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Sample records for hard photon production

  1. Recent PHENIX results on hard probes and direct photon production

    NASA Astrophysics Data System (ADS)

    Riabov, V.; PHENIX Collaboration

    2016-02-01

    A hot and dense matter called strongly interacting quark-gluon plasma (sQGP) is created in heavy ion collisions at RHIC energies. Detailed study of the properties of this new state of matter is a driving force of recent research at RHIC. In these proceedings we present most recent PHENIX results for system size and energy dependence of hadron and jet production at high transverse momentum in heavy ion collisions at RHIC. We also report latest results for direct photon production including soft direct photon yields and anisotropic flow.

  2. 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.

  3. Heavy-quark associated production with one hard photon at hadron colliders

    NASA Astrophysics Data System (ADS)

    Hartanto, Heribertus Bayu

    We present the calculation of heavy-quark associated production with a hard photon at hadron colliders, namely pp( pp) → QQgamma + X (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 ttgamma production we observe a sizeable reduction of the renormalization and factorization scale dependence when the NLO QCD corrections are included, while for bbgamma 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 bbgamma 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 bbgamma 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 p → gamma + b + X with Tevatron data.

  4. Delayed hard photons from gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Katz, J. I.

    1994-01-01

    The delayed hard (up to 25 GeV) photons observed more than an hour following a gamma-ray burst on 1994 February 17 may result from the collisions of relativistic nucleons with a dense cloud, producing pi(0). The required cloud density is approx. 2 x 10(exp 11)/cu cm. This cloud may be the remains of the disrupted envelope of a neutron star, and may survive as an excretion disk of approx. 10(exp 14) - 10 (exp 15) cm radius around the coalescing binary.

  5. Jet production and high p/sub T/ phenomena in photon-photon reactions

    SciTech Connect

    Wermes, N.

    1983-05-01

    The status of experimental investigations of high p/sub T/ phenomena and jet production in photon-photon collisions is reviewed. Taking the challenging questions on hard scattering processes in ..gamma gamma.. reactions as a guide, the experimental approach to these questions is summarized. Results from the PETRA experiments CELLO, JADE, PLUTO, and TASSO are presented including preliminary results on the Q/sup 2/-dependence of jet cross sections. Experimental limitations and background problems are discussed. 36 references.

  6. Charmonium production in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Avery, R. E.; Barbaro-Galtieri, A.; Barker, A. R.; Barnett, B. A.; Bauer, D. A.; Bay, A.; Bengtsson, H.-U.; Bobbink, G. J.; Buchanan, C. D.; Buijs, A.; Caldwell, D. O.; Chao, H.-Y.; Chun, S.-B.; Clark, A. R.; Cowan, G. D.; Crane, D. A.; Dahl, O. I.; Daoudi, M.; Derby, K. A.; Eastman, J. J.; Eberhard, P. H.; Edberg, T. K.; Eisner, A. M.; Enomoto, R.; Erné, F. C.; Fairfield, K. H.; Hauptman, J. M.; Hofmann, W.; Hylen, J.; Kamae, T.; Kaye, H. S.; Kenney, R. W.; Khacheryan, S.; Kofler, R. R.; Langeveld, W. G.; Layter, J. G.; Lin, W. T.; Linde, F. L.; Loken, S. C.; Lu, A.; Lynch, G. R.; Madaras, R. J.; Magnuson, B. D.; Masek, G. E.; Mathis, L. G.; Matthews, J. A.; Maxfield, S. J.; Miller, E. S.; Moses, W.; Nygren, D. R.; Oddone, P. J.; Paar, H. P.; Park, S. K.; Pellett, D. E.; Pripstein, M.; Ronan, M. T.; Ross, R. R.; Rouse, F. R.; Schwitkis, K. A.; Sens, J. C.; Shapiro, G.; Shen, B. C.; Slater, W. E.; Smith, J. R.; Steinman, J. S.; Stephens, R. W.; Stevenson, M. L.; Stork, D. H.; Strauss, M. G.; Sullivan, M. K.; Takahashi, T.; Toutounchi, S.; van Tyen, R.; Vandalen, G. J.; Vernon, W.; Wagner, W.; Wang, E. M.; Wang, Y.-X.; Wenzel, W. A.; Wolf, Z. R.; Yamamoto, H.; Yellin, S. J.; Zeitlin, C.

    1988-06-01

    We have searched for the two-photon production of the ηc, χ0, and χ2 charmonium states at the SLAC e+e- collider PEP in the channels γγ-->K+/-K0Sπ-/+, γγ-->K+K-π+π-, γγ-->π+π-π+π-, and γγ-->K+K-K+K-. We identify four ηc candidates in the K+K-K+K- channel on a negligible background; the one φφ event among them implies a 95%-confidence-level lower limit for Γγγ(ηc) of 1.7 keV. In the other channels we find no evidence for any of the three states. We establish 95%-C.L. upper limits Γγγ(ηc)<15.5 keV, Γγγ(χ0)<17.0 keV, and Γγγ(χ2)<4.2 keV. From all channels combined, we obtain the value Γγγ(ηc)<6.4+/-5.03.4 keV.

