the current thermal relic density at weak scale, implying the possibility of producing and detecting it in Large Hadron Collider. Assuming WIMPs being the maverick particle within collider, it is expected to be pair produced in association with a Standard Model particle. The presence of the WIMPs pair is inferred from the Missing Transverse Energy (MET) which is the vector sum of the imbalance in the transverse momentum plane recoils a Standard Model Particle. The collider is able to produce light mass Dark Matter which the traditional detection fail to detect due to the small momentum transfer involved in the interaction; on the other hand, the traditional detection is robust in detecting a higher Dark matter masses but the collider is suffered from the parton distribution function suppression. Topologically the processes are similar to the scattering processes in the direct detection thus complementary to the traditional Dark Matter detection. The collider searches are strongly motivated as the results are usually translated to the annihilation and scattering rates at more traditional Dark Matter-oriented experiments, thus a concordance approach is adapted. An overview of Dark Matter searches at the Large Hadron Collider will be covered in this paper.

  14. Electron Ion Collider transverse spin physics

    SciTech Connect

    Prokudin, Alexei

    2011-07-01

    Electron Ion Collider is a future high energy facility for studies of the structure of the nucleon. Three-dimensional parton structure is one of the main goals of EIC. In momentum space Transverse Momentum Dependent Distributions (TMDs) are the key ingredients to map such a structure. At leading twist spin structure of spin-1/2 hadron can be described by 8 TMDs. Experimentally these functions can be studied in polarised SIDIS experiments. We discuss Sivers distribution function that describes distribution of unpolarised quarks in a transversely polarised nucleon and transversity that measures distribution of transversely polarised quarks in a transversely polarised nucleon

  15. Electron Ion Collider transverse spin physics

    SciTech Connect

    Prokudin, Alexei

    2011-07-15

    Electron Ion Collider is a future high energy facility for studies of the structure of the nucleon. Three-dimensional parton structure is one of the main goals of EIC. In momentum space Transverse Momentum Dependent Distributions (TMDs) are the key ingredients to map such a structure. At leading twist spin structure of spin-1/2 hadron can be described by 8 TMDs. Experimentally these functions can be studied in polarised SIDIS experiments. We discuss Sivers distribution function that describes distribution of unpolarised quarks in a transversely polarised nucleon and transversity that measures distribution of transversely polarised quarks in a transversely polarised nucleon.

  16. Physics and Analysis at a Hadron Collider - An Introduction (1/3)

    ScienceCinema

    None

    2016-07-12

    This is the first lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This first lecture provides a brief introduction to hadron collider physics and collider detector experiments as well as offers some analysis guidelines. The lectures are aimed at graduate students.

  17. Precision Studies of Hadronic and Electro-Weak Interactions for Collider Physics. Final Report

    SciTech Connect

    Yost, Scott A

    2014-04-02

    This project was directed toward developing precision computational tools for proton collisions at the Large Hadron Collider, focusing primarily on electroweak boson production and electroweak radiative corrections. The programs developed under this project carried the name HERWIRI, for High Energy Radiation With Infra-Red Improvements, and are the first steps in an ongoing program to develop a set of hadronic event generators based on combined QCD and QED exponentiation. HERWIRI1 applied these improvements to the hadronic shower, while HERWIRI2 will apply the electroweak corrections from the program KKMC developed for electron-positron scattering to a hadronic event generator, including exponentiated initial and final state radiation together with first-order electroweak corrections to the hard process. Some progress was also made on developing differential reduction techniques for hypergeometric functions, for application to the computation of Feynman diagrams.

  18. Preliminary results of measurements of hadronic cross sections with the CMD-3 detector at the VEPP-2000 electron-positron collider

    NASA Astrophysics Data System (ADS)

    Fedotovich, G. V.; Anisenkov, A. V.; Aulchenko, V. M.; Akhmetshin, R. R.; Banzarov, V. S.; Bashtovoy, N. S.; Berkaev, D. E.; Bragin, A. V.; Vorobiov, A. I.; Gayazov, S. E.; Grebenuk, A. A.; Grigoriev, D. N.; Gromov, E. M.; Epifanov, D. A.; Erofeev, A. L.; Zharinov, Yu. M.; Ivanov, V. L.; Ignatov, F. V.; Kazanin, V. F.; Karpov, S. V.; Kirpotin, A. N.; Kovalenko, O. A.; Kozyrev, A. N.; Kozyrev, E. A.; Koop, I. A.; Krokovny, P. P.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Lukin, P. A.; Lysenko, A. P.; Mikhailov, K. Yu.; Okhapkin, V. S.; Perevedentsev, E. A.; Pestov, Yu. N.; Popov, A. S.; Razuvaev, G. P.; Rogovsky, Yu. A.; Romanov, A. L.; Ruban, A. A.; Ryzhenenkov, A. E.; Ryskulov, N. M.; Sibidanov, A. L.; Solodov, E. P.; Talyshev, A. A.; Titov, V. M.; Khazin, B. I.; Shatunov, P. Yu.; Shatunov, Yu. M.; Shwartz, B. A.; Shwartz, D. B.; Shebalin, V. E.; Shemyakin, D. N.; Eidelman, S. I.; Epshteyn, L. B.; Yudin, Yu. V.

    2015-07-01

    Experiments with the CMD-3 detector at the VEPP-2000 electron-positron collider in the range of center of mass collision energies from 0.32 to 2 GeV have been performed since December 2010. The amount of accumulated data corresponds to an integrated luminosity of about 60 pb-1. The resultsof a preliminary analysis are presented for the following annihilation channels: e + e - → 3(π+π-), 2(π+π-π0), K + K -π+π-, K + K -, , and π+π-. Since processes of electron-positron annihilation that involve the production of multihadron states proceed through several intermediate states, their analysis is necessary for the correct description of the emission-angle and invariant-mass distributions of product particles.

  19. Triggering at a high luminosity hadron collider

    SciTech Connect

    Price, L.E.; Wagner, R.G.; Abolins, M.A.

    1984-01-01

    The extreme interaction rate occurring at the SSC as described in the Reference Design Report poses the principal new challenge for the triggering system compared with detectors at previous accelerators. At SSC we must plan for about 10/sup 8/ interactions per second. If bunch crossings occur each 33 ns, there will be an average of 3 interactions in each bunch crossing. Potential problems for triggering are presented both by the high total rate and by the multiple interactions per bunch crossing, so that triggering events must be selected in the presence of other interactions independent of the inherent speed of either detector elements or triggering electronics. Three principal topics are considered in this report: (1) Practical selections to be made in a first-level trigger to reduce the rate by a factor of 1000. (2) Electronics expected to implement this first-level trigger, and (3) the ultimate trigger selections that must be used to select the approximately 1 Hz that can practically be recorded for detailed analysis. 11 references, 6 figures.

  20. A 233 km tunnel for lepton and hadron colliders

    SciTech Connect

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T.

    2012-12-21

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  1. A 233 km Tunnel for Lepton and Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T.

    2012-07-01

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of $e^+e^-$, $p \\bar{p}$, and $\\mu^+ \\mu^-$ collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV $e^+e^-$ colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV $e^+ e^-$ collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV $p \\bar{p}$ collider uses the high intensity Fermilab $\\bar{p}$ source, exploits high cross sections for $p \\bar{p}$ production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  2. Probing electroweak top quark couplings at hadron colliders

    SciTech Connect

    Baur, U.; Juste, A.; Orr, L.H.; Rainwater, D.

    2005-03-01

    We consider QCD tt{gamma} and ttZ production at hadron colliders as a tool to measure the tt{gamma} and ttZ couplings. At the Tevatron it may be possible to perform a first, albeit not very precise, test of the tt{gamma} vector and axial vector couplings in tt{gamma} production, provided that more than 5 fb{sup -1} of integrated luminosity are accumulated. The ttZ cross section at the Tevatron is too small to be observable. At the CERN Large Hadron Collider (LHC) it will be possible to probe the tt{gamma} couplings at the few-percent level, which approaches the precision which one hopes to achieve with a next-generation e{sup +}e{sup -} linear collider. The LHC's capability of associated QCD ttV (V={gamma},Z) production has the added advantage that the tt{gamma} and ttZ couplings are not entangled. For an integrated luminosity of 300 fb{sup -1}, the ttZ vector (axial vector) coupling can be determined with an uncertainty of 45-85% (15-20%), whereas the dimension-five dipole form factors can be measured with a precision of 50-55%. The achievable limits improve typically by a factor of 2-3 for the luminosity-upgraded (3 ab{sup -1}) LHC.

  3. Design Study for a Staged Very Large Hadron Collider

    SciTech Connect

    Chao, Alex W.

    2002-02-27

    Particle physics makes its greatest advances with experiments at the highest energy. The only sure way to advance to a higher-energy regime is through hadron colliders--the Tevatron, the LHC, and then, beyond that, a Very Large Hadron Collider. At Snowmass-1996 [1], investigators explored the best way to build a VLHC, which they defined as a 100 TeV collider. The goals in this study are different. The current study seeks to identify the best and cheapest way to arrive at frontier-energy physics, while simultaneously starting down a path that will eventually lead to the highest-energy collisions technologically possible in any accelerator using presently conceivable technology. This study takes the first steps toward understanding the accelerator physics issues, the technological possibilities and the approximate cost of a particular model of the VLHC. It describes a staged approach that offers exciting physics at each stage for the least cost, and finally reaches an energy one-hundred times the highest energy currently achievable.

  4. Precise Predictions for W + 3 Jet Production at Hadron Colliders

    SciTech Connect

    Berger, C.F.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Forde, D.; Gleisberg, T.; Ita, H.; Kosower, D.A.; Maitre, D.; /Durham U.

    2009-02-23

    We report on the first next-to-leading order QCD computation of W + 3-jet production in hadronic collisions including all partonic subprocesses. We compare the results with CDF data from the Tevatron, and find excellent agreement. The renormalization and factorization scale dependence is reduced substantially compared to leading-order calculations. The required one-loop matrix elements are computed using on-shell methods, implemented in a numerical program, BlackHat. We use the SHERPA package to generate the real-emission contributions and to integrate the various contributions over phase space. We use a leading-color (large-N{sub c}) approximation for the virtual part, which we confirm in W + 1,2-jet production to be valid to within three percent. The present calculation demonstrates the utility of on-shell methods for computing next-to-leading-order corrections to processes important to physics analyses at the Large Hadron Collider.

  5. QCD corrections to stoponium production at hadron colliders

    SciTech Connect

    Younkin, James E.; Martin, Stephen P.

    2010-03-01

    If the lighter top squark has no kinematically allowed two-body decays that conserve flavor, then it will live long enough to form hadronic bound states. The observation of the diphoton decays of stoponium could then provide a uniquely precise measurement of the top squark mass. In this paper, we calculate the cross section for the production of stoponium in a hadron collider at next-to-leading order (NLO) in QCD. We present numerical results for the cross section for production of stoponium at the LHC and study the dependence on beam energy, stoponium mass, and the renormalization and factorization scale. The cross-section is substantially increased by the NLO corrections, counteracting a corresponding decrease found earlier in the NLO diphoton branching ratio.

  6. Type II seesaw model and multilepton signatures at hadron colliders

    NASA Astrophysics Data System (ADS)

    Mitra, Manimala; Niyogi, Saurabh; Spannowsky, Michael

    2017-02-01

    We investigate multilepton signatures, arising from the decays of doubly charged and singly charged Higgs bosons in the Type II seesaw model. Depending on the vacuum expectation value of the triplet vΔ , the doubly and singly charged Higgs bosons can decay into a large variety of multilepton final states. We explore all possible decay modes corresponding to different regimes of vΔ that generate distinguishing four and five leptonic signatures. We focus on the 13 TeV Large Hadron Collider (LHC) and further extend the study to a very high energy proton-proton collider (VLHC) with a center-of-mass energy of 100 TeV. We find that a doubly charged Higgs boson of masses around 375 GeV can be discovered at immediate LHC runs. A heavier mass of 630 GeV can instead be discovered at the high-luminosity run of the LHC or at the VLHC with 30 fb-1 .

  7. Revealing Partons in Hadrons: From the ISR to the SPS Collider

    NASA Astrophysics Data System (ADS)

    Darriulat, Pierre; di Lella, Luigi

    2015-07-01

    Our understanding of the structure of hadrons has developed during the seventies and early eighties from a few vague ideas to a precise theory, Quantum Chromodynamics, that describes hadrons as made of elementary partons (quarks and gluons). Deep inelastic scattering of electrons and neutrinos on nucleons and electron-positron collisions have played a major role in this development. Less well known is the role played by hadron collisions in revealing the parton structure, studying the dynamic of interactions between partons and offering an exclusive laboratory for the direct study of gluon interactions. The present article recalls the decisive contributions made by the CERN Intersecting Storage Rings and, later, the proton-antiproton SPS Collider to this chapter of physics.

  8. NLO QCD corrections to ZZ jet production at hadron colliders

    SciTech Connect

    Binoth, T.; Gleisberg, T.; Karg, S.; Kauer, N.; Sanguinetti, G.; /Annecy, LAPTH

    2010-05-26

    A fully differential calculation of the next-to-leading order QCD corrections to the production of Z-boson pairs in association with a hard jet at the Tevatron and LHC is presented. This process is an important background for Higgs particle and new physics searches at hadron colliders. We find sizable corrections for cross sections and differential distributions, particularly at the LHC. Residual scale uncertainties are typically at the 10% level and can be further reduced by applying a veto against the emission of a second hard jet. Our results confirm that NLO corrections do not simply rescale LO predictions.

  9. A High Field Magnet Design for A Future Hadron Collider

    SciTech Connect

    Gupta, R.; Chow, K.; Dietderich, D.; Gourlay, S.; Millos, G.; McInturff, A.; Scanlan, R.

    1998-09-01

    US high energy physics community is exploring the possibilities of building a Very Large Hadron Collider (VLHC) after the completion of LHC. This paper presents a high field magnet design option based on Nb{sub 3}Sn technology. A preliminary magnetic and mechanical design of a 14-16 T, 2-in-1 dipole based on the 'common coil design' approach is presented. The computer code ROXIE has been upgraded to perform the field quality optimization of magnets based on the racetrack coil geometry. A magnet R&D program to investigate the issues related to high field magnet designs is also outlined.

  10. INTERACTION REGION LOCAL CORRECTION FOR THE LARGE HADRON COLLIDER.

    SciTech Connect

    WEI,J.; FISCHER,W.; PTITSIN,V.; OSTOJIC,R.; STRAIT,J.

    1999-03-29

    The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region (IB) quadrupoles and dipoles. In this paper we study the impact of the expected field errors of these magnets on the dynamic aperture (DA). Since the betatron phase advance is well defined for magnets that are located in regions of large beta functions, local corrections can be very effective and robust. We compare possible compensation schemes and propose a corrector layout to meet the required DA performance.

  11. Higgs boson production with heavy quarks at hadron colliders

    NASA Astrophysics Data System (ADS)

    Jackson, Christopher B.

    2005-11-01

    One of the remaining puzzles in particle physics is the origin of electroweak symmetry breaking. In the Standard Model (SM), a single doublet of complex scalar fields is responsible for breaking the SU(2) L x U(1)Y gauge symmetry thus giving mass to the electroweak gauge bosons via the Higgs mechanism and to the fermions via Yukawa couplings. The remnant of the process is a vet to he discovered scalar particle, the Higgs boson (h). However, current and future experiments at hadron colliders hold great promise. Of particular interest at hadron colliders is the production of a Higgs boson in association with a pair of heavy quarks, pp¯(pp) → QQ¯h, where Q can be either a top or a bottom quark. Indeed, the production of a Higgs boson with a pair of top quarks provides a very distinctive signal in hadronic collisions where background processes are formidable, and it will be instrumental in the discovery of a Higgs boson below about 130 GeV at the LHC. On the other hand, the production of a Higgs boson with bottom quarks can be strongly enhanced in models of new physics beyond the SM, e.g. supersymmetric models. If this is the case, bb¯h production will play a crucial role at the Tevatron where it could provide the first signal of new physics. Given the prominent role that Higgs production with heavy quarks can play at hadron colliders, it becomes imperative to have precise theoretical predictions for total and differential cross sections. In this dissertation, we outline and present detailed results for the next-to-leading order (NLO) calculation of the Quantum Chromodynamic (QCD) corrections to QQ¯h production at both the Tevatron and the LHC. This calculation involves several difficult issues due to the three massive particles in the final state, a situation which is at the frontier of radiative correction calculations in quantum field theory. We detail the novel techniques developed to deal with these challenges. The calculation of pp¯(pp) → bb¯h at NLO in

  12. Improving identification of dijet resonances at hadron colliders.

    PubMed

    Izaguirre, Eder; Shuve, Brian; Yavin, Itay

    2015-01-30

    The experimental detection of resonances has played a vital role in the development of subatomic physics. The overwhelming multijet backgrounds at the Large Hadron Collider (LHC) necessitate the invention of new techniques to identify resonances decaying into a pair of partons. In this Letter we introduce an observable that achieves a significant improvement in several key measurements at the LHC: the Higgs boson decay to a pair of b quarks; W±/Z0 vector-boson hadronic decay; and extensions of the standard model (SM) with a new hadronic resonance. Measuring the Higgs decay to b quarks is a central test of the fermion mass generation mechanism in the SM, whereas the W±/Z0 production rates are important observables of the electroweak sector. Our technique is effective in large parts of phase space where the resonance is mildly boosted and is particularly well suited for experimental searches dominated by systematic uncertainties, which is true of many analyses in the high-luminosity running of the LHC.

  13. Improving Identification of Dijet Resonances at Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Izaguirre, Eder; Shuve, Brian; Yavin, Itay

    2015-01-01

    The experimental detection of resonances has played a vital role in the development of subatomic physics. The overwhelming multijet backgrounds at the Large Hadron Collider (LHC) necessitate the invention of new techniques to identify resonances decaying into a pair of partons. In this Letter we introduce an observable that achieves a significant improvement in several key measurements at the LHC: the Higgs boson decay to a pair of b quarks; W±/Z0 vector-boson hadronic decay; and extensions of the standard model (SM) with a new hadronic resonance. Measuring the Higgs decay to b quarks is a central test of the fermion mass generation mechanism in the SM, whereas the W±/Z0 production rates are important observables of the electroweak sector. Our technique is effective in large parts of phase space where the resonance is mildly boosted and is particularly well suited for experimental searches dominated by systematic uncertainties, which is true of many analyses in the high-luminosity running of the LHC.

  14. Second-order QCD corrections to jet production at hadron colliders: the all-gluon contribution.

    PubMed

    Gehrmann-De Ridder, A; Gehrmann, T; Glover, E W N; Pires, J

    2013-04-19

    We report the calculation of next-to-next-to-leading order QCD corrections in the purely gluonic channel to dijet production and related observables at hadron colliders. Our result represents the first next-to-next-to-leading order calculation of a massless jet observable at hadron colliders, and opens the path towards precision QCD phenomenology with the LHC.

  15. Summary of the very large hadron collider physics and detector workshop

    SciTech Connect

    Anderson, G.; Berger, M.; Brandt, A.; Eno, S.

    1997-10-01

    One of the options for an accelerator beyond the LHC is a hadron collider with higher energy. Work is going on to explore accelerator technologies that would make such a machine feasible. This workshop concentrated on the physics and detector issues associated with a hadron collider with an energy in the center of mass of the order of 100 to 200 TeV.

  16. Collective accelerator for electron colliders

    SciTech Connect

    Briggs, R.J.

    1985-05-13

    A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch.

  17. Comparing Tsallis and Boltzmann temperatures from relativistic heavy ion collider and large hadron collider heavy-ion data

    NASA Astrophysics Data System (ADS)

    Gao, Y.-Q.; Liu, F.-H.

    2016-03-01

    The transverse momentum spectra of charged particles produced in Au + Au collisions at the relativistic heavy ion collider and in Pb + Pb collisions at the large hadron collider with different centrality intervals are described by the multisource thermal model which is based on different statistic distributions for a singular source. Each source in the present work is described by the Tsallis distribution and the Boltzmann distribution, respectively. Then, the interacting system is described by the (two-component) Tsallis distribution and the (two-component) Boltzmann distribution, respectively. The results calculated by the two distributions are in agreement with the experimental data of the Solenoidal Tracker At Relativistic heavy ion collider, Pioneering High Energy Nuclear Interaction eXperiment, and A Large Ion Collider Experiment Collaborations. The effective temperature parameters extracted from the two distributions on the descriptions of heavy-ion data at the relativistic heavy ion collider and large hadron collider are obtained to show a linear correlation.

  18. Acccelerator Physics Issues of a Very Large Hadron Collider

    SciTech Connect

    Chou, W.

    1997-06-01

    A Very Large Hadron Collider (VLHC) was proposed for the post-LHC future. This paper gives a quick survey of a number of accelerator physics issues based on the information obtained from a parameter spreadsheet SSP. The main technical challenges to build such a machine appear to be: the large number of events per crossing (in hundreds), enormous beam stored energy (equivalent to tens tons of TNT), ground motion (which is particularly harmful when the synchrotron frequency is in the sub-Hertz range), small dynamic aperture (due to long filling time), fast growth of the resistive wall instability (in a fraction of one turn), low threshold of the single bunch transverse instability (due to big machine size), strong synchrotron radiation (at a level close to the LEP) and short radiation damage lifetime, etc. Possible solutions to some of these problems will also be discussed.

  19. Calculations of bottom quark production at hadron colliders

    SciTech Connect

    Kuebel, D.

    1991-06-29

    This thesis studies Monte Carlo simulations of QCD heavy flavor production processes (p$\\bar{p}$ → Q($\\bar{Q}$)X) at hadron colliders. ISAJET bottom quark cross-sections are compared to the O(α$3\\atop{s}$) perturbative calculation of Nason, Dawson, and Ellis. These Monte Carlo cross-sections are computed from data samples which use different parton distribution functions and physics parameters. Distributions are presented in the heavy quark`s transverse momentum and rapidity. Correlations in rapidity and azimuthal angle are computed for the heavy flavor pair. Theory issues which arise are the behavior of the cross-section at low and high values of transverse momentum and the treatment of double counting problems in the flavor excitation samples. An important result is that ISAJET overestimates bottom quark production cross-sections and K factors. These findings are relevant for estimates of rates and backgrounds of heavy floor events.

  20. Calculations of bottom quark production at hadron colliders

    SciTech Connect

    Kuebel, D.

    1991-06-29

    This thesis studies Monte Carlo simulations of QCD heavy flavor production processes (p{bar p} {yields} Q({anti Q})X) at hadron colliders. ISAJET bottom quark cross-sections are compared to the O({alpha} {sub s}{sup 3}) perturbative calculation of Nason, Dawson, and Ellis. These Monte Carlo cross-sections are computed from data samples which use different parton distribution functions and physics parameters. Distributions are presented in the heavy quark's transverse momentum and rapidity. Correlations in rapidity and azimuthal angle are computed for the heavy flavor pair. Theory issues which arise are the behavior of the cross-section at low and high values of transverse momentum and the treatment of double counting problems in the flavor excitation samples. An important result is that ISAJET overestimates bottom quark production cross-sections and K factors. These findings are relevant for estimates of rates and backgrounds of heavy floor events.

  1. The physics of heavy quark distributions in hadrons: Collider tests

    DOE PAGES

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; ...

    2016-12-18

    Here, we present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction—the “intrinsic” quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ/Z/W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsicmore » heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.« less

  2. Flavour physics and the Large Hadron Collider beauty experiment.

    PubMed

    Gibson, Valerie

    2012-02-28

    An exciting new era in flavour physics has just begun with the start of the Large Hadron Collider (LHC). The LHCb (where b stands for beauty) experiment, designed specifically to search for new phenomena in quantum loop processes and to provide a deeper understanding of matter-antimatter asymmetries at the most fundamental level, is producing many new and exciting results. It gives me great pleasure to describe a selected few of the results here-in particular, the search for rare B(0)(s)-->μ+ μ- decays and the measurement of the B(0)(s) charge-conjugation parity-violating phase, both of which offer high potential for the discovery of new physics at and beyond the LHC energy frontier in the very near future.

  3. 120-mm supercondcting quadrupole for interaction regions of hadron colliders

    SciTech Connect

    Zlobin, A.V.; Kashikhin, V.V.; Mokhov, N.V.; Novitski, I.; /Fermilab

    2010-05-01

    Magnetic and mechanical designs of a Nb{sub 3}Sn quadrupole magnet with 120-mm aperture suitable for interaction regions of hadron colliders are presented. The magnet is based on a two-layer shell-type coil and a cold iron yoke. Special spacers made of a low-Z material are implemented in the coil mid-planes to reduce the level of radiation heat deposition and radiation dose in the coil. The quadrupole mechanical structure is based on aluminum collars supported by an iron yoke and a stainless steel skin. Magnet parameters including maximum field gradient and field harmonics, Nb3Sn coil pre-stress and protection at the operating temperatures of 4.5 and 1.9 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.

  4. Correlations of heavy quarks produced at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Younus, Mohammed; Jamil, Umme; Srivastava, Dinesh K.

    2012-02-01

    We study the correlations of heavy quarks produced in relativistic heavy-ion collisions and find them to be quite sensitive to the effects of the medium and the production mechanisms. In order to put this on a quantitative footing, as a first step, we analyze the azimuthal, transverse momentum, and rapidity correlations of heavy quark-antiquark (Q\\overline{Q}) pairs in pp collisions at {O}(α3s). This sets the stage for the identification and study of medium modification of similar correlations in the relativistic collision of heavy nuclei at the Large Hadron Collider. Next we study the additional production of charm quarks in heavy ion collisions due to multiple scatterings, namely jet-jet collisions, jet-thermal collisions, and thermal interactions. We find that these give rise to azimuthal correlations which are quite different from those arising from the prompt initial production at leading order and at next to leading order. Communicated by Professor Steffen Bass.

  5. The physics of heavy quark distributions in hadrons: Collider tests

    NASA Astrophysics Data System (ADS)

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; Smiesko, J.; Tokar, S.

    2017-03-01

    We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction-the "intrinsic" quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ / Z / W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.

  6. Precise Predictions for Z + 4 Jets at Hadron Colliders

    SciTech Connect

    Ita, H.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Kosower, D.A.; Maitre, D.

    2011-12-09

    We present the cross section for production of a Z boson in association with four jets at the Large Hadron Collider, at next-to-leading order in the QCD coupling. When the Z decays to neutrinos, this process is a key irreducible background to many searches for new physics. Its computation has been made feasible through the development of the on-shell approach to perturbative quantum field theory. We present the total cross section for pp collisions at {radical}s = 7 TeV, after folding in the decay of the Z boson, or virtual photon, to a charged-lepton pair. We also provide distributions of the transverse momenta of the four jets, and we compare cross sections and distributions to the corresponding ones for the production of a W boson with accompanying jets.

  7. Modification of Fox-Wolfram moments for hadron colliders

    NASA Astrophysics Data System (ADS)

    Spiller, L. A.

    2016-03-01

    Collisions of composite particles impose an arbitrary boost in the longitudinal direction on a given event. This implies that the centre-of-mass frame at hadron colliders is undetermined for processes with missing energy in the final state. This motivates the modification of the Fox-Wolfram moments such that the moments for a given event are identical when viewed in the lab or centre-of-mass frame of the beam. The resulting moments are invariant under rotations in the plane transverse to the beam and boosts parallel to the beam. These moments are then used to demonstrate improved signal separation in the channel where the Higgs decays to two b-quarks while being produced in association with a vector boson.

  8. Black Holes and other exotica at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglia, Marco

    2009-05-01

    If the fundamental scale of gravity is of the order of 1 TeV, black holes might be produced at the Large Hadron Collider. We present simulations of black holes and other exotic predictions of physics beyond the Standard Model - supersymmetry and string theory. Black hole events are simulated using the CATFISH Monte Carlo generator, simulations of string resonances use PYTHIA and supersymmetric simulations use a combination of ISAJET and PYTHIA. Our analysis shows that black holes can be discriminated from supersymmetry and string resonances. Isolated leptons with high transverse momentum can be used to distinguish black holes and supersymmetry. Z bosons and photons with high transverse momentum allow the discrimination of black holes and string resonances. The analysis of visible and missing energy /momenta, event-shape variables and multilepton events complement these techniques.

  9. The physics of heavy quark distributions in hadrons: Collider tests

    SciTech Connect

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; Smiesko, J.; Tokar, S.

    2016-12-18

    Here, we present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction—the “intrinsic” quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ/Z/W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.

  10. Searching for tt resonances at the CERN Large Hadron Collider

    SciTech Connect

    Baur, U.; Orr, L. H.

    2008-06-01

    Many new physics models predict resonances with masses in the TeV range which decay into a pair of top quarks. With its large cross section, tt production at the Large Hadron Collider (LHC) offers an excellent opportunity to search for such particles. We present a detailed study of the discovery potential of the CERN Large Hadron Collider for Kaluza-Klein (KK) excitations of the gluon in bulk Randall-Sundrum (RS) models in the tt{yields}l{sup {+-}}{nu}bbqq{sup '} (l=e, {mu}) final state. We utilize final states with one or two tagged b-quarks, and two, three or four jets (including b-jets). Our calculations take into account the finite resolution of detectors, the energy loss due to b-quark decays, the expected reduced b-tagging at large tt invariant masses, and include the background originating from Wbb+jets, (Wb+Wb)+jets, W+jets, and single top+jets production. We derive semirealistic 5{sigma} discovery limits for nine different KK gluon scenarios, and compare them with those for KK gravitons, and a Z{sub H} boson in the Littlest Higgs model. We also analyze the capabilities of the LHC experiments to differentiate between individual KK gluon models and measure the couplings of KK gluons to quarks. We find that, for the parameters and models chosen, KK gluons with masses up to about 4 TeV can be discovered at the LHC. The ability of the LHC to discriminate between different bulk RS models, and to measure the couplings of the KK gluons is found to be highly model dependent.

  11. Strong Electroweak Symmetry Breaking in the Large Hadron Collider Era

    NASA Astrophysics Data System (ADS)

    Evans, Jared Andrew

    2011-12-01

    With the Large Hadron Collider collecting data, both the pursuit of novel detection techniques and the exploration of new ideas are more important than ever. Novel detection techniques are essential in order for the community to garner the most worth from the machine. New ideas are needed both to expand the boundaries of what could be observed and to foster the creative mindset of the community that moves particle physics into fascinating, and often unexpected, directions. Discovering whether electroweak symmetry is broken strongly or weakly is one of the most pressing questions to be answered. Exploring the possibility of strong electroweak symmetry breaking is the topic of this work. The first of two major sectors in this work concerns the theory of conformal technicolor. We present the low energy minimal model for conformal technicolor and verify that it can satisfy current constraints from experiment. We will also provide a UV completion for this model, which realistically extends the sector with high-energy supersymmetry. Two complete models of flavor are presented. This is the first example of a complete, consistent model of strong electroweak symmetry breaking. The second of the two sectors discusses experimental signatures arising in a large class of general technicolor models at the Large Hadron Collider. The possible existence of narrow scalar states that can be produced via gluon-gluon fusion is first discussed. These states can decay into exotic final states of multiple electroweak gauge bosons, third generation particles and even light composite Higgs particles. A two Higgs doublet model is proposed as an effective way to model these exciting states. Lastly, we discuss the array of possible final states and their possible discovery.

  12. Two-photon production of leptons at hadron colliders in semielastic and elastic cases

    SciTech Connect

    Manko, A. Yu.; Shulyakovsky, R. G. E-mail: shulyakovsky@iaph.bas-net.by

    2016-03-15

    The mechanism of two-photon dilepton production is studied in the equivalent-photon (Weizsäcker–Williams) approximation. This approximation is shown to describe well experimental data from hadron accelerators. The respective total and differential cross sections were obtained for the LHC and for the Tevatron collider at various energies of colliding hadrons. The differential cross sections were studied versus the dilepton invariant mass, transverse momentum, and emission angle in the reference frame comoving with the center of mass of colliding hadrons. The cases of semielastic and inelastic collisions were examined.

  13. A new micro-strip tracker for the new generation of experiments at hadron colliders

    SciTech Connect

    Dinardo, Mauro E.

    2005-12-01

    This thesis concerns the development and characterization of a prototype Silicon micro-strip detector that can be used in the forward (high rapidity) region of a hadron collider. These detectors must operate in a high radiation environment without any important degradation of their performance. The innovative feature of these detectors is the readout electronics, which, being completely data-driven, allows for the direct use of the detector information at the lowest level of the trigger. All the particle hits on the detector can be readout in real-time without any external trigger and any particular limitation due to dead-time. In this way, all the detector information is available to elaborate a very selective trigger decision based on a fast reconstruction of tracks and vertex topology. These detectors, together with the new approach to the trigger, have been developed in the context of the BTeV R&D program; our aim was to define the features and the design parameters of an optimal experiment for heavy flavour physics at hadron colliders. Application of these detectors goes well beyond the BTeV project and, in particular, involves the future upgrades of experiments at hadron colliders, such as Atlas, CMS and LHCb. These experiments, indeed, are already considering for their future high-intensity runs a new trigger strategy a la BTeV. Their aim is to select directly at trigger level events containing Bhadrons, which, on several cases, come from the decay of Higgs bosons, Zo's or W±'s; the track information can also help on improving the performance of the electron and muon selection at the trigger level. For this reason, they are going to develop new detectors with practically the same characteristics as those of BTeV. To this extent, the work accomplished in this thesis could serve as guide-line for those upgrades.

  14. Design study for a staged Very Large Hadron Collider

    SciTech Connect

    Peter J. Limon et al.

    2001-06-26

    Advancing accelerator designs and technology to achieve the highest energies has enabled remarkable discoveries in particle physics. This report presents the results of a design study for a new collider at Fermilab that will create exceptional opportunities for particle physics--a two-stage very large hadron collider. In its first stage, the machine provides a facility for energy-frontier particle physics research, at an affordable cost and on a reasonable time scale. In a second-stage upgrade in the same tunnel, the VLHC offers the possibility of reaching 100 times the collision energy of the Tevatron. The existing Fermilab accelerator complex serves as the injector, and the collision halls are on the Fermilab site. The Stage-1 VLHC reaches a collision energy of 40 TeV and a luminosity comparable to that of the LHC, using robust superferric magnets of elegant simplicity housed in a large-circumference tunnel. The Stage-2 VLHC, constructed after the scientific potential of the first stage has been fully realized, reaches a collision energy of at least 175 TeV with the installation of high-field magnets in the same tunnel. It makes optimal use of the infrastructure developed for the Stage-1 machine, using the Stage-1 accelerator itself as the injector. The goals of this study, commissioned by the Fermilab Director in November 2000, are: to create reasonable designs for the Stage-1 and Stage-2 VLHC in the same tunnel; to discover the technical challenges and potential impediments to building such a facility at Fermilab; to determine the approximate costs of the major elements of the Stage-1 VLHC; and to identify areas requiring significant R and D to establish the basis for the design.

  15. ELECTRON COOLING AND ELECTRON-ION COLLIDERS AT BNL.

    SciTech Connect

    BEN-ZVI,I.

    2007-10-03

    Superconducting Energy Recovery Linacs (ERL) have significant potential uses in various fields, including High Energy Physics and Nuclear Physics. Brookhaven National Laboratory (BNL) is pursuing some of the potential applications in this area and the technology issues that are associated with these applications. The work addressed in this paper is carried out at BNL towards applications in electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for these applications are the generation of high currents of polarized or high-brightness unpolarized electrons, high-charge per bunch and high-current. One must address the associated issue of High-Order Modes generation and damping. Superconducting ERLs have great advantages for these applications as will be outlined in the text.

  16. Hadronic forward scattering: Predictions for the Large Hadron Collider and cosmic rays

    NASA Astrophysics Data System (ADS)

    Block, M. M.

    2006-12-01

    The status of hadron-hadron interactions is reviewed, with emphasis on the forward and near-forward scattering regions. Using unitarity, the optical theorem is derived. Analyticity and crossing symmetry, along with integral dispersion relations, are used to connect particle-particle and antiparticle-particle total cross sections and ρ-values, e.g., σpp, σ, ρpp and ρ, where ρ is the ratio of the real to the imaginary portion of the forward scattering amplitude. Real analytic amplitudes are then introduced to exploit analyticity and crossing symmetry. Again, from analyticity, finite energy sum rules (FESRs) are introduced from which new analyticity constraints are derived. These new analyticity conditions exploit the many very accurate low-energy experimental cross sections, i.e., they constrain the values of the asymptotic cross sections and their derivatives at low energies just above the resonance regions, allowing us new insights into duality. A robust fitting technique-using a minimization of the Lorentzian squared followed by the “Sieve” algorithm-is introduced in order to ‘clean up’ large data samples that are contaminated by outliers, allowing us to make much better fits to hadron-hadron scattering data over very large regions of energy. Experimental evidence for factorization theorems for γγ, γp and nucleon-nucleon collisions is presented. The Froissart bound is discussed-what do we mean here by the saturation of the Froissart bound? Using our analyticity constraints, new methods of fitting high-energy hadronic data are introduced which result in much more precise estimates of the fit parameters, allowing accurate extrapolations to much higher energies. It's shown that the γp, π±p and nucleon-nucleon cross sections all go asymptotically as ln2 s, saturating the bound, while conclusively ruling out lns and sα ( α∼0.08) behavior. Implications of this saturation for predictions of σpp and ρpp at the Large Hadron Collider (LHC) and for

  17. Low-cost hadron colliders at Fermilab: A discussion paper

    SciTech Connect

    Foster, G.W.; Malamud, E.

    1996-06-21

    New more economic approaches are required to continue the dramatic exponential rise in collider energies as represented by the well known Livingston plot. The old idea of low cost, low field iron dominated magnets in a small diameter pipe may become feasible in the next decade with dramatic recent advances in technology: (1) advanced tunneling technologies for small diameter, non human accessible tunnels, (2) accurate remote guidance systems for tunnel survey and boring machine steering, (3) high T{sub c} superconductors operating at liquid N{sub 2} or liquid H{sub 2} temperatures, (4) industrial applications of remote manipulation and robotics, (5) digitally multiplexed electronics to minimize cables, (6) achievement of high luminosities in p-p and p-{anti P} colliders. The goal of this paper is to stimulate continuing discussions on approaches to this new collider and to identify critical areas needing calculations, construction of models, proof of principle experiments, and full scale prototypes in order to determine feasibility and arrive at cost estimates.

  18. Accelerator physics in ERL based polarized electron ion collider

    SciTech Connect

    Hao, Yue

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  19. One-Loop Helicity Amplitudes for tt Production at Hadron Colliders

    SciTech Connect

    Badger, Simon; Sattler, Ralf; Yundin, Valery

    2011-04-01

    We present compact analytic expressions for all one-loop helicity amplitudes contributing to tt production at hadron colliders. Using recently developed generalized unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation.

  20. Supersymmetric dark matter in the harsh light of the Large Hadron Collider

    PubMed Central

    Peskin, Michael E.

    2015-01-01

    I review the status of the model of dark matter as the neutralino of supersymmetry in the light of constraints on supersymmetry given by the 7- to 8-TeV data from the Large Hadron Collider (LHC). PMID:25331902

  1. TOPICAL REVIEW A review of the mass measurement techniques proposed for the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Barr, Alan J.; Lester, Christopher G.

    2010-12-01

    We review the methods which have been proposed for measuring masses of new particles at the Large Hadron Collider paying particular attention to the kinematical techniques suitable for extracting mass information when invisible particles are expected.

  2. Visible Cascade Higgs Decays to Four Photons at Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Chang, Spencer; Fox, Patrick J.; Weiner, Neal

    2007-03-01

    The presence of a new singlet scalar particle a can open up new decay channels for the Higgs boson, through cascades of the form h→2a→X, possibly making discovery through standard model channels impossible. If a is CP odd, its decays are particularly sensitive to new physics. Quantum effects from heavy fields can naturally make h→4g the dominant decay which is difficult to observe at hadron colliders, and is allowed by CERN LEP for mh>82GeV. However, there are usually associated decays, either h→2g2γ or h→4γ, which are more promising. The decay h→4γ is a clean channel that can discover both a and h. At the CERN LHC with 300fb-1 of luminosity, a branching ratio of order 10-4 is sufficient for discovery for a large range of Higgs boson masses. With total luminosity of ˜8fb-1, discovery at the Fermilab Tevatron requires more than 5×10-3 in branching ratio.

  3. Dissecting multi-photon resonances at the large hadron collider

    NASA Astrophysics Data System (ADS)

    Allanach, B. C.; Bhatia, D.; Iyer, Abhishek M.

    2017-09-01

    We examine the phenomenology of the production, at the 13 TeV Large Hadron Collider (LHC), of a heavy resonance X, which decays via other new on-shell particles n into multi-(i.e. three or more) photon final states. In the limit that n has a much smaller mass than X, the multi-photon final state may dominantly appear as a two-photon final state because the γ s from the n decay are highly collinear and remain unresolved. We discuss how to discriminate this scenario from X → γ γ : rather than discarding non-isolated photons, it is better to relax the isolation criteria and instead form photon jets substructure variables. The spins of X and n leave their imprint upon the distribution of pseudo-rapidity gap Δ η between the apparent two-photon states. Depending on the total integrated luminosity, this can be used in many cases to claim discrimination between the possible spin choices of X and n, although the case where X and n are both scalar particles cannot be discriminated from the direct X → γ γ decay in this manner. Information on the mass of n can be gained by considering the mass of each photon jet.

  4. The hunt for new physics at the Large Hadron Collider.

    SciTech Connect

    AbdusSalam, S.; Adam-Bourdarios, C.; Aguilar-Saavedra, J. A.; Allanach, B.; Altunkaynak, B.; Wagner, C. E. M.

    2010-03-01

    The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem - is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades.

  5. Visible cascade Higgs decays to four photons at hadron colliders.

    PubMed

    Chang, Spencer; Fox, Patrick J; Weiner, Neal

    2007-03-16

    The presence of a new singlet scalar particle a can open up new decay channels for the Higgs boson, through cascades of the form h --> 2a --> X, possibly making discovery through standard model channels impossible. If a is CP odd, its decays are particularly sensitive to new physics. Quantum effects from heavy fields can naturally make h --> 4 g the dominant decay which is difficult to observe at hadron colliders, and is allowed by CERN LEP for m(h) > 82 GeV. However, there are usually associated decays, either h --> 2g2gamma or h --> 4gamma, which are more promising. The decay h-->4gamma is a clean channel that can discover both a and h. At the CERN LHC with 300 fb(-1) of luminosity, a branching ratio of order 10(-4) is sufficient for discovery for a large range of Higgs boson masses. With total luminosity of approximately 8 fb(-1), discovery at the Fermilab Tevatron requires more than 5 x 10(-3) in branching ratio.

  6. Precision muon tracking detectors for high-energy hadron colliders

    NASA Astrophysics Data System (ADS)

    Gadow, Ph.; Kortner, O.; Kroha, H.; Richter, R.

    2017-02-01

    Small-diameter muon drift tube (sMDT) chambers with 15 mm tube diameter are a cost-effective technology for high-precision muon tracking over large areas at high background rates as expected at future high-energy hadron colliders including HL-LHC. The chamber design and construction procedures have been optimised for mass production and provide sense wire positioning accuracy of better than 10 μm. The rate capability of the sMDT chambers has been extensively tested at the CERN Gamma Irradiation Facility. It exceeds the one of the ATLAS muon drift tube (MDT) chambers, which are operated at unprecedentedly high background rates of neutrons and γ-rays, by an order of magnitude, which is sufficient for almost the whole of the muon detector acceptance at FCC-hh at maximum luminosity. sMDT operational and construction experience exists from ATLAS muon spectrometer upgrades which are in progress or under preparation for LHC Phase 1 and 2.

  7. Resolving gluon fusion loops at current and future hadron colliders

    NASA Astrophysics Data System (ADS)

    Azatov, Aleksandr; Grojean, Christophe; Paul, Ayan; Salvioni, Ennio

    2016-09-01

    Inclusive Higgs measurements at the LHC have limited resolution on the gluon fusion loops, being unable to distinguish the long-distance contributions mediated by the top quark from possible short-distance new physics effects. Using an Effective Field Theory (EFT) approach we compare several proposed methods to lift this degeneracy, including toverline{t}h and boosted, off-shell and double Higgs production, and perform detailed projections to the High-Luminosity LHC and a future hadron collider. In addition, we revisit off-shell Higgs production. Firstly, we point out its sensitivity to modifications of the top- Z couplings, and by means of a general analysis we show that the reach is comparable to that of tree-level processes such as toverline{t}Z production. Implications for composite Higgs models are also discussed. Secondly, we assess the regime of validity of the EFT, performing an explicit comparison for a simple extension of the Standard Model containing one vector-like quark.

  8. Large hadron collider (LHC) project quality assurance plan

    SciTech Connect

    Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

    2002-09-30

    The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4).

  9. Discovering Higgs boson decays to lepton jets at hadron colliders.

    PubMed

    Falkowski, Adam; Ruderman, Joshua T; Volansky, Tomer; Zupan, Jure

    2010-12-10

    The Higgs boson may decay predominantly into a hidden sector, producing lepton jets instead of the standard Higgs signatures. We propose a search strategy for such a signal at hadron colliders. A promising channel is the associated production of the Higgs boson with a Z or W. The dominant background is Z or W plus QCD jets. The lepton jets can be discriminated from QCD jets by cutting on the electromagnetic fraction and charge ratio. The former is the fraction of jet energy deposited in the electromagnetic calorimeter and the latter is the ratio of energy carried by charged particles to the electromagnetic energy. We use a Monte Carlo description of detector response to estimate QCD rejection efficiencies of O(10⁻³) per jet. The expected 5σ (3σ) discovery reach in Higgs boson mass is ∼115 GeV (150 GeV) at the Tevatron with 10 fb⁻¹ of data and ∼110 GeV (130 GeV) at the 7 TeV LHC with 1 fb⁻¹.

  10. Using Data from the Large Hadron Collider in the Classroom

    NASA Astrophysics Data System (ADS)

    Smith, Jeremy

    2017-01-01

    Now is an exciting time for physics students, because they have access to technology and experiments all over the world that were unthinkable a generation ago. Therefore, now is also the ideal time to bring these experiments into the classroom, so students can see what cutting edge science looks like, both in terms of the underlying physics and in terms of the technology used to gather data. With the continued running of the Large Hadron Collider at CERN, and the lab's continued dedication to providing open, worldwide access to their data, there is a unique opportunity for students to use these data in a manner very similar to how it's done in the particle physics community. In this session, we will explore ways for students to analyze real data from the CMS experiment at the LHC, plot these data to discover patterns and signals, and use these plots to determine quantities such as the invariant masses of the W, Z and Higgs bosons. Furthermore, we will show how such activities already fit well into standard introductory physics classes, and can in fact enhance already-existing lessons in the topics of momentum, kinematics, energy and electromagnetism.

  11. Strange quark suppression and strange hadron production in pp collisions at energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

    SciTech Connect

    Long Haiyan; Feng Shengqin; Zhou Daimei; Yan Yuliang; Ma Hailiang; Sa Benhao

    2011-09-15

    The parton and hadron cascade model PACIAE based on PYTHIA is utilized to systematically investigate strange particle production in pp collisions at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). Globally speaking, the PACIAE results of the strange particle rapidity density at midrapidity and the transverse momentum distribution are better than those of PYTHIA (default) in comparison with STAR and ALICE experimental data. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism of strange quark suppression, added in the PACIAE model. The K/{pi} ratios as a function of reaction energy in pp collisions from CERN Super Proton Synchrotron (SPS) to LHC energies are also analyzed in this paper.

  12. Accelerator physics and technology challenges of very high energy hadron colliders

    DOE PAGES

    Shiltsev, Vladimir D.

    2015-08-20

    High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton–proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This article briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

  13. Accelerator physics and technology challenges of very high energy hadron colliders

    NASA Astrophysics Data System (ADS)

    Shiltsev, Vladimir D.

    2015-08-01

    High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton-proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

  14. Lepton jets and low-mass sterile neutrinos at hadron colliders

    NASA Astrophysics Data System (ADS)

    Dube, Sourabh; Gadkari, Divya; Thalapillil, Arun M.

    2017-09-01

    Sterile neutrinos, if they exist, are potential harbingers for physics beyond the Standard Model. They have the capacity to shed light on our flavor sector, grand unification frameworks, dark matter sector and origins of baryon antibaryon asymmetry. There have been a few seminal studies that have broached the subject of sterile neutrinos with low, electroweak-scale masses (i.e. ΛQCD≪mNR≪mW± ) and investigated their reach at hadron colliders using lepton jets. These preliminary studies nevertheless assume background-free scenarios after certain selection criteria which are overly optimistic and untenable in realistic situations. These lead to incorrect projections. The unique signal topology and challenging hadronic environment also make this mass-scale regime ripe for a careful investigation. With the above motivations, we attempt to perform the first systematic study of low, electroweak-scale, right-handed neutrinos at hadron colliders, in this unique signal topology. There are currently no active searches at hadron colliders for sterile neutrino states in this mass range, and we frame the study in the context of the 13 TeV high-luminosity Large Hadron Collider and the proposed FCC-hh/SppC 100 TeV p p -collider.

  15. A Calibration Technique for the ALICE Electromagnetic Calorimeter at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Cossyleon, Karen; Thomas, Chaan; Garcia-Solis, Edmundo; Ploskon, Mateusz; Jacobs, Peter

    2011-10-01

    The Large Hadron Collider at CERN is the world's largest and highest energy, particle and heavy ion collider. The LHC explores the frontiers of particle physics using high energy proton + proton collisions and the properties of the Quark-Gluon Plasma through the collision of heavy nuclei. ALICE is one of the four LHC experiments, specialized for the study of heavy ion collisions. This study presents our work on a detector of ALICE, the Electromagnetic Calorimeter. We are analyzing the proton-proton collision data recorded at 2.76 TeV. The ALICE TPC is used to isolate the tracks of eee- pairs that originate from the decay of J/ Ψ particle and that fall within the EMCal's acceptance. The TPC measures the momentum of these electron tracks, which is compared to the energy deposited by them in the EMCal. We therefore use the precise measurement of TPC momentum as the reference to calibrate the EMCal energy measurement. In this presentation we will show the steps taken to analyze the data, how we performed the matching of electron tracks from the J/ Ψ decay with the energy deposited in the EMCal and some preliminary results. Research funded by NSF grant PHY-0968903.

  16. Precise Predictions for W+4-Jet Production at the Large Hadron Collider

    SciTech Connect

    Berger, C. F.; Bern, Z.; Ita, H.; Dixon, L. J.; Cordero, F. Febres; Forde, D.; Gleisberg, T.; Kosower, D. A.; Maitre, D.

    2011-03-04

    We present the next-to-leading order (NLO) QCD results for W+4-jet production at hadron colliders. This is the first hadron-collider process with five final-state objects to be computed at NLO. It represents an important background to many searches for new physics at the energy frontier. Total cross sections, as well as distributions in the jet transverse momenta, are provided for the initial LHC energy of {radical}(s)=7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The calculation uses the BlackHat library along with the SHERPA package.

  17. Diffractive Higgs boson production at the Fermilab Tevatron and the CERN Large Hadron Collider.

    PubMed

    Enberg, R; Ingelman, G; Kissavos, A; Tîmneanu, N

    2002-08-19

    Improved possibilities to find the Higgs boson in diffractive events, having less hadronic activity, depend on whether the cross section is large enough. Based on the soft color interaction models that successfully describe diffractive hard scattering at DESY HERA and the Fermilab Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the CERN Large Hadron Collider.

  18. Quantitative Calculations for Black Hole Production at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bock, Nicolas; Humanic, Thomas J.

    The framework of large extra dimensions provides a way to explain why gravity is weaker than the other forces in nature. A consequence of this model is the possible production of D-dimensional black holes in high energy p-p collisions at the Large Hadron Collider. The present work uses the CATFISH black hole generator to study quantitatively how these events could be observed in the hadronic channel at midrapidity using a particle-tracking detector.

  19. Science and Technology of the TESLA Electron-Positron Linear Collider

    NASA Astrophysics Data System (ADS)

    Wagner, Albrecht

    2002-07-01

    Recent analyses of the long term future of particles physics in Asia, Europe, and the U.S.A. have led to the consensus that the next major facility to be built to unravel the secrets of the micro-cosmos is an electron-positron linear collider in the energy range of 500 to 1000 GeV. This collider should be constructed in an as timely fashion as possible to overlap with the Large Hadron Collider, under construction at CERN. Here, the scientific potential and the technological aspects of the TESLA projects, a superconducting collider with an integrated X-ray laser laboratory, are summarised.

  20. Aspects of Z boson production at higher orders at hadron colliders

    NASA Astrophysics Data System (ADS)

    Gavin, Ryan D.

    Electroweak gauge boson production is a critical component of physics studies performed at hadron colliders. It serves as a 'standard candle' at the Large Hadron Collider (LHC). In this thesis, various aspects of Z boson production at hadron colliders are considered. We introduce an improved version of the simulation code FEWZ ( Fully Exclusive W and Z Production) for hadron collider production of lepton pairs through the Drell-Yan process at next-to-next-to-leading-order in quantum chromodynamics (QCD). The program is fully differential in the phase space of leptons and additional hadronic radiation. We discuss improvements in performance and user customization through phase-space constraints and predefined histograms, illustrating the new features by presenting numerous phenomenological results for LHC physics. Considering new physics effects to electroweak gauge boson production at hadron colliders, we study the supersymmetric QCD corrections to dilepton production with an associated jet at the LHC. We investigate these effects to the integrated cross section and the kinematic distributions of the final state leptons and jet. Electroweak gauge bosons are intimately related to electroweak symmetry breaking, which is achieved in the Standard Model (SM) by the Higgs boson, a scalar particle. Extending the SM scalar sector with new color-octet scalars, we investigate the phenomenology of (8, 2)1/2 doublets by studying their properties and production mechanisms at the LHC. Studying these color-octet scalars provides a window to the underlying Yukawa structure of the scalar sector. We discuss the discovery potential of color-octet scalars at the LHC and their implications on adjoint SU(5) grand unified theories.

  1. Observation of exclusive electron-positron production in hadron-hadron collisions.

    PubMed

    Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Budroni, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Caron, B; Carosi, R; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Cyr, D; Daronco, S; D'Auria, S; Davies, T; D'Onofrio, M; Dagenhart, D; de Barbaro, P; Cecco, S De; Deisher, A; Lentdecker, G De; Dell'orso, M; Paoli, F Delli; Demortier, L; Deng, J; Deninno, M; Pedis, D De; Derwent, P F; Giovanni, G P Di; Dionisi, C; Ruzza, B Di; Dittmann, J R; Dituro, P; Dörr, C; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kovalev, A; Kraan, A C; Kraus, J; Kravchenko, I; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Manca, G; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moore, R; Morello, M; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Nachtman, J; Nagano, A; Naganoma, J; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pinfold, J; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ranjan, N; Rappoccio, S; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Sabik, S; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Saltzberg, D; Sánchez, C; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Sjolin, J; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; Denis, R St; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Veramendi, G; Veszpremi, V; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waschke, S; Waters, D; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

    2007-03-16

    We present the first observation of exclusive e(+)e(-) production in hadron-hadron collisions, using pp[over] collision data at (square root) s = 1.96 TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb(-1). We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E(T) > 5 GeV and pseudorapidity |eta| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9+/-0.3 events. These events are consistent in cross section and properties with the QED process pp[over] --> p + e(+)e(-) + p[over] through two-photon exchange. The measured cross section is 1.6(-0.3)(+0.5)(stat) +/- 0.3(syst) pb. This agrees with the theoretical prediction of 1.71+/-0.01 pb.

  2. Signatures for right-handed neutrinos at the large hadron collider.

    PubMed

    Huitu, Katri; Khalil, Shaaban; Okada, Hiroshi; Rai, Santosh Kumar

    2008-10-31

    We explore possible signatures for right-handed neutrinos in a TeV scale B-L extension of the standard model at the Large Hadron Collider. The studied four lepton signal has a tiny standard model background. We find the signal experimentally accessible at the LHC for the considered parameter regions.

  3. Signatures for Right-Handed Neutrinos at the Large Hadron Collider

    SciTech Connect

    Huitu, Katri; Rai, Santosh Kumar; Khalil, Shaaban; Okada, Hiroshi

    2008-10-31

    We explore possible signatures for right-handed neutrinos in a TeV scale B-L extension of the standard model at the Large Hadron Collider. The studied four lepton signal has a tiny standard model background. We find the signal experimentally accessible at the LHC for the considered parameter regions.

  4. Taking Energy to the Physics Classroom from the Large Hadron Collider at CERN

    ERIC Educational Resources Information Center

    Cid, Xabier; Cid, Ramon

    2009-01-01

    In 2008, the greatest experiment in history began. When in full operation, the Large Hadron Collider (LHC) at CERN will generate the greatest amount of information that has ever been produced in an experiment before. It will also reveal some of the most fundamental secrets of nature. Despite the enormous amount of information available on this…

  5. NCG gluon fusion for the Higgs production at large hadron colliders

    SciTech Connect

    Chadou, I.; Mebarki, N.; Bekli, M. R.

    2012-06-27

    A pure NCG gluon fusion contribution to the Higgs production at large hadron colliders is discussed. It is shown that the NCG results become relevant at very high energies. This can be a good signal for the space-time non commutativity events.

  6. Taking Energy to the Physics Classroom from the Large Hadron Collider at CERN

    ERIC Educational Resources Information Center

    Cid, Xabier; Cid, Ramon

    2009-01-01

    In 2008, the greatest experiment in history began. When in full operation, the Large Hadron Collider (LHC) at CERN will generate the greatest amount of information that has ever been produced in an experiment before. It will also reveal some of the most fundamental secrets of nature. Despite the enormous amount of information available on this…

  7. Physics and Analysis at a Hadron Collider - Searching for New Physics (2/3)

    ScienceCinema

    None

    2016-07-12

    This is the second lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This second lecture discusses techniques important for analyses searching for new physics using the CDF B_s --> mu+ mu- search as a specific example. The lectures are aimed at graduate students.

  8. Physics and Analysis at a Hadron Collider - Searching for New Physics (2/3)

    SciTech Connect

    2010-01-20

    This is the second lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This second lecture discusses techniques important for analyses searching for new physics using the CDF B_s --> mu+ mu- search as a specific example. The lectures are aimed at graduate students.

  9. Estimates of Hadronic Backgrounds in Future e+e- LinearColliders

    SciTech Connect

    Ohgaki, Tomomi

    1998-05-01

    We have estimated hadronic backgrounds for an e+e- linear collider at a center- of-mass energy of 5 TeV. In order to achieve a required luminosity in TeV e+ e- colliders, the high beamstrahlung parameter {Upsilon}, such as several thousands, is caused. In the high {Upsilon} regime, the {gamma}{gamma} luminosities due to the collision of beamstrahlung photons are calculated by using the CAIN code. According to the {gamma}{gamma} luminosity distribution, we have estimated the hadronic backgrounds of {gamma}{gamma} {yields} minijets based on the parton distributions of the Drees and Grassie model by the PYTHIA 5.7 code. The Japan Linear Collider (J LC-1) detector simulator is applied for selection performances in the detector.

  10. Advanced Concepts for Electron-Ion Collider

    SciTech Connect

    Yaroslav Derbenev

    2002-08-01

    A superconducting energy recovery linac (ERL) of 5 to 10 GeV was proposed earlier as an alternative to electron storage rings to deliver polarized electron beam for electron-ion collider (EIC). To enhance the utilization efficiency of electron beam from a polarized source, it is proposed to complement the ERL by circulator ring (CR) wherein the injected electrons undergo up to 100 revolutions colliding with the ion beam. In this way, electron injector and linac operate in pulsed current (beam energy recovery) regime of a relatively low average current, while the polarization is still easily delivered and preserved. To make it also easier delivering and manipulating the proton and light ion polarization, twisted (figure 8) synchrotrons are proposed for heavy particle booster and collider ring. Same type of beam orbit can be used then for electron circulator. Electron cooling (EC) of the ion beam is considered an inevitable component of high luminosity EIC (1033/s. cm2 or above). It is recognized that EC also gives a possibility to obtain very short ion bunches, that allows much stronger final focusing. At the same time, short bunches make feasible the crab crossing (and traveling focus for ion beam) at collision points, hence, allow maximizing the collision rate. As a result, one can anticipate the luminosity increase by one or two orders of magnitude.

  11. Progress towards next generation hadron colliders: FCC-hh, HE-LHC, and SPPC

    NASA Astrophysics Data System (ADS)

    Zimmermann, Frank; EuCARD-2 Extreme Beams Collaboration; Future Circular Collider (FCC) Study Collaboration

    2017-01-01

    A higher-energy circular proton collider is generally considered to be the only path available in this century for exploring energy scales well beyond the reach of the Large Hadron Collider (LHC) presently in operation at CERN. In response to the 2013 Update of the European Strategy for Particle Physics and aligned with the 2014 US ``P5'' recommendations, the international Future Circular Collider (FCC) study, hosted by CERN, is designing such future frontier hadron collider. This so-called FCC-hh will provide proton-proton collisions at a centre-of-mass energy of 100 TeV, with unprecedented luminosity. The FCC-hh energy goal is reached by combining higher-field, 16 T magnets, based on Nb3Sn superconductor, and a new 100 km tunnel connected to the LHC complex. In addition to the FCC-hh proper, the FCC study is also exploring the possibility of a High-Energy LHC (HE-LHC), with a centre-of-mass energy of 25-27 TeV, as could be achieved in the existing 27 km LHC tunnel using the FCC-hh magnet technology. A separate design effort centred at IHEP Beijing aims at developing and constructing a similar collider in China, with a smaller circumference of about 54 km, called SPPC. Assuming even higher-field 20 T magnets, by relying on high-temperature superconductor, the SPPC could reach a c.m. energy of about 70 TeV. This presentation will report the motivation and the present status of the R&D for future hadron colliders, a comparison of the three designs under consideration, the major challenges, R&D topics, the international technology programs, and the emerging global collaboration. Work supported by the European Commission under Capacities 7th Framework Programme project EuCARD-2, Grant Agreement 312453, and the HORIZON 2020 project EuroCirCol, Grant Agreement 654305.

  12. Drag of heavy quarks in quark gluon plasma at energies available at the CERN Large Hadron Collider (LHC)

    SciTech Connect

    Das, Santosh K.; Alam, Jan-e; Mohanty, Payal

    2010-07-15

    The drag and diffusion coefficients of charm and bottom quarks propagating through quark gluon plasma (QGP) have been evaluated for conditions relevant to nuclear collisions at the Large Hadron Collider (LHC). The dead cone and Landau-Pomeronchuk-Migdal (LPM) effects on radiative energy loss of heavy quarks have been considered. Both radiative and collisional processes of energy loss are included in the effective drag and diffusion coefficients. With these effective transport coefficients, we solve the Fokker-Plank (FP) equation for the heavy quarks executing Brownian motion in the QGP. The solution of the FP equation has been used to evaluate the nuclear suppression factor, R{sub AA}, for the nonphotonic single-electron spectra resulting from the semileptonic decays of hadrons containing charm and bottom quarks. The effects of mass on R{sub AA} have also been highlighted.

  13. ORAL ISSUE OF THE JOURNAL "USPEKHI FIZICHESKIKH NAUK": Physics at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Dremin, Igor M.

    2009-06-01

    The goals of the physics to be studied at the Large Hadron Collider (LHC) are very impressive. Four major experimental installations are ready to compete in obtaining and analyzing the data from high-energy hadron collisions. The main hope is to answer the most intricate questions ever asked concerning the most fundamental problems of matter and its fundamental forces and space structure. The design of the LHC and its four detectors is briefly described. We then review the main facts revealed previously by experimentalists at other accelerators. The most pertinent topics and the stage-by-stage plans for LHC investigations are discussed. Further prospects for high-energy physics are outlined.

  14. Higgs bosons, electroweak symmetry breaking, and the physics of the Large Hadron Collider

    SciTech Connect

    Quigg, Chris; /Fermilab /CERN

    2007-02-01

    The Large Hadron Collider, a 7 {circle_plus} 7 TeV proton-proton collider under construction at CERN (the European Laboratory for Particle Physics in Geneva), will take experiments squarely into a new energy domain where mysteries of the electroweak interaction will be unveiled. What marks the 1-TeV scale as an important target? Why is understanding how the electroweak symmetry is hidden important to our conception of the world around us? What expectations do we have for the agent that hides the electroweak symmetry? Why do particle physicists anticipate a great harvest of discoveries within reach of the LHC?

  15. Particle Physics after the Higgs-Boson Discovery: Opportunities for the Large Hadron Collider

    SciTech Connect

    Quigg, Chris

    2015-08-24

    The first run of the Large Hadron Collider at CERN brought the discovery of the Higgs boson, an apparently elementary scalar particle with a mass of 125 GeV, the avatar of the mechanism that hides the electroweak symmetry. Then, a new round of experimentation is beginning, with the energy of the proton–proton colliding beams raised to 6.5 TeV per beam, from 4 TeV at the end of the first run. I summarize what we have learned about the Higgs boson, and calls attention to some issues that will be among our central concerns in the near future.

  16. Particle Physics after the Higgs-Boson Discovery: Opportunities for the Large Hadron Collider

    DOE PAGES

    Quigg, Chris

    2015-08-24

    The first run of the Large Hadron Collider at CERN brought the discovery of the Higgs boson, an apparently elementary scalar particle with a mass of 125 GeV, the avatar of the mechanism that hides the electroweak symmetry. Then, a new round of experimentation is beginning, with the energy of the proton–proton colliding beams raised to 6.5 TeV per beam, from 4 TeV at the end of the first run. I summarize what we have learned about the Higgs boson, and calls attention to some issues that will be among our central concerns in the near future.

  17. The frontier of high energy physics and the large hadron collider

    SciTech Connect

    Mishra, Kalanand

    2013-09-09

    High Energy Physics explores the most fundamental questions about the nature of the universe, e.g., basic building blocks of matter and energy, existence of the smallest sub-atomic particles, dark matter, dark energy etc. The Large Hadron Collider (LHC) is the most powerful accelerator on earth located near Geneva, Switzerland. It recreates the conditions just after the Big Bang by colliding two proton beams head-on at very high energy every 25-50 nanosecond. With the recent discovery of Higgs boson, the LHC is firmly marching on to explore the TeV energy scale.

  18. The Large Hadron Collider from Conception to Commissioning: A Personal Recollection

    NASA Astrophysics Data System (ADS)

    Evans, Lyndon

    It is generally accepted that the birth of the Large Hadron Collider (LHC) was in the Lausanne Workshop in 1984 [1], where machine builders and experimentalists first got together to discuss the next big project for CERN. In reality, the seeds were sown much earlier, with the construction of the Intersecting Storage Rings at CERN, followed by the proton-antiproton colliders at CERN and at Fermilab. In this article I try to give a historical perspective on how the LHC came to be, as well as my own account of some of the political, technical and financial challenges that had to be met in order to make it a reality.

  19. TRADING STUDIES OF A VERY LARGE HADRON COLLIDER

    SciTech Connect

    RUGGIERO,A.G.

    1996-11-04

    The authors have shown that the design of the ELOISATRON can be approached in five separate steps. In this report they deal with the two major issues of the collider: the size and the strength of the superconducting magnets. The reference design of the SSC calls for a collider circumference of 86 km. It represents the largest size that until recently was judged feasible. The reference design of the LHC requires a bending field of 9 Tesla, that industries are presently determined to demonstrate. Clearly the large size of the project presents problem with magnet tolerances, and collider operation and management. The high field of the superconducting magnets needs to be demonstrated, and the high-field option in excess of 9 Tesla requires extensive research and development. It is obvious from the start that, if the ELOISATRON has to allow large beam energies, the circumference has also to be larger than that of the SSC, probably of few hundred kilometers. On the other end, Tevatron, RHIC and SSC type of superconducting magnets have been built and demonstrated on a large scale and proven to be cost effective and reliable. Their field, nevertheless, hardly can exceed a value of 7.5 Tesla, without major modifications that need to be studied. The LHC type of magnets may be capable of 9 Tesla, but they are being investigated presently by the European industries. It is desired that if one wants to keep the size of the ring under reasonable limits, a somewhat higher bending field is required for the ELOISATRON, especially if one wants also to take advantage of the synchrotron radiation effects. A field value of 13 Tesla, twice the value of the SSC superconducting magnets, has recently been proposed, but it clearly needs a robust program of research and development. This magnet will not probably be of the RHIC/SSC type and not even of the LHC type. It will have to be designed and conceived anew. In the following they examine two possible approaches. In the first approach

  20. Electroweak and flavor dynamics at hadron colliders - I

    SciTech Connect

    Elchtent, E.; Lane, K.

    1998-02-01

    This is the first of two reports cataloging the principal signatures of electroweak and flavor dynamics at {anti p}p and pp colliders. Here, we discuss some of the signatures of dynamical electroweak and flavor symmetry breaking. The framework for dynamical symmetry breaking we assume is technicolor, with a walking coupling {alpha}{sub TC}, and extended technicolor. The reactions discussed occur mainly at subprocess energies {radical}{cflx s}{approx_lt} 1 TeV. They include production of color-singlet and octet technirhos and their decay into pairs of technipions, longitudinal weak bosons, or jets. Technipions, in turn, decay predominantly into heavy fermions. This report will appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics (Snowmass 96).

  1. Shielding calculations for multi-TeV hadron colliders

    SciTech Connect

    Van Ginneken, A.; Yurista, P.; Yamaguchi, C.

    1987-01-01

    The present volume is most easily described as an extension of an earlier similar effort. The extension is mainly to higher energies but it also includes colliding beam simulations as well as muon production and transport. There is also a larger variety of geometries presented. But the purpose remains the same: to provide a collection of graphs which may serve as a rough guide in shielding applications. Detailed designs seldom resemble the idealized cases analyzed here and deserve specific computation with particular attention to any suspected weak spots. The graphs included here are intended to go no further than to form a useful starting point in design work. Such an approach is already quite effective at 1 TeV and below and will become even more so at higher energies where shielding costs are even larger. The choice of standard energies (5, 10 and 20 TeV) reflects the range of collider energies presently contemplated and allows for modest extrapolation outside this range. For fixed target results up to 1 TeV refs. 1 and 2 may be consulted. As in refs. 1 and 2, all results in this volume (except those pertaining to ``muon beams``) use the Monte Carlo code CASIM. Where {pi}{degrees} induced electromagnetic showers are included as, e.g., in muon production or in energy deposition, they are simulated with the AEGIS code. Predictions of CASIM (plus AEGIS where applicable) for target heating, induced radioactivity and absorbed dose in the sub-TeV regime agree quite well with experiment. Likewise CASIM results compare well with a set of absorbed dose measurements taken outside thick shields for a variety of beam loss and shielding geometries. The full extension of CASIM into the multi-TeV domain requires considerable modifications to both particle production and particle transport models. This extension is presently only partly completed.

  2. Gluon-gluon contributions to the production of continuum diphoton pairs at hadron colliders

    NASA Astrophysics Data System (ADS)

    Nadolsky, P. M.; Balázs, C.; Berger, E. L.; Yuan, C.-P.

    2007-07-01

    We compute the contributions to continuum photon pair production at hadron colliders from processes initiated by gluon-gluon and gluon-quark scattering into two photons through a four-leg virtual quark loop. Complete two-loop cross sections in perturbative quantum chromodynamics are combined with contributions from soft parton radiation resummed to all orders in the strong coupling strength. The structure of the resummed cross section is examined in detail, including a new type of unintegrated parton distribution function affecting azimuthal angle distributions of photons in the pair’s rest frame. As a result of this analysis, we predict diphoton transverse-momentum distributions in gluon-gluon scattering in wide ranges of kinematic parameters at the Fermilab Tevatron and the CERN Large Hadron Collider.

  3. Thermal Photon Radiation in High Multiplicity p+Pb Collisions at the Large Hadron Collider

    DOE PAGES

    Shen, Chun; Paquet, Jean-François; Denicol, Gabriel S.; ...

    2016-02-18

    We observed the collective behavior of hadronic particles in high multiplicity proton-lead collisions at the Large Hadron Collider, as well as in deuteron-gold collisions at the Relativistic Heavy-Ion Collider. In our work we present the first calculation, in the hydrodynamic framework, of thermal photon radiation from such small collision systems. Owing to their compact size, these systems can reach temperatures comparable to those in central nucleus-nucleus collisions. Moreover, the thermal photons can thus shine over the prompt background, and increase the low pT direct photon spectrum by a factor of 2–3 in 0%–1% p+Pb collisions at 5.02 TeV. This thermalmore » photon enhancement can therefore serve as a signature of the existence of a hot quark-gluon plasma during the evolution of these small collision systems, as well as validate hydrodynamic behavior in small systems.« less

  4. Highly Parallelized Pattern Matching Hardware for Fast Tracking at Hadron Colliders

    NASA Astrophysics Data System (ADS)

    Citraro, S.; Annovi, A.; Biesuz, N.; Giannetti, P.; Luciano, P.; Nasimi, H.; Piendibene, M.; Sotiropoulou, C.-L.; Volpi, G.

    2016-04-01

    A high-performance “pattern matching” implementation based on the Associative Memory (AM) system is presented. It is designed to solve the real-time hit-to-track association problem for particles produced in high-energy physics experiments at hadron colliders. The processing time of pattern recognition in CPU-based algorithms increases rapidly with the detector occupancy due to the limited computing power and input-output capacity of hardware available on the market. The AM system presented here solves the problem by being able to process even the most complex hadron collider events produced at a rate of 100 kHz with an average latency smaller than 10 μs. The board built for this goal is able to execute 12 petabyte comparisons per second, with peak power consumption below 250 W, uniformly distributed on the large area of the board.

  5. An energy recovery electron linac-on-ring collider

    SciTech Connect

    Merminga, L.; Krafft, G.A.; Lebedev, V.A.; Ben-Zvi, I.

    2000-09-14

    We present the design of high-luminosity electron-proton/ion colliders in which the electrons are produced by an Energy Recovering Linac (ERL). Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10{sup 33}(per nucleon) level have been proposed recently as a means for studying hadronic structure. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations (2) reduction of the synchrotron radiation load in the detectors (3) a wide range of continuous energy variability. Rf power and beam dump considerations require that the electron linac recover the beam energy. Based on extrapolations from actual measurements and calculations, energy recovery is expected to be feasible at currents of a few hundred mA and multi-GeV energies. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented. The feasibility of an energy recovery electron linac-on-proton ring collider is investigated and four conceptual point designs are shown corresponding to electron to proton energies of: 3 GeV on 15 GeV, 5 GeV on 50 GeV and 10 GeV on 250 GeV, and for gold ions with 100 GeV/A. The last two designs assume that the protons or ions are stored in the existing RHIC accelerator. Accelerator physics issues relevant to proton rings and energy recovery linacs are discussed and a list of required R and D for the realization of such a design is presented.

  6. Nucleon Decay and Neutrino Experiments, Experiments at High Energy Hadron Colliders, and String Theor

    SciTech Connect

    Jung, Chang Kee; Douglas, Michaek; Hobbs, John; McGrew, Clark; Rijssenbeek, Michael

    2013-07-29

    This is the final report of the DOE grant DEFG0292ER40697 that supported the research activities of the Stony Brook High Energy Physics Group from November 15, 1991 to April 30, 2013. During the grant period, the grant supported the research of three Stony Brook particle physics research groups: The Nucleon Decay and Neutrino group, the Hadron Collider Group, and the Theory Group.

  7. Probing neutrino oscillations in supersymmetric models at the Large Hadron Collider

    SciTech Connect

    Campos, F. de; Eboli, O. J. P.; Hirsch, M.; Valle, J. W. F.; Porod, W.

    2010-10-01

    The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation.

  8. Physics and Analysis at a Hadron Collider - Making Measurements (3/3)

    ScienceCinema

    None

    2016-07-12

    This is the third lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This third lecture discusses techniques important for analyses making a measurement (e.g. determining a cross section or a particle property such as its mass or lifetime) using some CDF top-quark analyses as specific examples. The lectures are aimed at graduate students.

  9. Next-to-Leading-Order QCD Corrections to tt+jet Production at Hadron Colliders

    SciTech Connect

    Dittmaier, S.; Uwer, P.; Weinzierl, S.

    2007-06-29

    We report on the calculation of the next-to-leading-order QCD corrections to the production of top-quark-top-antiquark pairs in association with a hard jet at the Fermilab Tevatron and the CERN Large Hadron Collider. We present results for the tt+jet cross section and the forward-backward charge asymmetry. The corrections stabilize the leading-order prediction for the cross section. The charge asymmetry receives large corrections.

  10. Next-to-Leading-Order QCD Corrections to WW+Jet Production at Hadron Colliders

    SciTech Connect

    Dittmaier, S.; Kallweit, S.; Uwer, P.

    2008-02-15

    We report on the calculation of the next-to-leading-order QCD corrections to the production of W-boson pairs in association with a hard jet at the Fermilab Tevatron and CERN Large Hadron Collider, which is an important source of background for Higgs boson and new-physics searches. The corrections stabilize the leading-order prediction for the cross section considerably, in particular, if a veto against the emission of a second hard jet is applied.

  11. Lattices for a high-field 30 TeV hadron collider

    SciTech Connect

    Peggs, S.; Dell, F.; Harrison, M.; Syphers, M.; Tepikian, S.

    1996-12-01

    Long arc cells would lead to major cost savings in a high field high T{sub c} hadron collider, operating in the regime of significant synchrotron radiation. Two such lattices, with half cell lengths of 110 and 260 m, are compared. Both allow flexible tuning, and have large dynamic apertures when dominated by chromatic sextupoles. Lattices with longer cells are much more sensitive to systematic magnet errors, which are expected to dominate.

  12. Determining the structure of Higgs couplings at the CERN LargeHadron Collider.

    PubMed

    Plehn, Tilman; Rainwater, David; Zeppenfeld, Dieter

    2002-02-04

    Higgs boson production via weak boson fusion at the CERN Large Hadron Collider has the capability to determine the dominant CP nature of a Higgs boson, via the tensor structure of its coupling to weak bosons. This information is contained in the azimuthal angle distribution of the two outgoing forward tagging jets. The technique is independent of both the Higgs boson mass and the observed decay channel.

  13. Study of vector boson decay and determination of the Standard Model parameters at hadronic colliders

    SciTech Connect

    Amidei, D.

    1991-01-11

    The power of the detectors and the datasets at hadronic colliders begins to allow measurement of the electroweak parameters with a precision that confronts the perturbative corrections to the theory. Recent measurements of M{sub z}, M{sub w}, and sin {theta}{sub w} by CDF and UA2 are reviewed, with some emphasis on how experimental precision is achieved, and some discussion of the import for the specifications of the Standard Model. 14 refs., 10 figs., 4 tabs.

  14. Discriminating supersymmetry and black holes at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglià, Marco

    2008-03-01

    We show how to differentiate the minimal supersymmetric extension of the standard model from black hole events at the CERN Large Hadron Collider. Black holes are simulated with the CATFISH generator. Supersymmetry simulations use a combination of pythia and isajet. Our study, based on event-shape variables, visible and missing momenta, and analysis of dilepton events, demonstrates that supersymmetry and black hole events at the LHC can be easily discriminated.

  15. [Calorimeter based detectors for high energy hadron colliders]. [Progress report

    SciTech Connect

    Not Available

    1992-08-04

    This document provides a progress report on research that has been conducted under DOE Grant DEFG0292ER40697 for the past year, and describes proposed work for the second year of this 8 year grant starting November 15, 1992. Personnel supported by the contract include 4 faculty, 1 research faculty, 4 postdocs, and 9 graduate students. The work under this grant has in the past been directed in two complementary directions -- DO at Fermilab, and the second SSC detector GEM. A major effort has been towards the construction and commissioning of the new Fermilab Collider detector DO, including design, construction, testing, the commissioning of the central tracking and the central calorimeters. The first DO run is now underway, with data taking and analysis of the first events. Trigger algorithms, data acquisition, calibration of tracking and calorimetry, data scanning and analysis, and planning for future upgrades of the DO detector with the advent of the FNAL Main Injector are all involved. The other effort supported by this grant has been towards the design of GEM, a large and general-purpose SSC detector with special emphasis on accurate muon measurement over a large solid angle. This effort will culminate this year in the presentation to the SSC laboratory of the GEM Technical Design Report. Contributions are being made to the detector design, coordination, and physics simulation studies with special emphasis on muon final states. Collaboration with the RD5 group at CERN to study muon punch through and to test cathode strip chamber prototypes was begun.

  16. Electron Cloud Effect in the Linear Colliders

    SciTech Connect

    Pivi, M

    2004-09-13

    Beam induced multipacting, driven by the electric field of successive positively charged bunches, may arise from a resonant motion of electrons, generated by secondary emission, bouncing back and forth between opposite walls of the vacuum chamber. The electron-cloud effect (ECE) has been observed or is expected at many storage rings [1]. In the beam pipe of the Damping Ring (DR) of a linear collider, an electron cloud is produced initially by ionization of the residual gas and photoelectrons from the synchrotron radiation. The cloud is then sustained by secondary electron emission. This electron cloud can reach equilibrium after the passage of only a few bunches. The electron-cloud effect may be responsible for collective effects as fast coupled-bunch and single-bunch instability, emittance blow-up or incoherent tune shift when the bunch current exceeds a certain threshold, accompanied by a large number of electrons in the vacuum chamber. The ECE was identified as one of the most important R&D topics in the International Linear Collider Report [2]. Systematic studies on the possible electron-cloud effect have been initiated at SLAC for the GLC/NLC and TESLA linear colliders, with particular attention to the effect in the positron main damping ring (MDR) and the positron Low Emittance Transport which includes the bunch compressor system (BCS), the main linac, and the beam delivery system (BDS). We present recent computer simulation results for the main features of the electron cloud generation in both machine designs. Thus, single and coupled-bunch instability thresholds are estimated for the GLC/NLC design.

  17. Enhancing the heavy Higgs boson [r arrow][ital WW] signal at hadron-hadron colliders

    SciTech Connect

    Field, R.D.; Griffin, P.A. )

    1994-07-01

    The jet-jet profile methods that we developed to enhance the heavy Higgs boson [r arrow][ital ZZ] signal over its backgrounds at a proton-proton collider energy of 40 TeV are extended to the heavy Higgs boson [r arrow][ital WW] signal and backgrounds. The dominant background is now the pair production of top quarks via the subprocess [ital gg][r arrow][ital t[bar t

  18. Planning and Realization of an Electron Ion Collider

    NASA Astrophysics Data System (ADS)

    Vigdor, Steven

    2009-10-01

    According to the 2007 Nuclear Physics Long Range Plan, ``An EIC with polarized beams has been embraced by the U.S. nuclear science community as embodying the vision for reaching the next QCD frontier.'' I will discuss the open questions of science, technology and strategy that are being addressed in order to convince the community to endorse a high priority for construction of such a facility in the next Long Range Plan. Both Brookhaven National Laboratory and Jefferson Lab have designs built upon their present facilities to achieve eventually an EIC with polarized electron beams up to 10-20 GeV colliding with polarized proton beams up to 250 GeV and with beams of heavy nuclei up to 100 GeV/nucleon. Both designs have introduced staging options that would achieve lower collision energies at a fraction of the full cost. I will discuss the science reach of an EIC as a function of its energy and luminosity goals, initial rough cost estimates for various designs, and the accelerator and detector research and development being launched to demonstrate technical feasibility of the ambitious design goals. I will also place these plans in the broader context of international discussions of possible electron-hadron colliders of both much lower and much higher energy.

  19. Radiation Damage Studies with Hadrons on Materials and Electronics

    SciTech Connect

    Spencer, J

    2004-07-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and {gamma}'s over their life[1]. Examples are NdFeB magnets considered for the damping rings and final focus, electronic and electro-optical devices to be utilized in detector readout and accelerator controls and CCDs required for the vertex detector. Effects of {gamma}'s on many materials have been presented[2] and our understanding of the situation for rare earth permanent magnets at PAC2003[3]. Here we give first measurements of the fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) together with the induced radioactivities. Damage appears to be proportional to the distances between the operating point and H{sub ci}.

  20. Hadrons from coalescence plus fragmentation in A A collisions at energies available at the BNL Relativistic Heavy Ion Collider to the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Minissale, Vincenzo; Scardina, Francesco; Greco, Vincenzo

    2015-11-01

    In a coalescence plus independent fragmentation approach we calculate the pT spectra of the main hadrons: π ,K ,p ,p ¯,Λ ,ϕ in a wide range of transverse momentum from low pT up to about 10 GeV. The approach in its main features was developed several years ago at Relativistic Heavy Ion Collider (RHIC) energy. Augmenting the model with the inclusion of some more main resonance decays, we show that the approach correctly predicts the evolution of the pT spectra from RHIC to LHC (Large Hadron Collider) energy and in particular the baryon-to-meson ratios p /π ,p ¯/π ,Λ /K that reach a value of the order of unit at pT˜3 GeV . This is achieved without any change of the coalescence parameters. The more recent availability of experimental data up to pT˜10 GeV for Λ spectrum as well as for p /π and Λ /K shows some lack of yield in a limited pT range around 6 GeV. This indicates that the baryons pT spectra from Albino-Kniehl-Kramer fragmentation functions are too flat at pT≲8 GeV . We also show that in a coalescence plus fragmentation approach one predicts a nearly pT independent p /ϕ ratio up to pT˜4 GeV followed by a significant decrease at higher pT. Such a behavior is driven by a similar radial flow effect at pT<2 GeV and the dominance of fragmentation for ϕ at larger pT.

  1. Muon colliders

    SciTech Connect

    Palmer, R.B. |; Sessler, A.; Skrinsky, A.

    1996-01-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity {micro}{sup +}{micro}{sup {minus}}colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed.

  2. Muon colliders

    NASA Astrophysics Data System (ADS)

    Palmer, R. B.; Sessler, A.; Skrinsky, A.; Tollestrup, A.; Baltz, A. J.; Chen, P.; Cheng, W.-H.; Cho, Y.; Courant, E.; Fernow, R. C.; Gallardo, J. C.; Garren, A.; Green, M.; Kahn, S.; Kirk, H.; Lee, Y. Y.; Mills, F.; Mokhov, N.; Morgan, G.; Neuffer, D.; Noble, R.; Norem, J.; Popovic, M.; Schachinger, L.; Silvestrov, G.; Summers, D.; Stumer, I.; Syphers, M.; Torun, Y.; Trbojevic, D.; Turner, W.; Van Ginneken, A.; Vsevolozhskaya, T.; Weggel, R.; Willen, E.; Winn, D.; Wurtele, J.

    1996-05-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity μ+μ- colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed.

  3. Observation of Exclusive Electron-Positron Production in Hadron-Hadron Collisions

    SciTech Connect

    Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.

    2006-11-01

    We present the first observation of exclusive e{sup +}e{sup -} production in hadron-hadron collisions, using p{bar p} collision data at {radical}s = 1.96 TeV taken by the Run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb{sup -1}. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E{sub T} > 5 GeV and pseudorapidity |{eta}| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9 {+-} 0.3 events. These events are consistent in cross section and properties with the QED process p{bar p} {yields} p + e{sup +}e{sup -} + {bar p} through two-photon exchange. The measured cross section is 1.6{sub -0.3}{sup +0.5}(stat) {+-} 0.3(syst) pb. This agrees with the theoretical prediction of 1.71 {+-} 0.01 pb.

  4. Theoretical studies of hadronic calorimetry for high luminosity, high energy colliders

    SciTech Connect

    Brau, J.E.; Gabriel, T.A.

    1989-01-01

    Experiments at the high luminosity, high energy colliders of the future are going to demand optimization of the state of the art of calorimetry design and construction. During the past few years, the understanding of the basic phenomenology of hadron calorimeters has advanced through paralleled theoretical and experimental investigations. The important underlying processes are reviewed to set the framework for the presentation of recent calculations of the expected performance of silicon detector based hadron calorimeters. Such devices employing uranium are expected to achieve the compensation condition (that is, e/h approx. 1.0) based on the understanding that has been derived from the uranium-liquid argon and uranium-plastic scintillator systems. In fact, even lead-silicon calorimeters are found to achieve the attractive value for the e/h ratio of 1.16 at 10 GeV. 62 refs., 22 figs., 3 tabs.

  5. Test of Relativistic Gravity for Propulsion at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Felber, Franklin

    2010-01-01

    A design is presented of a laboratory experiment that could test the suitability of relativistic gravity for propulsion of spacecraft to relativistic speeds. An exact time-dependent solution of Einstein's gravitational field equation confirms that even the weak field of a mass moving at relativistic speeds could serve as a driver to accelerate a much lighter payload from rest to a good fraction of the speed of light. The time-dependent field of ultrarelativistic particles in a collider ring is calculated. An experiment is proposed as the first test of the predictions of general relativity in the ultrarelativistic limit by measuring the repulsive gravitational field of bunches of protons in the Large Hadron Collider (LHC). The estimated `antigravity beam' signal strength at a resonant detector of each proton bunch is 3 nm/s2 for 2 ns during each revolution of the LHC. This experiment can be performed off-line, without interfering with the normal operations of the LHC.

  6. Probing charged Higgs boson couplings at a future circular hadron collider

    NASA Astrophysics Data System (ADS)

    Ćakır, I. T.; Kuday, S.; Saygın, H.; Şenol, A.; ćakır, O.

    2016-07-01

    Many of the new physics models predict a light Higgs boson similar to the Higgs boson of the Standard Model (SM) and also extra scalar bosons. Beyond the search channels for a SM Higgs boson, the future collider experiments will explore additional channels that are specific to extended Higgs sectors. We study the charged Higgs boson production within the framework of two Higgs doublet models (THDM) in the proton-proton collisions at a future circular hadron collider (FCC-hh). With an integrated luminosity of Lint=500 fb-1 at very high energy frontier (√{s }=100 TeV ), we obtain a significant coverage of the parameter space and distinguish the charged Higgs-top-bottom interaction within the THDM or other new physics models with charged Higgs boson mass up to 1.5 TeV.

  7. Light minimal supersymmetric standard model Higgs boson scenario and its test at hadron colliders.

    PubMed

    Belyaev, Alexander; Cao, Qing-Hong; Nomura, Daisuke; Tobe, Kazuhiro; Yuan, C-P

    2008-02-15

    We show that, in the minimal supersymmetric standard model, the possibility for the lightest CP-even Higgs boson to be lighter than Z boson (as low as about 60 GeV) is, contrary to the usual belief, not yet excluded by the CERN LEP2 Higgs search nor any direct searches for supersymmetric particles at high energy colliders. The characteristic of the light Higgs boson scenario (LHS) is that the ZZh coupling and the decay branching ratio Br(h/A-->bb) are simultaneously suppressed as a result of generic supersymmetric loop corrections. Consequently, the W(+/-)H(-/+)h coupling has to be large due to the sum rule of Higgs couplings to weak gauge bosons. We discuss the potential of the Fermilab Tevatron and B factories to test the LHS, and show that the associated neutral and charged Higgs boson production process, pp-->H(+/-)h(A), can completely probe the LHS at the CERN Large Hadron Collider.

  8. Boosting Higgs CP properties via VH production at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Godbole, Rohini; Miller, David J.; Mohan, Kirtimaan; White, Chris D.

    2014-03-01

    We consider ZH and WH production at the Large Hadron Collider, where the Higgs decays to a bbbar pair. We use jet substructure techniques to reconstruct the Higgs boson and construct angular observables involving leptonic decay products of the vector bosons. These efficiently discriminate between the tensor structure of the HVV vertex expected in the Standard Model and that arising from possible new physics, as quantified by higher dimensional operators. This can then be used to examine the CP nature of the Higgs as well as CP mixing effects in the HZZ and HWW vertices separately.

  9. Observable T{sub 7} Lepton Flavor Symmetry at the Large Hadron Collider

    SciTech Connect

    Cao Qinghong; Khalil, Shaaban; Ma, Ernest; Okada, Hiroshi

    2011-04-01

    More often than not, models of flavor symmetry rely on the use of nonrenormalizable operators (in the guise of flavons) to accomplish the phenomenologically successful tribimaximal mixing of neutrinos. We show instead how a simple renormalizable two-parameter neutrino mass model of tribimaximal mixing can be constructed with the non-Abelian discrete symmetry T{sub 7} and the gauging of B-L. This is also achieved without the addition of auxiliary symmetries and particles present in almost all other proposals. Most importantly, it is verifiable at the Large Hadron Collider.

  10. Diphoton signals in theories with large extra dimensions to NLO QCD at hadron colliders

    NASA Astrophysics Data System (ADS)

    Kumar, M. C.; Mathews, Prakash; Ravindran, V.; Tripathi, Anurag

    2009-02-01

    We present a full next-to-leading order (NLO) QCD corrections to diphoton production at the hadron colliders in both standard model and ADD model. The invariant mass and rapidity distributions of the diphotons are obtained using a semi-analytical two cut-off phase space slicing method which allows for a successful numerical implementation of various kinematical cuts used in the experiments. The fragmentation photons are systematically removed using smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only stabilise the perturbative predictions but also enhance the production cross section significantly.

  11. Accurate crab cavity modeling for the high luminosity Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Brett, D. R.; Appleby, R. B.; De Maria, R.; Garcia, J. Barranco; Garcia, R. Tomás; Hall, B.; Burt, G.

    2014-10-01

    As part of the Large Hadron Collider high luminosity upgrade it is proposed to include crab cavities in the lattice in order to enhance the luminosity. For one proposed cavity design the dynamics of the cavity is considered in terms of its impact upon the dynamic aperture of the machine. Taylor maps of the cavity are created and used to perform this analysis with a full assessment of their validity. Furthermore from these Taylor maps, symplectic methods are developed further, guided by the knowledge gained in the study of the physics contained in them.

  12. Transverse-momentum resummation for top-quark pairs at hadron colliders.

    PubMed

    Zhu, Hua Xing; Li, Chong Sheng; Li, Hai Tao; Shao, Ding Yu; Yang, Li Lin

    2013-02-22

    We develop a framework for a systematic resummation of the transverse momentum distribution of top-quark pairs produced at hadron colliders based on effective field theory. Compared to Drell-Yan and Higgs production, a novel soft function matrix is required to account for the soft gluon emissions from the final states. We calculate this soft function at the next-to-leading order, and perform the resummation at the next-to-next-to-leading logarithmic accuracy. We compare our results with parton shower programs and with the experimental data at the Tevatron and the LHC. We also discuss the implications for the top quark charge asymmetry.

  13. Electroweak corrections to top quark pair production in association with a hard photon at hadron colliders

    NASA Astrophysics Data System (ADS)

    Duan, Peng-Fei; Zhang, Yu; Wang, Yong; Song, Mao; Li, Gang

    2017-03-01

    We present the next-to-leading order (NLO) electroweak (EW) corrections to the top quark pair production associated with a hard photon at the current and future hadron colliders. The dependence of the leading order (LO) and NLO EW corrected cross sections on the photon transverse momentum cut are investigated. We also provide the LO and NLO EW corrected distributions of the transverse momentum of final top quark and photon and the invariant mass of top quark pair and top-antitop-photon system. The results show that the NLO EW corrections are significant in high energy regions due to the EW Sudakov effect.

  14. W production at large transverse momentum at the CERN Large Hadron Collider.

    PubMed

    Gonsalves, Richard J; Kidonakis, Nikolaos; Sabio Vera, Agustín

    2005-11-25

    We study the production of W bosons at large transverse momentum in pp collisions at the CERN Large Hadron Collider. We calculate the complete next-to-leading order (NLO) corrections to the differential cross section. We find that the NLO corrections provide a large increase to the cross section but, surprisingly, do not reduce the scale dependence relative to leading order (LO). We also calculate next-to-next-to-leading-order (NNLO) soft-gluon corrections and find that, although they are small, they significantly reduce the scale dependence thus providing a more stable result.