  7. Charmonium production in photon-photon collisions

    SciTech Connect

    Aihara, H.; Alston-Garnjost, M.; Avery, R.E.; Barbaro-Galtieri, A.; Barker, A.R.; Barnett, B.A.; Bauer, D.A.; Bengtsson, H.U.; Bobbink, G.J.; Bolognese, T.S.; Bross, A.D.; Buchanan, C.D.; Buijs, A.; Caldwell, D.O.; Chao, H.Y.; Chun, S.B.; Clark, A.R.; Cowan, G.D.; Crane, D.A.; Dahl, O.I.; Daoudi, M.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Edberg, T.K.; Eisner, A.M.; Enomoto, R.; Erne, F.C.; Fujii, T.; Gary, J.W.; Gorn, W.; Hauptman, J.M.; Hofmann, W.; Hylen, J.; Kamae, T.; Kaye, H.S.; Kees, K.H.; Kenney, R.W.; Winston, K.; Kofler, R.R.; Lander, R.L.; Langeveld, W.G.J.; Layter, J.G.; Lin, W.T.; Linde, F.L.; Loken, S.C.; Lu, A.; Lu, X.Q.; Lynch, G.R.; Madaras, R.J.; Maeshima, K.; Magnuson, B.D.; Masek, G.E.; Mathis, L.G.; Matthews, J.A.J.; Maxfield, S.J.; Miller, E.S.; Moses, W.; McNeil, R.R.; Nygren, D.R.; Oddone, P.R.; Paar, H.P.; Park, S.K.; Pellett, D.E.; Pripstein, M.; Ronan, M.T.; Ross, R.R.; Rouse, F.R.; Schwitkis, K.A.; Sens, J.C.; Shapiro, G.; Shen, B.C.; Slater, W.E.; Smit

    1987-01-01

    We have searched for the two-photon production of the /eta//sub c/, /chi//sub 0/ and /chi//sub 2/ charmonium states at the e/sup +/e/sup -/ collider PEP in the channels /gamma//gamma/ /yields/ K/sup +-/K/sub S//sup 0//pi//sup -+/, /gamma//gamma/ /yields/ K/sup +/K/sup -//pi//sup +//pi//sup -/, /gamma//gamma/ /yields/ /pi//sup +//pi//sup -//pi//sup +//pi//sup -/ and /gamma//gamma/ /yields/ K/sup +/K/sup -/K/sup +/K/sup -/. We identify four /eta//sub c/ candidates in the K/sup +/K/sup -/K/sup +/K/sup -/ channel, on a negligible background; this leads to a preliminary 95% C.L. lower limit for /Gamma//sub /gamma//gamma//(/eta//sup c/) of 1.6 keV. In the other channels we find no evidence for any of the three states and establish preliminary 95% C.L. upper limits /Gamma//sub /gamma//gamma//(/eta//sub c/) < 15 keV, /Gamma//sub /gamma//gamma//(/chi//sub 0/)< 14 keV and /Gamma//sub /gamma//gamma//(/chi//sub 2/) < 4.0 keV. Combining the results on the /eta//sub c/ from all channels we obtain the value /Gamma//sub /gamma//gamma//(/eta//sub c/) = 4.5/sub -3.6///sup -5.5 keV. 18 refs., 3 figs., 1 tab.

  8. Vector-vector production in photon-photon interactions

    NASA Astrophysics Data System (ADS)

    Ronan, Micheal T.

    1989-04-01

    Measurements of exclusive untagged ρ0ρ0,ρφ,K*K¯*, and ρω production and tagged ρ0ρ0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented.

  9. Comparison of photon-photon and photon-magnetic field pair production rates. [in neutron stars

    NASA Technical Reports Server (NTRS)

    Burns, M. L.; Harding, A. K.

    1983-01-01

    Neutron stars were proposed as the site of gamma-ray burst activity and the copious supply of MeV photons admits the possibility of electron-positron pair production. If the neutron star magnetic field is sufficiently intense (10 to the 12th power G), both photon-photon (2 gamma) and photon-magnetic field (gamma) pair production should be important mechanisms. Rates for the two processes were calculated using a Maxwellian distribution for the photons. The ratio of 1 gamma to 2 gamma pair production rates was obtained as a function of photon temperature and magnetic field strength.

  10. Comparison of Photon-photon and Photon-magnetic Field Pair Production Rates

    NASA Technical Reports Server (NTRS)

    Burns, M. L.; Harding, A. K.

    1983-01-01

    Neutron stars were proposed as the site of gamma-ray burst activity and the copious supply of MeV photons admits the possibility of electron-positron pair production. If the neutron star magnetic field is sufficiently intense ( 10 to the 12th power G), both photon-photon (2 gamma) and photon-magnetic field ( gamma) pair production should be important mechanisms. Rates for the two processes were calculated using a Maxwellian distribution for the photons. The ratio of 1 gamma to 2 gamma pair production rates was obtained as a function of photon temperature and magnetic field strength.

  11. Vector-vector production in photon-photon interactions

    SciTech Connect

    Ronan, M.T.

    1988-12-09

    Measurements of exclusive untagged /rho//sup 0//rho//sup 0/, /rho//phi/, K/sup *//bar K//sup */, and /rho/..omega.. production and tagged /rho//sup 0//rho//sup 0/ production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs.

  12. Vector-vector production in photon-photon interactions

    SciTech Connect

    Ronan, M. T.

    1989-04-25

    Measurements of exclusive untagged /rho//sup 0//rho0/,/rho//phi/,/ital K//sup *//ital K/bar /*/, and /rho/..omega.. production and tagged /rho//sup 0//rho0/ production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented.

  13. Hard Exclusive Meson Production at COMPASS

    NASA Astrophysics Data System (ADS)

    Ter Wolbeek, Johannes

    2016-02-01

    The concept of Generalized Parton Distributions (GPDs) combines two-dimensional spatial information given by form factors, with longitudinal momentum information from Parton Distribution Functions. GPDs provide comprehensive description of the nucleon structure involving a wealth of new information. For instance, according to Ji’s sum rule, the GPDs H and E enable access to the total angular momenta of quarks, antiquarks and gluons. While H can be approached using measurements of electroproduction cross sections, asymmetry measurements in hard exclusive meson production off transversely polarized targets can help to constrain the GPD E and chiral-odd GPDs. In 2007 and 2010 the COMPASS experiment at CERN collected data by scattering a 160GeV/c muon beam off a transversely polarized NH3 target. Exclusive vector-meson production μ + p → μ‧ + p + V with a ρ0 or ω meson in the final state is studied and five single-spin and three double-spin azimuthal asymmetries are measured.

  14. Multiple photon production in double parton scattering at the LHC

    NASA Astrophysics Data System (ADS)

    Palota da Silva, R.; Brenner Mariotto, C.; Goncalves, V. P.

    2016-04-01

    The high density of gluons in the initial state of hadronic collisions at LHC implies that the probability of multiple parton interactions within one proton-proton collision increases. In particular, the probability of having two or more hard interactions in a collision is not significantly suppressed with respect to the single interaction probability. In this contribution we study for the first time the production of prompt photons in double parton scattering processes. In particular, we estimate the rapidity distribution for the double Compton process, which leads to two photons plus two jets in the final state. Besides, we study the production of three and four photons in the final state, which are backgrounds to physics beyond the Standard Model.

  15. Photon-splitting limits to the hardness of emission in strongly magnetized soft gamma repeaters

    NASA Technical Reports Server (NTRS)

    Baring, Matthew G.

    1995-01-01

    Soft gamma repeaters are characterized by recurrent activity consisting of short-duration outbursts of high-energy emission that is typically of temperature less than 40 keV. One recent model of repeaters is that they originate in the environs of neutron stars with superstrong magnetic fields, perhaps greater than 10(exp 14) G. In such fields, the exotic process of magnetic photon splitting gamma yields gamma gamma acts very effectively to reprocess gamma-ray radiation down to hard X-ray energies. In this Letter, the action of photon splitting is considered in some detail, via the solution of photon kinetic equations, determining how it limits the hardness of emission in strongly magnetized repeaters, and thereby obtaining observational constraints to the field in SGR 1806-20.

  16. Observation of jet production by real photons

    NASA Astrophysics Data System (ADS)

    Adams, D.; Ahmad, S.; Akchurin, N.; Birmingham, P.; Breuer, H.; Chang, C. C.; Cihangir, S.; Corcoran, M. D.; Davis, W. L.; Gustafson, H. R.; Holmgren, H.; Kasper, P.; Kruk, J.; Lincoln, D.; Longo, M. J.; Marraffino, J.; McPherson, J.; Miettinen, H. E.; Morrow, G.; Mutchler, G. S.; Naples, D.; Onel, Y.; Skeens, J.; Thomas, G. P.; Traynor, M. M.; Waters, J. W.; Webster, M. S.; Xu, J. P.; Zhu, Q.

    1994-04-01

    Interactions of high energy photons on a hyrogen target have been studied using a large acceptance segmented calorimeter. The event topology clearly shows the production of dijet final states as predicted by perturbative QCD. The energy flow in the photon (forward) direction is compared both to Monte Carlo expectations and to that produced in πp interactions.

  17. Heavy flavor production from photons and hadrons

    SciTech Connect

    Heusch, C.A.

    1982-01-01

    The present state of the production and observation of hadrons containing heavy quarks or antiquarks as valence constituents, in reactions initiated by real and (space-like) virtual photon or by hadron beams is discussed. Heavy flavor production in e/sup +/e/sup -/ annihilation, which is well covered in a number of recent review papers is not discussed, and similarly, neutrino production is omitted due to the different (flavor-changing) mechanisms that are involved in those reactions. Heavy flavors from spacelike photons, heavy flavors from real photons, and heavy flavors from hadron-hadron collisions are discussed. (WHK)

  18. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

  19. Chargino production and decay in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Mayer, T.; Blöchinger, C.; Franke, F.; Fraas, H.

    2003-03-01

    We discuss the pair production of charginos in collisions of polarized photons, γγ rightarrow tilde{χ}_i^+ tilde{χ}_i^- (i = 1,2), and the subsequent leptonic decay of the lighter chargino tilde{χ}_1^+ rightarrow tilde{χ}_1^0 e^+ ν_e including the complete spin correlations. Analytical formulae are given for the polarization and the spin-spin correlations of the charginos. Since the production is a pure QED process the decay dynamics can be studied separately. For high energy photons from Compton backscattering of polarized laser pulses off polarized electron beams numerical results are presented for the cross section, the angular distribution and the forward-backward asymmetry of the decay positron. Finally we study the dependence on the gaugino mass parameter M1 and on the sneutrino mass for a gaugino-like MSSM scenario.

  20. Two-photon production of ω pairs

    NASA Astrophysics Data System (ADS)

    Albrecht, H.; Hamacher, T.; Hofmann, R. P.; Kirchhoff, T.; Mankel, R.; Nau, A.; Nowak, S.; Reßing, D.; Schröder, H.; Schulz, H. D.; Walter, M.; Wurth, R.; Hast, C.; Kapitza, H.; Kolanoski, H.; Kosche, A.; Lange, A.; Lindner, A.; Schieber, M.; Siegmund, T.; Spaan, B.; Thurn, H.; Töpfer, D.; Wegener, D.; Eckstein, P.; Frankl, C.; Graf, J.; Schmidtler, M.; Schramm, M.; Schubert, K. R.; Schwierz, R.; Waldi, R.; Reim, K.; Wegener, H.; Eckmann, R.; Kuipers, H.; Mai, O.; Mundt, R.; Oest, T.; Reiner, R.; Schmidt-Parzefall, W.; Stiewe, J.; Werner, S.; Ehret, K.; Hofmann, W.; Hüpper, A.; Knöpfle, K. T.; Spengler, J.; Krieger, P.; Macfarlane, D. B.; Prentice, J. D.; Saull, P. R. B.; Tzamariudaki, K.; van de Water, R. G.; Yoon, T.-S.; Schneider, M.; Weseler, S.; Kernel, G.; Križan, P.; Križnič, E.; Podobnik, T.; Živko, T.; Balagura, V.; Barsuk, S.; Belyaev, I.; Chistov, R.; Danilov, M.; Eiges, V.; Gershtein, L.; Gershtein, Yu.; Golutvin, A.; Igonkina, O.; Korolko, I.; Kostina, G.; Litvintsev, D.; Pakhlov, P.; Semenov, S.; Snizhko, A.; Tichomirov, I.; Zaitsev, Yu.; Argus Collaboration

    1996-02-01

    A maximum likelihood analysis of ARGUS data on two-photon production of π+π+π0π0π-π- is presented. A small fraction of events is due to the production of omega pairs. The γγ → ωω cross section has its maximum value close to threshold.