  15. Lower limit on dark matter production at the CERN Large Hadron Collider.

    PubMed

    Feng, Jonathan L; Su, Shufang; Takayama, Fumihiro

    2006-04-21

    We evaluate the prospects for finding evidence of dark matter production at the CERN Large Hadron Collider. We consider weakly interacting massive particles (WIMPs) and superWIMPs and characterize their properties through model-independent parametrizations. The observed relic density then implies lower bounds on dark matter production rates as functions of a few parameters. For WIMPs, the resulting signal is indistinguishable from background. For superWIMPs, however, this analysis implies significant production of metastable charged particles. For natural parameters, these rates may far exceed Drell-Yan cross sections and yield spectacular signals.

  16. Testing the handedness of a heavy {ital W}{prime} at future hadron colliders

    SciTech Connect

    Cvetic, M.; Langacker, P.; Liu, J.

    1994-03-01

    We show that the associated production {ital pp}{r_arrow}{ital W}{prime}{ital W} and the rare dec at future hadron colliders. For {ital M}{sub {ital W}{prime}}{similar_to}(1--3) TeV they would allow a clean determination on whether the {ital W}{prime} couples to {ital V}{minus}{ital A} or {ital V}+{ital A} currents. As an illustration a model in which the {ital W}{prime}{sup {plus_minus}} couples only to {ital V}{minus}{ital A} currents is contrasted with the left-right-symmetric models which involve {ital V}+{ital A} currents.

  17. Nonlinear damping of coherent transverse oscillations of a beam in hadron cyclic accelerators and colliders

    NASA Astrophysics Data System (ADS)

    Ivanov, I. N.; Melnikov, V. A.

    1997-02-01

    The correlation between the requirements for the quality of a beam and parameters of systems of damping of transverse coherent oscillations for modern hadron accelerators and colliders is considered. Special attention is directed to systems in which the signal in the kicker is not proportional to the signal of the pickup. It is shown that a nonlinear mode of suppression can provide a greater damping rate. Limiting beam blow-up at injection and accumulation is made possible by an appropriate choice of the discrimination level of the pickup signal.

  18. Kinematical Correlations for Higgs Boson Plus High P_{T} Jet Production at Hadron Colliders.

    PubMed

    Sun, Peng; Yuan, C-P; Yuan, Feng

    2015-05-22

    We investigate the effect of QCD resummation to kinematical correlations in the Higgs boson plus high transverse momentum (P(T)) jet events produced at hadron colliders. We show that at the complete one-loop order, the Collins-Soper-Sterman resummation formalism can be applied to derive the Sudakov form factor. We compare the singular behavior of resummation calculation to fixed order prediction in the case that a Higgs boson and high P(T) jet are produced nearly back to back in their transverse momenta, and find perfect agreement. The phenomenological importance of the resummation effect at the LHC is also demonstrated.

  19. Probing New Physics with Jets at the Large Hadron Collider (LHC)

    SciTech Connect

    Harris, Robert

    2007-08-29

    The Large Hadron Collider at CERN has the potential to make a major discovery as early as 2008 from simple measurements of events with two high energy jets. This talk will present the jet trigger and analysis plans of the CMS collaboration, which were produced at the LHC Physics Center at Fermilab. Plans to search the two jet channel for generic signals of new particles and forces will be discussed. I will present the anticipated sensitivity of the CMS experiment to a variety of models of new physics, including quark compositeness, technicolor, superstrings, extra dimensions and grand unification.

  20. Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider

    SciTech Connect

    Sun, Y.; Calaga, R.; Assmann, R.; Barranco, J.; Tomas, R.; Weiler, T.; Zimmermann, F.; Morita, A.

    2009-10-14

    Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The long-range beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing a crossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit, also degrade the collimation cleaning efficiency, and so on. In this paper, we explore the principal feasibility of LHC crab cavities from a beam dynamics point of view. The implications of the crab cavities for the LHC optics, analytical and numerical luminosity studies, dynamic aperture, aperture and beta beating, emittance growth, beam-beam tune shift, long-range collisions, and synchrobetatron resonances, crab dispersion, and collimation efficiency will be discussed.

  1. Quark-Hadron Duality in Electron Scattering

    SciTech Connect

    Wally Melnitchouk; Rolf Ent; Cynthia Keppel

    2004-08-01

    The duality between partonic and hadronic descriptions of physical phenomena is one of the most remarkable features of strong interaction physics. A classic example of this is in electron-nucleon scattering, in which low-energy cross sections, when averaged over appropriate energy intervals, are found to exhibit the scaling behavior expected from perturbative QCD. We present a comprehensive review of data on structure functions in the resonance region, from which the global and local aspects of duality are quantified, including its flavor, spin and nuclear medium dependence. To interpret the experimental findings, we discuss various theoretical approaches which have been developed to understand the microscopic origins of quark-hadron duality in QCD. Examples from other reactions are used to place duality in a broader context, and future experimental and theoretical challenges are identified.

  2. A particle consistent with the Higgs boson observed with the ATLAS detector at the Large Hadron Collider.

    PubMed

    2012-12-21

    Nearly 50 years ago, theoretical physicists proposed that a field permeates the universe and gives energy to the vacuum. This field was required to explain why some, but not all, fundamental particles have mass. Numerous precision measurements during recent decades have provided indirect support for the existence of this field, but one crucial prediction of this theory has remained unconfirmed despite 30 years of experimental searches: the existence of a massive particle, the standard model Higgs boson. The ATLAS experiment at the Large Hadron Collider at CERN has now observed the production of a new particle with a mass of 126 giga-electron volts and decay signatures consistent with those expected for the Higgs particle. This result is strong support for the standard model of particle physics, including the presence of this vacuum field. The existence and properties of the newly discovered particle may also have consequences beyond the standard model itself.

  3. Fully automated precision predictions for heavy neutrino production mechanisms at hadron colliders

    NASA Astrophysics Data System (ADS)

    Degrande, Céline; Mattelaer, Olivier; Ruiz, Richard; Turner, Jessica

    2016-09-01

    Motivated by TeV-scale neutrino mass models, we propose a systematic treatment of heavy neutrino (N ) production at hadron colliders. Our simple and efficient modeling of the vector boson fusion (VBF) W±γ →N ℓ± and N ℓ±+nj signal definitions resolve collinear and soft divergences that have plagued past studies, and is applicable to other color-singlet processes, e.g., associated Higgs (W±h), sparticle (ℓ˜±νℓ˜), and charged Higgs (h±±h∓) production. We present, for the first time, a comparison of all leading N production modes, including both gluon fusion (GF) g g →Z*/h*→N νℓ (-) and VBF. We obtain fully differential results up to next-to-leading order (NLO) in QCD accuracy using a Monte Carlo tool chain linking feynrules, nloct, and madgraph5_amc@nlo. Associated model files are publicly available. At the 14 TeV LHC, the leading order GF rate is small and comparable to the NLO N ℓ±+1 j rate; at a future 100 TeV Very Large Hadron Collider, GF dominates for mN=300 - 1500 GeV , beyond which VBF takes the lead.

  4. Heavy-Quark Associated Production with One Hard Photon at Hadron Colliders

    SciTech Connect

    Hartanto, Heribertus Bayu

    2013-01-01

    We present the calculation of heavy-quark associated production with a hard photon at hadron colliders, namely $pp(p\\bar p) → Q\\bar Q +X$γ (for $Q=t,b$), at Next-to-Leading Order (NLO) in Quantum Chromodynamics (QCD). We study the impact of NLO QCD corrections on the total cross section and several differential distributions at both the Tevatron and the Large Hadron Collider (LHC). For $t\\bar t$γ production we observe a sizeable reduction of the renormalization and factorization scale dependence when the NLO QCD corrections are included, while for $b\\bar b$γ production a considerable scale dependence still persists at NLO in QCD. This is consistent with what emerges in similar processes involving $b$ quarks and vector bosons and we explain its origin in detail. For $b\\bar b$γ production we study both the case in which at least one $b$ jet and the case in which at least two $b$ jets are observed. We perform the $b\\bar b$γ calculation using the Four Flavor Number Scheme (4FNS) and compare the case where at least one $b$ jet is observed with the corresponding results from the Five Flavor Number Scheme (5FNS) calculation. Finally we compare our results for $p\\bar p →+b+X$γ with the Tevatron data.

  5. A Study on Multi-Jets Final States at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Amouzegar, Maya; Halkiadakis, Eva; Lath, Amitabh; Thomas, Scott; Gershtein, Yuri; CMS Collaboration

    2016-03-01

    The LHC (Large Hadron Collider) at CERN, located in Geneva, Switzerland, collides protons at a center of mass energy of 13 TeV. The CMS (Compact Muon Solenoid) detector is one of the four experiments that detects collisions at the LHC. One of the new physics phenomenon that is looked for by the CMS detector is Supersymmetry (SUSY). In our method, we look for these particles by looking at multi-jets final states in interactions that produce up to 8 jets in their final states. By comparing jets in new physics signals with ones produced through QCD, we would be able to predict where new physics might be lying. Since the standard model interactions mostly produce di-jets, if there is an excess of jets at a certain energy, it is possible that a process beyond the standard model is producing those jets. Most of the simulated Monte Carlo signals considered are R-Parity Violating SUSY interactions. In order to perform these studies, we studied the jets' transverse momentum (Pt) divided by the total hadronic energy in the event (HT) as a function of the jet multiplicity, between 2 and 8 jets. If there is an excess of transverse momentum, there is the possibility that SUSY particles are created and are decaying into jets. The studies performed here were a result of the National Science Foundation Research Experiences for Undergraduates (REU) program, and has been supported by funding from NSF Grant PHY-1263280.

  6. Cooling of electronics in collider experiments

    SciTech Connect

    Richard P. Stanek et al.

    2003-11-07

    Proper cooling of detector electronics is critical to the successful operation of high-energy physics experiments. Collider experiments offer unique challenges based on their physical layouts and hermetic design. Cooling systems can be categorized by the type of detector with which they are associated, their primary mode of heat transfer, the choice of active cooling fluid, their heat removal capacity and the minimum temperature required. One of the more critical detector subsystems to require cooling is the silicon vertex detector, either pixel or strip sensors. A general design philosophy is presented along with a review of the important steps to include in the design process. Factors affecting the detector and cooling system design are categorized. A brief review of some existing and proposed cooling systems for silicon detectors is presented to help set the scale for the range of system designs. Fermilab operates two collider experiments, CDF & D0, both of which have silicon systems embedded in their detectors. A review of the existing silicon cooling system designs and operating experience is presented along with a list of lessons learned.

  7. An Energy Recovery Electron Linac On Ring Collider

    SciTech Connect

    Nikolitsa Merminga; Geoffrey Krafft; Valeri Lebedev; Ilan Ben-Zvi

    2001-09-01

    Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10{sup 33} (per nucleon) level have been proposed recently as a means for studying hadronic structure. Electron beam polarization appears to be crucial for many of the experiments. Two accelerator design scenarios have been examined in detail: colliding rings and recirculating linac-on-ring. Although the linac-on-ring scenario is not as well developed as the ring-ring scenario, comparable luminosities appear feasible. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations; (2) reduction of the synchrotron radiation load in the detectors; (3) a wide range of continuous energy variability. Rf power and beam dump considerations require that the electron linac recover the beam energy. This technology has been demonstrated at Jefferson Lab's IR FEL with cw current up to 5 mA and beam energy up to 50 MeV. Based on extrapolations from actual measurements and calculations, energy recovery is expected to be feasible at higher currents (a few hundred mA) and higher energies (a few GeV) as well. The report begins with a brief overview of Jefferson Lab's experience with energy recovery and summarize its benefits. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented next. The feasibility of an energy recovery electron linac-on-proton ring collider is investigated and four conceptual point designs are shown corresponding to electron to proton energies of: 3 GeV on 15 GeV, 5 GeV on 50 GeV and 10 GeV on 250 GeV, and for gold ions with 100 GeV/A. The last two designs assume that the protons or ions are stored in the existing RHIC accelerator. Accelerator physics issues relevant to proton rings and energy recovery linacs are discussed next and a list of required R and D for the realization of such a design is presented.

  8. Dual topological unitarization of hard and soft hadronic cross sections: A new approach to multiparticle production at hadron colliders in the TeV energy range

    SciTech Connect

    Ranft, J.; Hahn, K. . SSC Central Design Group); Aurenche, P.; Maire, P. . Lab. de Physique des Particules Elementaires); Bopp, F. . Fachbereich Physik); Capella, A.; Tran Thanh Van, J. . Lab. de Physique Theorique et Particules Elementaires); Kwi

    1987-12-01

    The dual topological unitarization of hard and soft hadronic collisions is formulated as a Monte-Carlo event generator for events containing both the soft (low p{perpendicular}) and hard (jets, minijets) component of hadron production. The parameters of the model are determined from fits to the energy dependence of the total and inelastic hadron cross-sections and from the predictions of the QCD-parton model for the perturbative hard constituent scattering cross sections. The properties of the model are studied. Good agreement of the model predictions is found with data at present accelerator and collider energies. The predictions of the model for TeV colliders are presented. Interesting changes of the produced multiparticle system are formed when selecting classes of events with and without hard jets or minijets. 35 refs., 22 figs., 3 tabs.

  9. Polarized Electron - Polarized Deuteron Deep-Inelastic Scattering in Electron-Ion Collider with Tagging

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak; Cosyn, Wim; Weiss, Christian

    2015-10-01

    For the past several years there have been an intensive research and development for the possible electron-ion collider that will be able to probe deep inelastic processes at unprecedentedly high energies in eA channel. One of the important advantages of the collider kinematics in DIS processes is the possibility for an unambiguous separation of hadrons emerging from DIS and hadrons fragmenting from the target nucleus. This creates a unique possibility for tagging the interacting nucleon with the recoil slow fragments in the DIS process. The situation is most clean for the deuteron target in which case the recoil particle is a nucleon. In addition, the possibility of having polarized deuteron beams will create unprecedented opportunities in probing polarization degrees of freedom for parton distributions in the interacting bound nucleon. In this work we develop a theoretical framework for the polarized electron-polarized deuteron deep inelastic scattering in which the recoil nucleon is detected in the target fragmentation region. Two main contributions for which theoretical models are developed are the plane-wave impulse approximation, in which no reinteractions are taking place between the final state products of DIS and the recoil nucleon.

  10. Analysis of the Laser Calibration System for the CMS HCAL at CERN's Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Lebolo, Luis

    2005-11-01

    The European Organization for Nuclear Physics' (CERN) Large Hadron Collider uses the Compact Muon Solenoid (CMS) detector to measure collision products from proton-proton interactions. CMS uses a hadron calorimeter (HCAL) to measure the energy and position of quarks and gluons by reconstructing their hadronic decay products. An essential component of the detector is the calibration system, which was evaluated in terms of its misalignment, linearity, and resolution. In order to analyze the data, the authors created scripts in ROOT 5.02/00 and C++. The authors also used Mathematica 5.1 to perform complex mathematics and AutoCAD 2006 to produce optical ray traces. The misalignment of the optical components was found to be satisfactory; the Hybrid Photodiodes (HPDs) were confirmed to be linear; the constant, noise and stochastic contributions to its resolution were analyzed; and the quantum efficiency of most HPDs was determined to be approximately 40%. With a better understanding of the laser calibration system, one can further understand and improve the HCAL.

  11. Beam Dynamics Considerations in Electron Ion Colliders

    NASA Astrophysics Data System (ADS)

    Krafft, Geoffrey

    2015-04-01

    The nuclear physics community is converging on the idea that the next large project after FRIB should be an electron-ion collider. Both Brookhaven National Lab and Thomas Jefferson National Accelerator Facility have developed accelerator designs, both of which need novel solutions to accelerator physics problems. In this talk we discuss some of the problems that must be solved and their solutions. Examples in novel beam optics systems, beam cooling, and beam polarization control will be presented. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

  12. First evidence for WW and WZ diboson production with semi-leptonic decays at a Hadron Collider

    SciTech Connect

    Haley, Joseph Glenn Biddle

    2009-06-01

    Presented is a measurement of the simultaneous production of a W± boson in association with a second weak boson (W± or Z0) in p$\\bar{p}$ collisions at √s = 1.96 TeV. Events are consider with one electron or one muon, missing transverse energy, and at least two hadronic jets. The data were collected by the D0 detector in Run IIa of the Tevatron accelerator and correspond to 1.07 fb-1 of integrated luminosity for each of the two channels (WW/WZ → evq$\\bar{q}$ and WW/WZ → μvq$\\bar{q}$). The cross section for WW + WZ production is measured to be 20.2 ± 2.5(stat) ± 3.6(sys) ± 1.2(lum) pb with a Gaussian significance of 4.4 standard deviations above the background-only scenario. This measurement is consistent with the Standard Model prediction and represents the first direct evidence for WW and WZ production with semi-leptonic decays at a hadron collider.

  13. Design Concept and Parameters of a 15 T $Nb_{3}Sn$ Dipole Demonstrator for a 100 TEV Hadron Collider

    SciTech Connect

    Zlobin, A. V.; Andreev, N.; Barzi, E.; Kashikhin, V. V.; Novitski, I.

    2015-06-01

    FNAL has started the development of a 15 T $Nb_{3}Sn$ dipole demonstrator for a 100 TeV scale hadron collider. This paper describes the design concept and parameters of the 15 T $Nb_{3}Sn$ dipole demonstrator. The dipole magnetic, mechanical and quench protection concept and parameters are presented and discussed.

  14. The B  ‑  L supersymmetric standard model with inverse seesaw at the large hadron collider

    NASA Astrophysics Data System (ADS)

    Khalil, S.; Moretti, S.

    2017-03-01

    We review the TeV scale B  ‑  L extension of the minimal supersymmetric standard model (BLSSM) where an inverse seesaw mechanism of light neutrino mass generation is naturally implemented and concentrate on its hallmark manifestations at the large hadron collider (LHC).

  15. Precise Predictions for W 4 Jet Production at the Large Hadron Collider

    SciTech Connect

    Berger, C.F.; Bern, Z.; Dixon, Lance J.; Cordero, F.Febres; Forde, D.; Gleisberg, T.; Ita, H.; Kosower, D.A.; Maitre, D.; /Durham U.

    2010-09-14

    We present the first next-to-leading order QCD results for W + 4-jet production at hadron colliders. Total cross sections, as well as distributions in the jet transverse momenta and in the total transverse energy HT, are provided for the initial LHC energy of {radical}s = 7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The virtual matrix elements and the most complicated real-emission matrix elements are handled by the BlackHat library, based on on-shell methods. The remaining parts of the calculation, including the integration over phase space, are performed by the SHERPA package.

  16. Cryogenic safety aspect of the low -$\\beta$ magnest systems at the Large Hadron Collider (LHC)

    SciTech Connect

    Darve, C.; /Fermilab

    2010-07-01

    The low-{beta} magnet systems are located in the LHC insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process and will allow proton collisions at a luminosity of up to 10{sup 34}cm{sup -2}s{sup -1}. Large radiation dose deposited at the proximity of the beam collisions dictate stringent requirements for the design and operation of the systems. The hardware commissioning phase of the LHC was completed in the winter of 2010 and permitted to validate this system safe operation. This paper presents the analysis used to qualify and quantify the safe operation of the low-{beta} magnet systems in the Large Hadron Collider (LHC) for the first years of operation.

  17. Commercial associative memory performance for applications in track-based triggers at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Webster, Jordan

    2017-01-01

    Dense track environments in pp collisions at the Large Hadron Collider (LHC) motivate the use of triggers with dedicated hardware for fast track reconstruction. The ATLAS Collaboration is in the process of implementing a Fast Tracker (FTK) trigger upgrade, in which Content Addressable Memories (CAMs) will be used to rapidly match hit patterns with large banks of simulated tracks. The FTK CAMs are produced primarily at the University of Pisa. However, commercial CAM technology is rapidly developing due to applications in computer networking devices. This poster presents new studies comparing FTK CAMs to cutting-edge ternary CAMs developed by Cavium. The comparison is intended to guide the design of future track-based trigger systems for the next Phase at the LHC.

  18. Exergy Analysis of the Cryogenic Helium Distribution System for the Large Hadron Collider (lhc)

    NASA Astrophysics Data System (ADS)

    Claudet, S.; Lebrun, Ph.; Tavian, L.; Wagner, U.

    2010-04-01

    The Large Hadron Collider (LHC) at CERN features the world's largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility.

  19. Signatures of non-universal gaugino and scalar masses at the Large Hadron Collider (LHC)

    SciTech Connect

    Bhattacharya, Subhaditya

    2008-11-23

    We perform a multichannel analysis in context of the Large Hadron Collider (LHC) for supersymmetric (SUSY) theories with high-scale non-universal gaugino masses arising from different non-singlet representations of SU(5) and SO(10) gauge groups in a SUSY-GUT scenario and non-universal scalar masses in form of squark-slepton non-universality, third family scalar non-universality and that arising due to SO(10) D-terms. We present the numerical predictions over a wide region of parameter space using event generator Pythia. Certain broad features emerge from the study which may be useful to identify these non-universal schemes and distinguish them from the minimal supergravity (mSUGRA) framework.

  20. Search for a light fermiophobic Higgs boson produced via gluon fusion at hadron colliders

    SciTech Connect

    Arhrib, Abdesslam; Benbrik, Rachid; Guedes, R. B.; Santos, R.

    2008-10-01

    In this study, we propose new Higgs production mechanisms with multiphoton final states in the fermiophobic limit of the two Higgs doublet model. The processes are: gg{yields}hh, gg{yields}Hh followed by H{yields}hh and gg{yields}Ah followed by A{yields}hZ. In the fermiophobic limit, gg{yields}hh and gg{yields}Ah{yields}hhZ would give rise to 4{gamma} signature while gg{yields}Hh{yields}hhh can give a 6{gamma} final state. We show that both the Fermilab Tevatron and CERN's Large Hadron Collider can probe a substantial slice of the parameter space in this fermiophobic scenario of the two Higgs doublet model. If observed the above processes can give some information on the triple Higgs couplings involved.

  1. W+ W- production at hadron colliders in next to next to leading order QCD.

    PubMed

    Gehrmann, T; Grazzini, M; Kallweit, S; Maierhöfer, P; von Manteuffel, A; Pozzorini, S; Rathlev, D; Tancredi, L

    2014-11-21

    Charged gauge boson pair production at the Large Hadron Collider allows detailed probes of the fundamental structure of electroweak interactions. We present precise theoretical predictions for on-shell W+ W- production that include, for the first time, QCD effects up to next to next to leading order in perturbation theory. As compared to next to leading order, the inclusive W+ W- cross section is enhanced by 9% at 7 TeV and 12% at 14 TeV. The residual perturbative uncertainty is at the 3% level. The severe contamination of the W+ W- cross section due to top-quark resonances is discussed in detail. Comparing different definitions of top-free W+ W- production in the four and five flavor number schemes, we demonstrate that top-quark resonances can be separated from the inclusive W+ W- cross section without a significant loss of theoretical precision.

  2. Black holes in many dimensions at the CERN Large Hadron Collider: testing critical string theory.

    PubMed

    Hewett, JoAnne L; Lillie, Ben; Rizzo, Thomas G

    2005-12-31

    We consider black hole production at the CERN Large Hadron Collider (LHC) in a generic scenario with many extra dimensions where the standard model fields are confined to a brane. With approximately 20 dimensions the hierarchy problem is shown to be naturally solved without the need for large compactification radii. We find that in such a scenario the properties of black holes can be used to determine the number of extra dimensions, . In particular, we demonstrate that measurements of the decay distributions of such black holes at the LHC can determine if is significantly larger than 6 or 7 with high confidence and thus can probe one of the critical properties of string theory compactifications.

  3. The discovery of the Higgs boson at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Nisati, A.; Tonelli, G.

    2015-11-01

    This paper summarises the work done by the ATLAS and CMS collaborations, and by the teams of the Large Hadron Collider at CERN, that led to the discovery of a new particle, with mass near 125GeV and properties consistent with the ones predicted for the Standard Model Higgs boson. An overview of the Standard Model, with a description of the role of the Higgs boson in the theory, and a summary of the searches for this particle prior to the LHC operations is also given. The paper presents the results obtained by ATLAS and CMS from the analysis of the full data set produced in the first physics run of LHC. After a short discussion on the implications of the discovery, the future prospects for the precision study of the new particle are lastly discussed.

  4. Transverse-momentum resummation for slepton-pair production at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bozzi, G.; Fuks, B.; Klasen, M.

    2006-07-01

    We perform a first precision calculation of the transverse-momentum (qT) distribution of slepton pair and slepton-sneutrino associated production at the CERN Large Hadron Collider. We implement soft-gluon resummation at the next-to-leading logarithmic level and consistently match the obtained result to the pure fixed-order perturbative result at leading order in the QCD coupling constant, i.e. O(αs). We give numerical predictions for τ˜1τ˜1* and τ˜1ν˜τ*+τ˜1*ν˜τ production, also implementing recent parametrizations of nonperturbative effects. The results show a relevant contribution of resummation both in the small and intermediate qT-regions and little dependence on unphysical scales and nonperturbative contributions.

  5. Landscape of supersymmetric particle mass hierarchies and their signature space at the CERN Large Hadron Collider.

    PubMed

    Feldman, Daniel; Liu, Zuowei; Nath, Pran

    2007-12-21

    The minimal supersymmetric standard model with soft breaking has a large landscape of supersymmetric particle mass hierarchies. This number is reduced significantly in well-motivated scenarios such as minimal supergravity and alternatives. We carry out an analysis of the landscape for the first four lightest particles and identify at least 16 mass patterns, and provide benchmarks for each. We study the signature space for the patterns at the CERN Large Hadron Collider by analyzing the lepton+ (jet> or =2) + missing P{T} signals with 0, 1, 2, and 3 leptons. Correlations in missing P{T} are also analyzed. It is found that even with 10 fb{-1} of data a significant discrimination among patterns emerges.

  6. Summary and highlights of the 14th Topical Conference on Hadron Collider Physics (HCP2002)

    SciTech Connect

    John Womersley

    2002-11-13

    First of all, I would like to thank the scientific committee, the conference organizers, the University of Karlsruhe and the Institute for Experimental Nuclear Physics, all of the speakers, and the conference secretariat, for making this an extremely well-organized and uniformly high-quality meeting. I would also like to thank all of the speakers who provided me with material for my talk before and during the conference. There is obviously no point in these proceedings in attempting to repeat all of the material from the individual contributions; by definition, these are all available earlier in this volume. In the written version, therefore, I will try to give a high level overview of the current state of hadron collider physics and to highlight the connections between the many presentations at this conference.

  7. Studying total proton-proton cross section collision at large hadron collider using gene expression programming

    NASA Astrophysics Data System (ADS)

    Radi, A.

    2017-06-01

    New technique is presented for modeling total cross section of proton-proton (p-p) collision from low to ultra-high energy regions using gene expression programming (GEP). GEP, as a machine learning technique is usually used for modeling physical phenomena by discovering a new function {{{σ }}}{{T}}(\\sqrt{s}). In case of modeling the p-p interactions at the Large Hadron Collider (LHC), GEP is used to simulate and predict the total cross-section which is a function of total center-of-mass from low to high energy √s. The discovered function shows a good match as compared with the other models. The predicted values of total cross section are in good agreement with Particle Data Group (PDG).

  8. Search for a light fermiophobic Higgs boson produced via gluon fusion at hadron colliders

    NASA Astrophysics Data System (ADS)

    Arhrib, Abdesslam; Benbrik, Rachid; Guedes, R. B.; Santos, R.

    2008-10-01

    In this study, we propose new Higgs production mechanisms with multiphoton final states in the fermiophobic limit of the two Higgs doublet model. The processes are: gg→hh, gg→Hh followed by H→hh and gg→Ah followed by A→hZ. In the fermiophobic limit, gg→hh and gg→Ah→hhZ would give rise to 4γ signature while gg→Hh→hhh can give a 6γ final state. We show that both the Fermilab Tevatron and CERN’s Large Hadron Collider can probe a substantial slice of the parameter space in this fermiophobic scenario of the two Higgs doublet model. If observed the above processes can give some information on the triple Higgs couplings involved.

  9. QCD corrections to associated production of tt{gamma} at hadron colliders

    SciTech Connect

    Duan Pengfei; Ma Wengan; Zhang Renyou; Han Liang; Guo Lei; Wang Shaoming

    2009-07-01

    We report on the next-to-leading order (NLO) QCD computation of top-quark pair production in association with a photon at the Fermilab Tevatron RUN II and CERN Large Hadron Collider. We describe the impact of the complete NLO QCD radiative corrections to this process, and provide the predictions of the leading order (LO) and NLO integrated cross sections, distributions of the transverse momenta of the top quark and photon for the LHC and Tevatron, and the LO and NLO forward-backward top-quark charge asymmetries for the Tevatron. We investigate the dependence of the LO and NLO cross sections on the renormalization/factorization scale, and find the scale dependence of the LO cross section is obviously improved by the NLO QCD corrections. The K-factor of the NLO QCD correction is 0.977(1.524) for the Tevatron (LHC)

  10. Higgs self-coupling measurements at a 100 TeV hadron collider

    DOE PAGES

    Barr, Alan J.; Dolan, Matthew J.; Englert, Christoph; ...

    2015-02-03

    An important physics goal of a possible next-generation high-energy hadron collider will be precision characterisation of the Higgs sector and electroweak symmetry breaking. A crucial part of understanding the nature of electroweak symmetry breaking is measuring the Higgs self-interactions. We study dihiggs production in proton-proton collisions at 100 TeV centre of mass energy in order to estimate the sensitivity such a machine would have to variations in the trilinear Higgs coupling around the Standard Model expectation. We focus on the bb¯γγ final state, including possible enhancements in sensitivity by exploiting dihiggs recoils against a hard jet. In conclusion, we findmore » that it should be possible to measure the trilinear self-coupling with 40% accuracy given 3/ab and 12% with 30/ab of data.« less

  11. Higgs self-coupling measurements at a 100 TeV hadron collider

    SciTech Connect

    Barr, Alan J.; Dolan, Matthew J.; Englert, Christoph; Ferreira de Lima, Enoque Danilo; Spannowsky, Michael

    2015-02-03

    An important physics goal of a possible next-generation high-energy hadron collider will be precision characterisation of the Higgs sector and electroweak symmetry breaking. A crucial part of understanding the nature of electroweak symmetry breaking is measuring the Higgs self-interactions. We study dihiggs production in proton-proton collisions at 100 TeV centre of mass energy in order to estimate the sensitivity such a machine would have to variations in the trilinear Higgs coupling around the Standard Model expectation. We focus on the bb¯γγ final state, including possible enhancements in sensitivity by exploiting dihiggs recoils against a hard jet. In conclusion, we find that it should be possible to measure the trilinear self-coupling with 40% accuracy given 3/ab and 12% with 30/ab of data.

  12. Viewpoint: the End of the World at the Large Hadron Collider?

    SciTech Connect

    Peskin, Michael E.; /SLAC

    2011-11-21

    New arguments based on astrophysical phenomena constrain the possibility that dangerous black holes will be produced at the CERN Large Hadron Collider. On 8 August, the Large Hadron Collider (LHC) at CERN injected its first beams, beginning an experimental program that will produce proton-proton collisions at an energy of 14 TeV. Particle physicists are waiting expectantly. The reason is that the Standard Model of strong, weak, and electromagnetic interactions, despite its many successes, is clearly incomplete. Theory says that the holes in the model should be filled by new physics in the energy region that will be studied by the LHC. Some candidate theories are simple quick fixes, but the most interesting ones involve new concepts of spacetime waiting to be discovered. Look up the LHC on Wikipedia, however, and you will find considerable space devoted to safety concerns. At the LHC, we will probe energies beyond those explored at any previous accelerator, and we hope to create particles that have never been observed. Couldn't we, then, create particles that would actually be dangerous, for example, ones that would eat normal matter and eventually turn the earth into a blob of unpleasantness? It is morbid fun to speculate about such things, and candidates for such dangerous particles have been suggested. These suggestions have been analyzed in an article in Reviews of Modern Physics by Jaffe, Busza, Wilczek, and Sandweiss and excluded on the basis of constraints from observation and from the known laws of physics. These conclusions have been upheld by subsequent studies conducted at CERN.

  13. Cross sections of hadronic reactions e + e - → K + K - nπ ( n =1,2,3) measured with the CMD3 detector at the VEPP-2000 electron-positron collider

    NASA Astrophysics Data System (ADS)

    Fedotovich, G. V.; Erofeev, A. L.; Ivanov, V. L.; Ryzhenenkov, A. E.; Shemyakin, D. N.; Anisenkov, A. V.; Aulchenko, V. M.; Akhmetshin, R. R.; Banzarov, V. S.; Bashtovoy, N. S.; Berkaev, D. E.; Bondar, A. E.; Bragin, A. V.; Vorobiev, A. I.; Eidelman, S. I.; Epifanov, D. A.; Epshteyn, L. B.; Gayazov, S. E.; Grebenuk, A. A.; Gribanov, S. S.; Grigoriev, D. N.; Ignatov, F. V.; Jarinov, Yu. M.; Kazanin, V. F.; Kasaev, A. S.; Karpov, S. V.; Kirpotin, A. N.; Kovalenko, O. A.; Kozyrev, A. N.; Kozyrev, E. A.; Koop, I. A.; Korobov, A. A.; Krokovny, P. P.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Lukin, P. A.; Lysenko, A. P.; Mikhailov, K. Yu.; Okhapkin, V. S.; Perevedentsev, E. A.; Pestov, Yu. N.; Popov, A. S.; Razuvaev, G. P.; Rogovsky, Yu. A.; Romanov, A. L.; Ruban, A. A.; Ryskulov, N. M.; Sibidanov, A. L.; Solodov, E. P.; Talyshev, A. A.; Titov, V. M.; Shatunov, P. Yu.; Shatunov, Yu. M.; Shwartz, B. A.; Shwartz, D. B.; Shebalin, V. E.; Yudin, Yu. V.

    2017-09-01

    We analyze the data on e + e - collisions at c.m.s. energies between 0.32 and 2 GeV collected in 2011-2013 with the CMD3 detector operating at the VEPP-3 e + e - collider of the Budker Institute of Nuclear Physics. The data correspond to an integrated luminosity of nearly 60 pb-1. Preliminary results e + e - → K + K - nπ ( n = 1, 2, 3) on the reactions with two charged kaons in the final state are presented, and the procedure for estimating the integrated luminosity for each energy setting is described.

  14. High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report

    SciTech Connect

    Apollinari, G.; Béjar Alonso, I.; Brüning, O.; Lamont, M.; Rossi, L.

    2015-12-17

    The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.

  15. A Novel method for modeling the recoil in W boson events at hadron collider

    SciTech Connect

    Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Aguilo, Ernest; Ahsan, Mahsana; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls /Northeastern U.

    2009-07-01

    We present a new method for modeling the hadronic recoil in W {yields} {ell}{nu} events produced at hadron colliders. The recoil is chosen from a library of recoils in Z {yields} {ell}{ell} data events and overlaid on a simulated W {yields} {ell}{nu} event. Implementation of this method requires that the data recoil library describe the properties of the measured recoil as a function of the true, rather than the measured, transverse momentum of the boson. We address this issue using a multidimensional Bayesian unfolding technique. We estimate the statistical and systematic uncertainties from this method for the W boson mass and width measurements assuming 1 fb{sup -1} of data from the Fermilab Tevatron. The uncertainties are found to be small and comparable to those of a more traditional parameterized recoil model. For the high precision measurements that will be possible with data from Run II of the Fermilab Tevatron and from the CERN LHC, the method presented in this paper may be advantageous, since it does not require an understanding of the measured recoil from first principles.

  16. Heavy-ion physics with the ALICE experiment at the CERN Large Hadron Collider.

    PubMed

    Schukraft, J

    2012-02-28

    After close to 20 years of preparation, the dedicated heavy-ion experiment A Large Ion Collider Experiment (ALICE) took first data at the CERN Large Hadron Collider (LHC) accelerator with proton collisions at the end of 2009 and with lead nuclei at the end of 2010. After a short introduction into the physics of ultra-relativistic heavy-ion collisions, this article recalls the main design choices made for the detector and summarizes the initial operation and performance of ALICE. Physics results from this first year of operation concentrate on characterizing the global properties of typical, average collisions, both in proton-proton (pp) and nucleus-nucleus reactions, in the new energy regime of the LHC. The pp results differ, to a varying degree, from most quantum chromodynamics-inspired phenomenological models and provide the input needed to fine tune their parameters. First results from Pb-Pb are broadly consistent with expectations based on lower energy data, indicating that high-density matter created at the LHC, while much hotter and larger, still behaves like a very strongly interacting, almost perfect liquid.

  17. Long term dynamics of the high luminosity Large Hadron Collider with crab cavities

    NASA Astrophysics Data System (ADS)

    Barranco García, J.; De Maria, R.; Grudiev, A.; Tomás García, R.; Appleby, R. B.; Brett, D. R.

    2016-10-01

    The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 200 - 300 fb-1 per year, including the contribution from the upgrade of the injector chain. For the HL-LHC the larger crossing angle together with a smaller beta function at the collision point would result in more than 70% luminosity loss due to the incomplete geometric overlap of colliding bunches. To recover head-on collisions at the high-luminosity particle-physics detectors ATLAS and CMS and benefit from the very low β* provided by the Achromatic Telescopic Squeezing (ATS) optics, a local crab cavity scheme provides transverse kicks to the proton bunches. The tight space constraints at the location of these cavities leads to designs which are axially non-symmetric, giving rise to high order multipoles components of the main deflecting mode and, since these kicks are harmonic in time, we expand them in a series of multipoles in a similar fashion as is done for static field magnets. In this work we calculate, for the first time, the higher order multipoles and their impact on beam dynamics for three different crab cavity prototypes. Different approaches to calculate the multipoles are presented. Furthermore, we perform the first calculation of their impact on the long term stability of the machine using the concept of dynamic aperture.

  18. Science and status of the Electron Ion Collider

    NASA Astrophysics Data System (ADS)

    Deshpande, A.

    The US Nuclear Science Advisory Committee (NSAC) recently recommended the construction of a high-luminosity, high-energy Electron Ion Collider (EIC), with polarized beams capable of colliding polarized electrons with polarized proton and light ion beams, and with any nucleus. The s range between 40GeV and 140GeV, and luminosity range from 1033‑34cm‑2s‑1 were recommended. It is anticipated that under the current guidance from the DOE, the collider could become operational in the second half of the 2020’s. This paper summarizes its science and the scope of this over all project.

  19. Probing Sea Quarks and Gluons: The Electron-Ion Collider Project

    NASA Astrophysics Data System (ADS)

    Horn, Tanja

    2014-03-01

    The 21st century holds great promise for reaching a new era for unlocking the mysteries of the structure of the atomic nucleus and the nucleons inside it governed by the theory of strong interactions (QCD). In particular, much remains to be learned about the dynamical basis of the structure of hadrons and nuclei in terms of the fundamental quarks and gluons. One of the main goals of existing and nearly completed facilities is to map out the spin flavor structure of the nucleons in the valence region. A future Electron-Ion Collider (EIC) would be the world's first polarized electron-proton collider, and the world's first e-A collider, and would seek the QCD foundation of nucleons and nuclei in terms of the sea quarks and gluons, matching to these valence quark studies. The EIC will provide a versatile range of kinematics and beam polarization, as well as beam species, to allow for mapping the spin and spatial structure of the quark sea and gluons, to discover the collective effects of gluons in atomic nuclei, and to understand the emergence of hadronic matter from color charge.

  20. Hadron physics at the new CW electron accelerators

    SciTech Connect

    Burkert, V.D.

    1990-01-01

    Major trends of the physics program related to the study of hadron structure and hadron spectroscopy at the new high current, high duty cycle electron machines are discussed. It is concluded that planned experiments at these machines may have important impact on our understanding of the strong interaction by studying the internal structure and spectroscopy of the nucleon and lower mass hyperon states.

  1. Fundamental cavity impedance and longitudinal coupled-bunch instabilities at the High Luminosity Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Baudrenghien, P.; Mastoridis, T.

    2017-01-01

    The interaction between beam dynamics and the radio frequency (rf) station in circular colliders is complex and can lead to longitudinal coupled-bunch instabilities at high beam currents. The excitation of the cavity higher order modes is traditionally damped using passive devices. But the wakefield developed at the cavity fundamental frequency falls in the frequency range of the rf power system and can, in theory, be compensated by modulating the generator drive. Such a regulation is the responsibility of the low-level rf (llrf) system that measures the cavity field (or beam current) and generates the rf power drive. The Large Hadron Collider (LHC) rf was designed for the nominal LHC parameter of 0.55 A DC beam current. At 7 TeV the synchrotron radiation damping time is 13 hours. Damping of the instability growth rates due to the cavity fundamental (400.789 MHz) can only come from the synchrotron tune spread (Landau damping) and will be very small (time constant in the order of 0.1 s). In this work, the ability of the present llrf compensation to prevent coupled-bunch instabilities with the planned high luminosity LHC (HiLumi LHC) doubling of the beam current to 1.1 A DC is investigated. The paper conclusions are based on the measured performances of the present llrf system. Models of the rf and llrf systems were developed at the LHC start-up. Following comparisons with measurements, the system was parametrized using these models. The parametric model then provides a more realistic estimation of the instability growth rates than an ideal model of the rf blocks. With this modeling approach, the key rf settings can be varied around their set value allowing for a sensitivity analysis (growth rate sensitivity to rf and llrf parameters). Finally, preliminary measurements from the LHC at 0.44 A DC are presented to support the conclusions of this work.

  2. Searches for Lorentz Violation in Top-Quark Production and Decay at Hadron Colliders

    SciTech Connect

    Whittington, Denver Wade

    2012-07-01

    We present a first-of-its-kind confirmation that the most massive known elementary particle obeys the special theory of relativity. Lorentz symmetry is a fundamental aspect of special relativity which posits that the laws of physics are invariant regardless of the orientation and velocity of the reference frame in which they are measured. Because this symmetry is a fundamental tenet of physics, it is important to test its validity in all processes. We quantify violation of this symmetry using the Standard-Model Extension framework, which predicts the effects that Lorentz violation would have on elementary particles and their interactions. The top quark is the most massive known elementary particle and has remained inaccessible to tests of Lorentz invariance until now. This model predicts a dependence of the production cross section for top and antitop quark pairs on sidereal time as the orientation of the experiment in which these events are produced changes with the rotation of the Earth. Using data collected with the DØ detector at the Fermilab Tevatron Collider, we search for violation of Lorentz invariance in events involving the production of a $t\\bar{t}$ pair. Within the experimental precision, we find no evidence for such a violation and set upper limits on parameters describing its possible strength within the Standard-Model Extension. We also investigate the prospects for extending this analysis using the ATLAS detector at the Large Hadron Collider which, because of the higher rate of $t\\bar{t}$ events at that experiment, has the potential to improve the limits presented here.

  3. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  4. Yield ratios of identified hadrons in p +p , p +Pb , and Pb +Pb collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Shao, Feng-lan; Wang, Guo-jing; Wang, Rui-qin; Li, Hai-hong; Song, Jun

    2017-06-01

    Yield ratios of identified hadrons observed in high multiplicity p +p and p +Pb collisions at the CERN Large Hadron Collider show remarkable similarity with those in Pb+Pb collisions, indicating some important and universal underlying dynamics in hadron production for different quark gluon final states. We use the quark combination model to explain the data of yield ratios in these three collision systems. The observed p /π and Λ /Ks0 can be reproduced simultaneously by quark combination, and these two ratios reflect the probability of baryon production at hadronization which is the same in the light sector and strange sector and is roughly constant in p +p , p +Pb , and Pb+Pb collision systems over three orders of magnitude in charged particle multiplicity. The data of Ks0/π , Λ /π , Ξ /π , and Ω /π show a hierarchy behavior relating to the strangeness content and are naturally explained by quark combination both in the saturate stage at high multiplicity and in the increase stage at moderate multiplicity. Our results suggest that the characteristic of quark combination is necessary in describing the production of hadrons in small systems created in p +p and p +Pb collisions.

  5. MEKS: A program for computation of inclusive jet cross sections at hadron colliders

    NASA Astrophysics Data System (ADS)

    Gao, Jun; Liang, Zhihua; Soper, Davison E.; Lai, Hung-Liang; Nadolsky, Pavel M.; Yuan, C.-P.

    2013-06-01

    EKS is a numerical program that predicts differential cross sections for production of single-inclusive hadronic jets and jet pairs at next-to-leading order (NLO) accuracy in a perturbative QCD calculation. We describe MEKS 1.0, an upgraded EKS program with increased numerical precision, suitable for comparisons to the latest experimental data from the Large Hadron Collider and Tevatron. The program integrates the regularized patron-level matrix elements over the kinematical phase space for production of two and three partons using the VEGAS algorithm. It stores the generated weighted events in finely binned two-dimensional histograms for fast offline analysis. A user interface allows one to customize computation of inclusive jet observables. Results of a benchmark comparison of the MEKS program and the commonly used FastNLO program are also documented. Program SummaryProgram title: MEKS 1.0 Catalogue identifier: AEOX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOX_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 9234 No. of bytes in distributed program, including test data, etc.: 51997 Distribution format: tar.gz Programming language: Fortran (main program), C (CUBA library and analysis program). Computer: All. Operating system: Any UNIX-like system. RAM: ˜300 MB Classification: 11.1. External routines: LHAPDF (https://lhapdf.hepforge.org/) Nature of problem: Computation of differential cross sections for inclusive production of single hadronic jets and jet pairs at next-to-leading order accuracy in perturbative quantum chromodynamics. Solution method: Upon subtraction of infrared singularities, the hard-scattering matrix elements are integrated over available phase space using an optimized VEGAS algorithm. Weighted events are generated and filled

  6. Update on the MEIC electron collider ring design

    SciTech Connect

    Lin, Fangei; Derbenev, Yaroslav S.; Harwood, Leigh; Hutton, Andrew; Morozov, Vasiliy; Pilat, Fulvia; Zhang, Yuhong; Cai, Y.; Nosochkov, Y. M.; Sullivan, Michael; Wang, M.-H; Wienands, Uli

    2015-09-01

    The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEP-II components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.

  7. Update on the MEIC electron collider ring design

    SciTech Connect

    Lin, F.; Derbenev, Ya. S.; Harwood, L.; Hutton, A.; Morozov, V. S.; Pilat, F.; Zhang, Y.; Cai, Y.; Nosochkov, Y. M.; Sullivan, M.; Wang, M-H; Wienands, U.

    2015-07-14

    The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEPII components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.

  8. B constraints and Higgs searches at hadron colliders in the MSSM

    NASA Astrophysics Data System (ADS)

    Menon, Arjun

    In this thesis we analyze the impact of B-physics and Higgs physics at LEP on standard and non-standard Higgs bosons searches at the Tevatron and the LHC, within the framework of minimal flavor violating supersymmetric models. The B-physics constraints we consider come from the experimental measurements of the rare B-decays b → sgamma and Bu → taunu and the experimental limit on the Bs → mu+mu- branching ratio. We show that these constraints are severe for large values of the trilinear soft breaking parameter At, rendering the non-standard Higgs searches at hadron colliders less promising. On the contrary these bounds are relaxed for small values of At and large values of the Higgsino mass parameter mu, enhancing the prospects for the direct detection of non-standard Higgs bosons at both colliders. We also consider the available ATLAS and CMS projected sensitivities in the Standard Model Higgs search channels, and we discuss the LHC's ability in probing the whole MSSM parameter space. In addition we also consider the expected Tevatron collider sensitivities in the Standard Model Higgs → bb channel to show that it may be able to find 3 sigma evidence in the B-physics allowed regions for small or moderate stop mixing parameter. We show that the already stringent Tevatron bound on the decay rate Bs → mu+mu - sets strong constraints on the possibility of generating large corrections to the mass difference DeltaMs of the Bs eigenstates. In doing this, we demonstrate that the former expressions derived for the analysis of the double penguin contributions in the kaon sector need to be corrected by additional terms for a realistic analysis of these effects. We also study a specific non-minimal flavor violating scenario, where there are flavor changing gluino-squark-quark interactions, governed by the CKM matrix elements, and show that the B and Higgs physics constraints are similar to the ones in the minimal flavor violating case. Finally we show that, in

  9. W+W-+3 -jet production at the Large Hadron Collider in next-to-leading-order QCD

    NASA Astrophysics Data System (ADS)

    Febres Cordero, F.; Hofmann, P.; Ita, H.