  1. Interspeaker Variability in Hard Palate Morphology and Vowel Production

    ERIC Educational Resources Information Center

    Lammert, Adam; Proctor, Michael; Narayanan, Shrikanth

    2013-01-01

    Purpose: Differences in vocal tract morphology have the potential to explain interspeaker variability in speech production. The potential acoustic impact of hard palate shape was examined in simulation, in addition to the interplay among morphology, articulation, and acoustics in real vowel production data. Method: High-front vowel production from…

  2. Prompt photon production in double-Pomeron-exchange events at the LHC

    NASA Astrophysics Data System (ADS)

    Kohara, A. K.; Marquet, C.

    2016-06-01

    Within the resolved Pomeron model of hard diffractive scattering, we compute prompt photon production in double-Pomeron-exchange events in proton-proton collisions. Using specific kinematical constraints chosen according to the acceptances of the forward proton detectors of experiments at the Large Hadron Collider, we provide estimates for inclusive and isolated photon production. This is done using the JetPhox program. We find that next-to-leading order corrections to the hard process are important and must be included in order to correctly constrain the quark and gluon content of the Pomeron from such processes at the LHC.

  3. Informativeness Improvement of Hardness Test Methods for Metal Product Assessment

    NASA Astrophysics Data System (ADS)

    Osipov, S.; Podshivalov, I.; Osipov, O.; Zhantybaev, A.

    2016-06-01

    The paper presents a combination of theoretical suggestions, results, and observations allowing to improve the informativeness of hardness testing process in solving problems of metal product assessment while in operation. The hardness value of metal surface obtained by a single measurement is considered to be random. Various measures of location and scattering of the random variable were experimentally estimated for a number of test samples using the correlation analysis, and their close interaction was studied. It was stated that in metal assessment, the main informative characteristics of hardness testing process are its average value and mean-square deviation for measures of location and scattering, respectively.

  4. rho/sup 0/. omega. production in photon photon interactions

    SciTech Connect

    Derby, K.A.

    1987-08-01

    The subject of this dissertation is the production of the rho/sup 0/..omega.. final state in photon photon interactions. The production of the rho/sup 0/..omega.. final state has been of interest primarily because of its similarity to the related process ..gamma gamma.. ..-->.. rho/sup 0/rho/sup 0/. The cross section for rho/sup 0/rho/sup 0/ production demonstrates a peaking near threshold, the mechanism of which has been the subject of considerable speculation. The data sample used for the analysis was obtained using the TPC detector facility at the PEP e/sup +/e/sup -/ storage ring, and corresponds to an integrated e/sup +/e/sup -/ luminosity of 64 pb/sup -1/ at 29 GeV center of mass energy. Our estimate of the rho/sup 0/..omega.. cross section is compared to the predictions of several models which have been used to account for the observed rho/sup 0/rho/sup 0/ cross section. The experimental results are consistent with the predictions of a threshold enhancement model, as well as those of a four quark (qq anti q anti q) resonance model. However, they disagree with the predictions of a t-channel factorization approach.

  5. Neutral Rho Omega Production in Photon Photon Interactions.

    NASA Astrophysics Data System (ADS)

    Derby, Kevin Arthur

    1987-09-01

    The subject of this dissertation is the production of the rho^0omega final state in photon photon interactions. The production of the rho^0omega final state has been of interest primarily because of its similarity to the related process gammagamma to rho^0rho ^0. The cross section for rho ^0rho^0 production demonstrates a peaking near threshold, the mechanism of which has been the subject of considerable speculation. The data sample used for the analysis was obtained using the TPC detector facility at the PEP e^+e^- storage ring and corresponds to an integrated e ^+e^- luminosity of 64 pb ^{-1} at 29 GeV center of mass energy. Our estimate of the rho^0 omega cross section is compared to the predictions of several models which have been used to account for the observed rho^0rho^0 cross section. The experimental results are consistent with the predictions of a threshold enhancement model as well as those of a four quark (qqqq) resonance model. However, they disagree with the predictions of a t-channel factorization approach.

  6. Isolated prompt photon production at CDF

    SciTech Connect

    Maas, P.A. )

    1992-11-01

    This note describes measurements of isolated prompt photon production at [radical]s = 1.8 TeV using the CDF experiment. The measurements are compared to recent NLO QCD calculations, including recently obtained parton distribution functions. Qualitatively, the QCD calculation with the new parton distribution functions agrees better with the data than the previous parton distribution functions.

  7. Hard photons and neutral pions as probes of hot and dense nuclear matter

    NASA Astrophysics Data System (ADS)

    Schutz, Y.; Martínez, G.; Marqués, F. M.; Marín, A.; Matulewicz, T.; Ostendorf, R. W.; Bożek, P.; Delagrange, H.; Díaz, J.; Franke, M.; Gudima, K. K.; Hlaváč, S.; Holzmann, R.; Lautridou, P.; Lefèvre, F.; Löhner, H.; Mittig, W.; Płoszajczak, M.; van Pol, J. H. G.; Québert, J.; Roussel-Chomaz, P.; Schubert, A.; Siemssen, R. H.; Simon, R. S.; Sujkowski, Z.; Toneev, V. D.; Wagner, V.; Wilschut, H. W.; Wolf, Gy.