    2017-02-01

    We present next-to-leading-order (NLO) QCD predictions to W+W- production in association with up to three jets at hadron colliders. We include contributions from couplings of the W bosons to light quarks as well as trilinear vector couplings. These processes are used in vector-boson coupling measurements, are background to Higgs signals and are needed to constrain many new physics scenarios. For the first time NLO QCD predictions are shown for electroweak di-vector boson production with three jets at a hadron collider. We show total and differential cross sections for the LHC with proton center-of-mass energies of 8 and 13 TeV. To perform the calculation we employ on-shell and unitarity methods implemented in the blackhat library along with the sherpa package. We have produced event files that can be accessed for future dedicated studies.

  10. CONCLUSIONS OF THE WORKSHOP [Hadron Colliders at the highest energy and luminosity

    SciTech Connect

    RUGGIERO,A.G.

    1996-11-04

    During this Workshop, it was concluded that a Proton-Proton Collider with an energy of 100 TeV per beam and a luminosity of about 10{sup 35} cm{sup {minus}2} s{sup {minus}1} is feasible. The most important technical requirement for the realization of such a project is a large bending field. For instance, a field of 13 Tesla would be desirable. This is twice the field of the SSC superconducting magnets, which very likely may be achieved in a non-too-far future by extrapolation of the present technology. The design of this Collider would follow very closely the methods used for the design of the SSC and of the LHC, with the major noticeable difference that, because of the larger bending field and the larger beam energy, the performance is determined by the effects of the Synchrotron Radiation in the similar manner they affect the performance of an electron-positron collider. This fact has considerable beneficial consequences since it allows the attainment of large luminosity by reducing the beam dimensions at collision and by requiring, to some degree, less number of particles per beam. On the other end. the losses to synchrotron radiation are to be absorbed by the cryogenic system, and the vacuum system should be capable to cope with them. A more significant rf system may also be required.

  11. Next-to-next-to-leading order N -jettiness soft function for one massive colored particle production at hadron colliders

    NASA Astrophysics Data System (ADS)

    Li, Hai Tao; Wang, Jian

    2017-02-01

    The N -jettiness subtraction has proven to be an efficient method to perform differential QCD next-to-next-to-leading order (NNLO) calculations in the last few years. One important ingredient of this method is the NNLO soft function. We calculate this soft function for one massive colored particle production at hadron colliders. We select the color octet and color triplet cases to present the final results. We also discuss its application in NLO and NNLO differential calculations.

  12. Journey in the search for the Higgs boson: the ATLAS and CMS experiments at the Large Hadron Collider.

    PubMed

    Della Negra, M; Jenni, P; Virdee, T S

    2012-12-21

    The search for the standard model Higgs boson at the Large Hadron Collider (LHC) started more than two decades ago. Much innovation was required and diverse challenges had to be overcome during the conception and construction of the LHC and its experiments. The ATLAS and CMS Collaboration experiments at the LHC have discovered a heavy boson that could complete the standard model of particle physics.

  13. ηc Hadroproduction at Large Hadron Collider Challenges NRQCD Factorization

    NASA Astrophysics Data System (ADS)

    Butenschoen, Mathias; He, Zhi-Guo; Kniehl, Bernd A.

    2017-03-01

    We report on our analysis [1] of prompt ηc meson production, measured by the LHCb Collaboration at the Large Hadron Collider, within the framework of non-relativistic QCD (NRQCD) factorization up to the sub-leading order in both the QCD coupling constant αs and the relative velocity v of the bound heavy quarks. We thereby convert various sets of J/ψ and χc,J long-distance matrix elements (LDMEs), determined by different groups in J/ψ and χc,J yield and polarization fits, to ηc and hc production LDMEs making use of the NRQCD heavy quark spin symmetry. The resulting predictions for ηc hadroproduction in all cases greatly overshoot the LHCb data, while the color-singlet model contributions alone would indeed be sufficient. We investigate the consequences for the universality of the LDMEs, and show how the observed tensions remain in follow-up works by other groups.

  14. Next-to-Leading Order Predictions for W + 3-Jet Distributions at Hadron Colliders

    SciTech Connect

    Berger, C.F.; Bern, Z.; Dixon, L.J.; Febres Cordero, F.; Forde, D.; Gleisberg, T.; Ita, H.; Kosower, D.A.; Maitre, D.; /Durham U.

    2009-12-09

    We present next-to-leading order QCD predictions for a variety of distributions in W + 3-jet production at both the Tevatron and the Large Hadron Collider. We include all subprocesses and incorporate the decay of the W boson into leptons. Our results are in excellent agreement with existing Tevatron data and provide the first quantitatively precise next-to-leading order predictions for the LHC. We include all terms in an expansion in the number of colors, confirming that the specific leading-color approximation used in our previous study is accurate to within three percent. The dependence of the cross section on renormalization and factorization scales is reduced significantly with respect to a leading-order calculation. We study different dynamical scale choices, and find that the total transverse energy is significantly better than choices used in previous phenomenological studies. We compute the one-loop matrix elements using on-shell methods, as numerically implemented in the BlackHat code. The remaining parts of the calculation, including generation of the real-emission contributions and integration over phase space, are handled by the SHERPA package.

  15. Development of N+ in P pixel sensors for a high-luminosity large hadron collider

    NASA Astrophysics Data System (ADS)

    Kamada, Shintaro; Yamamura, Kazuhisa; Unno, Yoshinobu; Ikegami, Yoichi

    2014-11-01

    Hamamatsu Photonics K. K. is developing an N+ in a p planar pixel sensor with high radiation tolerance for the high-luminosity large hadron collider (HL-LHC). The N+ in the p planar pixel sensor is a candidate for the HL-LHC and offers the advantages of high radiation tolerance at a reasonable price compared with the N+ in an n planar sensor, the three-dimensional sensor, and the diamond sensor. However, the N+ in the p planar pixel sensor still presents some problems that need to be solved, such as its slim edge and the danger of sparks between the sensor and readout integrated circuit. We are now attempting to solve these problems with wafer-level processes, which is important for mass production. To date, we have obtained a 250-μm edge with an applied bias voltage of 1000 V. To protect against high-voltage sparks from the edge, we suggest some possible designs for the N+ edge.

  16. The upgrade programme of the major experiments at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    La Rocca, P.; Riggi, F.

    2014-05-01

    After a successful data taking period at the CERN LHC by the major physics experiments (ALICE, ATLAS, CMS and LHCb) since 2009, a long-term plan is already envisaged to fully exploit the vast physics potential of the Large Hadron Collider (LHC) within the next two decades. The CERN accelerator complex will undergo a series of upgrades leading ultimately to increase both the collision energy and the luminosity, thus maximizing the amount of data delivered to all experiments. As a consequence, the experiments have also to cope with very high detector occupancies and operate in the hard radiation environment caused by a huge multiplicity of particles produced in each beam crossing. In parallel to the accelerator upgrades, the LHC experiments are planning various upgrades to their detector, trigger, and data acquisition systems. The main motivation for the upgrades is to extend and to improve their physics programme also in the increasingly challenging LHC environment. In this paper a general overview of the upgrade programme of the major experiments at LHC will be given, with some additional details concerning specifications and physics programme of new detector subsystems.

  17. Final implementation, commissioning, and performance of embedded collimator beam position monitors in the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Valentino, Gianluca; Baud, Guillaume; Bruce, Roderik; Gasior, Marek; Mereghetti, Alessio; Mirarchi, Daniele; Olexa, Jakub; Redaelli, Stefano; Salvachua, Belen; Valloni, Alessandra; Wenninger, Jorg

    2017-08-01

    During Long Shutdown 1, 18 Large Hadron Collider (LHC) collimators were replaced with a new design, in which beam position monitor (BPM) pick-up buttons are embedded in the collimator jaws. The BPMs provide a direct measurement of the beam orbit at the collimators, and therefore can be used to align the collimators more quickly than using the standard technique which relies on feedback from beam losses. Online orbit measurements also allow for reducing operational margins in the collimation hierarchy placed specifically to cater for unknown orbit drifts, therefore decreasing the β* and increasing the luminosity reach of the LHC. In this paper, the results from the commissioning of the embedded BPMs in the LHC are presented. The data acquisition and control software architectures are reviewed. A comparison with the standard alignment technique is provided, together with a fill-to-fill analysis of the measured orbit in different machine modes, which will also be used to determine suitable beam interlocks for a tighter collimation hierarchy.

  18. The CERN Large Hadron Collider as a tool to study high-energy density matter.

    PubMed

    Tahir, N A; Kain, V; Schmidt, R; Shutov, A; Lomonosov, I V; Gryaznov, V; Piriz, A R; Temporal, M; Hoffmann, D H H; Fortov, V E

    2005-04-08

    The Large Hadron Collider (LHC) at CERN will generate two extremely powerful 7 TeV proton beams. Each beam will consist of 2808 bunches with an intensity per bunch of 1.15x10(11) protons so that the total number of protons in one beam will be about 3x10(14) and the total energy will be 362 MJ. Each bunch will have a duration of 0.5 ns and two successive bunches will be separated by 25 ns, while the power distribution in the radial direction will be Gaussian with a standard deviation, sigma=0.2 mm. The total duration of the beam will be about 89 mus. Using a 2D hydrodynamic code, we have carried out numerical simulations of the thermodynamic and hydrodynamic response of a solid copper target that is irradiated with one of the LHC beams. These calculations show that only the first few hundred proton bunches will deposit a high specific energy of 400 kJ/g that will induce exotic states of high energy density in matter.

  19. Discerning new physics in toverline t production using top spin observables at hadron colliders

    NASA Astrophysics Data System (ADS)

    Fajfer, Svjetlana; Kamenik, Jernej F.; Melić, Blaženka

    2012-08-01

    Copious production of top-anti top quark pairs at hadron colliders has enabled various probes into the properties and interactions of top quarks. Among the various presently measured observables, the forward-backward asymmetry (FBA) in toverline t production measured at the Tevatron significantly deviates from the standard model predictions, and many models of new physics have been invented to explain the puzzle. We consider the consistency of the simplified single-resonance models containing a color octet axial-vector ("axigluon"), color triplet or sextet weak singlet scalars, weak isodoublet scalar, flavor-changing neutral Z ', or charged W ' vector boson with existing toverline t production measurements. Among the considered models only an axigluon can reproduce all Tevatron observables, without being in severe tension with the recent LHC results on toverline t production cross section, charge asymmetry and top-spin correlations. The LHC charge asymmetry measurements exclude the W ' and Z ' explanations of the Tevatron FBA anomaly. On the other hand, all scalar models predict notable deviations in several top spin observables, and the recent top spin correlation measurement using the "helicity" spin quantization axis by ATLAS already provides a significant constraint on possible explanations of the Tevatron FBA anomaly. Future precise measurements of top spin correlations and especially top polarization could differentiate between scalar t-channel models, while they are less sensitive to pure axigluon contributions.

  20. Jet Signals for Low Mass Strings at the Large Hadron Collider

    SciTech Connect

    Anchordoqui, Luis A.; Nawata, Satoshi; Goldberg, Haim; Taylor, Tomasz R.

    2008-05-02

    The mass scale M{sub s} of superstring theory is an arbitrary parameter that can be as low as few TeVs if the Universe contains large extra dimensions. We propose a search for the effects of Regge excitations of fundamental strings at the CERN Large Hadron Collider (LHC), in the process pp{yields}{gamma}+jet. The underlying parton process is dominantly the single photon production in gluon fusion, gg{yields}{gamma}g, with open string states propagating in intermediate channels. If the photon mixes with the gauge boson of the baryon number, which is a common feature of D-brane quivers, the amplitude appears already at the string disk level. It is completely determined by the mixing parameter--and it is otherwise model (compactification) independent. Even for relatively small mixing, 100 fb{sup -1} of LHC data could probe deviations from standard model physics, at a 5{sigma} significance, for M{sub s} as large as 3.3 TeV.

  1. Dijet Signals for Low Mass Strings at the Large Hadron Collider

    SciTech Connect

    Anchordoqui, Luis A.; Nawata, Satoshi; Goldberg, Haim; Taylor, Tomasz R.; Luest, Dieter; Stieberger, Stephan

    2008-12-12

    Assuming that the fundamental string mass scale is in the TeV range and the theory is weakly coupled, we discuss possible signals of string physics at the Large Hadron Collider (LHC). In D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first resonant pole to determine the discovery potential of LHC for the first Regge excitations of the quark and gluon. Remarkably, the reach of LHC after a few years of running can be as high as 6.8 TeV. Even after the first 100 pb{sup -1} of integrated luminosity, string scales as high as 4.0 TeV can be discovered. Data on pp{yields}direct{gamma}+ jet can provide corroboration for string physics at scales as high as 5 TeV.

  2. Taking energy to the physics classroom from the Large Hadron Collider at CERN

    NASA Astrophysics Data System (ADS)

    Cid, Xabier; Cid, Ramón

    2009-01-01

    In 2008, the greatest experiment in history began. When in full operation, the Large Hadron Collider (LHC) at CERN will generate the greatest amount of information that has ever been produced in an experiment before. It will also reveal some of the most fundamental secrets of nature. Despite the enormous amount of information available on this topic, it is not easy for non-specialists to know where the data comes from. The aim of this article is to introduce at a secondary school level a few simple physical calculations about power phenomena that will be present in the LHC: stored beam energy, power and LHC dipole, energy stored in the compact muon solenoid (CMS), energy stored in the ATLAS solenoid and toroid, delivered energy for radiofrequency (RF) cavities, and energy dissipated in dump blocks. In addition, we will be talking about one of the most important scientific institutions in the world and introducing the greatest experiment in history. The calculations that you will find in this article are adapted from physics at secondary school level, and in most cases they are just very simple approaches to the correct results.

  3. Higgs boson pair production in new physics models at hadron, lepton, and photon colliders

    SciTech Connect

    Asakawa, Eri; Harada, Daisuke; Okada, Yasuhiro; Kanemura, Shinya; Tsumura, Koji

    2010-12-01

    We study Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models; i.e., the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth generation fermion model and the vectorlike quark model. Cross sections for these processes can deviate significantly from the standard model predictions due to the one-loop correction to the triple Higgs boson coupling constant. For the one-loop induced processes such as gg{yields}hh and {gamma}{gamma}{yields}hh, where h is the (lightest) Higgs boson and g and {gamma} respectively represent a gluon and a photon, the cross sections can also be affected by new physics particles via additional one-loop diagrams. In the two-Higgs-doublet model and scalar leptoquark models, cross sections of e{sup +}e{sup -}{yields}hhZ and {gamma}{gamma}{yields}hh can be enhanced due to the nondecoupling effect in the one-loop corrections to the triple Higgs boson coupling constant. In the sequential fourth generation fermion model, the cross section for gg{yields}hh becomes very large because of the loop effect of the fermions. In the vectorlike quark model, effects are small because the theory has decoupling property. Measurements of the Higgs boson pair production processes can be useful to explore new physics through the determination of the Higgs potential.

  4. Soft functions for generic jet algorithms and observables at hadron colliders

    NASA Astrophysics Data System (ADS)

    Bertolini, Daniele; Kolodrubetz, Daniel; Neill, Duff; Pietrulewicz, Piotr; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.

    2017-07-01

    We introduce a method to compute one-loop soft functions for exclusive N - jet processes at hadron colliders, allowing for different definitions of the algorithm that determines the jet regions and of the measurements in those regions. In particular, we generalize the N -jettiness hemisphere decomposition of ref. [1] in a manner that separates the dependence on the jet boundary from the observables measured inside the jet and beam regions. Results are given for several factorizable jet definitions, including anti- k T , XCone, and other geometric partitionings. We calculate explicitly the soft functions for angularity measurements, including jet mass and jet broadening, in pp → L + 1 jet and explore the differences for various jet vetoes and algorithms. This includes a consistent treatment of rapidity divergences when applicable. We also compute analytic results for these soft functions in an expansion for a small jet radius R. We find that the small- R results, including corrections up to O({R}^2) , accurately capture the full behavior over a large range of R.

  5. High-energy resummation of direct photon production at hadronic colliders

    NASA Astrophysics Data System (ADS)

    Diana, Giovanni; Rojo, Juan; Ball, Richard D.

    2010-10-01

    Direct photon production is an important process at hadron colliders, being relevant both for precision measurement of the gluon density, and as background to Higgs and other new physics searches. Here we explore the implications of recently derived results for high-energy resummation of direct photon production for the interpretation of measurements at the Tevatron and the LHC. The effects of resummation are compared to various sources of theoretical uncertainties like PDFs and scale variations. We show how the high-energy resummation procedure stabilizes the logarithmic enhancement of the cross section at high energy which is present at any fixed order in the perturbative expansion starting at NNLO. The effects of high-energy resummation are found to be negligible at Tevatron, while they enhance the cross section by a few percent for pT≲10 GeV at the LHC. Our results imply that the discrepancy at small pT between fixed order NLO and Tevatron data cannot be explained by unresummed high-energy contributions.

  6. Physics requirements for the design of the ATLAS and CMS experiments at the Large Hadron Collider.

    PubMed

    Virdee, T S

    2012-02-28

    The ATLAS and CMS experiments at the CERN Large Hadron Collider are discovery experiments. Thus, the aim was to make them sensitive to the widest possible range of new physics. New physics is likely to reveal itself in addressing questions such as: how do particles acquire mass; what is the particle responsible for dark matter; what is the path towards unification; do we live in a world with more space-time dimensions than the familiar four? The detection of the Higgs boson, conjectured to give mass to particles, was chosen as a benchmark to test the performance of the proposed experiment designs. Higgs production is one of the most demanding hypothesized processes in terms of required detector resolution and background discrimination. ATLAS and CMS feature full coverage, 4π-detectors to measure precisely the energies, directions and identity of all the particles produced in proton-proton collisions. Realizing this goal has required the collaborative efforts of enormous teams of people from around the world.

  7. Search for Microscopic Black Hole Signatures at the Large Hadron Collider

    SciTech Connect

    Tsang, Ka Vang

    2011-05-01

    A search for microscopic black hole production and decay in proton-proton collisions at a center-of-mass energy of 7 TeV has been conducted using Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider. A total integrated luminosity of 35 pb-1 data sample, taken by CMS Collaboration in year 2010, has been analyzed. A novel background estimation for multi-jet events beyond TeV scale has been developed. A good agreement with standard model backgrounds, dominated by multi-jet production, is observed for various final-state multiplicities. Using semi-classical approximation, upper limits on minimum black hole mass at 95% confidence level are set in the range of 3.5 - 4.5 TeV for values of the Planck scale up to 3 TeV. Model-independent limits are provided to further constrain microscopic black hole models with additional regions of parameter space, as well as new physics models with multiple energetic final states. These are the first limits on microscopic black hole production at a particle accelerator.

  8. The upgraded Pixel Detector of the ATLAS Experiment for Run 2 at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Backhaus, M.

    2016-09-01

    During Run 1 of the Large Hadron Collider (LHC), the ATLAS Pixel Detector has shown excellent performance. The ATLAS collaboration took advantage of the first long shutdown of the LHC during 2013 and 2014 and extracted the ATLAS Pixel Detector from the experiment, brought it to surface and maintained the services. This included the installation of new service quarter panels, the repair of cables, and the installation of the new Diamond Beam Monitor (DBM). Additionally, a completely new innermost pixel detector layer, the Insertable B-Layer (IBL), was constructed and installed in May 2014 between a new smaller beam pipe and the existing Pixel Detector. With a radius of 3.3 cm the IBL is located extremely close to the interaction point. Therefore, a new readout chip and two new sensor technologies (planar and 3D) are used in the IBL. In order to achieve best possible physics performance the material budget was improved with respect to the existing Pixel Detector. This is realized using lightweight staves for mechanical support and a CO2 based cooling system. This paper describes the improvements achieved during the maintenance of the existing Pixel Detector as well as the performance of the IBL during the construction and commissioning phase. Additionally, first results obtained during the LHC Run 2 demonstrating the distinguished tracking performance of the new Four Layer ATLAS Pixel Detector are presented.

  9. Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC)

    SciTech Connect

    Darve, C.; Balle, C.; Casas-Cubillos, J.; Perin, A.; Vauthier, N.; /CERN

    2011-05-01

    The low-{beta} magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 10{sup 34}cm{sup -2}s{sup -1}. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-{beta} magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents the instrumentation used to optimize the engineering process and operation of the final focusing/defocusing quadrupole magnets for the first years of operation.

  10. Suppression of high-p{sub T} hadrons in Pb+Pb collisions at energies available at the CERN Large Hadron Collider

    SciTech Connect

    Chen Xiaofang; Wang Enke; Zhang Hanzhong; Hirano, Tetsufumi; Wang Xinnian

    2011-09-15

    The nuclear modification factor R{sub AA}(p{sub T}) for large transverse momentum pion spectra in Pb+Pb collisions at {radical}(s)=2.76 TeV is predicted within the next-to-leading order perturbative QCD parton model. The effect of jet quenching is incorporated through medium-modified fragmentation functions within the higher-twist approach. The jet transport parameter that controls medium modification is proportional to the initial parton density, and the coefficient is fixed by data on the suppression of large-p{sub T} hadron spectra obtained at the BNL Relativistic Heavy Ion Collider. Data on charged hadron multiplicity dN{sub ch}/d{eta}=1584{+-}80 in central Pb+Pb collisions from the ALICE experiment at the CERN Large Hadron Collider are used to constrain the initial parton density both for determining the jet transport parameter and the 3 + 1 dimensional (3 + 1D) ideal hydrodynamic evolution of the bulk matter that is employed for the calculation of R{sub PbPb}(p{sub T}) for neutral pions.

  11. Suppression of high-pT hadrons in Pb+Pb collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Chen, Xiao-Fang; Hirano, Tetsufumi; Wang, Enke; Wang, Xin-Nian; Zhang, Hanzhong

    2011-09-01

    The nuclear modification factor RAA(pT) for large transverse momentum pion spectra in Pb+Pb collisions at s=2.76 TeV is predicted within the next-to-leading order perturbative QCD parton model. The effect of jet quenching is incorporated through medium-modified fragmentation functions within the higher-twist approach. The jet transport parameter that controls medium modification is proportional to the initial parton density, and the coefficient is fixed by data on the suppression of large-pT hadron spectra obtained at the BNL Relativistic Heavy Ion Collider. Data on charged hadron multiplicity dNch/dη=1584±80 in central Pb+Pb collisions from the ALICE experiment at the CERN Large Hadron Collider are used to constrain the initial parton density both for determining the jet transport parameter and the 3 + 1 dimensional (3 + 1D) ideal hydrodynamic evolution of the bulk matter that is employed for the calculation of RPbPb(pT) for neutral pions.

  12. Simulation Study of RICH Detector for Particle Identification in Forward Region at Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Wong, Cheuk-Ping

    2015-04-01

    eRD11 R&D program is focusing on the technology exploration for hadron particle identification in the forward region of Electron-Ion Collider (EIC) for studying quark and gluon distributions inside the nucleon. A modular Ring Imaging Cherenkov (RICH) detector has been extensively studied in Geant4-based simulation. The detector consists of a block of aerogel, Fresnel lens, four side mirrors and a photosensor plane. The simulated performance of this detector will be presented in this talk. For the eRD11 Collaboration.

  13. HAWK 2.0: A Monte Carlo program for Higgs production in vector-boson fusion and Higgs strahlung at hadron colliders

    NASA Astrophysics Data System (ADS)

    Denner, Ansgar; Dittmaier, Stefan; Kallweit, Stefan; Mück, Alexander

    2015-10-01

    The Monte Carlo integrator HAWK provides precision predictions for Higgs production at hadron colliders in vector-boson fusion and Higgs strahlung, i.e. in production processes where the Higgs boson is Attached to WeaK bosons. The fully differential predictions include the full QCD and electroweak next-to-leading-order corrections. Results are computed as integrated cross sections and as binned distributions for important hadron-collider observables.

  14. Nuclear physics with a medium-energy Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Accardi, A.; Guzey, V.; Prokudin, A.; Weiss, C.

    2012-06-01

    A polarized ep/ eA collider (Electron-Ion Collider, or EIC) with variable center-of-mass energy √ s ˜ 20-70 GeV and luminosity ˜1034 cm-2 s-1 would be uniquely suited to address several outstanding questions of Quantum Chromodynamics (QCD) and the microscopic structure of hadrons and nuclei: i) the three-dimensional structure of the nucleon in QCD (sea quark and gluon spatial distributions, orbital motion, polarization, correlations); ii) the fundamental color fields in nuclei (nuclear parton densities, shadowing, coherence effects, color transparency); iii) the conversion of color charge to hadrons (fragmentation, parton propagation through matter, in-medium jets). We briefly review the conceptual aspects of these questions and the measurements that would address them, emphasizing the qualitatively new information that could be obtained with the collider. Such a medium-energy EIC could be realized at Jefferson Lab after the 12GeV Upgrade (MEIC), or at Brookhaven National Lab as the low-energy stage of eRHIC.

  15. Nuclear physics with a medium-energy Electron-Ion Collider

    SciTech Connect

    A. Accardi, V. Guzey, A. Prokudin, C. Weiss

    2012-06-01

    A polarized ep/eA collider (Electron-Ion Collider, or EIC) with variable center-of-mass energy {radical}s {approx} 20-70 GeV and a luminosity {approx}10{sup 34} cm{sup -2} s{sup -1} would be uniquely suited to address several outstanding questions of Quantum Chromodynamics (QCD) and the microscopic structure of hadrons and nuclei: (i) the three-dimensional structure of the nucleon in QCD (sea quark and gluon spatial distributions, orbital motion, polarization, correlations); (ii) the fundamental color fields in nuclei (nuclear parton densities, shadowing, coherence effects, color transparency); (iii) the conversion of color charge to hadrons (fragmentation, parton propagation through matter, in-medium jets). We briefly review the conceptual aspects of these questions and the measurements that would address them, emphasizing the qualitatively new information that could be obtained with the collider. Such a medium-energy EIC could be realized at Jefferson Lab after the 12 GeV Upgrade (MEIC), or at Brookhaven National Lab as the low-energy stage of eRHIC.

  16. Chiral electric field in relativistic heavy-ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Zhong, Yang; Yang, Chun-Bin; Cai, Xu; Feng, Sheng-Qin

    2016-08-01

    It has been proposed that electric fields may lead to chiral separation in quark-gluon plasma (QGP). This is called the chiral electric separation effect. The strong electromagnetic field and the QCD vacuum can both be completely produced in off-central nuclear-nuclear collision. We use the Woods-Saxon nucleon distribution to calculate the electric field distributions of off-central collisions. The chiral electric field spatial distribution at Relativistic Heavy-Ion Collider (RHIC) and Large Hadron Collider (LHC) energy regions are systematically studied in this paper. The dependence of the electric field produced by the thermal quark in the central position with different impact parameters on the proper time with different collision energies in the RHIC and LHC energy regions are studied in this paper. Supported by National Natural Science Foundation of China (11375069, 11435054, 11075061, 11221504) and Key Laboratory Foundation of Quark and Lepton Physics (Hua-Zhong Normal University)(QLPL2014P01)

  17. Beam losses from ultra-peripheral nuclear collisions between Pb ions in the Large Hadron Collider and their alleviation

    SciTech Connect

    Bruce, R.; Bocian, D.; Gilardoni, S.; Jowett, J.M.; /CERN

    2009-08-01

    Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC) at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte-Carlo shower simulation and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of {sup 208}Pb{sup 82+} ion operation in the LHC, with focus on the alice interaction region, and show that the expected heat load during nominal {sup 208}Pb{sup 82+} operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.

  18. Pre-Town Meeting on spin physics at an Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Aschenauer, Elke-Caroline; Balitsky, Ian; Bland, Leslie; Brodsky, Stanley J.; Burkardt, Matthias; Burkert, Volker; Chen, Jian-Ping; Deshpande, Abhay; Diehl, Markus; Gamberg, Leonard; Grosse Perdekamp, Matthias; Huang, Jin; Hyde, Charles; Ji, Xiangdong; Jiang, Xiaodong; Kang, Zhong-Bo; Kubarovsky, Valery; Lajoie, John; Liu, Keh-Fei; Liu, Ming; Liuti, Simonetta; Melnitchouk, Wally; Mulders, Piet; Prokudin, Alexei; Tarasov, Andrey; Qiu, Jian-Wei; Radyushkin, Anatoly; Richards, David; Sichtermann, Ernst; Stratmann, Marco; Vogelsang, Werner; Yuan, Feng

    2017-04-01

    A polarized ep/ eA collider (Electron-Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center-of-mass energy √{s} ˜ 20 to ˜ 100 GeV (upgradable to ˜ 150 GeV) and a luminosity up to ˜ 10^{34} cm-2s-1, would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three-dimensional structure of the nucleon (sea quark and gluon spatial distributions, orbital motion, polarization, and their correlations). This mini-review contains a short update on progress in these areas since the EIC White paper (A. Accardi et al., Eur. Phys. J. A 52, 268 (2016)).

  19. Report of Snowmass 2001 working group E2: Electron - positron colliders from the phi to the Z

    SciTech Connect

    Zhen-guo Zhao et al.

    2002-12-23

    We report on the status and plans of experiments now running or proposed for electron-positron colliders at energies between the {phi} and the Z. The e{sup +}e{sup -}B and charm factories we considered were PEP-II/BABAR, KEKB/Belle, superKEK, SuperBABAR, and CESR-c/CLEO-c. We reviewed the programs at the {phi} factory at Frascati and the proposed PEP-N facility at Stanford Linear Accelerator Center. We studied the prospects for B physics with a dedicated linear collider Z factory, associated with the TESLA high energy linear collider. In all cases, we compared the physics reach of these facilities with that of alternative experiments at hadron colliders or fixed target facilities.

  20. Bottom Production from Fixed-Target to Large Hadron Collider Energies

    SciTech Connect

    Nelson, R E; Vogt, R; Lourenco, C; Wohri, H K

    2010-11-30

    We present a state-of-the-art compilation of the existing bottom production cross sections in elementary collisions, from fixed-target to collider experiments. We then discuss the theoretical uncertainties on the total and differential bottom cross sections in the FONLL approach. In particular, we show total cross sections and kinematical distributions of the bottom hadrons and their decays: B {yields} e/{mu}X, B {yields} D {yields} e/{mu}, and B {yields} J/{psi}X. After seeing that the calculations give a good description of the existing measurements, we present detailed predictions for the LHC experiments in their specific phase space windows. Recent improvements in heavy quark production theory and experimental measurements at colliders, especially for bottom production, have shown that the perturbative QCD framework seems to work rather well, see Refs. [1, 2]. It is important to continue to validate this theoretical framework and its phenomenological inputs, extracted from other measurements, with new data such as that obtained by the CMS collaboration in pp collisions at {radical}s = 7 TeV. We validate the FONLL approach with lower energy data and also compare the results with preliminary LHC data. By showing good agreement between the calculations and the data, we demonstrate we can confidently extrapolate our results to energies appropriate for heavy-ion measurements. Total cross section calculations using the FONLL approach for pp {yields} B{bar B} show excellent agreement across a wide range of {radical}s at both full phase space and CDF phase space. This provides confidence that extrapolating to LHC energies will also show good agreement. Differential cross section FONLL calculations (d{sigma}/dp{sub T} and d{sigma}/d{eta}) at 7 TeV have been compared to preliminary CMS results. The agreement is quite striking. In addition, B fraction calculations have been made that also compare well to the CMS data. This should allow us to expect good agreement between

  1. Alternative positron-target design for electron-positron colliders

    SciTech Connect

    Donahue, R.J. ); Nelson, W.R. )

    1991-04-01

    Current electron-positron linear colliders are limited in luminosity by the number of positrons which can be generated from targets presently used. This paper examines the possibility of using an alternate wire-target geometry for the production of positrons via an electron-induced electromagnetic cascade shower. 39 refs., 38 figs., 5 tabs.

  2. Design considerations for the semi-digital hadronic calorimeter (SDHCAL) for future leptonic colliders

    NASA Astrophysics Data System (ADS)

    Pingault, A.

    2016-07-01

    The first technological SDHCAL prototype having been successfully tested, a new phase of R&D, to validate completely the SDHCAL option for the International Linear Detector (ILD) project of the International Linear Collider (ILC), has started with the conception and the realisation of a new prototype. The new one is intended to host few but large active layers of the future SDHCAL. The new active layers, made of Glass Resistive Plate Chambers (GRPC) with sizes larger than 2 m2 will be equipped with a new version of the electronic readout, fulfilling the requirements of the future ILD detector. The new GRPC are conceived to improve the homogeneity with a new gas distribution scheme. Finally the mechanical structure will be achieved using the electron beam welding technique. The progress realised will be presented and future steps will be discussed.

  3. Science Requirements and Conceptual Design for a Polarized Medium Energy Electron-Ion Collider at Jlab

    SciTech Connect

    Abeyratne, S; Ahmed, S; Barber, D; Bisognano, J; Bogacz, A; Castilla, A; Chevtsov, P; Corneliussen, S; Deconinck, W; Degtiarenko, P; Delayen, J; Derbenev, Ya; DeSilva, S; Douglas, D; Dudnikov, V; Ent, R; Erdelyi, B; Evtushenko, P; Fujii, Yu; Filatov, Yury; Gaskell, D; Geng, R; Guzey, V; Horn, T; Hutton, A; Hyde, C; Johnson, R; Kim, Y; Klein, F; Kondratenko, A; Kondratenko, M; Krafft, G; Li, R; Lin, F; Manikonda, S; Marhauser, F; McKeown, R; Morozov, V; Dadel-Turonski, P; Nissen, E; Ostroumov, P; Pivi, M; Pilat, F; Poelker, M; Prokudin, A; Rimmer, R; Satogata, T; Sayed, H; Spata, M; Sullivan, M; Tennant, C; Terzic, B; Tiefenback, M; Wang, M; Wang, S; Weiss, C; Yunn, B; Zhang, Y

    2012-08-01

    Researchers have envisioned an electron-ion collider with ion species up to heavy ions, high polarization of electrons and light ions, and a well-matched center-of-mass energy range as an ideal gluon microscope to explore new frontiers of nuclear science. In its most recent Long Range Plan, the Nuclear Science Advisory Committee (NSAC) of the US Department of Energy and the National Science Foundation endorsed such a collider in the form of a 'half-recommendation.' As a response to this science need, Jefferson Lab and its user community have been engaged in feasibility studies of a medium energy polarized electron-ion collider (MEIC), cost-effectively utilizing Jefferson Lab's already existing Continuous Electron Beam Accelerator Facility (CEBAF). In close collaboration, this community of nuclear physicists and accelerator scientists has rigorously explored the science case and design concept for this envisioned grand instrument of science. An electron-ion collider embodies the vision of reaching the next frontier in Quantum Chromodynamics - understanding the behavior of hadrons as complex bound states of quarks and gluons. Whereas the 12 GeV Upgrade of CEBAF will map the valence-quark components of the nucleon and nuclear wave functions in detail, an electron-ion collider will determine the largely unknown role sea quarks play and for the first time study the glue that binds all atomic nuclei. The MEIC will allow nuclear scientists to map the spin and spatial structure of quarks and gluons in nucleons, to discover the collective effects of gluons in nuclei, and to understand the emergence of hadrons from quarks and gluons. The proposed electron-ion collider at Jefferson Lab will collide a highly polarized electron beam originating from the CEBAF recirculating superconducting radiofrequency (SRF) linear accelerator (linac) with highly polarized light-ion beams or unpolarized light- to heavy-ion beams from a new ion accelerator and storage complex. Since the very

  4. Design and implementation of a crystal collimation test stand at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Mirarchi, D.; Hall, G.; Redaelli, S.; Scandale, W.

    2017-06-01

    Future upgrades of the CERN Large Hadron Collider (LHC) demand improved cleaning performance of its collimation system. Very efficient collimation is required during regular operations at high intensities, because even a small amount of energy deposited on superconducting magnets can cause an abrupt loss of superconducting conditions (quench). The possibility to use a crystal-based collimation system represents an option for improving both cleaning performance and impedance compared to the present system. Before relying on crystal collimation for the LHC, a demonstration under LHC conditions (energy, beam parameters, etc.) and a comparison against the present system is considered mandatory. Thus, a prototype crystal collimation system has been designed and installed in the LHC during the Long Shutdown 1 (LS1), to perform feasibility tests during the Run 2 at energies up to 6.5 TeV. The layout is suitable for operation with proton as well as heavy ion beams. In this paper, the design constraints and the solutions proposed for this test stand for feasibility demonstration of crystal collimation at the LHC are presented. The expected cleaning performance achievable with this test stand, as assessed in simulations, is presented and compared to that of the present LHC collimation system. The first experimental observation of crystal channeling in the LHC at the record beam energy of 6.5 TeV has been obtained in 2015 using the layout presented (Scandale et al., Phys Lett B 758:129, 2016). First tests to measure the cleaning performance of this test stand have been carried out in 2016 and the detailed data analysis is still on-going.

  5. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82+208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  6. Charge-multiplicity and collision-energy dependence of pt spectra from p-p collisions at the relativistic heavy-ion collider and large hadron collider

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2017-07-01

    A two-component (soft + hard) model (TCM) of hadron production in yields and spectra derived from the charge-multiplicity dependence of 200 GeV p-p collisions at the relativistic heavy ion collider is extended to describe p-p spectrum data from the large hadron collider (LHC) up to 13 TeV. The LHC data include spectrum ratios that provide only partial information on the TCM. The LHC ratio method is applied to well-understood 200 GeV spectrum data to derive an algebraic link between spectrum ratios and the full TCM. Some aspects of the form of the hard component on transverse momentum are found to be n ch dependent. LHC spectrum ratios are then analyzed to obtain n ch and collision-energy (over three orders of magnitude) dependence of isolated soft and hard TCM spectrum components. The energy dependence of the spectrum soft component is a new result suggesting a relation to Gribov diffusion. The spectrum hard component varies simply and smoothly with n ch suggesting bias of the underlying jet spectrum and linearly with QCD parameter {log}(s/{s}0), its properties consistent with minimum-bias reconstructed-jet spectrum measurements.

  7. Generation of ultrashort electron bunches by colliding laser pulses.

    PubMed

    Schroeder, C B; Lee, P B; Wurtele, J S; Esarey, E; Leemans, W P

    1999-05-01

    A proposed laser-plasma-based relativistic electron source [E. Esarey et al., Phys. Rev. Lett. 79, 2682 (1997)] using laser-triggered injection of electrons is investigated. The source generates ultrashort electron bunches by dephasing and trapping background plasma electrons undergoing fluid oscillations in an excited plasma wake. The plasma electrons are dephased by colliding two counterpropagating laser pulses which generate a slow phase velocity beat wave. Laser pulse intensity thresholds for trapping and the optimal wake phase for injection are calculated. Numerical simulations of test particles, with prescribed plasma and laser fields, are used to verify analytic predictions and to study the longitudinal and transverse dynamics of the trapped plasma electrons. Simulations indicate that the colliding laser pulse injection scheme has the capability to produce relativistic femtosecond electron bunches with fractional energy spread of order a few percent and normalized transverse emittance less than 1 mm mrad using 1 TW injection laser pulses.

  8. Towards future circular colliders

    NASA Astrophysics Data System (ADS)

    Benedikt, Michael; Zimmermann, Frank

    2016-09-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) presently provides proton-proton collisions at a center-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics program will extend through the second half of the 2030's. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ˜100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCCee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb3 S n superconductor, for the FCC-hh hadron collider, and a highly-efficient superconducting radiofrequency system for the FCC-ee lepton collider. Following the FCC concept, the Institute of High Energy Physics (IHEP) in Beijing has initiated a parallel design study for an e + e - Higgs factory in China (CEPC), which is to be succeeded by a high-energy hadron collider (SPPC). At present a tunnel circumference of 54 km and a hadron collider c.m. energy of about 70 TeV are being considered. After a brief look at the LHC, this article reports the motivation and the present status of the FCC study, some of the primary design challenges and R&D subjects, as well as the emerging global collaboration.

  9. Investigation and performance assessment of hydraulic schemes for the beam screen cooling for the Future Circular Collider of hadron beams

    NASA Astrophysics Data System (ADS)

    Kotnig, C.; Tavian, L.; Brenn, G.

    2017-02-01

    The international study at CERN of a possible future circular collider (FCC) considers an option for a very high energy hadron-hadron collider located in a quasi-circular underground tunnel of about 100 km of length. The technical segmentation of the collider foresees continuously cooled sections of up to 10.4 km; throughout the entire section length, more than 600 kW of heat mainly generated by the beam synchrotron radiation must be removed from the beam screen circuits at a mean temperature of 50 K. The cryogenic system has to be designed to extract the heat load dependably with a high-efficiency refrigeration process. Reliable and efficient cooling of the FCC beam screen in all possible operational modes requires a solid basic design as well as well-matched components in the final arrangement. After illustrating the decision making process leading to the selection of an elementary hydraulic scheme, this paper presents preliminary conceptual designs of the FCC beam screen cooling system and compares the different schemes regarding the technical advantages and disadvantages with respect to the exergetic efficiency.

  10. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    NASA Astrophysics Data System (ADS)

    Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

    2017-09-01

    As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  11. Direct photon elliptic flow at energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Kim, Young-Min; Lee, Chang-Hwan; Teaney, Derek; Zahed, Ismail

    2017-07-01

    We use an event-by-event hydrodynamical description of the heavy-ion collision process with Glauber initial conditions to calculate the thermal emission of photons. The photon rates in the hadronic phase follow from a spectral function approach and a density expansion, while in the partonic phase they follow from the Arnold-Moore-Yaffe (AMY) perturbative rates. The calculated photon elliptic flows are lower than those reported recently by both the ALICE and PHENIX collaborations.

  12. Muon collider design

    NASA Astrophysics Data System (ADS)

    Palmer, R.; Sessler, A.; Skrinsky, A.; Tollestrup, A.; Baltz, A.; Caspi, S.; P., Chen; W-H., Cheng; Y., Cho; Cline, D.; Courant, E.; Fernow, R.; Gallardo, J.; Garren, A.; Gordon, H.; Green, M.; Gupta, R.; Hershcovitch, A.; Johnstone, C.; Kahn, S.; Kirk, H.; Kycia, T.; Y., Lee; Lissauer, D.; Luccio, A.; McInturff, A.; Mills, F.; Mokhov, N.; Morgan, G.; Neuffer, D.; K-Y., Ng; Noble, R.; Norem, J.; Norum, B.; Oide, K.; Parsa, Z.; Polychronakos, V.; Popovic, M.; Rehak, P.; Roser, T.; Rossmanith, R.; Scanlan, R.; Schachinger, L.; Silvestrov, G.; Stumer, I.; Summers, D.; Syphers, M.; Takahashi, H.; Torun, Y.; Trbojevic, D.; Turner, W.; van Ginneken, A.; Vsevolozhskaya, T.; Weggel, R.; Willen, E.; Willis, W.; Winn, D.; Wurtele, J.; Zhao, Y.

    1996-11-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity \\mu^+ \\mu^- colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Detector background, polarization, and nonstandard operating conditions are discussed.

  13. Lattice design for the ERL electron ion collider in RHIC

    SciTech Connect

    Trbojevic, D.; Beebe-Wang, J.; Tsoupas, N.; Chang, X.; Kayran, D.; Ptitsyn, V.; Litvinenko, V.; Hao, Y.; Parker, B.; Pozdeyev, E.

    2010-05-23

    We present electron ion collider lattice design for the Relativistic Heavy Ion Collider (eRHIC) where the electrons have multi-passes through recirculating linacs (ERL) and arcs placed in the existing RHIC tunnel. The present RHIC interaction regions (IR's), where the electron ion collisions will occur, are modified to allow for the large luminosity. Staging of eRHIC will bring the electron energy from 4 up to 20 (30) GeV as the superconducting cavities are built and installed sequentially. The synchrotron radiation from electrons at the IR is reduced as they arrive straight to the collision while ions and protons come with 10 mrad crossing angle using the crab cavities.

  14. ACCELERATOR PHYSICS ISSUES FOR FUTURE ELECTRON ION COLLIDERS.

    SciTech Connect

    PEGGS,S.; BEN-ZVI,I.; KEWISCH,J.; MURPHY,J.

    2001-06-18

    Interest continues to grow in the physics of collisions between electrons and heavy ions, and between polarized electrons and polarized protons [1,2,3]. Table 1 compares the parameters of some machines under discussion. DESY has begun to explore the possibility of upgrading the existing HERA-p ring to store heavy ions, in order to collide them with electrons (or positrons) in the HERA-e ring, or from TESLA [4]. An upgrade to store polarized protons in the HERA-p ring is also under discussion [1]. BNL is considering adding polarized electrons to the RHIC repertoire, which already includes heavy and light ions, and polarized protons. The authors of this paper have made a first pass analysis of this ''eRHIC'' possibility [5]. MIT-BATES is also considering electron ion collider designs [6].

  15. Understanding the nuclear initial state with an electron ion collider

    NASA Astrophysics Data System (ADS)

    Toll, Tobias

    2013-09-01

    In these proceedings I describe how a future electron-ion collider will allow us to directly measure the initial spatial distribution of gluons in heavy ions, as well as its variance ("lumpiness") in exclusive diffraction. I show the feasibility of such a measurement by means of simulated data from the novel event generator Sartre.

  16. Simulation of tail distributions in electron-positron circular colliders

    SciTech Connect

    Irwin, J.

    1992-02-01

    In addition to the Gaussian shaped core region, particle bunches in electron-positron circular colliders have a rarefied halo region of importance in determining beam lifetimes and backgrounds in particle detectors. A method is described which allows simulation of halo particle distributions.

  17. An Electron-Ion Collider at Jefferson lab

    SciTech Connect

    A.W. Thomas

    2009-10-01

    Long term plans for the investigation of the quark and gluon structure of matter have for some time focussed on the possibility of an electron-ion collider, with the nuclear physics communities associated with JLab and BNL being particularly active. We briefly outline the current thinking on this subject at Jefferson lab.

  18. Simulation of tail distributions in electron-positron circular colliders

    SciTech Connect

    Irwin, J.

    1992-02-01

    In addition to the Gaussian shaped core region, particle bunches in electron-positron circular colliders have a rarefied halo region of importance in determining beam lifetimes and backgrounds in particle detectors. A method is described which allows simulation of halo particle distributions.

  19. Search for and Identification of Graviton Exchange Effects in Drell-Yan Process at Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Pankov, A. A.; Serenkova, I. A.; Tsytrinov, A. V.

    New physics signatures arising from different sources may be confused when first observed at future colliders. Thus it is important to examine how various scenarios may be differentiated given the availability of only limited information. Here, we explore the capability of the Large Hadron Collider (LHC) to distinguish spin-2 Kaluza-Klein towers of gravitons exchange from other new physics effects which might be conveniently parametrized by the four-fermion contact interactions. We find that the LHC with planned energies and luminosities will be capable of discovering (and identifying) graviton exchange effects in the large extra dimensions with the cutoff parameter of order 4.6 - 9.4 TeV (3.6 - 6.0 TeV) depending on energy, luminosity and number of extra dimensions.

  20. Probing small parton densities in ultraperipheral A A and pA collisions at the CERN large Hadron Collider.

    PubMed

    Strikman, Mark; Vogt, Ramona; White, Sebastian

    2006-03-03

    We calculate photoproduction rates for several hard processes in ultraperipheral proton-lead and lead-lead collisions at the CERN Large Hadron Collider (LHC) with square root of sNN = 8.8 and 5.5 TeV, respectively, which could be triggered in the large LHC detectors. We use ATLAS as an example. The lead ion is treated as a source of (coherently produced) photons with energies and intensities greater than those of equivalent ep collisions at the DESY collider HERA. We find very large rates for both inclusive and diffractive production that will extend the HERA x range by nearly an order of magnitude for similar virtualities. We demonstrate that it is possible to reach the kinematic regime where nonlinear effects are larger than at HERA.

  1. Momentum imbalance of D mesons in ultrarelativistic heavy-ion collisions at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Uphoff, Jan; Senzel, Florian; Xu, Zhe; Greiner, Carsten

    2014-06-01

    As a new observable for heavy flavor correlations the momentum imbalance AD of D mesons is proposed. It is defined analogously to the jet momentum imbalance AJ of fully reconstructed jets. However, because D mesons are flavor-tagged particles, no jet reconstruction is necessary. AD quantifies the influence of the medium created in heavy-ion collisions on correlated charm pairs. We present results with the partonic transport model Boltzmann approach to multiparton scatterings, which describes well the nuclear modification factor and elliptic flow of all heavy flavor particles at BNL Relativistic Heavy Ion Collider and Large Hadron Collider (LHC). The AD distribution in heavy-ion collisions at LHC is shifted to larger values of AD compared to proton-proton collisions. We argue that this shift is attributable to medium effects and can be explained partially by a path-length imbalance of charm pairs and partially by momentum fluctuations in the initial charm-pair distribution.

  2. Searches for and identification of effects of extra spatial dimensions in dilepton and diphoton production at the Large Hadron Collider

    SciTech Connect

    Pankov, A. A. Serenkova, I. A. Tsytrinov, A. V. Bednyakov, V. A.

    2015-06-15

    Prospects of discovering and identifying effects of extra spatial dimensions in dilepton and diphoton production at the Large Hadron Collider (LHC) are studied. Such effects may be revealed by the characteristic behavior of the invariant-mass distributions of dileptons and diphotons, and their identification can be performed on the basis of an analysis of their angular distributions. The discovery and identification reaches are estimated for the scale parameter M{sub S} of the Kaluza-Klein gravitational towers, which can be determined in experiments devoted to measuring the dilepton and diphoton channels at the LHC.

  3. Four-Jet Production at the Large Hadron Collider at Next-to-Leading Order in QCD

    NASA Astrophysics Data System (ADS)

    Bern, Z.; Diana, G.; Dixon, L. J.; Cordero, F. Febres; Höche, S.; Kosower, D. A.; Ita, H.; Maître, D.; Ozeren, K.

    2012-07-01

    We present the cross sections for production of up to four jets at the Large Hadron Collider, at next-to-leading order in the QCD coupling. We use the BlackHat library in conjunction with SHERPA and a recently developed algorithm for assembling primitive amplitudes into color-dressed amplitudes. We adopt the cuts used by ATLAS in their study of multijet events in pp collisions at s=7TeV. We include estimates of nonperturbative corrections and compare to ATLAS data. We store intermediate results in a framework that allows the inexpensive computation of additional results for different choices of scale or parton distributions.

  4. Large Hadron Collider at CERN: Beams generating high-energy-density matter.

    PubMed

    Tahir, N A; Schmidt, R; Shutov, A; Lomonosov, I V; Piriz, A R; Hoffmann, D H H; Deutsch, C; Fortov, V E

    2009-04-01

    This paper presents numerical simulations that have been carried out to study the thermodynamic and hydrodynamic responses of a solid copper cylindrical target that is facially irradiated along the axis by one of the two Large Hadron Collider (LHC) 7 TeV/ c proton beams. The energy deposition by protons in solid copper has been calculated using an established particle interaction and Monte Carlo code, FLUKA, which is capable of simulating all components of the particle cascades in matter, up to multi-TeV energies. These data have been used as input to a sophisticated two-dimensional hydrodynamic computer code BIG2 that has been employed to study this problem. The prime purpose of these investigations was to assess the damage caused to the equipment if the entire LHC beam is lost at a single place. The FLUKA calculations show that the energy of protons will be deposited in solid copper within about 1 m assuming constant material parameters. Nevertheless, our hydrodynamic simulations have shown that the energy deposition region will extend to a length of about 35 m over the beam duration. This is due to the fact that first few tens of bunches deposit sufficient energy that leads to high pressure that generates an outgoing radial shock wave. Shock propagation leads to continuous reduction in the density at the target center that allows the protons delivered in subsequent bunches to penetrate deeper and deeper into the target. This phenomenon has also been seen in case of heavy-ion heated targets [N. A. Tahir, A. Kozyreva, P. Spiller, D. H. H. Hoffmann, and A. Shutov, Phys. Rev. E 63, 036407 (2001)]. This effect needs to be considered in the design of a sacrificial beam stopper. These simulations have also shown that the target is severely damaged and is converted into a huge sample of high-energy density (HED) matter. In fact, the inner part of the target is transformed into a strongly coupled plasma with fairly uniform physical conditions. This work, therefore, has

  5. Accessing the Distribution of Linearly Polarized Gluons in Unpolarized Hadrons

    SciTech Connect

    Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian; /Cagliari U. /INFN, Cagliari

    2011-08-19

    Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this distribution of linearly polarized gluons is through cos2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future Electron-Ion Collider (EIC) or Large Hadron electron Collider (LHeC) experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.

  6. Compendium of equations for the design of a very large hadron collider

    SciTech Connect

    Ruggiero, A.G.

    1996-12-31

    In this report the author gives several relationships which are used for the preliminary design and to estimate the collider performance. He limits to the case of the performance during storage and colliding mode. These relationships are for: (1)Luminosity and beam-beam tune-shift; (2) microwave longitudinal instability; and (3) synchrotron radiation effects.

  7. Ion colliders

    SciTech Connect

    Fischer, W.

    2011-12-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  8. Development of Micro-Pattern Gas Detectors for the Upgrade of the Muon System of the CMS Experiment at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bouhali, Othmane

    2017-06-01

    After the discovery of the long awaited Higgs boson in 2012, the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) and its two general purpose experiments (ATLAS and CMS) are preparing to break new grounds in High Energy Physics (HEP). The international HEP collaboration has established a rigorous research program of exploring new physics at the high energy frontiers. The program includes substantial increase in the luminosity of the LHC putting detectors into a completely new and unprecedented harsh environment. In order to maintain their excellent performance, an upgrade of the existing detectors is mandatory. In this work we will describe ongoing efforts for the upgrade of the CMS muon detection system, in particular the addition of detection layers based on the Gas Electron Multiplier (GEM) technology. We will summarize the past 5-year R&D program and the future installation and operation plans.

  9. Transverse Momentum Dependent Parton Distribution/Fragmentation Functions at an Electron-Ion Collider

    SciTech Connect

    M. Anselmino, H. Avakian, D. Boer, F. Bradamante, M. Burkardt, J.P. Chen, E. Cisbani, M. Contalbrigo, D. Crabb, D. Dutta, L. Gamberg, H. Gao, D. Hasch, J. Huang, M. Huang, Z. Kang, C. Keppel, G. Laskaris, Z-T. Liang, M.X. Liu, N. Makins, R.D. Mckeown, A. Metz, Z-E. Meziani, B. Musch, J-C. Peng, A. Prokudin, X. Qian, Y. Qiang, J.W. Qiu, P. Rossi, P. Schweitzer, J. Soffer, V. Sulkosky, Y. Wang, B. Xiao, Q. Ye, Q-J. Ye, F. Yuan, X. Zhan, Y. Zhang, W. Zheng, J. Zhou

    2011-03-01

    We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse momentum dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. We then present simulation results on experimental studies of TMDs through measurements of single spin asymmetries (SSA) from semi-inclusive deep-inelastic scattering (SIDIS) processes with an EIC, and discuss the requirement of the detector for SIDIS measurements. The dynamics of parton correlations in the nucleon is further explored via a study of SSA in D (`D) production at large transverse momenta with the aim of accessing the unexplored tri-gluon correlation functions. The workshop participants identified the SSA measurements in SIDIS as a golden program to study TMDs in both the sea and valence quark regions and to study the role of gluons, with the Sivers asymmetry measurements as examples. Such measurements will lead to major advancement in our understanding of TMDs in the valence quark region, and more importantly also allow for the investigation of TMDs in the sea quark region along with a study of their evolution.

  10. Experimental search for W/Z pairs and Higgs bosons at very high energy hadron-hadron colliders

    SciTech Connect

    Alverson, G.; Bengtsson, H.U.; Hauptman, J.; Hedin, D.; Herrero, M.J.; Wang, E.; Linn, S.; Young, C.; Milliken, B.; Paige, F.

    1987-03-01

    We study, from an experimental point of view, the main ways to detect standard high mass Higgs bosons (from 300 GeV up to about 1 TeV) when they decay into W- and Z-pairs at the SSC. We also consider the corresponding W- and Z/sup 0/-pair continuum which may itself provide interesting physics, and we pay some attention to the case of an intermediate mass charged Higgs decaying into tau..nu../sub tau/ (m/sub H+-/ = 300 GeV). We first explain why and how high energy pp colliders may search for Higgs' and we compare their possible performances to those of the e/sup +/e/sup -/ and ep colliders at all possible mass scale (from few tens of GeV's up to 1 TeV). We then estimate the rates of the signals and the main backgrounds. We define the main characteristics of these events as reproduced by M.C. generators (especially implemented with these processes) and simulated through an idealized 4..pi.. fine-grained calorimeter. A trigger strategy for W- and Z-pairs is derived from this study. 26 refs., 28 figs.

  11. Discovery and measurement of excited b hadrons at the Collider Detector at Fermilab

    SciTech Connect

    Pursley, Jennifer Marie

    2007-08-01

    This thesis presents evidence for the B**0 and Σ$(*)±\\atop{b}$ hadrons in proton-antiproton collisions at a center of mass energy of 1.96 TeV, using data collected by the Collider Detector at Fermilab. In the search for B**0 → B± π, two B± decays modes are reconstructed: B± → J/ΨK±, where J/Ψ → μ+μ-, and B± → $\\bar{D}$0π±, where $\\bar{D}$0 → K± π±. Both modes are reconstructed using 370 ± 20 pb-1 of data. Combining the B± meson with a charged pion to reconstruct B**0 led to the observation and measurement of the masses of the two narrow B**0 states, B$1\\atop{0}$ and B$*0\\atop{2}$, of m(B$1\\atop{0}$) = 5734 ± 3(stat.) ± 2(syst.) MeV/c2; m(B$*0\\atop{2}$) = 5738 ± 5(stat.) ± 1(syst.) MeV/c{sup 2}. In the search for Σ$(*)±\\atop{b}$ → Λ$0\\atop{b}$π±, the Λ$0\\atop{b}$ is reconstructed in the decay mode Λ$0\\atop{b}$ → Λ$+\\atop{c}$π-, where Λ$+\\atop{c}$→ pK- π+, using 1070 ± 60 pb-1 of data. Upon combining the Λ$0\\atop{b}$ candidate with a charged pion, all four of the Σ$(*)±\\atop{b}$ states are observed and their masses measured to be: m(Σ$+\\atop{b}$) = 5807.8$+2.0\\atop{-2.2}$(stat.) ± 1.7(syst.) MeV/c2; m(Σ$+\\atop{b}$) = 5815.2 ± 1.0(stat.) ± 1.7(syst.) MeV/c2; m(Σ$*+\\atop{b}$) = 5829.0$+1.6\\atop{-1.8}$(stat.)$+1.7\\atop{-1.8}$(syst.) MeV/c 2; M(Σ$*-±\\atop{b}$) - 5836.4 ± 2.0(stat.)$+1.8\\atop{-1.7}$(syst.) MeV/c2. This is the first observation of Σ$(*)±\\atop{b}$ baryons.

  12. eRHIC - Future Electron-Ion Collider at BNL

    SciTech Connect

    Ptitsyn, V.

    2006-07-11

    The work on the detailed design of electron-ion collider, eRHIC, on the basis of existing RHIC machine is underway. eRHIC aims to be an instrument for the exploration of important QCD aspects using collisions of polarized electrons and positrons on ions and polarized protons in the center of mass energy range of 30-100 GeV, with a luminosity of 1032-1034 cm-2s-1 for c-p and 1030-1032 cm-2s-1 for c-Au collisions. An electron accelerator, which delivers about 0.5A polarized electron beam current in the electron energy range of 5 to 10 GeV, would be constructed at BNL, near the existing RHIC complex and would intersect an ion ring in at least one of the available ion ring interaction regions. One design option considers the circular electron machine based on the accelerator technology similar to that of storage rings at the e+-e- B-factories. Another pursued design option employs an energy recovery linac for electron acceleration. This option paves way to higher luminosities but meets challenges of developments of high current electron polarized source and high beam power ERL technologies. To maximize the collider luminosity certain upgrades are considered for RHIC ion rings.

  13. High-energy high-luminosity electron-ion collider eRHIC

    SciTech Connect

    Litvinenko, V.N.; Ben-Zvi, I.; Hammons, L.; Hao, Y.; Webb, S.; et al

    2011-08-09

    In this paper, we describe a future electron-ion collider (EIC), based on the existing Relativistic Heavy Ion Collider (RHIC) hadron facility, with two intersecting superconducting rings, each 3.8 km in circumference. The replacement cost of the RHIC facility is about two billion US dollars, and the eRHIC will fully take advantage and utilize this investment. We plan adding a polarized 5-30 GeV electron beam to collide with variety of species in the existing RHIC accelerator complex, from polarized protons with a top energy of 325 GeV, to heavy fully-striped ions with energies up to 130 GeV/u. Brookhaven's innovative design, is based on one of the RHIC's hadron rings and a multi-pass energy-recovery linac (ERL). Using the ERL as the electron accelerator assures high luminosity in the 10{sup 33}-10{sup 34} cm{sup -2} sec{sup -1} range, and for the natural staging of eRHIC, with the ERL located inside the RHIC tunnel. The eRHIC will provide electron-hadron collisions in up to three interaction regions. We detail the eRHIC's performance in Section 2. Since first paper on eRHIC paper in 2000, its design underwent several iterations. Initially, the main eRHIC option (the so-called ring-ring, RR, design) was based on an electron ring, with the linac-ring (LR) option as a backup. In 2004, we published the detailed 'eRHIC 0th Order Design Report' including a cost-estimate for the RR design. After detailed studies, we found that an LR eRHIC has about a 10-fold higher luminosity than the RR. Since 2007, the LR, with its natural staging strategy and full transparency for polarized electrons, became the main choice for eRHIC. In 2009, we completed technical studies of the design and dynamics for MeRHIC with 3-pass 4 GeV ERL. We learned much from this evaluation, completed a bottom-up cost estimate for this $350M machine, but then shelved the design. In the same year, we turned again to considering the cost-effective, all-in-tunnel six-pass ERL for our design of the high

  14. The VEPP-2000 electron-positron collider: First experiments

    SciTech Connect

    Berkaev, D. E. Shwartz, D. B.; Shatunov, P. Yu.; Rogovskii, Yu. A.; Romanov, A. L.; Koop, I. A.; Shatunov, Yu. M.; Zemlyanskii, I. M.; Lysenko, A. P.; Perevedentsev, E. A.; Stankevich, A. S.; Senchenko, A. I.; Khazin, B. I.; Anisenkov, A. V.; Gayazov, S. E.; Kozyrev, A. N.; Ryzhenenkov, A. E.; Shemyakin, D. N.; Epshtein, L. B.; Serednyakov, S. I.; and others

    2011-08-15

    In 2007, at the Institute of Nuclear Physics (Novosibirsk), the construction of the VEPP-2000 electron-positron collider was completed. The first electron beam was injected into the accelerator structure with turned-off solenoids of the final focus. This mode was used to tune all subsystems of the facility and to train the vacuum chamber using synchrotron radiation at electron currents of up to 150 mA. The VEPP-2000 structure with small beta functions and partially turned-on solenoids was used for the first testing of the 'round beams' scheme at an energy of 508 MeV. Beam-beam effects were studied in strong-weak and strong-strong modes. Measurements of the beam sizes in both cases showed a dependence corresponding to model predictions for round colliding beams. Using a modernized SND (spherical neutral detector), the first energy calibration of the VEPP-2000 collider was performed by measuring the excitation curve of the phimeson resonance; the phi-meson mass is known with high accuracy from previous experiments at VEEP-2M. In October 2009, a KMD-3 (cryogenic magnetic detector) was installed at the VEPP-2000 facility, and the physics program with both the SND and LMD-3 particle detectors was started in the energy range of 1-1.9 GeV. This first experimental season was completed in summer 2010 with precision energy calibration by resonant depolarization.

  15. Probing the Quark Sea and Gluons: the Electron-Ion Collider Projects

    SciTech Connect

    Rolf Ent

    2012-04-01

    EIC is the generic name for the nuclear science-driven Electron-Ion Collider presently considered in the US. Such an EIC would be the world’s first polarized electron-proton collider, and the world’s first e-A collider. Very little remains known about the dynamical basis of the structure of hadrons and nuclei in terms of the fundamental quarks and gluons of Quantum Chromodynamics (QCD). A large community effort to sharpen a compelling nuclear science case for an EIC occurred during a ten-week program taking place at the Institute for Nuclear Theory (INT) in Seattle from September 13 to November 19, 2010. The critical capabilities of a stage-I EIC are a range in center-of-mass energies from 20 to 70 GeV and variable, full polarization of electrons and light ions (the latter both longitudinal and transverse), ion species up to A=200 or so, multiple interaction regions, and a high luminosity of about 10{sup 34} electron-nucleons per cm{sup 2} and per second. The physics program of such a stage-I EIC encompass inclusive measurements (ep/A{yields}e'+X), which require detection of the scattered lepon and/or the full scattered hadronic debris with high precision, semi-inclusive processes (ep/A{yields}e'+h+X), which require detection in coincidence with the scattered lepton of at least one (current or target region) hadron; and exclusive processes (ep/A{yields}e'+N'/A'+{gamma}/m), which require detection of all particles in the reaction. The main science themes of an EIC are to i) map the spin and spatial structure of quarks and gluons in nucleons, ii) discover the collective effects of gluons in atomic nuclei, and (iii) understand the emergence of hadronic matter from color charge. In addition, there are opportunities at an EIC for fundamental symmetry and nucleon structure measurements using the electroweak probe. To truly make headway to image the sea quarks and gluons in nucleons and nuclei, the EIC needs high luminosity over a range of energies as more exclusive

  16. ERHIC, A FUTURE ELECTRON-ION COLLIDER AT BNL

    SciTech Connect

    PTITSYN,V.; AHRENS L.; ET AL.

    2004-07-05

    The authors review recent progress in the design of eRHIC, a proposed high luminosity, polarized electron-ion collider which would make use of the existing RHIC machine. The eRHIC collider aims to provide collisions of electrons and positrons on ions and protons in the center-of-mass energy range of 30-100 GeV, with a luminosity of 10{sup 32}-10{sup 34} cm{sup -2}s{sup -1} for e-p and 10{sup 30}-10{sup 32} cm{sup -2}s{sup -1} for e-Au collisions. An essential design requirement is to provide longitudinally polarized beams of electrons and protons (and, possibly lighter ions) at the collisions point. An eRHIC ZDR [1] has been prepared which considers various aspects of the accelerator design. An electron accelerator, which delivers about 0.5A polarized electron beam current in the electron energy range of 5 to 10 GeV, would be constructed at BNL, near the existing RHIC complex and would intersect an ion ring in at least one of the available ion ring interaction regions. In order to reach the luminosity goals, some upgrades in the ion rings would also be required.

  17. High Energy Colliders

    NASA Astrophysics Data System (ADS)

    Palmer, R. B.; Gallardo, J. C.

    INTRODUCTION PHYSICS CONSIDERATIONS GENERAL REQUIRED LUMINOSITY FOR LEPTON COLLIDERS THE EFFECTIVE PHYSICS ENERGIES OF HADRON COLLIDERS HADRON-HADRON MACHINES LUMINOSITY SIZE AND COST CIRCULAR e^{+}e^- MACHINES LUMINOSITY SIZE AND COST e^{+}e^- LINEAR COLLIDERS LUMINOSITY CONVENTIONAL RF SUPERCONDUCTING RF AT HIGHER ENERGIES γ - γ COLLIDERS μ ^{+} μ^- COLLIDERS ADVANTAGES AND DISADVANTAGES DESIGN STUDIES STATUS AND REQUIRED R AND D COMPARISION OF MACHINES CONCLUSIONS DISCUSSION

  18. Polarized positrons and electrons at the linear collider

    NASA Astrophysics Data System (ADS)

    Moortgat-Pick, G.; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A. A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke, J.; Clendenin, J. E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Dreiner, H. K.; Eberl, H.; Ellis, J.; Flöttmann, K.; Fraas, H.; Franco-Sollova, F.; Franke, F.; Freitas, A.; Goodson, J.; Gray, J.; Han, A.; Heinemeyer, S.; Hesselbach, S.; Hirose, T.; Hohenwarter-Sodek, K.; Juste, A.; Kalinowski, J.; Kernreiter, T.; Kittel, O.; Kraml, S.; Langenfeld, U.; Majerotto, W.; Martinez, A.; Martyn, H.-U.; Mikhailichenko, A.; Milstene, C.; Menges, W.; Meyners, N.; Mönig, K.; Moffeit, K.; Moretti, S.; Nachtmann, O.; Nagel, F.; Nakanishi, T.; Nauenberg, U.; Nowak, H.; Omori, T.; Osland, P.; Pankov, A. A.; Paver, N.; Pitthan, R.; Pöschl, R.; Porod, W.; Proulx, J.; Richardson, P.; Riemann, S.; Rindani, S. D.; Rizzo, T. G.; Schälicke, A.; Schüler, P.; Schwanenberger, C.; Scott, D.; Sheppard, J.; Singh, R. K.; Sopczak, A.; Spiesberger, H.; Stahl, A.; Steiner, H.; Wagner, A.; Weber, A. M.; Weiglein, G.; Wilson, G. W.; Woods, M.; Zerwas, P.; Zhang, J.; Zomer, F.

    2008-05-01

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  19. Les Houches guidebook to Monte Carlo generators for hadron collider physics

    SciTech Connect

    Dobbs, Matt A.; Frixione, Stefano; Laenen, Eric; Tollefson, Kirsten

    2004-03-01

    Recently the collider physics community has seen significant advances in the formalisms and implementations of event generators. This review is a primer of the methods commonly used for the simulation of high energy physics events at particle colliders. We provide brief descriptions, references, and links to the specific computer codes which implement the methods. The aim is to provide an overview of the available tools, allowing the reader to ascertain which tool is best for a particular application, but also making clear the limitations of each tool.

  20. Les Houches Guidebook to Monte Carlo generators for hadron collider physics

    SciTech Connect

    Dobbs, M.A

    2004-08-24

    Recently the collider physics community has seen significant advances in the formalisms and implementations of event generators. This review is a primer of the methods commonly used for the simulation of high energy physics events at particle colliders. We provide brief descriptions, references, and links to the specific computer codes which implement the methods. The aim is to provide an overview of the available tools, allowing the reader to ascertain which tool is best for a particular application, but also making clear the limitations of each tool.

  1. Single electron yields from semileptonic charm and bottom hadron decays in Au +Au collisions at √{sN N}=200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Bathe, S.; Baublis, V.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Dairaku, S.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; Donadelli, M.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Edwards, S.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; Hayashi, S.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Horaguchi, T.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Javani, M.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kawall, D.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kimelman, B.; Kinney, E.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Linden Levy, L. A.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Midori, J.; Mignerey, A. C.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, H. J.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nukariya, A.; Nyanin, A. S.; Obayashi, H.; O'Brien, E.; Ogilvie, C. A.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J.-C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.

    2016-03-01

    The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy flavor production in minimum bias Au +Au collisions at √{sN N}=200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons. Previous heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transverse momentum are measured in Au +Au collisions. We compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in p +p collisions at √{sN N}=200 GeV and find the fractions to be similar within the large uncertainties on both measurements for pT>4 GeV/c . We use the bottom electron fractions in Au +Au and p +p along with the previously measured heavy flavor electron RA A to calculate the RA A for electrons from charm and bottom hadron decays separately. We find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3

  2. Single electron yields from semileptonic charm and bottom hadron decays in Au+Au collisions at sNN=200 GeV

    DOE PAGES

    Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

    2016-03-07

    We measured open heavy flavor production in minimum bias Au + Au collisions at √s(NN) = 200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons, using the PHENIX Collaboration at the Relativistic Heavy Ion Collider. In the past, heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transversemore » momentum are measured in Au + Au collisions. Here, we compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in p + p collisions at √s(NN) = 200 GeV and find the fractions to be similar within the large uncertainties on both measurements for p(T) > 4 GeV/c. We use the bottom electron fractions in Au + Au and p + p along with the previously measured heavy flavor electron R(AA) to calculate the R(AA) for electrons from charm and bottom hadron decays separately. Finally, we find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3 < p(T) < 4 GeV/c.« less

  3. Dynamic aperture computation for the as-built CERN Large Hadron Collider and impact of main dipoles sorting

    NASA Astrophysics Data System (ADS)

    Fartoukh, S.; Giovannozzi, M.

    2012-04-01

    During the design phase of the CERN Large Hadron Collider the dynamic aperture, i.e. the amplitude of the domain in phase space where the particle motion is stable, was used as one of the most important figures-of-merit to specify the field quality of the various types of superconducting magnets and to quantify the machine performance. The programme of magnetic measurements performed during the production and acceptance testing of the magnets generated a large amount of information, which was used to obtain a best estimate of the dynamic aperture of the actual machine. In this paper the results of massive numerical simulations based on the measured field quality of several optical configurations and beam energies, are presented and discussed. The effect of the sorting of the main dipoles on the final value of the dynamic aperture has also been studied and the results are reviewed in detail.

  4. The effect of neutron skin on inclusive prompt photon production in Pb + Pb collisions at Large Hadron Collider energies

    NASA Astrophysics Data System (ADS)

    De, Somnath

    2017-04-01

    Recent experiments on lead ({{{Pb}}}82208) nuclei have observed the celebrated phenomenon of the neutron skin thickness of low energy nuclear physics. Skin thickness provides a measure of the extension of the spatial distribution of neutrons inside the atomic nucleus than protons. We have studied the effect of neutron skin thickness on inclusive prompt photon production in Pb + Pb collisions at Large Hadron Collider energies. We have calculated the ‘central-to-peripheral ratio’ ({R}{cp}) of prompt photon production with and without accounting for the neutron skin effect. The neutron skin causes a characteristic enhancement of the ratio, in particular at forward rapidity, which is distinguishable in our calculation. However, a very precise direct photon measurement up to large transverse momenta would be necessary to constrain the feature in experiment.

  5. Single top quark production in heavy ion collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Baskakov, A. V.; Boos, E. E.; Dudko, L. V.; Lokhtin, I. P.; Snigirev, A. M.

    2015-10-01

    The article presents analysis of the single top quark production in PbPb collisions at the CERN Large Hadron Collider at center-of-mass energy 5.5 TeV per nucleon pair. The analysis is performed with CompHEP and PYQUEN event generators. The neutron and proton content in the nuclei is taken into account. NLO precision has been implemented to simulate kinematic properties and rate of single top production. The modification of different characteristics of single top quark decay products due to interactions of jet partons in quark-gluon medium, and the specific charge asymmetry of top/antitop quark yields due to the isospin effect are evaluated.

  6. Determining the dark matter relic density in the minimal supergravity stau-neutralino coannihilation region at the Large Hadron Collider.

    PubMed

    Arnowitt, Richard; Dutta, Bhaskar; Gurrola, Alfredo; Kamon, Teruki; Krislock, Abram; Toback, David

    2008-06-13

    We examine the stau-neutralino coannihilation (CA) mechanism of the early Universe. We use the minimal supergravity (mSUGRA) model and show that from measurements at the CERN Large Hadron Collider one can predict the dark matter relic density with an uncertainty of 6% with 30 fb(-1) of data, which is comparable to the direct measurement by the Wilkinson Microwave Anisotropy Probe. This is done by measuring four mSUGRA parameters m(0), m(1/2), A(0), and tanbeta without requiring direct measurements of the top squark and bottom squark masses. We also provide precision measurements of the gaugino, squark, and lighter stau masses in this CA region without assuming gaugino universality.

  7. CERN-RD39 collaboration activities aimed at cryogenic silicon detector application in high-luminosity Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Li, Zheng; Eremin, Vladimir; Verbitskaya, Elena; Dehning, Bernd; Sapinski, Mariusz; Bartosik, Marcin R.; Alexopoulos, Andreas; Kurfürst, Christoph; Härkönen, Jaakko

    2016-07-01

    Beam Loss Monitors (BLM) made of silicon are new devices for monitoring of radiation environment in the vicinity of superconductive magnets of the Large Hadron Collider. The challenge of BLMs is extreme radiation hardness, up to 1016 protons/cm2 while placed in superfluid helium (temperature of 1.9 K). CERN BE-BI-BL group, together with CERN-RD39 collaboration, has developed prototypes of BLMs and investigated their device physics. An overview of this development-results of the in situ radiation tests of planar silicon detectors at 1.9 K, performed in 2012 and 2014-is presented. Our main finding is that silicon detectors survive under irradiation to 1×1016 p/cm2 at 1.9 K. In order to improve charge collection, current injection into the detector sensitive region (Current Injection Detector (CID)) was tested. The results indicate that the detector signal increases while operated in CID mode.

  8. ELECTRON BEAM STABILITY REQUIREMENTS FOR LINAC-RING ELECTRON-ION COLLIDERS.

    SciTech Connect

    MONTAG, C.

    2005-05-16

    In recent years, linac-ring electron-ion colliders have been proposed at a number of laboratories around the world. While the linac-ring approach overcomes the beam-beam tuneshift limitation on the electron beam, it also introduces noise into the ion beam, via the beam-beam interaction with electron bunches of slightly fluctuating intensity and transverse size. The effect of these fluctuations is studied using a linearized model of the beam-beam interaction. Upper limits for the rms jitter amplitudes of electron beam parameters for various linac-ring electron-ion colliders are presented.

  9. Hadronic cross sections measurement with the SND detector at VEPP-2000 e+e- collider

    NASA Astrophysics Data System (ADS)

    Achasov, M. N.; Barnyakov, A. Yu; Barnyakov, M. Yu; Beloborodov, K. I.; Berdyugin, A. V.; Berkaev, D. E.; Blinov, V. E.; Bobrovnikov, V. S.; Bogdanchikov, A. G.; Botov, A. A.; Buzykaev, A. R.; Dimova, T. V.; Druzhinin, V. P.; Golubev, V. B.; Kardapoltsev, L. V.; Kirpotin, A. N.; Kononov, S. A.; Koop, I. A.; Korol, A. A.; Koshuba, S. V.; Kovrizhin, D. P.; Kravchenko, D. P.; Kupich, A. S.; Lysenko, A. P.; Martin, K. A.; Obrazovsky, A. E.; Onuchin, A. P.; Pakhtusova, E. V.; Kharlamov, A. G.; Romanov, A. L.; Senchenko, A. I.; Shatunov, P. Yu; Shatunov, Yu M.; Shtol, D. A.; Shwartz, D. B.; Silagadze, Z. K.; Skrinsky, A. N.; Surin, I. K.; Tikhonov, Yu A.; Usov, Yu V.; Vasiljev, A. V.; Zemlyansky, I. M.

    2015-11-01

    The cross sections {{{e}}}+{{{e}}}-\\to {π }+{π }-, 3π , 4π , ω {π }0, K+K-, η {π }+{π }-, η γ , {{p}}\\bar{{{p}}},{{n}}\\bar{{{n}}} have been measured with the spherical neutral detector at the VEPP-2000 e+e- collider in the energy range from 0.3 to 2.0 GeV.

  10. NLO QED contributions to top-pair production at hadron colliders

    SciTech Connect

    Hollik, W.; Kollar, M.

    2008-01-01

    Electroweak one-loop calculations for production of top-quark pairs at colliders are completed by providing the missing QED type contributions from real and virtual photons, where also effects from interference between QED and QCD contributions have to be taken into account. Moreover, photon-induced tt production is included as another partonic channel.

  11. Crabbing System for an Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Castilla, Alejandro

    As high energy and nuclear physicists continue to push further the boundaries of knowledge using colliders, there is an imperative need, not only to increase the colliding beams' energies, but also to improve the accuracy of the experiments, and to collect a large quantity of events with good statistical sensitivity. To achieve the latter, it is necessary to collect more data by increasing the rate at which these pro- cesses are being produced and detected in the machine. This rate of events depends directly on the machine's luminosity. The luminosity itself is proportional to the frequency at which the beams are being delivered, the number of particles in each beam, and inversely proportional to the cross-sectional size of the colliding beams. There are several approaches that can be considered to increase the events statistics in a collider other than increasing the luminosity, such as running the experiments for a longer time. However, this also elevates the operation expenses, while increas- ing the frequency at which the beams are delivered implies strong physical changes along the accelerator and the detectors. Therefore, it is preferred to increase the beam intensities and reduce the beams cross-sectional areas to achieve these higher luminosities. In the case where the goal is to push the limits, sometimes even beyond the machines design parameters, one must develop a detailed High Luminosity Scheme. Any high luminosity scheme on a modern collider considers--in one of their versions--the use of crab cavities to correct the geometrical reduction of the luminosity due to the beams crossing angle. In this dissertation, we present the design and testing of a proof-of-principle compact superconducting crab cavity, at 750 MHz, for the future electron-ion collider, currently under design at Jefferson Lab. In addition to the design and validation of the cavity prototype, we present the analysis of the first order beam dynamics and the integration of the crabbing

  12. 62-TeV center of mass hadron collider with superbunch beams

    SciTech Connect

    Ryuji Yamada et al.

    2001-11-05

    The scheme of a 62-TeV center of mass p-p collider with superbunch beams at Fermilab is proposed as a practical and realistically achievable future project. It will be built in two stages, using the same tunnel, first with a 2 Tesla low field magnet collider ring and later with a 10 Tesla high field magnet collider ring. Both low and high field magnets have twin bore aperture and will be installed in the tunnel with the circumference of 87.25 km. In each bore a proton beam is accelerated, using induction cavities to increase luminosity. In the first stage they install a 7 TeV accelerator ring with operating field of 2 Tesla, based on the superferric transmission-line design. This ring will be operated at a 14-TeV center of mass collider. This will have the same energy as the LHC, but it will have 15 times higher luminosity, namely 1.5 x 10{sup 35}/cm{sup 2}/sec. The estimated synchrotron radiation is negligible with this machine. The existing Fermilab accelerator system, including the 150 GeV main injector, will be used as the injector system. Its rough cost estimation and schedule for this first stage are presented. In the second stage proton beams are accelerated, also using induction cavities up to 31 TeV with the 10 Tesla dipole magnets. The counter circulating beams will collide with the 62-TeV center of mass energy. With the superbunch beams they can expect the luminosity can be increased about 15 times more than the conventional method with RF cavities. It will be 10{sup 35}/cm{sup 2}/sec. In the second stage, the synchrotron radiation power will be about 12 W/m, and they need an elaborated beam screen.

  13. Measurement of the hadronic cross section in electron-positron annihilation

    SciTech Connect

    Clearwater, S.

    1983-11-01

    This thesis describes the most precise measurement to date of the ratio R, the hadronic cross section in lowest order electron-positron annihilation to the cross section for muon pair production in lowest order electron-positron annihilation. This experiment is of interest because R is a fundamental parameter that tests in a model independent way the basic assumptions of strong interaction theories. According to the assumptions of one of these theories the value of R is determined simply from the electric charges, spin, and color assignments of the produced quark-pairs. The experiment was carried out with the MAgnetic Calorimeter using collisions of 14.5 GeV electrons and positrons at the 2200m circumference PEP storage ring at SLAC. The MAC detector is one of the best-suited collider detectors for measuring R due to its nearly complete coverage of the full angular range. The data for this experiment were accumulated between February 1982 and April 1983 corresponding to a total event sample of about 40,000 hadronic events. About 5% of the data were taken with 14 GeV beams and the rest of the data were taken with 14.5 GeV beams. A description of particle interactions and experimental considerations is given.

  14. Electron density and plasma dynamics of a colliding plasma experiment

    SciTech Connect

    Wiechula, J. Schönlein, A.; Iberler, M.; Hock, C.; Manegold, T.; Bohlender, B.; Jacoby, J.

    2016-07-15

    We present experimental results of two head-on colliding plasma sheaths accelerated by pulsed-power-driven coaxial plasma accelerators. The measurements have been performed in a small vacuum chamber with a neutral-gas prefill of ArH{sub 2} at gas pressures between 17 Pa and 400 Pa and load voltages between 4 kV and 9 kV. As the plasma sheaths collide, the electron density is significantly increased. The electron density reaches maximum values of ≈8 ⋅ 10{sup 15} cm{sup −3} for a single accelerated plasma and a maximum value of ≈2.6 ⋅ 10{sup 16} cm{sup −3} for the plasma collision. Overall a raise of the plasma density by a factor of 1.3 to 3.8 has been achieved. A scaling behavior has been derived from the values of the electron density which shows a disproportionately high increase of the electron density of the collisional case for higher applied voltages in comparison to a single accelerated plasma. Sequences of the plasma collision have been taken, using a fast framing camera to study the plasma dynamics. These sequences indicate a maximum collision velocity of 34 km/s.

  15. Physics Opportunity with an Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Rossi, Patrizia

    2016-11-01

    Understanding the emergence of nucleons and nuclei and their interactions from the properties and dynamics of quarks and gluons in Quantum Chromodynamics (QCD) is a fundamental and compelling goal of nuclear science. A high-energy, high-luminosity polarized electron-ion collider (EIC) will be needed to explore and advance many aspects of QCD studies in the gluon dominated regions in nucleon and nuclei. The federal Nuclear Science Advisory Committee unanimously approved a high-energy electro-ion collider to explore a new frontier in physics research. In fact, the committee calls the collider the country's next “highest priority” in new facility construction, and is one of four main recommendations contained in its 2015 Long Range Plan for Nuclear Science. Two proposals for the EIC are being considered in the U.S.: one each at Jefferson Laboratory (JLab) and at Brookhaven National Laboratory (BNL). An overview of the physics opportunities an EIC presents to the nuclear science community in future decades is presented.

  16. Physics Opportunity with an Electron-Ion Collider

    SciTech Connect

    Rossi, Patrizia

    2016-12-01

    Understanding the emergence of nucleons and nuclei and their interactions from the properties and dynamics of quarks and gluons in Quantum Chromodynamics (QCD) is a fundamental and compelling goal of nuclear science. A high-energy, high-luminosity polarized electron-ion collider (EIC) will be needed to explore and advance many aspects of QCD studies in the gluon dominated regions in nucleon and nuclei. The federal Nuclear Science Advisory Committee unanimously approved a high-energy electro-ion collider to explore a new frontier in physics research. In fact, the committee calls the collider the country's next "highest priority" in new facility construction, and is one of four main recommendations contained in its 2015 Long Range Plan for Nuclear Science. Two proposals for the EIC are being considered in the U.S.: one each at Jefferson Laboratory (JLab) and at Brookhaven National Laboratory (BNL). An overview of the physics opportunities an EIC presents to the nuclear science community in future decades is presented.

  17. Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    The ALICE Collaboration

    2016-01-01

    ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density ρμ > 5.9 m-2. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 1016 eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. The development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.

  18. Evidence for x-dependent proton color fluctuations in pA collisions at the CERN Large Hadron Collider

    DOE PAGES

    Alvioli, M.; Cole, B. A.; Frankfurt, L.; ...

    2016-01-21

    The centrality dependence of forward jet production in pA collisions at the Large Hadron Collider (LHC) has been found to grossly violate the Glauber model prediction in a way that depends on the x in the proton. In this paper, we argue that this modification pattern provides the first experimental evidence for x-dependent proton color fluctuation effects. On average, parton configurations in the projectile proton containing a parton with large x interact with a nuclear target with a significantly smaller than average cross section and have smaller than average size. We implement the effects of fluctuations of the interaction strengthmore » and, using the ATLAS analysis of how hadron production at backward rapidities depends on the number of wounded nucleons, make quantitative predictions for the centrality dependence of the jet production rate as a function of the x-dependent interaction strength σ(x). We find that σ(x) ~ 0.6(σ) gives a good description of the data at x = 0.6. Finally, these findings support an explanation of the European Muon Collaboration effect as arising from the suppression of small-size nucleon configurations in the nucleus.« less

  19. Eventwise mean-pt fluctuations versus minimum-bias jets (minijets) at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2015-08-01

    Fluctuation measurements of eventwise mean transverse momentum for p -p and Pb-Pb collisions at the CERN Large Hadron Collider (LHC) have been reported recently. In that study it was concluded that the strength of "nonstatistical" fluctuations decreases with increasing particle multiplicity nch (or A -A centrality) and is nearly independent of collision energy over a large interval. Among several potential mechanisms for those trends the onset of thermalization and collectivity are mentioned. The LHC analysis employed one fluctuation measure selected from several possibilities. An alternative fluctuation measure reveals a strong increase of pt fluctuations with nc h (or A -A centrality) and collision energy, consistent with previous measurements at the BNL Relativistic Heavy Ion Collider (RHIC). The pt fluctuation data for LHC p -p collisions can be described accurately by a two-component (soft +hard ) model (TCM) in which the hard component represents dijet production. The data for Pb-Pb collisions are described accurately by a TCM reference for more-peripheral collisions (suggesting transparent collisions), but the data deviate quantitatively from the reference for more-central collisions, suggesting a modification of jet formation. Overall fluctuation data trends suggest that minimum-bias jets (minijets) dominate pt fluctuations at both the LHC and the RHIC.

  20. Drell-Yan process as an avenue to test a noncommutative standard model at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    J, Selvaganapathy; Das, Prasanta Kumar; Konar, Partha

    2016-06-01

    We study the Drell-Yan process at the Large Hadron Collider in the presence of the noncommutative extension of the standard model. Using the Seiberg-Witten map, we calculate the production cross section to first order in the noncommutative parameter Θμ ν . Although this idea has been evolving for a long time, only a limited amount of phenomenological analysis has been completed, and this was mostly in the context of the linear collider. An outstanding feature from this nonminimal noncommutative standard model not only modifies the couplings over the SM production channel but also allows additional nonstandard vertices which can play a significant role. Hence, in the Drell-Yan process, as studied in the present analysis, one also needs to account for the gluon fusion process at the tree level. Some of the characteristic signatures, such as oscillatory azimuthal distributions, are an outcome of the momentum-dependent effective couplings. We explore the noncommutative scale ΛNC≥0.4 TeV , considering different machine energy ranging from 7 to 13 TeV.

  1. Crab Crossing Schemes and Studies for Electron Ion Collider

    SciTech Connect

    S. Ahmed, Y. Derbenev, V. Morozov, A. Castilla, G.A. Krafft, B. Yunn, Y. Zhang, J.R. Delayen

    2011-09-01

    This report shows our progress in crab crossing consideration for future electron-ion collider envisioned at JLab. In this design phase, we are evaluating two crabbing schemes viz., the deflecting and dispersive. The mathematical formulations and lattice design for these schemes are discussed in this paper. Numerical simulations involving particle tracking through a realistic deflecting RF cavity and optics illustrate the desired crab tilt of 25 mrad for 1.35 MV. Evolution of beam propagation are shown which provides the physical insight of the crabbing phenomenon.

  2. INTERACTION REGION DESIGN FOR THE ELECTRON-ION COLLIDER ERHIC.

    SciTech Connect

    MONTAG, C.; PARKER, B.; TEPIKIAN, S.; ET AL.

    2005-05-16

    To facilitate the study of collisions between 10 GeV polarized electrons and 100 GeV/u heavy ions or 250 GeV polarized protons at luminosities in the 10{sup 33} cm{sup -2} sec{sup -1} range (e-p case), adding a 10 GeV electron storage ring to the existing RHIC complex has been proposed. The interaction region of this electron-ion collider eRHIC has to provide the required low-beta focusing, while simultaneously accommodating the synchrotron radiation fan generated by beam separation close to the interaction point, which is particularly challenging. The latest design status of the eRHIC interaction region will be presented.

  3. Pre-Town Meeting on spin physics at an Electron-Ion Collider

    DOE PAGES

    Aschenauer, Elke-Caroline; Balitsky, Ian; Bland, Leslie; ...

    2017-04-14

    A polarized ep/eA collider (Electron-Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center-of-mass energy √s ~ 20 to ~ 100 GeV (upgradable to ~ 150 GeV) and a luminosity up to ~1034 cm-2s-1, would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three-dimensional structure of the nucleon (sea quark and gluon spatial distributions,more » orbital motion, polarization, and their correlations). Finally, this mini-paper contains a short update on progress in these areas since the EIC White paper (A. Accardi et al., Eur. Phys. J. A 52, 268 (2016)).« less

  4. Quartified leptonic color, bound states, and future electron-positron collider

    NASA Astrophysics Data System (ADS)

    Kownacki, Corey; Ma, Ernest; Pollard, Nicholas; Popov, Oleg; Zakeri, Mohammadreza

    2017-06-01

    The [ SU (3) ] 4 quartification model of Babu, Ma, and Willenbrock (BMW), proposed in 2003, predicts a confining leptonic color SU (2) gauge symmetry, which becomes strong at the keV scale. It also predicts the existence of three families of half-charged leptons (hemions) below the TeV scale. These hemions are confined to form bound states which are not so easy to discover at the Large Hadron Collider (LHC). However, just as J / ψ and ϒ appeared as sharp resonances in e-e+ colliders of the 20th century, the corresponding 'hemionium' states are expected at a future e-e+ collider of the 21st century.

  5. TMDs and GPDs at a future Electron-Ion Collider

    SciTech Connect

    Ent, Rolf

    2016-06-21

    With two options studied at Brookhaven National Lab and Jefferson Laboratory the U.S., an Electron-Ion Collider (EIC) of energy √s=20-100 GeV was under design. Furthermore, the recent 2015 US Nuclear Science Long-Range Planning effort included a future EIC as a recommendation for future construction. The EIC will be unique in colliding polarised electrons off polarised protons and light nuclei, providing the spin degrees of freedom essential to pursue its physics program driven by spin structure, multi-dimensional tomographic images of protons and nuclei, and discovery of the role of collective effects of gluons in nuclei. The foreseen luminosity of the EIC, coupled with its energy variability and reach, will allow unprecedented three-dimensional imaging of the gluon and sea quark distributions, via both TMDs and GPDs, and to explore correlations amongst them. Its hermetic detection capability of correlated fragments promises to similar allow for precise tomographic images of the quark-gluon landscape in nuclei, transcending from light few-body nuclei to the heaviest nuclei, and could uncover how the TMD and GPD landscape changes when gluons display an anticipated collective behavior at the higher energies.

  6. TMDs and GPDs at a future Electron-Ion Collider

    DOE PAGES

    Ent, Rolf

    2016-06-21

    With two options studied at Brookhaven National Lab and Jefferson Laboratory the U.S., an Electron-Ion Collider (EIC) of energy √s=20-100 GeV was under design. Furthermore, the recent 2015 US Nuclear Science Long-Range Planning effort included a future EIC as a recommendation for future construction. The EIC will be unique in colliding polarised electrons off polarised protons and light nuclei, providing the spin degrees of freedom essential to pursue its physics program driven by spin structure, multi-dimensional tomographic images of protons and nuclei, and discovery of the role of collective effects of gluons in nuclei. The foreseen luminosity of the EIC,more » coupled with its energy variability and reach, will allow unprecedented three-dimensional imaging of the gluon and sea quark distributions, via both TMDs and GPDs, and to explore correlations amongst them. Its hermetic detection capability of correlated fragments promises to similar allow for precise tomographic images of the quark-gluon landscape in nuclei, transcending from light few-body nuclei to the heaviest nuclei, and could uncover how the TMD and GPD landscape changes when gluons display an anticipated collective behavior at the higher energies.« less

  7. 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.