    1997-02-01

    The dynamics of heavy-ion collisions is studied in an energy domain in the vicinity of the Fermi energy. The early history of the collision is analyzed from the theoretical and experimental point of view in which the message conveyed by bremsstrahlung photons and neutral pions is exploited. The Boltzmann-Uehling-Uhlenbeck model and the Dubna Cascade Model, both based on similar principles but each adopting different computation technics, are briefly described and their respective predictions are discussed. In particular the emission pattern of bremsstrahlung photons is discussed. The photon production has been measured in the systems 86Kr+ 58Ni at 60 A MeV, 181Ta+ 197Au at 40 A MeV and 208Pb+ 197Au at 30 A MeV and energy spectra, angular distributions and two-photon correlations have been analyzed. We find that bremsstrahlung photons are emitted from two distinct sources that can be correlated with nuclear-matter density oscillations. The properties of photon emission are discussed in terms of collective properties of nuclear matter. The high energy tail of the photon spectrum is interpreted by π0 and Δ decay but predominantly by radiative capture of pions. The π0 absorption in the nuclear medium is further analyzed by examining their emission pattern.

  8. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

    DOE PAGESBeta

    Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Kroll, Thomas; Chollet, Mathieu; Feng, Yiping; Glownia, James M.; Kern, Jan; Lemke, Henrik T.; Nordlund, Dennis; et al

    2015-04-15

    X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure andmore » its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source.« less

  9. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

    PubMed Central

    Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Kroll, Thomas; Chollet, Mathieu; Feng, Yiping; Glownia, James M.; Kern, Jan; Lemke, Henrik T.; Nordlund, Dennis; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Weng, Tsu-Chien; Bergmann, Uwe

    2015-01-01

    X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure and its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source. PMID:25931076

  10. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

    SciTech Connect

    Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Kroll, Thomas; Chollet, Mathieu; Feng, Yiping; Glownia, James M.; Kern, Jan; Lemke, Henrik T.; Nordlund, Dennis; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Weng, Tsu -Chien; Bergmann, Uwe

    2015-04-15

    X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure and its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source.

  11. Measurement of the space-time extent of the hard-photon emitting source in heavy-ion collisions at 100 MeV/nucleon

    SciTech Connect

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Turrisi, R.; Barbera, R.; Riggi, F.; Rizza, G.; Russo, G.; Turrisi, R.; Russo, G.

    1997-05-01

    The correlation between the couples of high-energy photons (E{sub {gamma}}{gt}30MeV) detected in the reactions induced by a {sup 36}Ar beam on {sup 27}Al, {sup 112}Sn, and {sup 197}Au targets at 95 MeV/nucleon has been analyzed with the intensity interferometry technique. Both the size and lifetime of the emitting source have been quantitatively evaluated. Results support the nucleon-nucleon picture as the dominant hard-photon production mechanism. {copyright} {ital 1997} {ital The American Physical Society}

  12. Two-photon dilepton production in proton-proton collisions: Two alternative approaches

    NASA Astrophysics Data System (ADS)

    Łuszczak, Marta; Schäfer, Wolfgang; Szczurek, Antoni

    2016-04-01

    We investigate different methods to incorporate the effect of photons in hard processes. We compare the two different approaches used for calculating cross sections for the two-photon p p →l+l-X process. In one of the approaches the photon is treated as a collinear parton in the proton. In the second approach the recently proposed kT factorization method is used. We discuss how results of the collinear parton model depend on the initial condition for the QCD evolution and discuss an approximate treatment where the photon is excluded from the combined QCD-QED evolution. We demonstrate that it is not necessary to put the photon into the evolution equation as is often done, but it is sufficient to use a simplified approach in which the photon couples to quarks and antiquarks, which by themselves undergo DGLAP evolution equations. We discuss the sensitivity of the results to the choice of structure function parametrization and experimental cuts in the kT factorization approach. We explicitly display regions of x and Q2 (arguments of structure functions) relevant for different experiments. We compare the results of our calculations with recent experimental data for dilepton production and find that in most cases the contribution of the photon-photon mechanism is rather small. We discuss how to enhance the photon-photon contribution. We also compare our results to those of recent measurements of exclusive and semiexclusive e+e- pair production with certain experimental data by the CMS Collaboration.

  13. Undulator-Based Production of Polarized Photons

    SciTech Connect

    Professor Kirk McDonald

    2008-05-29

    "Project Title: Undulator-Based Production of Polarized Photons" DOE Contract Number: FG02-04ER41355 Principal Investigator: Prof. Kirk McDonald Period of Performance: 09/10/2004 thru 08/31/2006 This award was to fund Princeton's activity on SLAC experiment E166, "Undulator-Based Production of Polarized Positrons" which was performed at SLAC during June and September 2005. Princeton U. fabricated a magnetic spectrometer for this experiment, and participated in the commissioning, operation, and analysis of the experiment, for which Prof. McDonald was a co-spokesperson. The experiment demonstrated that an intense positron beam with 80% longitudinal polarization could be generated by conversion of MeVenergy circularly polarized photons in a thin target, which photons were generated by passage of high-energy electrons through a helical undulator. This technique has since been adopted as the baseline for the polarized positron source of the proposed International Linear Collider. Results of the experiment have been published in Physical Review Letters, vol 100, p 210801 (2008) [see attached .pdf file], and a longer paper is in preparation.

  14. Satellite project "CORONAS-PHOTON" for study of solar hard radiation

    NASA Astrophysics Data System (ADS)

    Kotov, Yu.; Cor-Phot Team

    "CORONAS-PHOTON" is the Russian mission for study of the solar hard electromagnetic radiation in the very wide energy range from Extreme UV up to high-energy gamma - radiation. GOAL OF PROJECT: The investigation of energy accumulation and its transformation into energy of accelerated particles processes during solar flares; the study of the acceleration mechanisms, propagation and interaction of fast particles in the solar atmosphere; the study of the solar activity correlation with physical-chemical processes in the Earth upper atmosphere. SCIENTIFIC PAYLOAD CAPABILITY Radiation / Energy region / Detector type: Full solar disk X- radiation / 2keV - 2000MeV / Prop. counter; NaI(Tl); Full solar disk X- and γ-radiation / NaI(Tl)/CsI(Na) phoswich; Full solar disk X- and γ-radiation and solar neutrons / 20 - 300MeV / YalO_3(Ce); CsI(Tl); Hard X-ray polarization in large flares / 20 - 150keV / p-terphenyl scatterer and CsI(Na) absorbers; Full solar disk EUV-radiation monitoring / 6 spectral windows in <10 - 130nm / Filtered photodiodes; Solar images in narrow spectral bands and monochromatic emission lines of hot plasma / Emission of HeII, SiXI, FeXXI, FeXXIII, MgXII ions / Multi-layer and Bregg spherical crystal quartz mirrors with CCDs; Additionally, the temporal and energy spectra of electrons (0.2-14MeV), protons (1-61MeV) and nuclei (Z<26, 2-50MeV/nuclon) at the satellite orbit will be registrated by several instruments. MAIN CHARACTERISTICS OF SPACECRAFT: Spacecraft weight: 1900 kg; Orbit type: Circular; Scientific payload weight: 540 kg; Height: 500 km; Orientation to the Sun [arc min]: better 5; Inclination: 82.5 degree; Instability of orientation [deg/s]: less 0.005; Solar - synchronous orbit is under study. Launching date of "CORONAS-PHOTON" spacecraft is 2006.

  15. Hard photon processes in electron-positron annihilation at 29 GeV

    SciTech Connect

    Gold, M.S.

    1986-11-01

    The hard photon processes ..mu mu gamma.. and hadrons + ..gamma.. in e/sup +/e/sup -/ annihilation at 29 GeV have been studied. The study is based on an integrated luminosity of 226 pb/sup -1/ taken at PEP with the Mark II detector. For the ..mu mu gamma.. process, a small fraction of non-planar events are observed with missing momentum along the beam direction. The resulting missing energy spectrum is consistent with that expected from higher order effects. The observed cross section is consistent with the predicted cross section for this process, sigma/sup exp/sigma/sup th/ = .90 +- .05 +- .06. The observed hard photon energy spectrum and mass distributions are found to be in agreement with O(..cap alpha../sup 3/) QED. The measured charge asymmetry is in good agreement with the predicted value, A/sub exp/A/sub th/ = .83 +- .25 +- .12. The ..mu gamma.. invariant mass distribution is used to place a limit on a possible excited muon coupling G..gamma../M* for excited muon masses in the range 1 < M* < 21 GeV of (G..gamma../M*)/sup 2/ < 10/sup -5/ GeV/sup -2/ at a 95% confidence level. In the hadrons + ..gamma.. process, evidence for final state radiation is found in an excess of events over that predicted from initial state radiation alone of 253 +- 54 +- 60 events. Further evidence for final state radiation is found in a large hadronic charge asymmetry A/sub Had+..gamma../= (-24.6 +- 5.5)%.

  16. Study of two-photon corrections in the pp{yields}e{sup +}e{sup -} process: Hard rescattering mechanism

    SciTech Connect

    Guttmann, Julia; Vanderhaeghen, Marc; Kivel, Nikolai

    2011-05-01

    We investigate the two-photon corrections to the process pp{yields}e{sup +}e{sup -} at large momentum transfer, aimed to access the timelike nucleon form factors. We estimate the two-photon corrections using a hard rescattering mechanism, which has already been used to calculate the corresponding corrections to elastic electron-proton scattering. Using different nucleon distribution amplitudes, we find that the two-photon corrections to the pp{yields}e{sup +}e{sup -} cross sections in the momentum transfer range 5-30 GeV{sup 2} is below the 1% level.

  17. Resonance production in two-photon interactions

    SciTech Connect

    Roe, N.A.

    1989-02-01

    Resonance production in two-photon interactions is studied using data collected with the ASP detector at the PEP e/sup +/e/sup /minus// storage ring located at the Stanford Linear Accelerator Center. The ASP detector is a non-magnetic lead-glass calorimeter constructed from 632 lead-glass bars. It covers 94% of 4..pi.. in solid angle, extending to within 20/degree/ of the beamline. Lead-scintillator calorimeters extend the coverage to within 21 mr of the beamline on both sides. Energy resolution of ..sqrt..E/10%, where E is the energy is GeV, is achieved for electrons and photons in the lead-glass calorimeter, and particle trajectories are reconstructed with high efficiency. A total luminosity of 108 pb/sup /minus/1/ was collected with the ASP detector at a center-of-mass energy of 29 GeV. The observed process is e/sup +/e/sup /minus// ..-->.. e/sup +/e/sup /minus//..gamma..*..gamma..* ..-->.. e/sup +/e/sup /minus//X, is a pseudoscalar resonance (J/sup PC/ = 0/sup /minus/+/) and ..gamma..* is a virtual (mass /ne/ 0) photon. The outgoing electrons scatter down the beampipe and are not detected. The observed resonances are the /eta/ and /eta/' mesons, with masses of 549 and 958 MeV, respectively. They are detected in the ..gamma gamma.. decay mode; a total of 2380 +- 49 /eta/ ..-->.. ..gamma gamma.. and 568 +- 26 /eta/' ..-->.. ..gamma gamma.. events are observed. From the number of events, the detection efficiency, and the calculated production cross sections the radiative widths, GAMMA/sub ..gamma gamma../, of the /eta/ and /eta/' were measured and found to be: GAMMA/sub ..gamma gamma../(/eta/) = .481 +- .010 +- .047keV and GAMMA/sub ..gamma gamma../(/eta/') = 4.71 +- .22 +- .70keV. These results are in good agreement with the world average values. 67 refs., 42 figs., 20 tabs.