  8. TMDs and GPDs at a future Electron-Ion Collider

    SciTech Connect

    Ent, Rolf

    2016-06-21

    With two options studied at Brookhaven National Lab and Jefferson Laboratory the U.S., an Electron-Ion Collider (EIC) of energy √s=20-100 GeV was under design. Furthermore, the recent 2015 US Nuclear Science Long-Range Planning effort included a future EIC as a recommendation for future construction. The EIC will be unique in colliding polarised electrons off polarised protons and light nuclei, providing the spin degrees of freedom essential to pursue its physics program driven by spin structure, multi-dimensional tomographic images of protons and nuclei, and discovery of the role of collective effects of gluons in nuclei. The foreseen luminosity of the EIC, coupled with its energy variability and reach, will allow unprecedented three-dimensional imaging of the gluon and sea quark distributions, via both TMDs and GPDs, and to explore correlations amongst them. Its hermetic detection capability of correlated fragments promises to similar allow for precise tomographic images of the quark-gluon landscape in nuclei, transcending from light few-body nuclei to the heaviest nuclei, and could uncover how the TMD and GPD landscape changes when gluons display an anticipated collective behavior at the higher energies.

  9. Search for radiative $B$-hadron decays with the Collider Detector at Fermilab

    SciTech Connect

    Tanaka, Masashi

    2001-01-01

    Radiative decays of B hadrons, $\\bar{B}$d → $\\bar{K}$*0 γ(pγ), $\\bar{B}$s → Φγ ($\\bar{K}$*0), and Λb → Λγ (nγ), occur via the quark transition b → s(d) that involves a loop ("penguin") diagram. In addition, the existence of non-SM heavy charged particles such as a supersymmetric charged Higgs can affect the amplitude of the penguin loop.

  10. Indications of conical emission of charged hadrons at the BNL relativistic heavy ion collider.

    PubMed

    Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Beavis, D R; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Biritz, B; Bland, L C; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Braidot, E; Brandin, A V; Bruna, E; Bueltmann, S; Burton, T P; Bystersky, M; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Callner, J; Catu, O; Cebra, D; Cendejas, R; Cervantes, M C; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Choi, K E; Christie, W; Chung, S U; Clarke, R F; Codrington, M J M; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Daugherity, M; De Silva, C; de Moura, M M; Dedovich, T G; Dephillips, M; Derevschikov, A A; de Souza, R Derradi; Didenko, L; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunlop, J C; Dutta Mazumdar, M R; Edwards, W R; Efimov, L G; Elhalhuli, E; Elnimr, M; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Eun, L; Fachini, P; Fatemi, R; Fedorisin, J; Feng, A; Filip, P; Finch, E; Fine, V; Fisyak, Y; Gagliardi, C A; Gaillard, L; Gangadharan, D R; Ganti, M S; Garcia-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y N; Gordon, A; Grebenyuk, O; Grosnick, D; Grube, B; Guertin, S M; Guimaraes, K S F F; Gupta, A; Gupta, N; Guryn, W; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Heppelmann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D J; Hollis, R S; Huang, H Z; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jin, F; Jones, P G; Joseph, J; Judd, E G; Kabana, S; Kajimoto, K; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kopytine, M; Kotchenda, L; Kouchpil, V; Kravtsov, P; Kravtsov, V I; Krueger, K; Krus, M; Kuhn, C; Kumar, L; Kurnadi, P; Lamont, M A C; Landgraf, J M; Lapointe, S; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Levine, M J; Li, C; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, Y G; Mahapatra, D P; Majka, R; Mall, O I; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Matis, H S; Matulenko, Yu A; McShane, T S; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mischke, A; Mitchell, J; Mohanty, B; Molnar, L; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, C; Netrakanti, P K; Ng, M J; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okada, H; Okorokov, V; Olson, D; Pachr, M; Page, B S; Pal, S K; Pandit, Y; Panebratsev, Y; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Poskanzer, A M; Potukuchi, B V K S; Prindle, D; Pruneau, C; Pruthi, N K; Putschke, J; Raniwala, R; Raniwala, S; Ray, R L; Reed, R; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Rykov, V; Sahoo, R; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shi, S S; Shi, X-H; Sichtermann, E P; Simon, F; Singaraju, R N; Skoby, M J; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thein, D; Thomas, J H; Tian, J; Timmins, A R; Timoshenko, S; Tlusty, D; Tokarev, M; Trainor, T A; Tram, V N; Trattner, A L; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van Leeuwen, M; Vander Molen, A M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasilevski, I M; Vasiliev, A N; Videbaek, F; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Wada, M; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, Q; Wang, X; Wang, X L; Wang, Y; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, Y; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yepes, P; Yoo, I-K; Yue, Q; Zawisza, M; Zbroszczyk, H; Zhan, W; Zhang, H; Zhang, S; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zuo, J X

    2009-02-06

    Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at sqrt[s_{NN}]=200 GeV by the STAR experiment. Dijet structures are observed in pp, d+Au and peripheral Au+Au collisions. An additional structure is observed in central Au+Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be theta=1.37+/-0.02(stat)-0.07+0.06(syst), independent of p_{ perpendicular}.

  11. Indications of Conical Emission of Charged Hadrons at the BNL Relativistic HeavyIon Collider

    SciTech Connect

    STAR Coll

    2009-02-09

    Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d + Au, and Au + Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment. Dijet structures are observed in pp, d + Au and peripheral Au + Au collisions. An additional structure is observed in central Au + Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be {theta} = 1.37 {+-} 0.02(stat){sub -0.07}{sup +0.06}(syst), independent of p{sub {perpendicular}}.

  12. Indications of conical emission of charged hadrons at the BNL relativistic heavy ion collider.

    SciTech Connect

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H. M.; Underwood, D. G.; High Energy Physics; Univ. of Illinois; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physic Lab.; STAR Collaboration

    2009-01-01

    Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment. Dijet structures are observed in pp, d+Au and peripheral Au+Au collisions. An additional structure is observed in central Au+Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be {theta} = 1.37 {+-} 0.02(stat){sub -0.07}{sup +0.06} (syst), independent of p.

  13. Associated Higgs-W-boson production at hadron colliders: a fully exclusive QCD calculation at NNLO.

    PubMed

    Ferrera, Giancarlo; Grazzini, Massimiliano; Tramontano, Francesco

    2011-10-07

    We consider QCD radiative corrections to standard model Higgs-boson production in association with a W boson in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. Our calculation includes finite-width effects, the leptonic decay of the W boson with its spin correlations, and the decay of the Higgs boson into a bb pair. We present selected numerical results at the Tevatron and the LHC.

  14. Bruno Touschek: From Betatrons to Electron-Positron Colliders

    NASA Astrophysics Data System (ADS)

    Bernardini, Carlo; Pancheri, Giulia; Pellegrini, Claudio

    Bruno Touschek’s life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders and storage rings, and made important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology, environmental sciences and cultural heritage studies. We describe Touschek’s life in Austria, where he was born, in Germany, where he participated in the construction of a betatron during WWII, and in Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his lifestyle and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE.

  15. Bruno Touschek: From Betatrons to Electron-Positron Colliders

    NASA Astrophysics Data System (ADS)

    Bernardini, Carlo; Pancheri, Giulia; Pellegrini, Claudio

    Bruno Touschek's life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders and storage rings, and made important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology, environmental sciences and cultural heritage studies. We describe Touschek's life in Austria, where he was born, in Germany, where he participated in the construction of a betatron during WWII, and in Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his lifestyle and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE.

  16. Modeling Crabbing Dynamics in an Electron-Ion Collider

    SciTech Connect

    Castilla, Alejandro; Morozov, Vasiliy S.; Satogata, Todd J.; Delayen, Jean R.

    2015-09-01

    A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.

  17. Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider

    SciTech Connect

    Miller, David Wilkins

    2012-03-20

    This thesis presents the first measurement of 6 hadronic event shapes in proton-proton collisions at a center-of-mass energy of {radical}s = 7 TeV using the ATLAS detector at the Large Hadron Collider. Results are presented at the particle-level, permitting comparisons to multiple Monte Carlo event generator tools. Numerous tools and techniques that enable detailed analysis of the hadronic final state at high luminosity are described. The approaches presented utilize the dual strengths of the ATLAS calorimeter and tracking systems to provide high resolution and robust measurements of the hadronic jets that constitute both a background and a signal throughout ATLAS physics analyses. The study of the hadronic final state is then extended to jet substructure, where the energy flow and topology within individual jets is studied at the detector level and techniques for estimating systematic uncertainties for such measurements are commissioned in the first data. These first substructure measurements in ATLAS include the jet mass and sub-jet multiplicity as well as those concerned with multi-body hadronic decays and color flow within jets. Finally, the first boosted hadronic object observed at the LHC - the decay of the top quark to a single jet - is presented.

  18. The Polarized Electron Source for the International Collider (ILC) Project

    SciTech Connect

    Brachmann, A.; Clendenin, J.E.; Garwin, E.L.; Ioakeimidi, K.; Kirby, R.e.; Maruyama, T.; Prescott, C.Y.; Sheppard, J.; Turner, J.; Zhou, F.; /SLAC

    2006-12-01

    ILC project will be the next large high energy physics tool that will use polarized electrons (and positrons). For this machine spin physics will play an important role. The polarized electron source design is based on electron injectors built for the Stanford Linear Collider (polarized) and Tesla Test Facility (un-polarized). The ILC polarized electron source will provide a 5GeV spin polarized electron beam for injection into the ILC damping ring. Although most ILC machine parameters have been achieved by the SLC or TTF source, features of both must be integrated into one design. The bunch train structure presents unique challenges to the source laser drive system. A suitable laser system has not yet been demonstrated and is part of the ongoing R&D program for ILC at SLAC. Furthermore, ILC injector R&D incorporates photocathode development, increasing available polarization, and improving operational properties in gun vacuum systems. Another important area of research and development is advancing the design of DC and RF electron gun technology for polarized sources. This presentation presents the current status of the design and outlines aspects of the relevant R&D program carried out within the ILC community.

  19. A new boson with a mass of 125 GeV observed with the CMS experiment at the Large Hadron Collider.

    PubMed

    2012-12-21

    The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force-the W(+), W(-), and Z(0) bosons-as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 × 10(6). The new particle is a boson with spin not equal to 1 and has a mass of about 125 [corrected] giga-electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle.

  20. A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    CMS Collabortion; Abbaneo, D.; Abbiendi, G.; Abbrescia, M.; Abdullin, S.; Abdulsalam, A.; Acharya, B. S.; Acosta, D.; Acosta, J. G.; Adair, A.; Adam, W.; Adam, N.; Adamczyk, D.; Adams, T.; Adams, M. R.; Adiguzel, A.; Adler, V.; Adolphi, R.; Adzic, P.; Afanasiev, S.; Agostino, L.; Agram, J.-L.; Aguilar-Benitez, M.; Aguilo, E.; Ahmad, M.; Ahmad, M. K. H.; Ahuja, S.; Akchurin, N.; Akgun, U.; Akgun, B.; Akin, I. V.; Alagoz, E.; Albajar, C.; Albayrak, E. A.; Albergo, S.; Albert, M.; Albrow, M.; Alcaraz Maestre, J.; Aldá Júnior, W. L.; Aldaya Martin, M.; Alemany-Fernandez, R.; Alexander, J.; Aliev, T.; Alimena, J.; Allfrey, P.; Almeida, N.; Alverson, G.; Alves, G. A.; Aly, A.; Amaglobeli, N.; Amapane, N.; Ambroglini, F.; Amsler, C.; Anagnostou, G.; Anastassov, A.; Andelin, D.; Anderson, J.; Anderson, M.; Andrea, J.; Andreev, Yu.; Andreev, V.; Andreev, V.; Andrews, W.; Anfreville, M.; Angelini, F.; Anghel, I. M.; Anisimov, A.; Anjos, T. S.; Ansari, M. H.; Antonelli, L.; Anttila, E.; Antunovic, Z.; Apanasevich, L.; Apollinari, G.; Appelt, E.; Apresyan, A.; Apyan, A.; Arce, P.; Arcidiacono, R.; Ardalan, F.; Arenton, M. W.; Arezzini, S.; Arfaei, H.; Argiro, S.; Arisaka, K.; Arndt, K.; Arneodo, M.; Arora, S.; Asavapibhop, B.; Asawatangtrakuldee, C.; Asghar, M. I.; Askew, A.; Aspell, P.; Assran, Y.; Ata, M.; Atac, M.; Attebury, G.; Attikis, A.; Auffray, E.; Autermann, C.; Auzinger, G.; Avdeeva, E.; Avery, P.; Avetisyan, A.; Avila, C.; Awad, A.; Ayan, A. S.; Azarkin, M.; Azhgirey, I.; Aziz, T.; Azzi, P.; Azzolini, V.; Azzurri, P.; Baarmand, M. M.; Babb, J.; Baccaro, S.; Bacchetta, N.; Bachtis, M.; Baden, A.; Badgett, W.; Badier, J.; Baechler, J.; Baffioni, S.; Bagaturia, I.; Bagliesi, G.; Bai, Y.; Bailleux, D.; Baillon, P.; Bainbridge, R.; Bakhshiansohi, H.; Bakirci, M. N.; Bakken, J. A.; Balazs, M.; Baldin, B.; Ball, A. H.; Ball, G.; Ballin, J.; Ban, Y.; Banerjee, S.; Banerjee, S.; Bäni, L.; Banicz, K.; Bansal, M.; Bansal, S.; Banzuzi, K.; Barashko, V.; Barbagli, G.; Barberis, E.; Barbone, L.; Barczyk, A.; Bard, R.; Barfuss, A. F.; Bargassa, P.; Barge, D.; Baringer, P.; Barker, A.; Barnes, V. E.; Barnett, B. A.; Barney, D.; Barone, L.; Barrass, T.; Bartalini, P.; Barth, C.; Bartoloni, A.; Basegmez, S.; Basso, L.; Basti, A.; Bateman, E.; Battilana, C.; Bauer, J.; Bauer, D.; Bauer, G.; Bauerdick, L. A. T.; Baulieu, G.; Baumbaugh, B.; Baumgartel, D.; Baur, U.; Bayshev, I.; Bazterra, V. E.; Bean, A.; Beauceron, S.; Beaudette, F.; Beaumont, W.; Beaupere, N.; Becheva, E.; Bedjidian, M.; Beernaert, K.; Behner, F.; Behr, J.; Behrenhoff, W.; Behrens, U.; Belforte, S.; Beliy, N.; Belknap, D.; Bell, A. J.; Bell, K. W.; Bellan, R.; Bellato, M.; Bellazzini, R.; Bellinger, J. N.; Belotelov, I.; Belyaev, A.; Belyaev, A.; Benaglia, A.; Bencze, G.; Bendavid, J.; Benedetti, D.; Benelli, G.; Benettoni, M.; Benhabib, L.; Beni, N.; Benitez, J. F.; Benussi, L.; Benvenuti, A. C.; Beranek, S.; Beretvas, A.; Bergauer, T.; Berger, J.; Bergholz, M.; Beri, S. B.; Bernardes, C. A.; Bernardini, J.; Bernardino Rodrigues, N.; Bernet, C.; Berry, D.; Berry, E.; Berryhill, J.; Bertl, W.; Bertoldi, M.; Berzano, U.; Besancon, M.; Besson, A.; Betchart, B.; Betev, B.; Bethani, A.; Betts, R. R.; Beuselinck, R.; Bhandari, V.; Bhardwaj, A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharya, S.; Bhattacharya, S.; Bhatti, A.; Bheesette, S.; Bialas, W.; Bialkowska, H.; Biallass, P.; Bian, J. G.; Bianchi, G.; Bianchini, L.; Bianco, S.; Biasini, M.; Biasotto, M.; Biino, C.; Bilei, G. M.; Bilin, B.; Bilki, B.; Binkley, M.; Bisello, D.; Bitioukov, S.; Blau, B.; Blekman, F.; Blobel, V.; Bloch, D.; Bloch, P.; Bloom, K.; Bluj, M.; Blüm, P.; Blumenfeld, B.; Blyweert, S.; Boccali, T.; Bocci, A.; Bochenek, J.; Bockelman, B.; Bodek, A.; Bodin, D.; Boimska, B.; Bolla, G.; Bolognesi, S.; Bolton, T.; Bonacorsi, D.; Bonato, A.; Bondu, O.; Bonnett Del Alamo, M.; Bontenackels, M.; Boos, E.; Borcherding, F.; Bornheim, A.; Borras, K.; Borrello, L.; Bortignon, P.; Bortoletto, D.; Bose, T.; Bose, S.; Böser, C.; Bosi, F.; Bostock, F.; Botta, C.; Boudoul, G.; Bouhali, O.; Boulahouache, C.; Bourilkov, D.; Boutemeur, M.; Boutigny, D.; Boutle, S.; Bradley, D.; Braibant-Giacomelli, S.; Branca, A.; Branson, A.; Branson, J. G.; Brauer, R.; Braunschweig, W.; Breedon, R.; Breto, G.; Breuker, H.; Brew, C.; Brez, A.; Brigliadori, L.; Brigljevic, V.; Brinkerhoff, A.; Brito, L.; Broccolo, G.; Brochero Cifuentes, J. A.; Brochet, S.; Brom, J.-M.; Brona, G.; Brooke, J. J.; Broutin, C.; Brown, R. M.; Brownson, E.; Brun, H.; Bruno, G.; Buchmann, M. A.; Buchmuller, O.; Bucinskaite, I.; Budd, H.; Buege, V.; Bujak, A.; Bunichev, V.; Bunin, P.; Bunkowski, K.; Bunn, J.; Buontempo, S.; Burgmeier, A.; Burkett, K.; Busson, P.; Busza, W.; Butler, A. P. H.; Butler, P. H.; Butler, J. N.; Butt, J.; Butz, E.; Bylsma, B.

    2012-12-01

    The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force—the W+, W-, and Z0 bosons—as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 × 106. The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga-electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle.

  1. Highly Polarized Ion Sources for Electron Ion Colliders (EIC)

    SciTech Connect

    V.G. Dudnikov, R.P. Johnson, Y.S. Derbenev, Y. Zhang

    2010-03-01

    The operation of the RHIC facility at BNL and the Electron Ion Colliders (EIC) under development at Jefferson Laboratory and BNL need high brightness ion beams with the highest polarization. Charge exchange injection into a storage ring or synchrotron and Siberian snakes have the potential to handle the needed polarized beam currents, but first the ion sources must create beams with the highest possible polarization to maximize collider productivity, which is proportional to a high power of the polarization. We are developing one universal H-/D- ion source design which will synthesize the most advanced developments in the field of polarized ion sources to provide high current, high brightness, ion beams with greater than 90% polarization, good lifetime, high reliability, and good power efficiency. The new source will be an advanced version of an atomic beam polarized ion source (ABPIS) with resonant charge exchange ionization by negative ions. An integrated ABPIS design will be prepared based on new materials and an optimized magnetic focusing system. Polarized atomic and ion beam formation, extraction, and transport for the new source will be computer simulated.

  2. First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

    SciTech Connect

    Aaltonen, T.; Adelman, Jahred A.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E.; Anastassov, A.; Annovi, Alberto; Antos, Jaroslav; Apollinari, G.; Apresyan, A.; /Purdue U. /Waseda U.

    2009-05-01

    We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V = W,Z) where one boson decays to a dijet final state. The data correspond to 3.5 fb{sup -1} of integrated luminosity of p{bar p} collisions at {radical}s = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516 {+-} 239(stat) {+-} 144(syst) diboson candidate events and measure a cross section {sigma}(p{bar p} {yields} VV + X) of 18.0 {+-} 2.8(stat) {+-} 2.4(syst) {+-} 1.1(lumi) pb, in agreement with the expectations of the standard model.

  3. First observation of vector boson pairs in a hadronic final state at the tevatron collider.

    PubMed

    Aaltonen, T; Adelman, J; Akimoto, T; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'Orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; Di Canto, A; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Garosi, P; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Osterberg, K; Griso, S Pagan; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Renz, M; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Rutherford, B; Saarikko, H; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Trovato, M; Tsai, S-Y; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wagner-Kuhr, J; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Weinelt, J; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Würthwein, F; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

    2009-08-28

    We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V = W, Z) where one boson decays to a dijet final state. The data correspond to 3.5 fb(-1) of integrated luminosity of pp[over ] collisions at sqrt[s] = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516 + or - 239(stat) + or - 144(syst) diboson candidate events and measure a cross section sigma(pp[over ]-->VV + X) of 18.0 + or - 2.8(stat) + or - 2.4(syst) + or -1.1(lumi) pb, in agreement with the expectations of the standard model.

  4. First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartsch, V.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Beringer, J.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bolla, G.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Bridgeman, A.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burke, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Calancha, C.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Choudalakis, G.; Chuang, S. H.; Chung, K.; Chung, W. H.; Chung, Y. S.; Chwalek, T.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Compostella, G.; Convery, M. E.; Conway, J.; Cordelli, M.; Cortiana, G.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Almenar, C. Cuenca; Cuevas, J.; Culbertson, R.; Cully, J. C.; Dagenhart, D.; Datta, M.; Davies, T.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lorenzo, G.; Dell'Orso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; Derwent, P. F.; di Canto, A.; di Giovanni, G. P.; Dionisi, C.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Donini, J.; Dorigo, T.; Dube, S.; Efron, J.; Elagin, A.; Erbacher, R.; Errede, D.; Errede, S.; Eusebi, R.; Fang, H. C.; Farrington, S.; Fedorko, W. T.; Feild, R. G.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garberson, F.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Genser, K.; Gerberich, H.; Gerdes, D.; Gessler, A.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C. M.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, K.; Hahn, S. R.; Halkiadakis, E.; Han, B.-Y.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harper, S.; Harr, R. F.; Harris, R. M.; Hartz, M.; Hatakeyama, K.; Hays, C.; Heck, M.; Heijboer, A.; Heinemann, B.; Heinrich, J.; Henderson, C.; Herndon, M.; Heuser, J.; Hewamanage, S.; Hidas, D.; Hill, C. S.; Hirschbuehl, D.; Hocker, A.; Hou, S.; Houlden, M.; Hsu, S.-C.; Huffman, B. T.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; Kar, D.; Karchin, P. E.; Kato, Y.; Kephart, R.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Knuteson, B.; Ko, B. R.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kubo, T.; Kuhr, T.; Kulkarni, N. P.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, E.; Lee, H. S.; Lee, S. W.; Leone, S.; Lewis, J. D.; Lin, C.-S.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, T.; Lockyer, N. S.; Loginov, A.; Loreti, M.; Lovas, L.; Lucchesi, D.; Luci, C.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lyons, L.; Lys, J.; Lysak, R.; MacQueen, D.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maki, T.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Marino, C. P.; Martin, A.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Maruyama, T.; Mastrandrea, P.; Masubuchi, T.; Mathis, M.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Merkel, P.; Mesropian, C.; Miao, T.; Miladinovic, N.; Miller, R.; Mills, C.; Milnik, M.; Mitra, A.; Mitselmakher, G.; Miyake, H.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Fernandez, P. Movilla; Mülmenstädt, J.; Mukherjee, A.; Muller, Th.; Mumford, R.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Nagano, A.; Naganoma, J.; Nakamura, K.; Nakano, I.; Napier, A.; Necula, V.; Nett, J.; Neu, C.; Neubauer, M. S.; Neubauer, S.; Nielsen, J.; Nodulman, L.; Norman, M.; Norniella, O.; Nurse, E.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Osterberg, K.; Griso, S. Pagan; Palencia, E.; Papadimitriou, V.; Papaikonomou, A.; Paramonov, A. A.; Parks, B.; Pashapour, S.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Peiffer, T.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pinera, L.; Pitts, K.; Plager, C.; Pondrom, L.; Poukhov, O.; Pounder, N.; Prakoshyn, F.; Pronko, A.; Proudfoot, J.; Ptohos, F.; Pueschel, E.; Punzi, G.; Pursley, J.; Rademacker, J.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Renz, M.; Rescigno, M.; Richter, S.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Rossi, M.; Rossin, R.; Roy, P.; Ruiz, A.; Russ, J.; Rusu, V.; Rutherford, B.; Saarikko, H.; Safonov, A.; Sakumoto, W. K.; Saltó, O.; Santi, L.; Sarkar, S.; Sartori, L.; Sato, K.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, A.; Schmidt, E. E.; Schmidt, M. A.; Schmidt, M. P.; Schmitt, M.; Schwarz, T.; Scodellaro, L.; Scribano, A.; Scuri, F.; Sedov, A.; Seidel, S.; Seiya, Y.; Semenov, A.; Sexton-Kennedy, L.; Sforza, F.; Sfyrla, A.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shiraishi, S.; Shochet, M.; Shon, Y.; Shreyber, I.; Sinervo, P.; Sisakyan, A.; Slaughter, A. J.; Slaunwhite, J.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snihur, R.; Soha, A.; Somalwar, S.; Sorin, V.; Spreitzer, T.; Squillacioti, P.; Stanitzki, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Strycker, G. L.; Suh, J. S.; Sukhanov, A.; Suslov, I.; Suzuki, T.; Taffard, A.; Takashima, R.; Takeuchi, Y.; Tanaka, R.; Tecchio, M.; Teng, P. K.; Terashi, K.; Thom, J.; Thompson, A. S.; Thompson, G. A.; Thomson, E.; Tipton, P.; Ttito-Guzmán, P.; Tkaczyk, S.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Tourneur, S.; Trovato, M.; Tsai, S.-Y.; Tu, Y.; Turini, N.; Ukegawa, F.; Vallecorsa, S.; van Remortel, N.; Varganov, A.; Vataga, E.; Vázquez, F.; Velev, G.; Vellidis, C.; Vidal, M.; Vidal, R.; Vila, I.; Vilar, R.; Vine, T.; Vogel, M.; Volobouev, I.; Volpi, G.; Wagner, P.; Wagner, R. G.; Wagner, R. L.; Wagner, W.; Wagner-Kuhr, J.; Wakisaka, T.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Weinberger, M.; Weinelt, J.; Wester, W. C., III; Whitehouse, B.; Whiteson, D.; Wicklund, A. B.; Wicklund, E.; Wilbur, S.; Williams, G.; Williams, H. H.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, C.; Wright, T.; Wu, X.; Würthwein, F.; Xie, S.; Yagil, A.; Yamamoto, K.; Yamaoka, J.; Yang, U. K.; Yang, Y. C.; Yao, W. M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Yu, S. S.; Yun, J. C.; Zanello, L.; Zanetti, A.; Zhang, X.; Zheng, Y.; Zucchelli, S.

    2009-08-01

    We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W, Z) where one boson decays to a dijet final state. The data correspond to 3.5fb-1 of integrated luminosity of p pmacr collisions at s=1.96TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516±239(stat)±144(syst) diboson candidate events and measure a cross section σ(p pmacr →VV+X) of 18.0±2.8(stat)±2.4(syst)±1.1(lumi)pb, in agreement with the expectations of the standard model.

  5. A comprehensive framework for studying W ' and Z ' bosons at hadron colliders with automated jet veto resummation

    NASA Astrophysics Data System (ADS)

    Fuks, Benjamin; Ruiz, Richard

    2017-05-01

    The production of high-mass, color-singlet particles in hadron collisions is universally accompanied by initial state QCD radiation that is predominantly soft with respect to the hard process scale Q and/or collinear with respect to the beam axis. At TeV-scale colliders, this is in contrast to top quark and multijet processes, which are hard and central. Consequently, vetoing events with jets possessing transverse momenta above p T Veto in searches for new color-singlet states can efficiently reduce non-singlet backgrounds, thereby increasing experimental sensitivity. To quantify this generic observation, we in-vestigate the production and leptonic decay of a Sequential Standard Model W ' boson at the 13 TeV Large Hadron Collider. We systematically consider signal and background processes at next-to-leading-order (NLO) in QCD with parton shower (PS) matching. For color-singlet signal and background channels, we resum Sudakov logarithms of the form α s j ( p T Veto ) log k ( Q/ p T Veto ) up to next-to-next-to-leading logarithmic accuracy (NNLL) with NLO matching. We obtain our results using the M adG raph5_ aMC@NLO and M adG raph5_ aMC@NLO-SCET frameworks, respectively. Associated Universal F eyn-R ules Output model files capable of handling NLO+PS- and NLO+NNLL-accurate computations are publicly available. We find that within their given uncertainties, both the NLO+PS and NLO+NNLL(veto) calculations give accurate and consistent predictions. Consequently, jet vetoes applied to color-singlet processes can be reliably modeled at the NLO+PS level. With respect to a b-jet veto of p T Veto = 30 GeV, flavor-agnostic jet vetoes of p T Veto = 30 - 40 GeV can further reduce single top and t\\overline{t} rates by a factor of 2-50 at a mild cost of the signal rate. Jet vetoes can increase the signal-to-noise ratios by roughly 10% for light W ' boson masses of 30 - 50 GeV and 25%-250% for masses of 300-800 GeV.

  6. SLAC electron-positron colliders: present and future

    SciTech Connect

    Richter, B.

    1986-09-01

    Stanford University's colliding beam program is outlined, including the SPEAR and PEP colliders and the SLAC linear collider. The accelerator developments to be pursued on these facilities are discussed, as well as advanced accelerator research and development. The items covered in the advanced accelerator research include beamstrahlung, stability requirements, breakdown limits, and power sources. (LEW)

  7. Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

    DOE PAGES

    Adam, J.

    2016-01-19

    ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. Here, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. Our analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more thanmore » 100 reconstructed muons and corresponding to a muon areal density rho(mu) > 5.9 m(-2). Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 10(16) eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. Furthermore, the development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.« less

  8. Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

    SciTech Connect

    Collaboration: ALICE Collaboration

    2016-01-01

    ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density ρ{sub μ} > 5.9 m{sup −2}. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 10{sup 16} eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. The development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.

  9. Top++: A program for the calculation of the top-pair cross-section at hadron colliders

    NASA Astrophysics Data System (ADS)

    Czakon, Michał; Mitov, Alexander

    2014-11-01

    We present the program Top++ for the numerical evaluation of the total inclusive cross-section for producing top quark pairs at hadron colliders. The program calculates the cross-section in (a) fixed order approach with exact next-to-next-to leading order (NNLO) accuracy and (b) by including soft-gluon resummation for the hadronic cross-section in Mellin space with full next-to-next-to-leading logarithmic (NNLL) accuracy. The program offers the user significant flexibility through the large number (29) of available options. Top++ is written in C++. It has a very simple to use interface that is intuitive and directly reflects the physics. The running of the program requires no programming experience from the user. Catalogue identifier: AETR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETR_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License No. of lines in distributed program, including test data, etc.: 15 896 No. of bytes in distributed program, including test data, etc.: 695 919 Distribution format: tar.gz Programming language: C++. Computer: any running a unix operating system. Program was developed and tested with GNU Compiler Collection, C++ compiler. Operating system: Linux; Mac OS X; can be adapted for other unix systems. RAM: typically less than 200 MB. Classification: 11.1. External routines: GNU Scientific Library (GSL); the Les Houches Accord pdf Interface (LHAPDF). Nature of problem: computation of the total cross-section in perturbative QCD. Solution method: numerical integration of the product of hard partonic cross-section (with or without soft gluon resummation) with two parton distribution functions. Additional comments: sub per-mill accuracy achievable in realistic time (program does not employ Monte Carlo methods). Running time: depending on the options. The program is optimized for speed.

  10. Shape and flow fluctuations in ultracentral Pb + Pb collisions at the energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Shen, Chun; Qiu, Zhi; Heinz, Ulrich

    2015-07-01

    In ultracentral heavy-ion collisions, anisotropic hydrodynamic flow is generated by density fluctuations in the initial state rather than by geometric overlap effects. For a given centrality class, the initial fluctuation spectrum is sensitive to the method chosen for binning the events into centrality classes. We show that sorting events by total initial entropy or by total final multiplicity yields event classes with equivalent statistical fluctuation properties, in spite of viscous entropy production during the fireball evolution. With this initial entropy-based centrality definition we generate several classes of ultracentral Pb + Pb collisions at Cern Large Hadron Collider energies and evolve the events using viscous hydrodynamics with nonzero shear but vanishing bulk viscosity. Comparing the predicted anisotropic flow coefficients for charged hadrons with CMS data we find that both the Monte Carlo Glauber (MC-Glb) and Monte Carlo Kharzeev-Levin-Nardi (MC-KLN) models produce initial fluctuation spectra that are incompatible with the measured final anisotropic flow power spectrum, for any choice of the specific shear viscosity. In spite of this failure, we show that the hydrodynamic model can qualitatively explain, in terms of event-by-event fluctuations of the anisotropic flow coefficients and flow angles, the breaking of flow factorization for elliptic, triangular, and quadrangular flow measured by the CMS experiment. For elliptic flow, this factorization breaking is large in ultracentral collisions. We conclude that the bulk of the experimentally observed flow factorization breaking effects are qualitatively explained by hydrodynamic evolution of initial-state fluctuations, but that their quantitative description requires a better understanding of the initial fluctuation spectrum.

  11. Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

    SciTech Connect

    Adam, J.

    2016-01-19

    ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. Here, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. Our analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density rho(mu) > 5.9 m(-2). Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 10(16) eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. Furthermore, the development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.

  12. Distinguishing the Higgs Boson from the Dilaton at the Large Hadron Collider

    SciTech Connect

    Goldberger, Walter D.; Skiba, Witold; Grinstein, Benjamin

    2008-03-21

    It is likely that the LHC will observe a color- and charge-neutral scalar whose decays are consistent with those of the standard model (SM) Higgs boson. The Higgs interpretation of such a discovery is not the only possibility. For example, electroweak symmetry breaking could be triggered by a spontaneously broken, nearly conformal sector. The spectrum of states at the electroweak scale would then contain a narrow scalar resonance, the pseudo-Goldstone boson of conformal symmetry breaking, with Higgs-boson-like properties. If the conformal sector is strongly coupled, this pseudodilaton may be the only new state accessible at high energy colliders. We discuss the prospects for distinguishing this mode from a minimal Higgs boson at the LHC and ILC. The main discriminants between the two scenarios are (i) cubic self-interactions and (ii) a potential enhancement of couplings to massless SM gauge bosons.

  13. Electron-cloud build-up in hadron machines

    SciTech Connect

    Furman, M.A.

    2004-08-09

    The first observations of electron-proton coupling effect for coasting beams and for long-bunch beams were made at the earliest proton storage rings at the Budker Institute of Nuclear Physics (BINP) in the mid-60's [1]. The effect was mainly a form of the two-stream instability. This phenomenon reappeared at the CERN ISR in the early 70's, where it was accompanied by an intense vacuum pressure rise. When the ISR was operated in bunched-beam mode while testing aluminum vacuum chambers, a resonant effect was observed in which the electron traversal time across the chamber was comparable to the bunch spacing [2]. This effect (''beam-induced multipacting''), being resonant in nature, is a dramatic manifestation of an electron cloud sharing the vacuum chamber with a positively-charged beam. An electron-cloud-induced instability has been observed since the mid-80's at the PSR (LANL) [3]; in this case, there is a strong transverse instability accompanied by fast beam losses when the beam current exceeds a certain threshold. The effect was observed for the first time for a positron beam in the early 90's at the Photon Factory (PF) at KEK, where the most prominent manifestation was a coupled-bunch instability that was absent when the machine was operated with an electron beam under otherwise identical conditions [4]. Since then, with the advent of ever more intense positron and hadron beams, and the development and deployment of specialized electron detectors [5-9], the effect has been observed directly or indirectly, and sometimes studied systematically, at most lepton and hadron machines when operated with sufficiently intense beams. The effect is expected in various forms and to various degrees in accelerators under design or construction. The electron-cloud effect (ECE) has been the subject of various meetings [10-15]. Two excellent reviews, covering the phenomenology, measurements, simulations and historical development, have been recently given by Frank Zimmermann [16

  14. Reaching record-low β* at the CERN Large Hadron Collider using a novel scheme of collimator settings and optics

    NASA Astrophysics Data System (ADS)

    Bruce, R.; Bracco, C.; De Maria, R.; Giovannozzi, M.; Mereghetti, A.; Mirarchi, D.; Redaelli, S.; Quaranta, E.; Salvachua, B.

    2017-03-01

    The Large Hadron Collider (LHC) at CERN is built to collide intense proton beams with an unprecedented energy of 7 TeV. The design stored energy per beam of 362 MJ makes the LHC beams highly destructive, so that any beam losses risk to cause quenches of superconducting magnets or damage to accelerator components. Collimators are installed to protect the machine and they define a minimum normalized aperture, below which no other element is allowed. This imposes a limit on the achievable luminosity, since when squeezing β* (the β-function at the collision point) to smaller values for increased luminosity, the β-function in the final focusing system increases. This leads to a smaller normalized aperture that risks to go below the allowed collimation aperture. In the first run of the LHC, this was the main limitation on β*, which was constrained to values above the design specification. In this article, we show through theoretical and experimental studies how tighter collimator openings and a new optics with specific phase-advance constraints allows a β* as small as 40 cm, a factor 2 smaller than β*=80 cm used in 2015 and significantly below the design value β*=55 cm, in spite of a lower beam energy. The proposed configuration with β*=40 cm has been successfully put into operation and has been used throughout 2016 as the LHC baseline. The decrease in β* compared to 2015 has been an essential contribution to reaching and surpassing, in 2016, the LHC design luminosity for the first time, and to accumulating a record-high integrated luminosity of around 40 fb-1 in one year, in spite of using less bunches than in the design.

  15. New fast beam profile monitor for electron-positron colliders

    SciTech Connect

    Bogomyagkov, A. V.; Gurko, V. F.; Zhuravlev, A. N.; Zubarev, P. V.; Kiselev, V. A.; Meshkov, O. I.; Muchnoi, N. Yu.; Selivanov, A. N.; Smaluk, V. V.; Khilchenko, A. D.

    2007-04-15

    A new fast beam profile monitor has been developed at the Budker Institute of Nuclear Physics. This monitor is based on the Hamamatsu multianode photomultiplier with 16 anode strips and provides turn-by-turn measurement of the transverse beam profile. The device is equipped with an internal memory, which has enough capacity to store 131 072 samples of the beam profile. The dynamic range of the beam profile monitor allows us to study turn-by-turn beam dynamics within the bunch charge range from 1 pC up to 10 nC. Using this instrument, we have investigated at the VEPP-4M electron-positron collider a number of beam dynamics effects which cannot be observed by other beam diagnostics tools.

  16. Measurement of the top-quark pair production cross-section using final states with an electron or a muon and a hadronically decaying τ-lepton

    NASA Astrophysics Data System (ADS)

    Takahashi, Yuta

    2014-08-01

    A measurement of the top-quark pair production cross-section is reported using proton-proton collision data at √{ s} = 7 TeV recorded by ATLAS experiment at the Large Hadron Collider. Events are extracted from 2.05 fb-1 of data by requiring an isolated electron or muon, a large missing transverse momentum, two or more energetic jets and a hadronically decaying τ-lepton. The measured cross-section, σttbar = 186 ± 13 (stat.) ± 20 (syst.) ± 7 (lumi.) pb, is in good agreement with the Standard Model prediction.

  17. Thermal Photon Radiation in High Multiplicity p+Pb Collisions at the Large Hadron Collider

    SciTech Connect

    Shen, Chun; Paquet, Jean-François; Denicol, Gabriel S.; Jeon, Sangyong; Gale, Charles

    2016-02-18

    We observed the collective behavior of hadronic particles in high multiplicity proton-lead collisions at the Large Hadron Collider, as well as in deuteron-gold collisions at the Relativistic Heavy-Ion Collider. In our work we present the first calculation, in the hydrodynamic framework, of thermal photon radiation from such small collision systems. Owing to their compact size, these systems can reach temperatures comparable to those in central nucleus-nucleus collisions. Moreover, the thermal photons can thus shine over the prompt background, and increase the low pT direct photon spectrum by a factor of 2–3 in 0%–1% p+Pb collisions at 5.02 TeV. This thermal photon enhancement can therefore serve as a signature of the existence of a hot quark-gluon plasma during the evolution of these small collision systems, as well as validate hydrodynamic behavior in small systems.

  18. Hadronization of partons

    SciTech Connect

    Albino, S.

    2010-07-15

    The description of inclusive production of single unpolarized light hadrons using fragmentation functions in the framework of the factorization theorem is reviewed. The factorization of observables into perturbatively calculable quantities and these universal fragmentation functions are summarized and some improvements beyond the standard fixed order approach are discussed. The extraction of fragmentation functions for light charged ({pi}{sup {+-}}, K{sup {+-}}, and p/p) and neutral (K{sub S}{sup 0} and {Lambda}/{Lambda}) hadrons using these theoretical tools is discussed through global fits to experimental data from reactions at various colliders, in particular from accurate e{sup +}e{sup -} reactions at the Large Electron-Position Collider (LEP), and the subsequent successful predictions of other experimental data, such as data gathered at Hadron Electron Ring Accelerator (HERA), the Tevatron, and the Relativistic Heavy Ion Collider (RHIC), from these fitted fragmentation functions as allowed by factorization universality. These global fits also impose competitive constraints on {alpha}{sub s}(M{sub Z}). Emphasis is placed on the need for accurate data from pp(p) and ep reactions in which the hadron species is identified in order to constrain the separate fragmentation functions of the gluon and each quark flavor for each hadron species.

  19. Design studies for the next generation electron ion colliders

    NASA Astrophysics Data System (ADS)

    Sayed, Hisham Kamal; Bogacz, S. A.; Krafft, G.

    2014-04-01

    The next generation Electron Ion Collider (EIC) at Thomas Jefferson National Accelerator Facility (JLAB) utilizes a figure-8 shaped ion and electron rings. EIC has the ability to preserve the ion polarization during acceleration, where the electron ring matches in footprint with a figure-8 ion ring. The electron ring is designed to deliver a highly polarized high luminous electron beam at interaction point (IP). The main challenges of the electron ring design are the chromaticity compensation and maintaining high beam polarization of 70% at all energies 3-11 GeV without introducing transverse orbital coupling before the IP. The very demanding detector design limits the minimum distance between the final focus quadrupole and the interaction point to 3.5 m which results in a large β function inside the final focus quadrupoles leading to increased beam chromaticity. In this paper, we present a novel chromaticity compensation scheme that mitigates IP chromaticity by a compact chromaticity compensation section with multipole magnet components. In addition, a set of spin rotators are utilized to manipulate the polarization vector of the electron beam in order to preserve the beam polarization. The spin rotator solenoids introduce undesired coupling between the horizontal and vertical betatron motion of the beam. We introduce a compact and modular orbit decoupling insert that can fit in the limited space of the straight section in the figure-8 ring. We show a numerical study of the figure-8 ring design with the compact straight section, which includes the interaction region, chromaticity compensation section, and the spin rotators, the figure-8 design performance is evaluated with particle tracking.

  20. Design studies for the next generation electron ion colliders

    SciTech Connect

    Sayed, Hisham Kamal; Bogacz, Slawomir A.; Krafft, Geoffrey A.

    2014-04-01

    The next generation Electron Ion Collider (EIC) at Thomas Jefferson National Accelerator Facility (JLAB) utilizes a figure-8 shaped ion and electron rings. EIC has the ability to preserve the ion polarization during acceleration, where the electron ring matches in footprint with a figure-8 ion ring. The electron ring is designed to deliver a highly polarized high luminous electron beam at interaction point (IP). The main challenges of the electron ring design are the chromaticity compensation and maintaining high beam polarization of 70% at all energies 3–11 GeV without introducing transverse orbital coupling before the IP. The very demanding detector design limits the minimum distance between the final focus quadrupole and the interaction point to 3.5 m which results in a large β function inside the final focus quadrupoles leading to increased beam chromaticity. In this paper, we present a novel chromaticity compensation scheme that mitigates IP chromaticity by a compact chromaticity compensation section with multipole magnet components. In addition, a set of spin rotators are utilized to manipulate the polarization vector of the electron beam in order to preserve the beam polarization. The spin rotator solenoids introduce undesired coupling between the horizontal and vertical betatron motion of the beam. We introduce a compact and modular orbit decoupling insert that can fit in the limited space of the straight section in the figure-8 ring. We show a numerical study of the figure-8 ring design with the compact straight section, which includes the interaction region, chromaticity compensation section, and the spin rotators, the figure-8 design performance is evaluated with particle tracking.

  1. Charm and bottom production in inclusive double Pomeron exchange in heavy-ion collisions at energies available at the CERN Large Hadron Collider

    SciTech Connect

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T.

    2011-01-15

    The inclusive double Pomeron exchange cross section for heavy-quark pair production is calculated for nucleus-nucleus collisions at the Large Hadron Collider. The present estimate is based on hard diffractive factorization, corrected by absorptive corrections and nuclear effects. The theoretical uncertainties for nuclear collisions are investigated and a comparison to other approaches is presented. The production channels giving a similar final state configuration are discussed as well.

  2. Kaluza-Klein gluon + jets associated production at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Iyer, A. M.; Mahmoudi, F.; Manglani, N.; Sridhar, K.

    2016-08-01

    The Kaluza-Klein excitations of gluons offer the exciting possibility of probing bulk Randall-Sundrum (RS) models. In these bulk models either a custodial symmetry or a deformation of the metric away from AdS is invoked in order to deal with electroweak precision tests. Addressing both these models, we suggest a new channel in which to study the production of KK-gluons (gKK): one where it is produced in association with one or more hard jets. The cross-section for the gKK + jets channel is significant because of several contributing sub-processes. In particular, the 1-jet and the 2-jet associated processes are important because at these orders in QCD the qg and the gg initial states respectively come into play. We have performed a hadron-level simulation of the signal and present strategies to effectively extract the signal from what could potentially be a huge background. We present results for the kinematic reach of the LHC Run-II for different gKK masses in bulk-RS models.

  3. Integrated analysis of particle interactions at hadron colliders Report of research activities in 2010-2015

    SciTech Connect

    Nadolsky, Pavel M.

    2015-08-31

    The report summarizes research activities of the project ”Integrated analysis of particle interactions” at Southern Methodist University, funded by 2010 DOE Early Career Research Award DE-SC0003870. The goal of the project is to provide state-of-the-art predictions in quantum chromodynamics in order to achieve objectives of the LHC program for studies of electroweak symmetry breaking and new physics searches. We published 19 journal papers focusing on in-depth studies of proton structure and integration of advanced calculations from different areas of particle phenomenology: multi-loop calculations, accurate long-distance hadronic functions, and precise numerical programs. Methods for factorization of QCD cross sections were advanced in order to develop new generations of CTEQ parton distribution functions (PDFs), CT10 and CT14. These distributions provide the core theoretical input for multi-loop perturbative calculations by LHC experimental collaborations. A novel ”PDF meta-analysis” technique was invented to streamline applications of PDFs in numerous LHC simulations and to combine PDFs from various groups using multivariate stochastic sampling of PDF parameters. The meta-analysis will help to bring the LHC perturbative calculations to the new level of accuracy, while reducing computational efforts. The work on parton distributions was complemented by development of advanced perturbative techniques to predict observables dependent on several momentum scales, including production of massive quarks and transverse momentum resummation at the next-to-next-to-leading order in QCD.

  4. Sources of machine-induced background in the ATLAS and CMS detectors at the CERN Large Hadron Collider

    SciTech Connect

    Bruce, R.; et al.,

    2013-11-21

    One source of experimental background in the CERN Large Hadron Collider (LHC) is particles entering the detectors from the machine. These particles are created in cascades, caused by upstream interactions of beam protons with residual gas molecules or collimators. We estimate the losses on the collimators with SixTrack and simulate the showers with FLUKA and MARS to obtain the flux and distribution of particles entering the ATLAS and CMS detectors. We consider some machine configurations used in the first LHC run, with focus on 3.5 TeV operation as in 2011. Results from FLUKA and MARS are compared and a very good agreement is found. An analysis of logged LHC data provides, for different processes, absolute beam loss rates, which are used together with further simulations of vacuum conditions to normalize the results to rates of particles entering the detectors. We assess the relative importance of background from elastic and inelastic beam-gas interactions, and the leakage out of the LHC collimation system, and show that beam-gas interactions are the dominating source of machine-induced background for the studied machine scenarios. Our results serve as a starting point for the experiments to perform further simulations in order to estimate the resulting signals in the detectors.

  5. Fluid dynamical prediction of changed v{sub 1} flow at energies available at the CERN Large Hadron Collider

    SciTech Connect

    Csernai, L. P.; Magas, V. K.; Stoecker, H.; Strottman, D. D.

    2011-08-15

    Substantial collective flow is observed in collisions between lead nuclei at Large Hadron Collider (LHC) as evidenced by the azimuthal correlations in the transverse momentum distributions of the produced particles. Our calculations indicate that the global v{sub 1}-flow, which at RHIC peaked at negative rapidities (named third flow component or antiflow), now at LHC is going to turn toward forward rapidities (to the same side and direction as the projectile residue). Potentially this can provide a sensitive barometer to estimate the pressure and transport properties of the quark-gluon plasma. Our calculations also take into account the initial state center-of-mass rapidity fluctuations, and demonstrate that these are crucial for v{sub 1} simulations. In order to better study the transverse momentum flow dependence we suggest a new ''symmetrized''v{sub 1}{sup S}(p{sub t}) function, and we also propose a new method to disentangle global v{sub 1} flow from the contribution generated by the random fluctuations in the initial state. This will enhance the possibilities of studying the collective Global v{sub 1} flow both at the STAR Beam Energy Scan program and at LHC.

  6. Prospects for identification the direct and indirect effects of extra spatial dimensions at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Pankov, A. A.; Serenkova, I. A.; Tsytrinov, A. V.; Bednyakov, V. A.

    2017-05-01

    The existence of massive graviton states, that may be produced as real and virtual particles in high-energy proton collisions, is predicted by the modern developments of Kaluza-Klein models with extra spatial dimensions. The direct and indirect signatures of large and warped extra spatial dimensions may be revealed by analyzing the specific characteristics of dilepton and diphoton final states formed in proton-proton collisions at the Large Hadron Collider (LHC). Virtual effects in the Kaluza-Klein models with large extra spatial dimensions can be discovered by the specic behavior of the dilpton and diphoton invariant-mass distributions, and their identication (in case of discovery) can be performed by the analysis of their angular distributions with integrated center-edge asymmetry. Assuming the nominal values of the LHC collision energy (14 TeV) and luminosity (100 fb-1), for the models with large extra spatial dimensions we find that the sensitivity to the cutoff parameter M S will extend up to 8.5 and 7.6 TeV for their discovery and identification, respectively. For the Randall-Sundrum model with a warped extra dimension, the LHC experiments will be sensitive to the graviton resonance with mass up to 4.4 and 3.1 TeV for its discovery and identification, respectively.

  7. Sources of machine-induced background in the ATLAS and CMS detectors at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bregliozzi, G.; Burkhardt, H.; Cerutti, F.; Ferrari, A.; Huhtinen, M.; Lechner, A.; Levinsen, Y.; Mereghetti, A.; Mokhov, N. V.; Tropin, I. S.; Vlachoudis, V.

    2013-11-01

    One source of experimental background in the CERN Large Hadron Collider (LHC) is particles entering the detectors from the machine. These particles are created in cascades, caused by upstream interactions of beam protons with residual gas molecules or collimators. We estimate the losses on the collimators with SixTrack and simulate the showers with FLUKA and MARS to obtain the flux and distribution of particles entering the ATLAS and CMS detectors. We consider some machine configurations used in the first LHC run, with focus on 3.5 TeV operation as in 2011. Results from FLUKA and MARS are compared and a very good agreement is found. An analysis of logged LHC data provides, for different processes, absolute beam loss rates, which are used together with further simulations of vacuum conditions to normalize the results to rates of particles entering the detectors. We assess the relative importance of background from elastic and inelastic beam-gas interactions, and the leakage out of the LHC collimation system, and show that beam-gas interactions are the dominating source of machine-induced background for the studied machine scenarios. Our results serve as a starting point for the experiments to perform further simulations in order to estimate the resulting signals in the detectors.

  8. W- and Z-boson production with a massive bottom-quark pair at the Large Hadron Collider

    SciTech Connect

    Cordero, F. Febres; Reina, L.; Wackeroth, D.

    2009-08-01

    We present total and differential cross sections for Wbb and Zbb production at the CERN Large Hadron Collider with a center-of-mass energy of {radical}(s)=14 TeV, including next-to-leading order (NLO) QCD corrections and full bottom-quark mass effects. We also provide numerical results obtained with a center-of-mass energy of {radical}(s)=10 TeV. We study the scale uncertainty of the total cross sections due to the residual renormalization- and factorization-scale dependence of the truncated perturbative series. While in the case of Zbb production the scale uncertainty of the total cross section is reduced by NLO QCD corrections, the Wbb production process at NLO in QCD still suffers from large scale uncertainties, in particular, in the inclusive case. We also perform a detailed comparison with a calculation that considers massless bottom quarks, as implemented in the Monte Carlo program MCFM. The effects of a nonzero bottom-quark mass (m{sub b}) cannot be neglected in phase-space regions where the relevant kinematic observable, such as the transverse-momentum of the bottom quarks or the invariant-mass of the bottom-quark pair, are of the order of m{sub b}. The effects on the total production cross sections are usually smaller than the residual scale uncertainty at NLO in QCD.

  9. Thermomechanical assessment of the effects of a jaw-beam angle during beam impact on Large Hadron Collider collimators

    NASA Astrophysics Data System (ADS)

    Cauchi, Marija; Assmann, R. W.; Bertarelli, A.; Carra, F.; Lari, L.; Rossi, A.; Mollicone, P.; Sammut, N.

    2015-02-01

    The correct functioning of a collimation system is crucial to safely and successfully operate high-energy particle accelerators, such as the Large Hadron Collider (LHC). However, the requirements to handle high-intensity beams can be demanding, and accident scenarios must be well studied in order to assess if the collimator design is robust against possible error scenarios. One of the catastrophic, though not very probable, accident scenarios identified within the LHC is an asynchronous beam dump. In this case, one (or more) of the 15 precharged kicker circuits fires out of time with the abort gap, spraying beam pulses onto LHC machine elements before the machine protection system can fire the remaining kicker circuits and bring the beam to the dump. If a proton bunch directly hits a collimator during such an event, severe beam-induced damage such as magnet quenches and other equipment damage might result, with consequent downtime for the machine. This study investigates a number of newly defined jaw error cases, which include angular misalignment errors of the collimator jaw. A numerical finite element method approach is presented in order to precisely evaluate the thermomechanical response of tertiary collimators to beam impact. We identify the most critical and interesting cases, and show that a tilt of the jaw can actually mitigate the effect of an asynchronous dump on the collimators. Relevant collimator damage limits are taken into account, with the aim to identify optimal operational conditions for the LHC.

  10. Spin identification of graviton resonances in the process pp {sup {yields}}e{sup +}e{sup -} + X at the Large Hadron Collider (LHC)

    SciTech Connect

    Serenkova, I. A. Pankov, A.A. Tsytrinov, A.V.; Bednyakov, V. A.

    2010-07-15

    Prospects for discovering heavy graviton resonances in decays to an electron-positron pair and for identifying the nature of these resonances in the ATLAS experiment at the Large Hadron Collider (LHC) are investigated. Gravitons in the Randall-Sundrum model, which features extra spatial dimensions, are considered by way of example. A comparative analysis of effects of new different-spin heavy resonances, scalar [supersymmetric neutrino (sneutrino)], vector (new gauge Z' boson), and tensor (graviton) ones, is performed in order to identify the graviton spin. An identification of gravitons is performed by using the integrated center-edge asymmetry. For LHC, the graviton discovery (identification) reach is found to be 2.1 TeV (1.2 TeV) and 3.9 TeV (2.9 TeV) at a confidence level of 5{delta} (95%) for the graviton coupling constants of k/bar M {sub Pl} = 0.01 and 0.1, respectively. This analysis is the most general, since, for the first time, it takes into account the possible existence of scalar resonances, which affects substantially quantitative estimates of the identification reach.

  11. GUT models at current and future hadron colliders and implications to dark matter searches

    NASA Astrophysics Data System (ADS)

    Arcadi, Giorgio; Lindner, Manfred; Mambrini, Yann; Pierre, Mathias; Queiroz, Farinaldo S.

    2017-08-01

    Grand Unified Theories (GUT) offer an elegant and unified description of electromagnetic, weak and strong interactions at high energy scales. A phenomenological and exciting possibility to grasp GUT is to search for TeV scale observables arising from Abelian groups embedded in GUT constructions. That said, we use dilepton data (ee and μμ) that has been proven to be a golden channel for a wide variety of new phenomena expected in theories beyond the Standard Model to probe GUT-inspired models. Since heavy dilepton resonances feature high signal selection efficiencies and relatively well-understood backgrounds, stringent and reliable bounds can be placed on the mass of the Z‧ gauge boson arising in such theories. In this work, we obtain 95% C.L. limits on the Z‧ mass for several GUT-models using current and future proton-proton colliders with √{ s} = 13 TeV , 33 TeV ,and 100 TeV, and put them into perspective with dark matter searches in light of the next generation of direct detection experiments.

  12. (Calorimeter based detectors for high energy hadron colliders). [State Univ. of New York

    SciTech Connect

    Not Available

    1992-08-04

    This document provides a progress report on research that has been conducted under DOE Grant DEFG0292ER40697 for the past year, and describes proposed work for the second year of this 8 year grant starting November 15, 1992. Personnel supported by the contract include 4 faculty, 1 research faculty, 4 postdocs, and 9 graduate students. The work under this grant has in the past been directed in two complementary directions -- DO at Fermilab, and the second SSC detector GEM. A major effort has been towards the construction and commissioning of the new Fermilab Collider detector DO, including design, construction, testing, the commissioning of the central tracking and the central calorimeters. The first DO run is now underway, with data taking and analysis of the first events. Trigger algorithms, data acquisition, calibration of tracking and calorimetry, data scanning and analysis, and planning for future upgrades of the DO detector with the advent of the FNAL Main Injector are all involved. The other effort supported by this grant has been towards the design of GEM, a large and general-purpose SSC detector with special emphasis on accurate muon measurement over a large solid angle. This effort will culminate this year in the presentation to the SSC laboratory of the GEM Technical Design Report. Contributions are being made to the detector design, coordination, and physics simulation studies with special emphasis on muon final states. Collaboration with the RD5 group at CERN to study muon punch through and to test cathode strip chamber prototypes was begun.

  13. Reliability of Beam Loss Monitors System for the Large Hadron Collider

    SciTech Connect

    Guaglio, G.; Dehning, B.; Santoni, C.

    2004-11-10

    The employment of superconducting magnets in high energy colliders opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particle losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data have been processed by reliability software (Isograph). The analysis ranges from the components data to the system configuration.

  14. Free Electron Laser for Gamma-Gamma Collider at a Low-Energy Option of International Linear Collider

    SciTech Connect

    Saldin, Evgeny; Schneidmiller, Evgeny; Yurkov, Mikhail; Seryi, Andrei; /SLAC

    2009-10-30

    Different scenarios of a start-up with International Linear Collider (ILC) are under discussion at the moment in the framework of the Global Design Effort (GDE). One of them assumes construction of the ILC in stages from some minimum CM energy up to final target of 500 GeV CM energy. Gamma-gamma collider with CM energy of 180GeV is considered as a candidate for the first stage of the facility. In this report we present conceptual design of a free electron laser as a source of primary photons for the first stage of ILC.

  15. JLab: Probing Hadronic Physics with Electrons and Photons

    SciTech Connect

    Elton Smith

    2003-09-01

    Precision measurements of the structure of nucleons and nuclei in the regime of strong interaction QCD are now possible with the availability of high current polarized electron beams, polarized targets, and recoil polarimeters, in conjunction with modern spectrometers and detector instrumentation. The physics at JLab will be highlighted using two recent measurements of general interest. The ratio of the proton electric to magnetic form factors indicates the importance of the role of angular momentum in the structure of the nucleon. The existence of 5-quark configurations in the ground state wavefunctions of hadrons is confirmed by a narrow peak attributed to an exotic baryon with strangeness S=+1. These and other examples will be used to illustrate the capabilities and focus of the experimental program at JLab.

  16. A study on dual readout crystal calorimeter for hadron and jet energy measurement at a future lepton collider

    SciTech Connect

    Yeh, G.P.; /Fermilab

    2010-01-01

    Studies of requirements and specifications of crystals are necessary to develop a new generation of crystals for dual readout crystal hadron or total absorption calorimeter. This is a short and basic study of the characteristics and hadron energy measurement of PbWO4 and BGO crystals for scintillation and Cerenkov Dual Readout hadron calorimeter.

  17. Mass and Spin Measurement Techniques (for the Large Hadron Collider):. Lectures Given at TASI 2011, Boulder, Colorado

    NASA Astrophysics Data System (ADS)

    Lester, Christopher G.

    2013-12-01

    For TASI 2011, I was asked to give a series of lectures on "Mass and Spin Measurement Techniques" with relevance to the Large Hadron Collider. This document provides a written record of those lectures - or more precisely of what I said while giving the lectures - warts and all. It is provided as my contribution to the proceedings primarily for the benefit of those who heard the lectures first hand and may wish to refer back to them. What it is not is a scientific paper or a teaching resource. Though lecture slides may be prepared in advance, what is actually said in a lecture is usually extemporaneous, may be partial, can be influenced by audience reaction, and may not even make sense without a visual record of the concomitant gesticulations of the lecturer. More worryingly, some of the statements made may be down-right false, if the lecturer's tongue is in a twist. Accordingly, these proceedings are provided without warranty of any kind - not least in respect of accuracy or impartiality. The lectures were intended to engage the audience and get them thinking about a number of topics that they had not seen before. They were not expected to be the sort of sombre or well-balanced overview of the field that one might hope to achive in a review. These proceedings are provided to jog the memory of those who saw the lectures first hand, and for little other purpose. Footnotes, where they appear, indicate text/thoughts I have added during the editing process that were not voiced during the lectures themselves. Copies of the lecture slides are inserted at approximately the locations they would have become visible in the lectures.

  18. Mono-jet, -photon and - Z signals of a supersymmetric ( B - L) model at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Abdallah, W.; Fiaschi, J.; Khalil, S.; Moretti, S.

    2016-02-01

    Search for invisible final states produced at the Large Hadron Collider (LHC) by new physics scenarios are normally carried out resorting to a variety of probes emerging from the initial state, in the form of single-jet, -photon and - Z boson signatures. These are particularly effective for models of Supersymmetry (SUSY) in presence of R-parity conservation, owing to the presence in their spectra of a stable neutralino as a Dark Matter (DM) candidate. We assume here as theoretical framework the Supersymmetric version of the ( B - L) extension of the Standard Model (BLSSM), wherein a mediator for invisible decays can be the Z ' boson present in this scenario. The peculiarity of the signal is thus that the final state objects carry a very large (transverse) missing energy, since the Z ' is naturally massive and constrained by direct searches and Electro-Weak Precision Tests (EWPTs) to be at least in the TeV scale region. Under these circumstances the efficiency in accessing the invisible final state and rejecting the Standard Model (SM) background is very high. This somehow compensates the rather meagre production rates. Another special feature of this invisible BLSSM signal is its composition, which is often dominated by sneutrino decays (alongside the more traditional neutrino and neutralino modes). Sensitivity of the CERN machine to these two features can therefore help disentangling the BLSSM from more popular SUSY models. We assess in this analysis the scope of the LHC in establishing the aforementioned invisible signals through a sophisticated signal-to-background simulation carried out in presence of parton shower, hadronisation as well as detector effects. We find that significant sensitivity exists already after 300 fb-1 during Run 2. We find that mono-jet events can be readily accessible at the LHC, so as to enable one to claim a prompt discovery, while mono-photon and - Z signals can be used as diagnostic tools of the underlying scenario.

  19. New Photocathode materials for electron-ion-colliders

    SciTech Connect

    Lukaszew, Rosa A.

    2015-02-25

    Our aim has been to explore new photocathode materials and schemes to develop strategies and technologies for next generation nuclear physics accelerator capabilities, particularly for Electron Ion Colliders (EIC). Thus, we investigated thin film deposition and ensuing properties for several adequate magnetic materials applicable to spin-polarized photocathodes. We also implemented a full experimental setup for light incidence at an acute angle onto the photocathode surface in order to excite surface Plasmon resonance hence increasing light absorption by a metallic surface. We successfully tested the setup with a thermionic cathode as well as Plasmonic silver-MgO samples and obtained very encouraging results. Our first results are very encouraging since the photocurrent measured on this preliminary plasmonic Ag-MgO sample under low power (~ 1mW) cw red light from a HeNe laser was 256 pA, thus two orders magnitude larger than that reported by others following also plasmonic approaches. We extended our studies to shorter wavelengths and we also started preliminary work on chemically ordered MnAl thin films –a component of the tertiary Ag-Mn-Al (silmanal) alloy in order to develop spin-polarized photocathodes capable of sustaining surface Plasmon resonance. It is worthwhile mentioning that a graduate student has been directly involved during this project ensuring the training of next generation of scientists in this area of research.

  20. Experimental Opportunities for Few Body Physics at an Electron Ion Collider

    NASA Astrophysics Data System (ADS)

    Hyde, Charles

    2016-03-01

    A high energy electron-ion collider (EIC) is proposed as the next major facility in the United States for studying the QCD structure of matter. I will discuss the following key few-body physics topics enabled by an EIC: 1. Spatial imaging of quarks and gluons in the nucleon via deep virtual exclusive reactions (DVES). Momentum imaging of quarks and gluons via Semi-Inclusive Deep Inelastic Scattering (SIDIS) in both the current and projectile fragmentation regimes. These experiments will span the kinematic range from large xBj where the nucleon can be fruitfully described as a few-body quark system, to low xBj, where the structure is dominated by the quark-gluon sea; 2. Spectator nucleon tagging of Deep Inelastic Scattering (DIS) in light nuclei and DVES with identification of the nuclear final state are probes of both neutron structure and the quark-gluon structure of nuclear binding; 3. Evaporation and projectile fragmentation in DIS on nuclei as a probe of the dynamic generation of mass of a fast quark or gluon as it propagates through the nuclear medium and evolves into a final state hadron. I will also discuss proposed detectors to implement this program. U.S. Dept of Energy.

  1. Towards a Small Emittance Design of the JLEIC Electron Collider Ring

    SciTech Connect

    Lin, Fanglei; Derbenev, Yaroslav; Hutton, Andrew M.; Morozov, Vasiliy; Pilat, Fulvia C.; Zhang, Yuhong

    2016-05-01

    The electron collider ring of the Jefferson Lab Electron-Ion Collider (JLEIC) is designed to provide an electron beam with a small beam size at the IP for collisions with an ion beam in order to reach a desired high luminosity. For a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance that can be obtained through a linear optics design. This paper briefly describes the baseline design of the electron collider ring reusing PEP-II components and considering their parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and reports a few approaches to reducing the equilibrium emittance in the electron collider ring.

  2. Interaction region design for the electron-nucleon collider ENC at FAIR

    SciTech Connect

    Montag, C.; Jankowiak, A.; Lehrach, A.

    2010-05-23

    To facilitate studies of collisions between polarized electron and protons at {radical}s = 14 GeV; constructing an electron-nucleon collider at the FAIR facility has been proposed. This machine would collide the stored 15 GeV polarized proton beam in the HESR with a polarized 3.3 GeV electron beam circulating in an additional storage ring. We describe the interaction region design of this facility, which utilizes the PANDA detector.

  3. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    ScienceCinema

    None

    2016-07-12

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

  4. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    SciTech Connect

    2010-02-17

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

  5. eRHIC, the BNL design for a future Electron-Ion Collider

    NASA Astrophysics Data System (ADS)

    Roser, Thomas

    2016-03-01

    With the addition of a 20 GeV polarized electron accelerator to the existing Brookhaven Relativistic Heavy Ion Collider (RHIC), the world's only high energy heavy ion and polarized proton collider, a future eRHIC facility will be able to produce polarized electron-nucleon collisions at center-of-mass energies of up to 145 GeV and cover the whole science case as outlined in the Electron-Ion Collider White Paper and endorsed by the 2015 Nuclear Physics Long Range Plan with high luminosity. The presentation will describe the eRHIC design concepts and recent efforts to reduce the technical risks of the project.

  6. Measurement of s (pp → tt) in the t + jets channel using 4.7 FB-1 of data from the atlas experiment of The Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Sytsma, Michael J.

    The top quark is the heaviest of the known elementary particles in the Standard Model. Top quark decay can result into various final states; therefore, careful study of its production rate and other properties is very important for particle physics. With the shutdown of the Tevatron, The Large Hadron Collider (LHC) is the only facility currently capable of studying top quark properties. The data obtained by proton-proton collisions in the LHC is recorded by two general purpose detectors, ATLAS and CMS. The results in the dissertation are from the ATLAS detector. A new measurement is reported of σ(pp → tt¯) at s = 7 TeV using 4.7 fb -1 of data collected during 2011. In this analysis, the final state of the top quark decay is a hadronically decaying tau lepton and a pair of light quark jets. Only those events in which the tau lepton subsequently decays to one or three charged hadrons, zero or more neutral hadrons and a tau neutrino, are selected. Boosted Decision Trees are used for hadronic tau identification. The signature thus consists of one hadronically decaying tau lepton and four or more jets, of which at least one is initiated by a b quark accompanying the W in the top quark decays, and a large net missing momentum in the transverse plane due to the energetic neutrino-antineutrino pair. This momentum is not detected by the ATLAS detector. For multi-jet background estimation, a template fitting method is used. The template is fitted to the data to obtain the fractions for the signal and it's various backgrounds. The measured cross section along with the uncertainties on the statistics, systematics and luminosity is: σtt¯ = 170.6 +/- 12 (stat.) +19-20 (syst.) +/- 3 (lumi.) pb..

  7. Top Quark Pair Production in Association with a Jet with Next-to-Leading-Order QCD Off-Shell Effects at the Large Hadron Collider.

    PubMed

    Bevilacqua, G; Hartanto, H B; Kraus, M; Worek, M

    2016-02-05

    We present a complete description of top quark pair production in association with a jet in the dilepton channel. Our calculation is accurate to next-to-leading order (NLO) in QCD and includes all nonresonant diagrams, interferences, and off-shell effects of the top quark. Moreover, nonresonant and off-shell effects due to the finite W gauge boson width are taken into account. This calculation constitutes the first fully realistic NLO computation for top quark pair production with a final state jet in hadronic collisions. Numerical results for differential distributions as well as total cross sections are presented for the Large Hadron Collider at 8 TeV. With our inclusive cuts, NLO predictions reduce the unphysical scale dependence by more than a factor of 3 and lower the total rate by about 13% compared to leading-order QCD predictions. In addition, the size of the top quark off-shell effects is estimated to be below 2%.

  8. Strong and Electroweak Corrections to the Production of a Higgs Boson+2 Jets via Weak Interactions at the Large Hadron Collider

    SciTech Connect

    Ciccolini, M.; Denner, A.; Dittmaier, S.

    2007-10-19

    Radiative corrections of strong and electroweak interactions are presented at next-to-leading order for the production of a Higgs boson plus two hard jets via weak interactions at the CERN Large Hadron Collider. The calculation includes all weak-boson fusion and quark-antiquark annihilation diagrams as well as the corresponding interferences. The electroweak corrections, which are discussed here for the first time, reduce the cross sections by 5% and thus are of the same order of magnitude as the QCD corrections.

  9. Strong and electroweak corrections to the production of a Higgs boson+2 jets via weak interactions at the Large Hadron Collider.

    PubMed

    Ciccolini, M; Denner, A; Dittmaier, S

    2007-10-19

    Radiative corrections of strong and electroweak interactions are presented at next-to-leading order for the production of a Higgs boson plus two hard jets via weak interactions at the CERN Large Hadron Collider. The calculation includes all weak-boson fusion and quark-antiquark annihilation diagrams as well as the corresponding interferences. The electroweak corrections, which are discussed here for the first time, reduce the cross sections by 5% and thus are of the same order of magnitude as the QCD corrections.

  10. Using kinematic variables to extract information from semi-invisible decays of heavy particles at hadron colliders

    NASA Astrophysics Data System (ADS)

    Kim, Doojin

    We examine the ways of extracting information from semi-invisible decays of (new) heavy particles at hadron colliders, i.e., such heavy particles are assumed to decay into visible/Standard Model (SM) particles and invisible particles. As a concrete realization, we employ the models with the stable weakly interacting massive particle (WIMP), a well-motivated dark matter (DM) candidate. By definition, dark matter is not seen by the detectors, i.e., invisible. Typically, stability of dark matter is ensured by introducing a new (unbroken) symmetry under which the DM is non-trivially charged while the SM particles are uncharged. Also, many new physics models contain other heavier particles which are charged under the same symmetry so that such heavier particles must decay into (invisible) DM particles along with the relevant visible/SM particles. In particular, we study how to determine the masses of DM and heavy particles and the nature of the above-mentioned DM stabilization symmetries. For this purpose we take three kinematic variables as the main toolkits. We first discuss the distribution of the invariant mass formed by the visible part in the associated decays. As the second variable, we include the invisible part in forming the invariant mass. Because we are not aware of the longitudinal momentum of invisible particles, such a quantity is constructed in the plane transverse to the beam pipe, which is therefore called "transverse" mass. This is typically suitable for a singly produced heavy particle. Since the DM stabilization symmetries lead to pair-production of heavier particles, we here consider the "stransverse/MT2" type variable, a simple generalization of the transverse mass. Finally, we consider the energy spectrum of visible particle(s), which is not Lorentz-invariant at all even under longitudinal boosts. The relevant strategy is predicated upon the new observations that we shall make about physical implications of the peak position in such an energy

  11. VINCIA for hadron colliders

    NASA Astrophysics Data System (ADS)

    Fischer, N.; Prestel, S.; Ritzmann, M.; Skands, P.

    2016-11-01

    We present the first public implementation of antenna-based QCD initial- and final-state showers. The shower kernels are 2→ 3 antenna functions, which capture not only the collinear dynamics but also the leading soft (coherent) singularities of QCD matrix elements. We define the evolution measure to be inversely proportional to the leading poles, hence gluon emissions are evolved in a p_perp measure inversely proportional to the eikonal, while processes that only contain a single pole (e.g., g→ qbar{q}) are evolved in virtuality. Non-ordered emissions are allowed, suppressed by an additional power of 1/Q^2. Recoils and kinematics are governed by exact on-shell 2→ 3 phase-space factorisations. This first implementation is limited to massless QCD partons and colourless resonances. Tree-level matrix-element corrections are included for QCD up to O(α _s^4) (4 jets), and for Drell-Yan and Higgs production up to O(α _s^3) ( V / H + 3 jets). The resulting algorithm has been made publicly available in Vincia 2.0.

  12. VINCIA for hadron colliders

    DOE PAGES

    Fischer, Nadine; Prestel, S.; Ritzmann, M.; ...

    2016-10-28

    We present the first public implementation of antenna-based QCD initial- and final-state showers. The shower kernels are 2→3 antenna functions, which capture not only the collinear dynamics but also the leading soft (coherent) singularities of QCD matrix elements. We define the evolution measure to be inversely proportional to the leading poles, hence gluon emissions are evolved in a p⊥ measure inversely proportional to the eikonal, while processes that only contain a single pole (e.g., g → qq¯) are evolved in virtuality. Non-ordered emissions are allowed, suppressed by an additional power of 1/Q2. Recoils and kinematics are governed by exact on-shellmore » 2 → 3 phase-space factorisations. This first implementation is limited to massless QCD partons and colourless resonances. Tree-level matrix-element corrections are included for QCD up to O(α4s) (4 jets), and for Drell–Yan and Higgs production up to O(α3s) (V / H + 3 jets). Finally, the resulting algorithm has been made publicly available in Vincia 2.0.« less

  13. Production of high intensity electron bunches for the SLAC Linear Collider

    SciTech Connect

    James, M.B.

    1987-08-01

    This thesis describes the design and performance of a high intensity electron injecfor for the SLAC Linear Collider. Motivation for the collider and the specifications for the injector are discussed. An analytic theory of the bunching and capture of electrons by rf fields is discussed in the limit of low space charge and small signal. The design and performance of SLAC's main injector are described to illustrate a successful application of this theory. The bunching and capture of electrons by rf fields are then discussed in the limit of high space charge and large signal, and a description of the design of the collider injector follows. In the limit of high space charge forces and large rf signals, the beam dynamics are considerably more complex and numerical simulations are required to predict particle motion. A computer code which models the longitudinal dynamics of electrons in the presence of space charge and rf fields is described. The results of the simulations, the resulting collider injector design and the various components which make up the collider injector are described. These include the gun, subharmonic bunchers, traveling-wave buncher and velocity-of-light accelerator section. Finally, the performance of the injector is described including the beam intensity, bunch length, transverse emittance and energy spectrum. While the final operating conditions differ somewaht from the design, the performance of the collider injector is in good agreement with the numerical simulations and meets all of the collider specifications. 28 refs.

  14. Color octet electron search potential of FCC based e–p colliders

    NASA Astrophysics Data System (ADS)

    Acar, Y. C.; Kaya, U.; Oner, B. B.; Sultansoy, S.

    2017-04-01

    Resonant production of color octet electrons, e 8, at the FCC based e–p colliders is analyzed. It is shown that e-FCC will cover much a wider region of e 8 masses compared to the LHC. Moreover, with the highest electron beam energy, the e 8 search potential of the e-FCC exceeds that of the FCC p–p collider. If e 8 is discovered earlier by the FCC p–p collider, e-FCC will give an opportunity to handle very important additional information. For example, the compositeness scale can be probed up to the hundreds of TeV region.

  15. Design of Electron and Ion Crabbing Cavities for an Electron-Ion Collider

    SciTech Connect

    Alejandro Castilla Loeza, Geoffrey Krafft, Jean Delayen

    2012-07-01

    Beyond the 12 GeV upgrade at the Jefferson Lab a Medium Energy Electron-Ion Collider (MEIC) has been considered. In order to achieve the desired high luminosities at the Interaction Points (IP), the use of crabbing cavities is under study. In this work, we will present to-date designs of superconducting cavities, considered for crabbing both ion and electron bunches. A discussion of properties such as peak surface fields and higher-order mode separation will be presented. Keywords: super conducting, deflecting cavity, crab cavity.

  16. Probing short-range nucleon-nucleon interactions with an electron-ion collider

    DOE PAGES

    Miller, Gerald A.; Sievert, Matthew D.; Venugopalan, Raju

    2016-04-07

    For this research, we derive the cross section for exclusive vector meson production in high-energy deeply inelastic scattering off a deuteron target that disintegrates into a proton and a neutron carrying large relative momentum in the final state. This cross section can be expressed in terms of a novel gluon transition generalized parton distribution (T-GPD); the hard scale in the final state makes the T-GPD sensitive to the short-distance nucleon-nucleon interaction. We perform a toy model computation of this process in a perturbative framework and discuss the time scales that allow the separation of initial- and final-state dynamics in themore » T-GPD. We outline the more general computation based on the factorization suggested by the toy computation: In particular, we discuss the relative role of “pointlike” and “geometric” Fock configurations that control the parton dynamics of short-range nucleon-nucleon scattering. With the aid of exclusive J/ψ production data at the Hadron-Electron Ring Accelerator at DESY, as well as elastic nucleon-nucleon cross sections, we estimate rates for exclusive deuteron photodisintegration at a future Electron-Ion Collider (EIC). Our results, obtained using conservative estimates of EIC integrated luminosities, suggest that center-of-mass energies sNN ~12GeV2 of the neutron-proton subsystem can be accessed. We argue that the high energies of the EIC can address outstanding dynamical questions regarding the short-range quark-gluon structure of nuclear forces by providing clean gluon probes of such “knockout” exclusive reactions in light and heavy nuclei.« less

  17. Probing short-range nucleon-nucleon interactions with an electron-ion collider

    NASA Astrophysics Data System (ADS)

    Miller, Gerald A.; Sievert, Matthew D.; Venugopalan, Raju

    2016-04-01

    We derive the cross section for exclusive vector meson production in high-energy deeply inelastic scattering off a deuteron target that disintegrates into a proton and a neutron carrying large relative momentum in the final state. This cross section can be expressed in terms of a novel gluon transition generalized parton distribution (T-GPD); the hard scale in the final state makes the T-GPD sensitive to the short-distance nucleon-nucleon interaction. We perform a toy model computation of this process in a perturbative framework and discuss the time scales that allow the separation of initial- and final-state dynamics in the T-GPD. We outline the more general computation based on the factorization suggested by the toy computation: In particular, we discuss the relative role of "pointlike" and "geometric" Fock configurations that control the parton dynamics of short-range nucleon-nucleon scattering. With the aid of exclusive J /ψ production data at the Hadron-Electron Ring Accelerator at DESY, as well as elastic nucleon-nucleon cross sections, we estimate rates for exclusive deuteron photodisintegration at a future Electron-Ion Collider (EIC). Our results, obtained using conservative estimates of EIC integrated luminosities, suggest that center-of-mass energies sNN˜12 GeV2 of the neutron-proton subsystem can be accessed. We argue that the high energies of the EIC can address outstanding dynamical questions regarding the short-range quark-gluon structure of nuclear forces by providing clean gluon probes of such "knockout" exclusive reactions in light and heavy nuclei.

  18. Probing short-range nucleon-nucleon interactions with an electron-ion collider

    SciTech Connect

    Miller, Gerald A.; Sievert, Matthew D.; Venugopalan, Raju

    2016-04-07

    For this research, we derive the cross section for exclusive vector meson production in high-energy deeply inelastic scattering off a deuteron target that disintegrates into a proton and a neutron carrying large relative momentum in the final state. This cross section can be expressed in terms of a novel gluon transition generalized parton distribution (T-GPD); the hard scale in the final state makes the T-GPD sensitive to the short-distance nucleon-nucleon interaction. We perform a toy model computation of this process in a perturbative framework and discuss the time scales that allow the separation of initial- and final-state dynamics in the T-GPD. We outline the more general computation based on the factorization suggested by the toy computation: In particular, we discuss the relative role of “pointlike” and “geometric” Fock configurations that control the parton dynamics of short-range nucleon-nucleon scattering. With the aid of exclusive J/ψ production data at the Hadron-Electron Ring Accelerator at DESY, as well as elastic nucleon-nucleon cross sections, we estimate rates for exclusive deuteron photodisintegration at a future Electron-Ion Collider (EIC). Our results, obtained using conservative estimates of EIC integrated luminosities, suggest that center-of-mass energies sNN ~12GeV2 of the neutron-proton subsystem can be accessed. We argue that the high energies of the EIC can address outstanding dynamical questions regarding the short-range quark-gluon structure of nuclear forces by providing clean gluon probes of such “knockout” exclusive reactions in light and heavy nuclei.

  19. Alternate approaches to future electron-positron linear colliders

    SciTech Connect

    Loew, G.A.

    1998-07-01

    The purpose of this article is two-fold: to review the current international status of various design approaches to the next generation of e{sup +}e{sup {minus}} linear colliders, and on the occasion of his 80th birthday, to celebrate Richard B. Neal`s many contributions to the field of linear accelerators. As it turns out, combining these two tasks is a rather natural enterprise because of Neal`s long professional involvement and insight into many of the problems and options which the international e{sup +}e{sup {minus}} linear collider community is currently studying to achieve a practical design for a future machine.

  20. Role of net baryon density on rapidity width of identified particles from the lowest energies available at the CERN Super Proton Synchrotron to those at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Hussain, Nur; Bhattacharjee, Buddhadeb

    2017-08-01

    Widths of the rapidity distributions of various identified hadrons generated with the UrQMD-3.4 event generator at all the Super Proton Synchrotron (SPS) energies have been presented and compared with the existing experimental results. An increase in the width of the rapidity distribution of Λ could be seen with both Monte Carlo (MC) and experimental data for the studied energies. Using MC data, the study has been extended to Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. A similar jump, as observed in the plot of rapidity width versus rest mass at Alternating Gradient Synchrotron (AGS) and all SPS energies, persists even at RHIC and LHC energies, confirming its universal nature from AGS to the highest LHC energies. Such observation indicates that pair production may not be the only mechanism of particle production at the highest LHC energies. However, with MC data, the separate mass scaling for mesons and baryons is found to exist even at the top LHC energy.

  1. Freeze-out conditions in proton-proton collisions at the highest energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Das, Sabita; Mishra, Debadeepti; Chatterjee, Sandeep; Mohanty, Bedangadas

    2017-01-01

    The freeze-out conditions in proton-proton collisions at √{sNN}=200 , 900, and 7000 GeV have been extracted by fits to the mean hadron yields at midrapidity within the framework of the statistical model of an ideal gas of hadrons and resonances in the grand canonical ensemble. The variation of the extracted freeze-out thermal parameters and the goodness of the fits with √{sN N} are discussed. We find the extracted temperature and baryon chemical potential of the freeze-out surface to be similar in p +p and heavy-ion collisions. On the other hand, the thermal behavior of the strange hadrons is qualitatively different in p +p as compared to A +A collisions. We find an additional parameter accounting for nonequilibrium strangeness production is essential for describing the p +p data. This is in contrast to A +A where the nonequilibrium framework could be successfully replaced by a sequential and complete equilibrium model with an early freeze-out of the strange hadrons.

  2. Single and double production of the Higgs boson at hadron and lepton colliders in minimal composite Higgs models

    NASA Astrophysics Data System (ADS)

    Kanemura, Shinya; Kaneta, Kunio; Machida, Naoki; Odori, Shinya; Shindou, Tetsuo

    2016-07-01

    In the composite Higgs models, originally proposed by Georgi and Kaplan, the Higgs boson is a pseudo Nambu-Goldstone boson (pNGB) of spontaneous breaking of a global symmetry. In the minimal version of such models, global SO(5) symmetry is spontaneously broken to SO(4), and the pNGBs form an isospin doublet field, which corresponds to the Higgs doublet in the Standard Model (SM). Predicted coupling constants of the Higgs boson can in general deviate from the SM predictions, depending on the compositeness parameter. The deviation pattern is determined also by the detail of the matter sector. We comprehensively study how the model can be tested via measuring single and double production processes of the Higgs boson at the LHC and future electron-positron colliders. The possibility to distinguish the matter sector among the minimal composite Higgs models is also discussed. In addition, we point out differences in the cross section of double Higgs boson production from the prediction in other new physics models.

  3. Beam-Beam Study on the Upgrade of Beijing Electron Positron Collider

    SciTech Connect

    Wang, S.; Cai, Y.; /SLAC

    2006-02-10

    It is an important issue to study the beam-beam interaction in the design and performance of such a high luminosity collider as BEPCII, the upgrade of Beijing Electron Positron Collider. The weak-strong simulation is generally used during the design of a collider. For performance a large scale tune scan, the weak-strong simulation studies on beam-beam interaction were done, and the geometry effects were taken into account. The strong-strong simulation studies were done for investigating the luminosity goal and the dependence of the luminosity on the beam parameters.

  4. Depolarization due to beam-beam interaction in electron-positron linear colliders

    SciTech Connect

    Yokoya, K. ); Chen, P. )

    1989-05-05

    We investigate two major mechanisms which induce depolarization of electron beams during beam-beam interaction in linear colliders. These are the classical spin precession under the collective field of the oncoming beam, and the spin-flip effect from beamstrahlung. Analytic formulas are derived for estimating these depolarization effects. As examples, we estimate the depolarization in the Stanford Linear Collider (SLC) and a possible future TeV linear collider (TLC). The effects are found to be negligibly small for SLC and not very large for TLC.

  5. Depolarization due to beam-beam interaction in electron-positron linear colliders

    SciTech Connect

    Yokoya, Kaoru; Chen, Pisin

    1988-09-01

    We investigate two major mechanisms which induce depolarization of electron beams during beam-beam interaction in linear colliders. These are the classical spin precession under the collective field of the oncoming beam, and the spin-flip effect from beamstrahlung. Analytic formulas are derived for estimating these depolarization effects. As examples, we estimate the depolarization in the Stanford Linear Collider (SLC) and a possible future TeV linear collider (TLC). The effects are found to be negligibly small for SLC and not very large for TLC. 7 refs., 1 fig.

  6. High baryon densities in heavy ion collisions at energies attainable at the BNL Relativistic Heavy-Ion Collider and the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Li, Ming; Kapusta, Joseph I.

    2017-01-01

    In very high-energy collisions nuclei are practically transparent to each other but produce very hot nearly baryon-free matter in the so-called central rapidity region. The energy in the central rapidity region comes from the kinetic energy of the colliding nuclei. We calculate the energy and rapidity loss of the nuclei using the color glass condensate model. This model also predicts the excitation energy of the nuclear fragments. Using a space-time picture of the collision we calculate the baryon and energy densities of the receding baryonic fireballs. For central collisions of gold nuclei at the highest energy attainable at the Relativistic Heavy-Ion Collider, for example, we find baryon densities more than ten times that of atomic nuclei over a large volume.

  7. First year of Mark-J: physics with high energy electron-positron colliding beams. Report No. 107

    SciTech Connect

    Aachen DESY M.I.T. NIKHEF Peking Collaboration

    1980-04-01

    This report reviews the experimental investigation of high energy e/sup +/e/sup -/ interactions by the MARK J collaboration at PETRA, the electron-positron colliding beam accelerator at DESY in Hamburg, West Germany. The physics objectives include studies of several purely electromagnetic processes and hadronic final states, which further our knowledge of the nature of the fundamental constituents and of their strong, electromagnetic and weak interactions. Before discussing the physics results, the main features and the principal components of the MARK J detector are discussed in terms of design, function, and performance. Several aspects of the online data collection and the offline analysis are also outlined. Results are presented on tests of quantum electrodynamics using e/sup +/e/sup -/ ..-->.. e/sup +/e/sup -/, ..mu../sup +/..mu../sup -/ and tau/sup +/tau/sup -/, on the measurement of R, the ratio of the hadronic to the point-like muon pair cross section, on the search for new quark flavors, on the discovery of three jet events arising from the radiation of hard noncollinear gluons as predicted by quantum chromodynamics, and on the determination of the strong coupling constant ..cap alpha../sub s/.

  8. Probing triple-Higgs productions via 4b2γ decay channel at a 100 TeV hadron collider

    DOE PAGES

    Chen, Chien-Yi; Yan, Qi-Shu; Zhao, Xiaoran; ...

    2016-01-11

    We report that the quartic self-coupling of the Standard Model Higgs boson can only be measured by observing the triple-Higgs production process, but it is challenging for the LHC Run 2 or International Linear Collider (ILC) at a few TeV because of its extremely small production rate. In this paper, we present a detailed Monte Carlo simulation study of the triple-Higgs production through gluon fusion at a 100 TeV hadron collider and explore the feasibility of observing this production mode. We focus on the decay channel HHH →more » $$b\\bar{b}$$$b\\bar{b}$$γγ, investigating detector effects and optimizing the kinematic cuts to discriminate the signal from the backgrounds. Our study shows that, in order to observe the Standard Model triple-Higgs signal, the integrated luminosity of a 100 TeV hadron collider should be greater than 1.8×104 ab₋1. We also explore the dependence of the cross section upon the trilinear (λ3) and quartic (λ4) self-couplings of the Higgs. Ultimately, we find that, through a search in the triple-Higgs production, the parameters λ3 and λ4 can be restricted to the ranges [₋1,5] and [₋20,30], respectively. We also examine how new physics can change the production rate of triple-Higgs events. For example, in the singlet extension of the Standard Model, we find that the triple-Higgs production rate can be increased by a factor of O(10).« less

  9. Measurement of very forward neutron energy spectra for 7 TeV proton-proton collisions at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Berti, E.; Bonechi, L.; Bongi, M.; Castellini, G.; D'Alessandro, R.; Del Prete, M.; Haguenauer, M.; Itow, Y.; Kasahara, K.; Kawade, K.; Makino, Y.; Masuda, K.; Matsubayashi, E.; Menjo, H.; Mitsuka, G.; Muraki, Y.; Okuno, Y.; Papini, P.; Perrot, A.-L.; Ricciarini, S.; Sako, T.; Sakurai, N.; Sugiura, Y.; Suzuki, T.; Tamura, T.; Tiberio, A.; Torii, S.; Tricomi, A.; Turner, W. C.; Zhou, Q. D.

    2015-11-01

    The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC √{ s} = 7 TeV proton-proton collisions with the pseudo-rapidity η ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results, and the DPMJET 3.04 model describes our results well at the lower pseudo-rapidity ranges. However, no model perfectly explains the experimental results over the entire pseudo-rapidity range. The experimental data indicate a more abundant neutron production rate relative to the photon production than any model predictions studied here.

  10. Theories of statistical equilibrium in electron-positron colliding-beam storage rings

    SciTech Connect

    Schonfeld, J.F.

    1985-01-01

    In this lecture I introduce you to some recent theoretical work that represents a significant and long overdue departure from the mainstream of ideas on the physics of colliding- beam storage rings. The goal of the work in question is to understand analytically - without recourse to computer simulation - the role that dissipation and noise play in the observed colliding-beam behavior of electron-positron storage rings.

  11. Future colliders

    SciTech Connect

    Palmer, R.B.; Gallardo, J.C.

    1996-10-01

    The high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, pp), of lepton (e{sup +}e{sup {minus}}, {mu}{sup +} {mu}{sup {minus}}) and photon-photon colliders are considered. Technical arguments for increased energy in each type of machine are presented. Their relative size, and the implications of size on cost are discussed.

  12. Measurement of the Inclusive $Z \\to ee$ Production Cross Section in Proton-Proton Collisions at $\\sqrt{s}$ = 7TeV and $Z \\to ee$ Decays as Standard Candles for Luminosity at the Large Hadron Collider

    SciTech Connect

    Werner, Jeremy

    2011-01-01

    This thesis comprises a precision measurement of the inclusive \\Zee production cross section in proton-proton collisions provided by the Large Hadron Collider (LHC) at a center-of-mass energy of $\\sqrt{s}=7$~TeV and the absolute luminosity based on \\Zee decays. The data was collected by the Compact Muon Solenoid (CMS) detector near Geneva, Switzerland during the year of 2010 and corresponds to an integrated luminosity of $\\int\\mathcal{L}dt = 35.9\\pm 1.4$~pb$^{-1}$. Electronic decays of $Z$ bosons allow one of the first electroweak measurements at the LHC, making the cross section measurement a benchmark of physics performance after the first year of CMS detector and LHC machine operations. It is the first systematic uncertainty limited \\Zee cross section measurement performed at $\\sqrt{s}=7$~TeV. The measured cross section pertaining to the invariant mass window $M_{ee}\\in (60,120)$~GeV is reported as: $\\sigma(pp\\to Z+X) \\times \\mathcal{B}( Z\\to ee ) = 997 \\pm 11 \\mathrm{(sta t)} \\pm 19 \\mathrm{(syst)} \\pm 40 \\mathrm{(lumi)} \\textrm{ pb}$, which agrees with the theoretical prediction calculated to NNLO in QCD. Leveraging \\Zee decays as ``standard candles'' for measuring the absolute luminosity at the LHC is examined; they are produced copiously, are well understood, and have clean detector signatures. Thus the consistency of the inclusive \\Zee production cross section measurement with the theoretical prediction motivates inverting the measurement to instead use the \\Zee signal yield to measure the luminosity. The result, which agrees with the primary relative CMS luminosity measurement calibrated using Van der Meer separation scans, is not only the most precise absolute luminosity measurement performed to date at a hadron collider, but also the first one based on a physics signal at the LHC.