  18. 2-ps Hard X-Ray Streak Camera Measurements at Sector 7 Beamline of the Advanced Photon Source

    SciTech Connect

    Chollet, M.; Ahr, B.; Walko, D.A.; Rose-Petruck, C.; Adams, B.

    2011-08-02

    A hard X-ray streak camera capable of 2-ps time resolution is in operation at the Sector 7 beamline of the Advanced Photon Source. It is used for laser-pump, X-ray probe experiments using the Ti:Sapphire femtosecond laser system installed on the beamline. This streak camera, combined with standardized and prealigned experimental setups, can perform time-resolved liquid-phase absorption spectroscopy, reflectivity, and diffraction experiments.

  19. Pion and kaon pair production in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Avery, R. E.; Barbaro-Galtieri, A.; Barker, A. R.; Barnes, A. V.; Barnett, B. A.; Bauer, D. A.; Bengtsson, H.-U.; Bintinger, D. L.; Blumenfeld, B. J.; Bobbink, G. J.; Bross, A. D.; Buchanan, C. D.; Buijs, A.; Cain, M. P.; Caldwell, D. O.; Chamberlain, O.; Chien, C.-Y.; Clark, A. R.; Cowan, G. D.; Crane, D. A.; Dahl, O. I.; Derby, K. A.; Eastman, J. J.; Eberhard, P. H.; Eisner, A. M.; Enomoto, R.; Erné, F. C.; Fujii, T.; Gabioud, B.; Gary, J. W.; Gorn, W.; Hauptman, J. M.; Hofmann, W.; Huth, J. E.; Hylen, J.; Joshi, U. P.; Kamae, T.; Kaye, H. S.; Kees, K. H.; Kenney, R. W.; Kerth, L. T.; Ko, Winston; Koda, R. I.; Kofler, R. R.; Kwong, K. K.; Lander, R. L.; Langeveld, W. G.; Layter, J. G.; Linde, F. L.; Lindsey, C. S.; Loken, S. C.; Lu, A.; Lu, X.-Q.; Lynch, G. R.; Madaras, R. J.; Maeshima, K.; Magnuson, B. D.; Marx, J. N.; Maruyama, K.; Masek, G. E.; Mathis, L. G.; Matthews, J. A.; Maxfield, S. J.; Melnikoff, S. O.; Miller, E. S.; Moses, W.; McNeil, R. R.; Nemethy, P.; Nygren, D. R.; Oddone, P. J.; Paar, H. P.; Park, D. A.; Pellett, D. E.; Pripstein, M.; Ronan, M. T.; Ross, R. R.; Rouse, F. R.; Sauerwein, R. R.; Schwitkis, K. A.; Sens, J. C.; Shapiro, G.; Shapiro, M. D.; Shen, B. C.; Slater, W. E.; Smith, J. R.; Steinman, J. S.; Stevenson, M. L.; Stork, D. H.; Strauss, M. G.; Sullivan, M. K.; Takahashi, T.; Thompson, J. R.; Toge, N.; van Tyen, R.; van Uitert, B.; Vandalen, G. J.; van Daalen Wetters, R. F.; Vernon, W.; Wagner, W.; Wang, E. M.; Wang, Y. X.; Wayne, M. R.; Wenzel, W. A.; White, J. T.; Williams, M. C.; Wolf, Z. R.; Yamamoto, H.; Yamauchi, M.; Yellin, S. J.; Zeitlin, C.; Zhang, W.-M.

    1986-07-01

    We report measurements of the two-photon processes e+e--->e+e-π+π- and e+e--->e+e-K+K-, at an e+e- center-of-mass energy of 29 GeV. In the π+π- data a high-statistics analysis of the f(1270) results in a γγ width Γ(γγ-->f)=3.2+/-0.4 keV. The π+π- continuum below the f mass is well described by a QED Born approximation, whereas above the f mass it is consistent with a QCD-model calculation if a large contribution from the f is assumed. For the K+K- data we find agreement of high-mass continuum with the QCD prediction; limits on f'(1520) and theta(1720) formation are presented.

  20. Pion and kaon pair production in photon-photon collisions

    SciTech Connect

    Aihara, H.; Alston-Garnjost, M.; Avery, R.E.; Barbaro-Galtieri, A.; Barker, A.R.; Barnes, A.V.; Barnett, B.A.; Bauer, D.A.; Bengtsson, H.; Bintinger, D.L.; Blumenfeld, B.J.; Bobbink, G.J.; Bross, A.D.; Buchanan, C.D.; Buijs, A.; Cain, M.P.; Caldwell, D.O.; Chamberlain, O.; Chien, C.; Clark, A.R.; Cowan, G.D.; Crane, D.A.; Dahl, O.I.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Eisner, A.M.; Enomoto, R.; Erne-acute-accent, F.C.; Fujii, T.; Gabioud, B.; Gary, J.W.; Gorn, W.; Hauptman, J.M.; Hofmann, W.; Huth, J.E.; Hylen, J.; Joshi, U.P.; Kamae, T.; Kaye, H.S.; Kees, K.H.; Kenney, R.W.; Kerth, L.T.; Ko, W.; Koda, R.I.; Kofler, R.R.; Kwong, K.K.; Lander, R.L.; Langeveld, W.G.J.; Layter, J.G.; Linde, F.L.; Lindsey, C.S.; Loken, S.C.; Lu, A.; Lu, X.; Lynch, G.R.; Madaras, R.J.; Maeshima, K.; Magnuson, B.D.; Marx, J.N.; Maruyama, K.; Masek, G.E.; Mathis, L.G.; Matthews, J.A.J.; Maxfield, S.J.; Melnikoff, S.O.; Miller, E.S.; Moses, W.; McNeil, R.R.; Nemethy, P.; Nygren, D.R.; Oddone, P.J.; Pa