  13. Single and double SM-like Higgs boson production at future electron-positron colliders in composite 2HDMs

    NASA Astrophysics Data System (ADS)

    De Curtis, Stefania; Moretti, Stefano; Yagyu, Kei; Yildirim, Emine

    2017-05-01

    We investigate single- and double-h , the discovered Standard-Model- (SM) like Higgs boson, production at future e+e- colliders in composite 2-Higgs doublet models (C2HDMs) and elementary 2-Higgs doublet models (E2HDMs) with a softly broken Z2 symmetry. We first survey their parameter spaces allowed by theoretical bounds from perturbative unitarity and vacuum stability as well as by future data at the Large Hadron Collider with an integrated luminosity up to 3000 fb-1 under the assumption that no new Higgs boson is detected. We then discuss how different the cross sections can be between the two scenarios when κV , the h V V (V =W±,Z ) coupling normalized to the SM value, is taken to be the same value in both scenarios. We find that if κV2 is found to be, e.g., 0.98, then the cross sections in C2HDMs with f (the compositeness scale) in the TeV region can be maximally changed to be about -15 % , -18 %, -50 % and -35 % for the e+e-→t t ¯h , e+e-→Z h h , e+e-→e+e-h h and e+e-→t t ¯h h processes, respectively, with respect to those in E2HDMs. Thus, a future electron-positron collider has the potential to discriminate between E2HDMs and C2HDMs, even when only h event rates are measured.

  14. The signatures of doubly charged leptons in future linear colliders

    NASA Astrophysics Data System (ADS)

    Guo, Yu-Chen; Yue, Chong-Xing; Liu, Zhi-Cheng

    2017-08-01

    We discuss the production of the doubly charged leptons in future linear electron positron colliders, such as the International Linear Collider and Compact Linear Collider. Such states are introduced in extended weak-isospin multiplets by composite models. We discuss the production cross section of {e}-γ \\to {L}--{W}+ and carry out analyses for hadronic, semi-leptonic and pure leptonic channels based on the full simulation performance of the silicon detector. The 3- and 5-sigma statistical significance exclusion curves are provided in the model parameter space. It is found that the hadronic channel could offer the most possible detectable signature.

  15. Higgs physics at the CLIC electron-positron linear collider

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abusleme, A.; Afanaciev, K.; Alipour Tehrani, N.; Balázs, C.; Benhammou, Y.; Benoit, M.; Bilki, B.; Blaising, J.-J.; Boland, M. J.; Boronat, M.; Borysov, O.; Božović-Jelisavčić, I.; Buckland, M.; Bugiel, S.; Burrows, P. N.; Charles, T. K.; Daniluk, W.; Dannheim, D.; Dasgupta, R.; Demarteau, M.; Díaz Gutierrez, M. A.; Eigen, G.; Elsener, K.; Felzmann, U.; Firlej, M.; Firu, E.; Fiutowski, T.; Fuster, J.; Gabriel, M.; Gaede, F.; García, I.; Ghenescu, V.; Goldstein, J.; Green, S.; Grefe, C.; Hauschild, M.; Hawkes, C.; Hynds, D.; Idzik, M.; Kačarević, G.; Kalinowski, J.; Kananov, S.; Klempt, W.; Kopec, M.; Krawczyk, M.; Krupa, B.; Kucharczyk, M.; Kulis, S.; Laštovička, T.; Lesiak, T.; Levy, A.; Levy, I.; Linssen, L.; Lukić, S.; Maier, A. A.; Makarenko, V.; Marshall, J. S.; Martin, V. J.; Mei, K.; Milutinović-Dumbelović, G.; Moroń, J.; Moszczyński, A.; Moya, D.; Münker, R. M.; Münnich, A.; Neagu, A. T.; Nikiforou, N.; Nikolopoulos, K.; Nürnberg, A.; Pandurović, M.; Pawlik, B.; Perez Codina, E.; Peric, I.; Petric, M.; Pitters, F.; Poss, S. G.; Preda, T.; Protopopescu, D.; Rassool, R.; Redford, S.; Repond, J.; Robson, A.; Roloff, P.; Ros, E.; Rosenblat, O.; Ruiz-Jimeno, A.; Sailer, A.; Schlatter, D.; Schulte, D.; Shumeiko, N.; Sicking, E.; Simon, F.; Simoniello, R.; Sopicki, P.; Stapnes, S.; Ström, R.; Strube, J.; Świentek, K. P.; Szalay, M.; Tesař, M.; Thomson, M. A.; Trenado, J.; Uggerhøj, U. I.; van der Kolk, N.; van der Kraaij, E.; Vicente Barreto Pinto, M.; Vila, I.; Vogel Gonzalez, M.; Vos, M.; Vossebeld, J.; Watson, M.; Watson, N.; Weber, M. A.; Weerts, H.; Wells, J. D.; Weuste, L.; Winter, A.; Wojtoń, T.; Xia, L.; Xu, B.; Żarnecki, A. F.; Zawiejski, L.; Zgura, I.-S.

    2017-07-01

    The Compact Linear Collider (CLIC) is an option for a future {e+}{e-} collider operating at centre-of-mass energies up to 3 {TeV} , providing sensitivity to a wide range of new physics phenomena and precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages: √{s} = 350 {GeV} , 1.4 and 3 {TeV} . The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung (e+e- → ZH) and {W} {W} -fusion (e+e- → H ν_{!e} {\\bar{{ν }}_{!e} ), resulting in precise measurements of the production cross sections, the Higgs total decay width Γ_{{H}}, and model-independent determinations of the Higgs couplings. Operation at √{s} > 1 {TeV} provides high-statistics samples of Higgs bosons produced through {W} {W} -fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes {e+}{e-} → t {\\bar{t}} {H} and {e+}{e-} → {H} {H} {{ν}}_{!e} {\\bar{{ν }}}_{!e} allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit.

  16. Confronting fragmentation function universality with single hadron inclusive production at HERA and e{sup +}e{sup -} colliders

    SciTech Connect

    Albino, S.; Kniehl, B. A.; Kramer, G.; Sandoval, C.

    2007-02-01

    Predictions for light charged hadron production data in the current fragmentation region of deeply inelastic scattering from the H1 and ZEUS experiments are calculated using perturbative quantum chromodynamics at next-to-leading order, and using fragmentation functions obtained by fitting to similar data from e{sup +}e{sup -} reactions. General good agreement is found when the magnitude Q{sup 2} of the hard photon's virtuality is sufficiently large. The discrepancy at low Q and small scaled momentum x{sub p} is reduced by incorporating mass effects of the detected hadron. By performing quark tagging, the contributions to the overall fragmentation from the various quark flavours in the ep reactions are studied and compared to the contributions in e{sup +}e{sup -} reactions. The yields of the various hadron species are also calculated.

  17. Coherent electron cooling.

    PubMed

    Litvinenko, Vladimir N; Derbenev, Yaroslav S

    2009-03-20

    Cooling intense high-energy hadron beams poses a major challenge for modern accelerator physics. The synchrotron radiation emitted from such beams is feeble; even in the Large Hadron Collider (LHC) operating with 7 TeV protons, the longitudinal damping time is about 13 hours. None of the traditional cooling methods seem able to cool LHC-class protons beams. In this Letter, we present a novel method of coherent electron cooling based on a high-gain free-electron laser (FEL). This technique could be critical for reaching high luminosities in hadron and electron-hadron colliders.

  18. RF System Requirements for a Medium-Energy Electron-Ion Collider (MEIC) at JLab

    SciTech Connect

    Rimmer, Robert A; Hannon, Fay E; Guo, Jiquan; Huang, Shichun; Huang, Yulu; Wang, Haipeng; Wang, S

    2015-09-01

    JLab is studying options for a medium energy electron-ion collider that could fit on the JLab site and use CEBAF as a full-energy electron injector. A new ion source, linac and booster would be required, together with collider storage rings for the ions and electrons. In order to achieve the maximum luminosity these will be high-current storage rings with many bunches. We present the high-level RF system requirements for the storage rings, ion booster ring and high-energy ion beam cooling system, and describe the technology options under consideration to meet them. We also present options for staging that might reduce the initial capital cost while providing a smooth upgrade path to a higher final energy. The technologies under consideration may also be useful for other proposed storage ring colliders or ultimate light sources.

  19. Unbunched beam electron-proton instability in the PSR and advanced hadron facilities

    SciTech Connect

    Wang, Tai-Sen; Pisent, A.; Neuffer, D.V.

    1989-01-01

    We studied the possibility of the occurrence of transverse instability induced by trapped electrons in unbunched beams in the Proton Storage Ring and the proposed Advance Hadron Facility (AHF) at Los Alamos, as well as in the proposed Kaon Factory at TRIUMF. We found that the e-p instability may be possible for unbunched beams in the PSR but is unlikely to occur in the advanced hadron facilities. 8 refs., 4 figs.

  20. Seventh symposium on EBIS/T and their applications combined with a workshop on ion sources for hadron colliders, a satellite meeting to ICIS'97 (invited)

    NASA Astrophysics Data System (ADS)

    Becker, R.

    1998-02-01

    The 7th symposium on EBIS and EBIT and their applications has been organized by M. Kleinod and R. Becker in Gelnhausen, Germany the week before ICIS'97. It was combined with a workshop on ion sources for hadron colliders being reported on by J. Alessi. Former EBIS symposia which have taken place are: 1977 at GSI, Darmstadt, Germany; 1981 in Saclay and Orsay, France; 1985 at Cornell University, Ithaca, New York; 1988 at Brookhaven National Lab (BNL), Brookhaven, New York; 1991 at JINR, Dubna, Russia; and 1994 at MSI, Stockholm, Sweden. The next one will be organized in the year 2000 by Krsto Prelec, BNL and Martin Stöckli, Manhattan, Kansas.

  1. Next-to-leading order QCD corrections to the single top quark production via model-independent tqg flavor-changing neutral-current couplings at hadron colliders

    SciTech Connect

    Gao Jun; Li Chongsheng; Zhang Jiajun; Zhu Huaxing

    2009-12-01

    We present the calculations of the complete next-to-leading order (NLO) QCD effects on the single top productions induced by model-independent tqg flavor-changing neutral-current couplings at hadron colliders. Our results show that, for the tcg coupling, the NLO QCD corrections can enhance the total cross sections by about 60% and 30%, and for the tug coupling by about 50% and 20% at the Tevatron and LHC, respectively, which means that the NLO corrections can increase the experimental sensitivity to the flavor-changing neutral-current couplings by about 10%-30%. Moreover, the NLO corrections reduce the dependence of the total cross sections on the renormalization or factorization scale significantly, which lead to increased confidence on the theoretical predictions. Besides, we also evaluate the NLO corrections to several important kinematic distributions, and find that for most of them the NLO corrections are almost the same and do not change the shape of the distributions.

  2. Next-to-leading order QCD predictions for A{sup 0}{gamma} associated production at the CERN Large Hadron Collider

    SciTech Connect

    Dai Liang; Shao Dingyu; Gao Jun; Zhang Hao; Li Chongsheng

    2011-03-01

    We calculate the complete next-to-leading order (NLO) QCD corrections (including SUSY QCD corrections) to the inclusive total cross sections of the associated production processes pp{yields}A{sup 0}{gamma}+X in the minimal supersymmetric standard model (MSSM) at the CERN Large Hadron Collider (LHC). Our results show that the enhancement of the total cross sections from the NLO QCD corrections can reach 25%{approx}15% for 200 GeV

  3. DETERMINING THE RATIO OF THE H+ YIELDS TV TO H+ YIELDS TB DECAY RATES FOR LARGE TAN BETA AT THE LARGE HADRON COLLIDER.

    SciTech Connect

    ASSAMAGAN,K.A.GUASCH,J.MORETTI,S.PENARANDA,S.

    2003-05-27

    We present results on the determination of the observable ratio R = BR(H{sup +} {yields} {tau}{sup +}{nu}{sup -})/BR(H{sup +} {yields} t{bar b}) of charged Higgs boson decay rates as a discriminant quantity between Supersymmetric and non-Supersymmetric models. Simulation of measurements of this quantity through the analysis of the charged Higgs production process gb {yields} tbH{sup +} and relative backgrounds in the two above decay channels has been performed in the context of ATLAS. A {approx} 12-14% accuracy on R can be achieved for tan {beta} = 50, m{sub H{sup {+-}}} = 300-500 GeV and after an integrated luminosity of 300 fb{sup -1}. With this precision measurement, the Large Hadron Collider (LHC) can easily discriminate between models for the two above scenarios, so long as tan {beta} > 20.

  4. Results of a higgs boson searches in the ATLAS and CMS experiments at the large hadron collider at energies 7 and 8 TeV

    SciTech Connect

    Artamonov, A. A.; Epshteyn, V. S.; Gavrilov, V. B.; Gavrilyuk, A. A.; Gorbounov, P. A.; Jokin, A. S.; Lychkovskaya, N. V.; Popov, V. P.; Safronov, G. B.; Shamanov, V. V.; Shatalov, P. B.; Spiridonov, A. A.; Tsukerman, I. I.

    2016-05-15

    Recent achievements of the ATLAS and CMS experiments at the Large Hadron Collider searching for a Higgs boson are summarized. A new particle with the mass of 125 GeV and properties expected for the Standard Model Higgs boson was discovered three years ago in these experiments in proton-proton collisions when analyzing part of the data taken at the centre-of-mass energies 7 TeV and 8 TeV in 2011 and 2012 year exposures. Today all the data are processed and fully analyzed. Experimental results of studies of individual Higgs boson decay channels as well as their combination to extract such properties as mass, signal strength, coupling constants, spin and parity are reviewed. All experimental results are found to be compatible with the Standard Model predictions.

  5. O (αs3) analysis of inclusive jet and di-jet production in heavy ion reactions at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    He, Yuncun; Vitev, Ivan; Zhang, Ben-Wei

    2012-07-01

    Jets physics in heavy ion reactions is an important new area of active research at the Relativistic Heavy Ion Collider (RHIC) and at the Large Hadron Collider (LHC) that paves the way for novel tests of QCD multi-parton dynamics in dense nuclear matter. At present, perturbative QCD calculations of hard probes in elementary nucleon-nucleon reactions can be consistently combined with the effects of the nuclear medium up to O (αs3). While such accuracy is desirable but not necessary for leading particle tomography, it is absolutely essential for the new jet observables. With this motivation, we present first results and predictions to O (αs3) for the recent LHC lead-lead (Pb + Pb) run at a center-of-mass energy of 2.76 TeV per nucleon-nucleon pair. Specifically, we focus on the suppression of the single and double inclusive jet cross sections. Our analysis includes not only final-state inelastic parton interactions in the QGP, but also initial-state cold nuclear matter effects and an estimate of the non-perturbative hadronization corrections. We demonstrate how an enhanced di-jet asymmetry in central Pb + Pb reactions at the LHC, recently measured by the ATLAS and CMS experiments, can be derived from these results. We show quantitatively that a fraction of this enhancement may be related to the ambiguity in the separation between the jet and the soft background medium and/or the diffusion of the parton shower energy away from the jet axis through collisional processes. We point to a suite of measurements that can help build a consistent picture of parton shower modification in heavy ion collisions at the LHC.

  6. First measurement and correction of nonlinear errors in the experimental insertions of the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Maclean, E. H.; Tomás, R.; Giovannozzi, M.; Persson, T. H. B.

    2015-12-01

    Nonlinear magnetic errors in low-β insertions can contribute significantly to detuning with amplitude, linear and nonlinear chromaticity, and lead to degradation of dynamic aperture and beam lifetime. As such, the correction of nonlinear errors in the experimental insertions of colliders can be of critical significance for successful operation. This is expected to be of particular relevance to the LHC's second run and its high luminosity upgrade, as well as to future colliders such as the Future Circular Collider. Current correction strategies envisioned for these colliders assume it will be possible to calculate optimized local corrections through the insertions, using a magnetic model of the errors. This paper shows however, that reliance purely upon magnetic measurements of the nonlinear errors of insertion elements is insufficient to guarantee a good correction quality in the relevant low-β* regime. It is possible to perform beam-based examination of nonlinear magnetic errors via the feed-down to readily observed beam properties upon application of closed orbit bumps, and methods based upon feed-down to tune have been utilized at RHIC, SIS18, and SPS. This paper demonstrates the extension of such methodology to include direct observation of feed-down to linear coupling in the LHC. It is further shown that such beam-based studies can be used to complement magnetic measurements performed during LHC construction, in order to validate and refine the magnetic model of the collider. Results from first attempts of the measurement and correction of nonlinear errors in the LHC experimental insertions are presented. Several discrepancies of beam-based studies with respect to the LHC magnetic model are reported.

  7. Overview and Actual Understanding of the Electron Cloud Effect and Instabilities in the Future Linear Colliders

    SciTech Connect

    Pivi, M.

    2004-12-03

    The electron cloud is potentially an important effect in linear colliders. Many of the effects have been evaluated. Actions to suppress the electron cloud are required for the GLC/NLC positron main damping ring (MDR or DR) and the low emittance transport lines as well as for the TESLA damping ring. There is an ongoing R&D program studying a number of possible remedies to reduce the secondary electron yield below that required.

  8. Proton enhancement at large pT at the CERN large hadron collider without structure in associated-particle distribution.

    PubMed

    Hwa, Rudolph C; Yang, C B

    2006-07-28

    The production of pions and protons in the pT range between 10 and 20 GeV/c for Pb+Pb collisions at CERN LHC is studied in the recombination model. It is shown that the dominant mechanism for hadronization is the recombination of shower partons from neighboring jets when the jet density is high. Protons are more copiously produced than pions in that pT range because the coalescing partons can have lower momentum fractions, but no thermal partons are involved. The proton-to-pion ratio can be as high as 20. When such high pT hadrons are used as trigger particles, there will not be any associated particles that are not in the background.

  9. Supersymmetric QCD one-loop effects in (un)polarized top-pair production at hadron colliders

    SciTech Connect

    Berge, Stefan; Hollik, Wolfgang; Mosle, Wolf M.; Wackeroth, Doreen

    2007-08-01

    We study the effects of O({alpha}{sub s}) supersymmetric QCD (SQCD) corrections on the total production rate and kinematic distributions of polarized and unpolarized top-pair production in pp and pp collisions. At the Fermilab Tevatron pp collider, top-quark pairs are mainly produced via quark-antiquark annihilation, qq{yields}tt, while at the CERN LHC pp collider gluon-gluon scattering, gg{yields}tt, dominates. We compute the complete set of O({alpha}{sub s}) SQCD corrections to both production channels and study their dependence on the parameters of the minimal supersymmetric standard model. In particular, we discuss the prospects for observing strong, loop-induced SUSY effects in top-pair production at the Tevatron run II and the LHC.

  10. Physics opportunities at the future eRHIC electron-ion collider

    NASA Astrophysics Data System (ADS)

    Fazio, Salvatore

    2017-03-01

    The 2015 nuclear physics long-range plan endorsed the realization of an electron-ion collider as the next large construction project in the United States. This new collider will provide definite answers to the following questions: How are the sea quarks and gluons, and their spins, distributed in space and momentum inside the nucleon? How are these quark and gluon distributions correlated with overall nucleon properties, such as spin direction? What is the role of the orbital motion of sea quarks and gluons in building up the nucleon spin? The eRHIC project is the Brookhaven National Laboratory's vision for the realization of the future electron-ion collider. eRHIC, with its high luminosity (> 1033 cm-2 s-1), wide kinematic reach in center-of-mass-energy (45 GeV to 145 GeV) since day-1 and highly polarized nucleon (P ≈ 70%) and electron (P ≈ 80%) beams provides an unprecedented opportunity to reach new frontiers in our understanding of the internal dynamic structure of nucleons. We give a brief description of the eRHIC project and highlight several key high precision measurements from the planned broad physics program at the future electron-ion collider and the expected impact on our current understanding of the spatial structure of nucleons and nuclei, and the transition from a non-saturated to a saturated state of nuclear matter.

  11. High Energy Photon Beam Generation For QCD Explorer Based γP Colliders

    NASA Astrophysics Data System (ADS)

    Ciftci, A. K.; Aksakal, H.; Nergiz, Z.

    2007-04-01

    Combination of two linear accelerator projects, namely CLIC (Compact Linear Collider) and ILC (International Linear Collider) with LHC(Large Hadron Collider) offer an opportunity to build γp collider. High energy photons are produced by the Compton backscattering of the laser photons off high energy electrons at the conversion region. Then, Compton backscattered photons are collided with protons at the interaction region. In this study, conversion properties and optimum laser and electron beam parameters for CLIC and ILC are determined using CAIN simulation program.

  12. Klystron switching power supplies for the Internation Linear Collider

    SciTech Connect

    Fraioli, Andrea; /Cassino U. /INFN, Pisa

    2009-12-01

    The International Linear Collider is a majestic High Energy Physics particle accelerator that will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. ILC will complement the Large Hadron Collider (LHC), a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by producing electron-positron collisions at center of mass energy of about 500 GeV. In particular, the subject of this dissertation is the R&D for a solid state Marx Modulator and relative switching power supply for the International Linear Collider Main LINAC Radio Frequency stations.

  13. Analysis of Beam-Beam Kink Instability in a Linac-Ring Electron-Ion Collider

    SciTech Connect

    V. Lebedev; J. Bisognano; R. Li; B. Yunn

    2001-06-01

    A linac-ring collision scheme was considered in recent proposals of electron-gold colliders (eRHIC) and polarized-electron light-ion colliders (EPIC). The advantages of using an energy-recovered linac for the electron beam is that it avoids the limitation of beam-beam tune shift inherent in a storage ring, pertains good beam quality and easy manipulation of polarization. However, the interaction of the ion beam in the storage ring with the electron beam from the linac acts analogously to a transverse impedance, and can induce unstable behavior of the ion beam similar to the strong head-tail instability. In this paper, this beam-beam kink instability with head-tail effect is analyzed using the linearized Vlasov equation, and the threshold of transverse mode coupling instability is obtained.

  14. LEIC - A Polarized Low Energy Electron-ion Collider at Jefferson Lab

    SciTech Connect

    Derbenev, Yaroslav S.; Hutton, Andrew M.; Krafft, Geoffrey A.; Li, Rui; Lin, Fanglei; Morozov, Vasiliy; Nissen, Edward W.; Yunn, Byung C.; Zhang, He; Sullivan, Michael K.; Zhang, Yuhong

    2013-06-01

    A polarized electron-ion collider is envisioned as the future nuclear science program at JLab beyond the 12 GeV CEBAF. Presently, a medium energy collider (MEIC) is set as an immediate goal with options for a future energy upgrade. A comprehensive design report for MEIC has been released recently. The MEIC facility could also accommodate electron and proton/ion collisions in a low CM energy range, covering proton energies from 10 to 25 GeV and ion energies with a similar magnetic rigidity, for additional science reach. In this paper, we present a conceptual design of this low energy collider, LEIC, showing its luminosity can reach above 10{sup 33} cm{sup -2}s{sup -1}. The design specifies that the large booster of the MEIC is converted to a low energy ion collider ring with an interaction region and an electron cooler integrated into it. The design provides options for either sharing the detector with the MEIC or a dedicated low energy detector in a third collision point, with advantages of either a minimum cost or extra detection parallel to the MEIC operation, respectively. The LEIC could be positioned as the first and low cost phase of a multi-stage approach to realize the full MEIC.

  15. Feedback scheme for kink instability in ERL based electron ion collider

    SciTech Connect

    Hao, Y.; Litvinenko, V.N.; Ptitsyn, V.

    2011-03-28

    Kink instability presents one of the limiting factors from achieving higher luminosity in ERL based electron ion collider (EIC). However, we can take advantage of the flexibility of the linac and design a feedback system to cure the instability. This scheme raises the threshold of kink instability dramatically and provides opportunity for higher luminosity. We studied the effectiveness of this system and its dependence on the amplitude and phase of the feedback. In this paper we present results of theses studies of this scheme and describe its theoretical and practical limitations. The main advantage of an energy recovery linac (ERL) based electron ion collider (EIC) over a ring-ring type counterpart is the higher achievable luminosity. In ERL-based version, one electron beam collides with the opposing ion beam only once so that the beam-beam parameter can largely exceed the usual limitation in an electron collider ring, while the beam-beam parameter for the ion beam remains small values. The resulting luminosity may be enhanced by one order of magnitude. The beam dynamics related challenges also arise as the luminosity boost in ERL based EIC due to the significant beam-beam effect on the electron beam. The effects on the electron beam include the additional large beam-beam tune shift and nonlinear emittance growth, which are discussed. The ion beam may develop a head-tail type instability, referred as 'kink instability', through the interaction with the electron beam. In this paper, we discuss the feasibility of an active feedback system to mitigate the kink instability, by taking advantage of the flexibility of ERL. Throughout the paper, we will discuss the collision between proton and electron beam. Any other ion species can be scaled by its charge Z and ion mass A.

  16. A high-granularity plastic scintillator tile hadronic calorimeter with APD readout for a linear collider detector

    NASA Astrophysics Data System (ADS)

    Andreev, V.; Cvach, J.; Danilov, M.; Devitsin, E.; Dodonov, V.; Eigen, G.; Garutti, E.; Gilitzky, Yu.; Groll, M.; Heuer, R.-D.; Janata, M.; Kacl, I.; Korbel, V.; Kozlov, V.; Meyer, H.; Morgunov, V.; Němeček, S.; Pöschl, R.; Polák, I.; Raspereza, A.; Reiche, S.; Rusinov, V.; Sefkow, F.; Smirnov, P.; Terkulov, A.; Valkár, Š.; Weichert, J.; Zálešák, J.

    2006-08-01

    We report upon the performance of an analog hadron calorimeter prototype, where plastic scintillator tiles are read out with wavelength-shifting fibers coupled to avalanche photodiodes. This prototype configuration has been tested using a positron beam at DESY with energies between 1 and 6 GeV. We present different detector calibration methods, show measurements for noise, linearity, and energy resolution and discuss gain monitoring with an LED system. The results are in good agreement with our simulation studies and previous measurements using silicon photomultiplier readout.

  17. Diphoton production at hadron colliders: a fully differential QCD calculation at next-to-next-to-leading order.

    PubMed

    Catani, Stefano; Cieri, Leandro; de Florian, Daniel; Ferrera, Giancarlo; Grazzini, Massimiliano

    2012-02-17

    We consider direct diphoton production in hadron collisions, and we compute the next-to-next-to-leading order QCD radiative corrections at the fully differential level. Our calculation uses the q(T) subtraction formalism, and it is implemented in a parton-level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state photons and the associated jet activity and to compute the corresponding distributions in the form of bin histograms. We present selected numerical results related to Higgs boson searches at the LHC and corresponding results at the Tevatron.

  18. Controlled laser plasma wakefield acceleration of electrons via colliding pulse injection in non-collinear geometry

    NASA Astrophysics Data System (ADS)

    Toth, Csaba; Nakamura, Kei; Geddes, Cameron; Panasenko, Dmitriy; Plateau, Guillaume; Matlis, Nicholas; Schroeder, Carl; Esarey, Eric; Leemans, Wim

    2007-11-01

    Colliding laser pulses [1] have been proposed as a method for controlling injection of electrons into a laser wakefield accelerator (LWFA) and hence producing high quality electron beams with energy spread below 1% and normalized emittances < 1 micron. The. One pulse excites a plasma wake, and a collinear pulse following behind it collides with a counterpropagating pulse forming a beat pattern that boosts background electrons into accelerating phase. A variation of the original method uses only two laser pulses [2] which may be non-collinear. The first pulse drives the wake, and beating of the trailing edge of this pulse with the colliding pulse injects electrons. Non-collinear injection avoids optical elements on the electron beam path (avoiding emittance growth). We report on progress of non-collinear experiments at LBNL, using the Ti:Sapphire laser at the LOASIS facility of LBNL. New results indicate that the electron beam properties are affected by the presence of the second beam. [1] E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997) [2] G. Fubiani, Phys. Rev. E 70, 016402 (2004)

  19. Heavy-ion physics studies for the Future Circular Collider

    NASA Astrophysics Data System (ADS)

    Armesto, N.; Dainese, A.; d'Enterria, D.; Masciocchi, S.; Roland, C.; Salgado, C. A.; van Leeuwen, M.; Wiedemann, U. A.

    2014-11-01

    The Future Circular Collider (FCC) design study is aimed at assessing the physics potential and the technical feasibility of a new collider with centre-of-mass energies, in the hadron-hadron collision mode including proton and nucleus beams, more than seven times larger than the nominal LHC energies. An electron-positron collider in the same tunnel is also considered as an intermediate step, which in the long term would allow for electron-hadron collisions. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of quark-gluon plasma, gluon saturation, photon-induced collisions, as well as connections with the physics of ultra-high-energy cosmic rays.

  20. Studies of hadron-electron separators for the ZEUS barrel calorimeter

    SciTech Connect

    Ambats, I.; Bortz, D.; Connolly, A.

    1995-05-25

    Two possible upgrades, a shower maximum detector and a presampler, designed to improve the low energy electron/hadron separation capabilities of the ZEUS barrel calorimeter are described and test-beam results are reported. The presampler can also be used to correct for energy loss of particles traversing the dead material in front of the calorimeter.

  1. Z0-tagged jet event asymmetry in heavy-ion collisions at the CERN large hadron collider.

    PubMed

    Neufeld, R B; Vitev, I

    2012-06-15

    Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of Z0/γ*-tagged jet events in sqrt[s]=2.76  TeV reactions at the LHC. Our results combine the O(G(F)α(s)2) perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense strongly interacting matter. We find that a strong asymmetry is generated in central lead-lead reactions that has little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for its shape and magnitude.

  2. Particle multiplicities in lead-lead collisions at the CERN large hadron collider from nonlinear evolution with running coupling corrections.

    PubMed

    Albacete, Javier L

    2007-12-31

    We present predictions for the pseudorapidity density of charged particles produced in central Pb-Pb collisions at the LHC. Particle production in such collisions is calculated in the framework of k(t) factorization. The nuclear unintegrated gluon distributions at LHC energies are determined from numerical solutions of the Balitsky-Kovchegov equation including recently calculated running coupling corrections. The initial conditions for the evolution are fixed by fitting Relativistic Heavy Ion Collider data at collision energies square root[sNN]=130 and 200 GeV per nucleon. We obtain dNch(Pb-Pb)/deta(square root[sNN]=5.5 TeV)/eta=0 approximately 1290-1480.

  3. THE ELECTRON ION COLLIDER. A HIGH LUMINOSITY PROBE OF THE PARTONIC SUBSTRUCTURE OF NUCLEONS AND NUCLEI.

    SciTech Connect

    EDITED BY M.S. DAVIS

    2002-02-01

    By the end of this decade, the advancement of current and planned research into the fundamental structure of matter will require a new facility, the Electron Ion Collider (EIC). The EIC will collide high-energy beams of polarized electrons from polarized protons and neutrons, and unpolarized beams of electrons off atomic nuclei with unprecedented intensity. Research at the EIC will lead to a detailed understanding of the structure of the proton, neutron, and atomic nuclei as described by Quantum Chromo-Dynamics (QCD), the accepted theory of the strong interaction. The EIC will establish quantitative answers to important questions by delivering dramatically increased precision over existing and planned experiments and by providing completely new experimental capabilities. Indeed, the EIC will probe QCD in a manner not possible previously. This document presents the scientific case for the design, construction and operation of the EIC. While realization of the EIC requires a significant advance in the development of efficient means of producing powerful beams of energetic electrons, an important consideration for choosing the site of the EIC is the planned upgrade to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The upgrade planned for RHIC will fully meet the requirements for the ion beam for the EIC, providing a distinct advantage in terms of cost, schedule and the final operation.

  4. Overview of a high luminosity {mu}{sup +}{mu}{sup {minus}} collider

    SciTech Connect

    Palmer, R.B.; Gallardo, J.C.

    1997-03-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should be regarded as complementary. Parameters are given of a 4 TeV high luminosity {mu}{sup +}{mu}{sup {minus}} collider, and of a 0.5 TeV lower luminosity demonstration machine. The authors discuss the various systems in such muon colliders.

  5. Environmental assessment for the proposed B-Factory (Asymmetric Electron Positron Collider)

    SciTech Connect

    Not Available

    1993-11-01

    This document presents the potential environmental consequences associated with the construction and operation of an Asymmetric Electron Positron Collider, also known as a B-Factory. DOE proposes to modify either the existing Positron-Electron Project at the Stanford Linear Accelerator Center (SLAC) or the Cornell Electron Storage Ring (CESR) at Cornell University. PEP and CESR provide the most technically promising and practical options for a B-Factory. A B-Factory can be constructed by modifying the existing facilities and with minor or no conventional construction. Details involved with the upgrade along with two alternatives to the proposed action are described.

  6. Electron-Ion Collider at CEBAF: New Insights and Conceptual Progress

    SciTech Connect

    Yaroslav Derbenev; Andrei Afanasev; Kevin Beard; Lawrence Cardman; Swapan Chattopadhyay; Pavel Degtiarenko; Jean Delayen; Rolf Ent; Andrew Hutton; Geoffrey Krafft; Rui Li; Nikolitsa Merminga; Benard Poelker; Byung Yunn; Petr Ostroumov

    2004-07-01

    We report on progress in the conceptual development of the proposed high luminosity (up to 1035 cm-2s-1) and efficient spin manipulation (using ''figure 8'' boosters and collider rings) Electron-Ion Collider at the CEBAF. This facility would use a polarized 5-7 GeV electron beam from a superconducting energy recovering linac with a kicker-operated circulator ring, and a 30-150 GeV ion beam in a storage ring (for polarized p, d, 3He, Li and unpolarized totally stripped nuclei up to Ar). Ultra-high luminosity is envisioned to be achieved with very short crab-crossing bunches at 1.5 GHz repetition rate. Our recent studies were concentrated on understanding beam-beam interaction, ion beam instabilities, luminosity lifetime due to intrabeam scatterings, ERL-ring synchronization, and ion spin control. We also proposed a preliminary conceptual design of the interaction region.

  7. Feasibility study of TPC at electron positron colliders at Z pole operation

    NASA Astrophysics Data System (ADS)

    Zhao, M.; Ruan, M.; Qi, H.; Gao, Y.

    2017-07-01

    TPC is a promising technology for the future electron positron colliders. However, its application might be limited at high event rate and high hit occupancies. In this paper, we study the feasibility of using TPC at the circular electron positron collider (CEPC) at Z pole using full simulated Z→ qbar q samples, by evaluating the local charge density and voxel occupancy at different TPC parameters. Our study shows that the TPC could be applied to the CEPC Z pole operation if back flow ion is controlled to per mille level. We also find that the distortion is considerable for the FCC-ee Z pole operation. And a few approaches are proposed to reduce the distortion.

  8. Design and construction of a prototype superfluid helium cryostat for the short straight sections of the CERN Large Hadron Collider (LHC)

    SciTech Connect

    Cameron, W.; Jenny, B.; Riddone, G.; Rohmig, P.; Weelderen, R. van

    1994-12-31

    The lattice of the CERN Large Hadron Collider (LHC) will contain 384 Short Straight Section (SSS) units, one in every 51 m half-cell. A Short Straight Section is composed of a twin aperture high-field superconducting quadrupole, two combined-function corrector magnets, and quench protection diodes, all operating in pressurised helium II at 1.9 K. The SSS cryostat also contains a barrier for sectoring the insulation vacuum, and a Technical Service Module housing beam diagnostics, current feedthroughs and instrumentation capillaries, as well as cryogenic valves and pipework serving the local half-cell cooling loop. The helium vessel with its magnets, weighing about 6000 kg, stands on two low heat leak supports. Separate vacuum manifolds permit pumping the beam pipes every 51 m. Two thermal insulation systems, the radiative insulation and a gaseous helium cooled thermal shield, intercept incoming radiative and conductive heat. All these components must be arranged to perform without interference and within the tight constraints of minimum transverse and longitudinal space occupancy. The design and function of the prototype SSS and its main features, covering mechanical and thermal aspects as well a construction details, are described.

  9. Search for heavy resonances decaying to taus in 7 TeV proton-proton collisions at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Gurrola, Alfredo, III

    Over the last few decades, the Standard Model (SM) of particle physics has been used as a means of understanding the world around us. However, there is an increasing amount of data that suggests the SM of particle physics only describes nature up to energies of the electroweak scale. Extensions to the SM have been developed as a means of explaining experimental observation. If these extensions are indeed the correct mathematical descriptions of nature, the Large Hadron Collider (LHC), located at the European Center for Nuclear Research (CERN) near Geneva, Switzerland, is expected to produce new and exciting physics signatures that can shed light on the evolution of our universe since the early hypothesized Big Bang. Of particular interest are models that may lead to events with highly energetic tau lepton pairs. In this dissertation, focus is placed on a possible search for new heavy gauge bosons decaying to highly energetic tau pairs using a data sample corresponding to an integrated luminosity of 36 pb--1 of proton-proton collisions at s = 7 TeV collected with the CMS detector at the CERN LHC. The number of observed events in the data is in good agreement with the predictions for SM background processes. In the context of the Sequential SM, a Z' with mass less than 468 GeV/c² is excluded at 95% credibility level, exceeding the sensitivity by the Tevatron experiments at the Fermi National Accelerator Laboratory.

  10. Hadronic resonance production in d+au collisions at {radical}{ovr s}{sub NN} =200 GeV measured at the BNL relativistic heavy ion collider.

    SciTech Connect

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H. M.; Underwood, D. G.; STAR Collaboration; High Energy Physics; Univ. of Illinois; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physic Lab.

    2008-01-01

    We present the first measurements of the {rho}(770){sup 0},K*(892), {Delta}(1232){sup ++}, {sigma}(1385), and {Lambda}(1520) resonances in d+Au collisions at {radical}s{sub NN} = 200 GeV, reconstructed via their hadronic decay channels using the STAR detector (the solenoidal tracker at the BNL Relativistic Heavy Ion Collider). The masses and widths of these resonances are studied as a function of transverse momentum p{sub T}. We observe that the resonance spectra follow a generalized scaling law with the transverse mass m{sub T}. The of resonances in minimum bias collisions are compared with the of {pi},K and {bar p}. The {rho}{sup 0}/{pi}{sup -}, K{sup +}/K{sup -}, {Delta}{sup ++}/p, {Sigma}(1385)/{Lambda}, and {Lambda}(1520)/{Lambda} ratios in d+Au collisions are compared with the measurements in minimum bias p+p interactions, where we observe that both measurements are comparable. The nuclear modification factors (R{sub dAu}) of the {rho}{sup 0},K{sup +}, and {Sigma}{sup +} scale with the number of binary collisions (N{sub bin}) for p{sub T} > 1.2 GeV/c.

  11. Next-to-leading order QCD predictions for t{gamma} associated production via model-independent flavor-changing neutral-current couplings at hadron colliders

    SciTech Connect

    Zhang Yue; Li Bohua; Li Chongsheng; Gao Jun; Zhu Huaxing

    2011-05-01

    We present the complete next-to-leading order (NLO) QCD predictions for the t{gamma} associated production induced by model-independent tq{gamma} and tqg flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the tq{gamma} and tqg FCNC couplings for this process. Our results show that, for the tq{gamma} couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the tq{gamma}, tqg FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the tu{gamma} and tug FCNC couplings, and by about 80% for the tc{gamma} and tcg FCNC couplings at the LHC, respectively. Moreover, the NLO corrections reduce the dependence of the total cross section on the renormalization and factorization scale significantly. We also evaluate the NLO corrections for several important kinematic distributions.

  12. Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at energies available at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Vovchenko, V.; Karpenko, Iu. A.; Gorenstein, M. I.; Satarov, L. M.; Mishustin, I. N.; Kämpfer, B.; Stoecker, H.

    2016-08-01

    Partonic matter produced in the early stage of ultrarelativistic nucleus-nucleus collisions is assumed to be composed mainly of gluons, and quarks and antiquarks are produced at later times. To study the implications of such a scenario, the dynamical evolution of a chemically nonequilibrated system is described by ideal (2+1)-dimensional hydrodynamics with a time dependent (anti)quark fugacity. The equation of state interpolates linearly between the lattice data for the pure gluonic matter and the lattice data for the chemically equilibrated quark-gluon plasma. The spectra and elliptic flows of thermal dileptons and photons are calculated for central Pb+Pb collisions at the CERN Large Hadron Collider energy of √{sN N}=2.76 TeV. We test the sensitivity of the results to the choice of equilibration time, including also the case where the complete chemical equilibrium of partons is reached already at the initial stage. It is shown that a suppression of quarks at early times leads to a significant reduction of the yield of the thermal dileptons, but only to a rather modest suppression of the pT distribution of direct photons. It is demonstrated that an enhancement of photon and dilepton elliptic flows might serve as a promising signature of the pure-glue initial state.

  13. Total Hadron Cross Section, New Particles, and Muon Electron Events in e{sup +}e{sup -} Annihilation at SPEAR

    DOE R&D Accomplishments Database

    Richter, B.

    1976-01-01

    The review of total hadron electroproduction cross sections, the new states, and the muon--electron events includes large amount of information on hadron structure, nine states with width ranging from 10's of keV to many MeV, the principal decay modes and quantum numbers of some of the states, and limits on charm particle production. 13 references. (JFP)

  14. Progress on the design of the polarized Medium-energy Electron Ion Collider at JLAB

    SciTech Connect

    Lin, F.; Bogacz, A.; Brindza, P.; Camsonne, A.; Daly, E.; Derbenev, Ya. S.; Douglas, D.; Ent, R.; Gaskell, D.; Geng, R.; Grames, J.; Guo, J.; Harwood, L.; Hutton, A.; Jordan, K.; Kimber, A.; Krafft, G.; Li, R.; Michalski, T.; Morozov, V. S.; Nadel-Turonski, P.; /Jefferson Lab /Argonne /DESY /Moscow , Inst. Phys. Tech., Dolgoprydny /Dubna, JINR /Northern Illinois U. /Old Doominion U. /Novosibirsk, GOO Zaryad /SLAC /Texas A-M

    2015-07-14

    The Medium-energy Electron Ion Collider (MEIC) at JLab is designed to provide high luminosity and high polarization needed to reach new frontiers in the exploration of nuclear structure. The luminosity, exceeding 1033 cm-2s-1 in a broad range of the center-of-mass (CM) energy and maximum luminosity above 1034 cm-2s-1, is achieved by high-rate collisions of short small-emittance low-charge bunches made possible by high-energy electron cooling of the ion beam and synchrotron radiation damping of the electron beam. The polarization of light ion species (p, d, 3He) can be easily preserved and manipulated due to the unique figure-8 shape of the collider rings. A fully consistent set of parameters have been developed considering the balance of machine performance, required technical development and cost. This paper reports recent progress on the MEIC accelerator design including electron and ion complexes, integrated interaction region design, figure-8-ring-based electron and ion polarization schemes, RF/SRF systems and ERL-based high-energy electron cooling. Luminosity performance is also presented for the MEIC baseline design.

  15. Single electron yields from semileptonic charm and bottom hadron decays in Au+Au collisions at sNN=200 GeV

    SciTech Connect

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Bathe, S.; Baublis, V.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C. -H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Dairaku, S.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; DeBlasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; Donadelli, M.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Edwards, S.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; Hayashi, S.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Horaguchi, T.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Javani, M.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kawall, D.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E. -J.; Kim, G. W.; Kim, M.; Kim, Y. -J.; Kim, Y. K.; Kimelman, B.; Kinney, E.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Linden Levy, L. A.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Midori, J.; Mignerey, A. C.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, H. J.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nukariya, A.; Nyanin, A. S.; Obayashi, H.; O'Brien, E.; Ogilvie, C. A.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J. -C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T. -A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Vale, C.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Voas, B.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; White, A. S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.

    2016-03-07

    We measured open heavy flavor production in minimum bias Au + Au collisions at √s(NN) = 200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons, using the PHENIX Collaboration at the Relativistic Heavy Ion Collider. In the past, heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transverse momentum are measured in Au + Au collisions. Here, we compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in p + p collisions at √s(NN) = 200 GeV and find the fractions to be similar within the large uncertainties on both measurements for p(T) > 4 GeV/c. We use the bottom electron fractions in Au + Au and p + p along with the previously measured heavy flavor electron R(AA) to calculate the R(AA) for electrons from charm and bottom hadron decays separately. Finally, we find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3 < p(T) < 4 GeV/c.

  16. Radiative return capabilities of a high-energy, high-luminositye+e-collider

    DOE PAGES

    Karliner, Marek; Low, Matthew; Rosner, Jonathan L.; ...

    2015-08-14

    An electron-positron collider operating at a center-of-mass energy ECM can collect events at all lower energies through initial-state radiation (ISR or radiative return). We explore the capabilities for radiative return studies by a proposed high-luminosity collider at ECM = 250 or 90 GeV, to fill in gaps left by lower-energy colliders such as PEP, PETRA, TRISTAN, and LEP. These capabilities are compared with those of the lower-energy e+e- colliders as well as hadron colliders such as the Tevatron and the CERN Large Hadron Collider (LHC). Some examples of accessible questions in dark photon searches and heavy flavor spectroscopy are given.

  17. Concepts for ELIC - A High Luminosity CEBAF Based Electron-Light Ion Collider

    SciTech Connect

    Ya. Derbenev, A. Bogacz, G. Krafft, R. Li, L. Merminga, B. Yunn, Y. Zhang

    2006-09-01

    A CEBAF accelerator based electron-light ion collider (ELIC) of rest mass energy from 20 to 65 GeV and luminosity from 10^33 to 10^35 cm6-2s^-1 with both beams polarized is envisioned as a future upgrade to CEBAF. A two step upgrade scenario is under study: CEBAF accelerator-ring-ring scheme (CRR) as the first step, and a multi-turn ERL-ring as the second step, to attain a better electron emittance and maximum luminosity. In this paper we report results of our studies of the CRR version of ELIC.

  18. 100 kW CW highly-efficient multi-beam klystron for a future electron-ion collider

    NASA Astrophysics Data System (ADS)

    Teryaev, Vladimir E.; Shchelkunov, Sergey V.; Jiang, Yong; Hirshfield, Jay L.

    2017-03-01

    Initial results are presented for the development of a CW highly-efficient RF source needed for operation of a future electron-ion collider. The design of this compact multi-beam klystron yields high efficiency (above 70%) for the power output of 125 kW at 952.6 MHz. The klystron is to work for the RF systems for ion acceleration in the polarized Medium-energy Electron Ion Collider as being developed at Thomas Jefferson National Accelerator Facility.

  19. HADRON ACCELERATORS: Electron proton instability in the CSNS ring

    NASA Astrophysics Data System (ADS)

    Wang, Na; Qin, Qing; Liu, Yu-Dong

    2009-06-01

    The electron proton (e-p) instability has been observed in many proton accelerators. It will induce transverse beam size blow-up, cause beam loss and restrict the machine performance. Much research work has been done on the causes, dynamics and cures of this instability. A simulation code is developed to study the e-p instability in the ring of the China Spallation Neutron Source (CSNS).

  20. Analyses of 476 MHz and 952 MHz Crab Cavities for JLAB Electron Ion Collider

    SciTech Connect

    Park, HyeKyoung; Castilla, Alejandro; Delayen, Jean R.; De Silva, Subashini U.; Morozov, Vasiliy

    2016-05-01

    The Center for Accelerator Science at Old Dominion University has designed, fabricated and successfully tested a crab cavity for Electron Ion Collider at Jefferson Lab (JLEIC) [1]. This proof-of-principle cavity was based on the earlier MEIC design which used 748.5 MHz RF system. The updated JLEIC (called MEIC earlier) design [2] utilizes the components from PEP-II. It results in the change on the bunch repetition rate of stored beam to 476.3 MHz. The ion ring collider will eventually require 952.6 MHz crab cavities. This paper will present the analyses of crab cavities of both 476 MHz and 952 MHz options. It compares advantages and disadvantages of the options which provide the JLEIC design team important technical information for a system down selection.