    1986-07-28

    We report measurements of the two-photon processes e-italic/sup +/e/sup -/..-->..e/sup +/e/sup -/..pi../sup +/..pi../sup -/ and e-italic/sup +/e/sup -/..-->..e/sup +/e/sup -/K/sup +/K/sup -/, at an e-italic/sup +/e/sup -/ center-of-mass energy of 29 GeV. In the ..pi../sup +/..pi../sup -/ data a high-statistics analysis of the f-italic(1270) results in a ..gamma gamma.. width GAMMA(..gamma gamma -->..f-italic) = 3.2 +- 0.4 keV. The ..pi../sup +/..pi../sup -/ continuum below the f-italic mass is well described by a QED Born approximation, whereas above the f-italic mass it is consistent with a QCD-model calculation if a large contribution from the f-italic is assumed. For the K-italic/sup +/K/sup -/ data we find agreement of high-mass continuum with the QCD prediction; limits on f-italic'(1520) and t-italich-italice-italict-italica-italic(1720) formation are presented.

  1. Production and elliptic flow of dileptons and photons in a matrix model of the quark-gluon plasma.

    PubMed

    Gale, Charles; Hidaka, Yoshimasa; Jeon, Sangyong; Lin, Shu; Paquet, Jean-François; Pisarski, Robert D; Satow, Daisuke; Skokov, Vladimir V; Vujanovic, Gojko

    2015-02-20

    We consider a nonperturbative approach to the thermal production of dileptons and photons at temperatures near the critical temperature in QCD. The suppression of colored excitations at low temperature is modeled by including a small value of the Polyakov loop, in a "semi"-quark-gluon plasma (QGP). Comparing the semi-QGP to the perturbative QGP, we find a mild enhancement of thermal dileptons. In contrast, to leading logarithmic order in weak coupling there are far fewer hard photons from the semi-QGP than the usual QGP. To illustrate the possible effects on photon and dilepton production in heavy-ion collisions, we integrate the rate with a simulation using ideal hydrodynamics. Dileptons uniformly exhibit a small flow, but the strong suppression of photons in the semi-QGP tends to weight the elliptical flow of photons to that generated in the hadronic phase. PMID:25763954

  2. Neutralino pair production at the photon-photon collider for the τ˜-coannihilation scenario

    NASA Astrophysics Data System (ADS)

    Sonmez, Nasuf

    2016-03-01

    Supersymmetry (SUSY) is a theory which gives an explanation for the strong and electroweak interactions from the grand unification scale down to the weak scale. The search for supersymmetric particles still continues at full speed at the LHC without success. The main task at the ILC is complementing the LHC result and also search for new physics. In this study, the neutralino pair production via photon-photon collision is studied for the t˜-coannihilation scenario in the context of MSSM at the ILC. In the calculation, all the possible one loop diagrams are taken into account for the photon-photon interaction. We present the production cross section and distribution of various observables for the lightest and next-to-lightest neutralino pairs for benchmark models which are specifically presented in the light of LHC8 data analysis, employing these benchmark models for neutralino pair production could show the potential of the ILC concerning the dark matter searches in supersymmetry.

  3. Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals.

    PubMed

    Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

    2016-04-14

    Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information. PMID:27020686

  4. Optimization of radiation hardness and charge collection of edgeless silicon pixel sensors for photon science

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Tartarotti Maimone, D.; Pennicard, D.; Sarajlic, M.; Graafsma, H.

    2014-12-01

    Recent progress in active-edge technology of silicon sensors enables the development of large-area tiled silicon pixel detectors with small dead space between modules by utilizing edgeless sensors. Such technology has been proven in successful productions of ATLAS and Medipix-based silicon pixel sensors by a few foundries. However, the drawbacks of edgeless sensors are poor radiation hardness for ionizing radiation and non-uniform charge collection by edge pixels. In this work, the radiation hardness of edgeless sensors with different polarities has been investigated using Synopsys TCAD with X-ray radiation-damage parameters implemented. Results show that if no conventional guard ring is present, none of the current designs are able to achieve a high breakdown voltage (typically < 30 V) after irradiation to a dose of ~ 10 MGy. In addition, a charge-collection model has been developed and was used to calculate the charges collected by the edge pixels of edgeless sensors when illuminated with X-rays. The model takes into account the electric field distribution inside the pixel sensor, the absorption of X-rays, drift and diffusion of electrons and holes, charge sharing effects, and threshold settings in ASICs. It is found that the non-uniform charge collection of edge pixels is caused by the strong bending of the electric field and the non-uniformity depends on bias voltage, sensor thickness and distance from active edge to the last pixel (``edge space"). In particular, the last few pixels close to the active edge of the sensor are not sensitive to low-energy X-rays ( < 10 keV), especially for sensors with thicker Si and smaller edge space. The results from the model calculation have been compared to measurements and good agreement was obtained. The model can be used to optimize the edge design. From the edge optimization, it is found that in order to guarantee the sensitivity of the last few pixels to low-energy X-rays, the edge space should be kept at least 50% of

  5. Meson production in photon and neutrino experiments

    SciTech Connect

    Shimony, J.S.

    1988-01-01

    The reaction {gamma}p {yields} {rho}{sup 0}{sub fast}p{pi}{sup +}{pi}{sup {minus}} has been studied with the linearly polarized 20 GeV monochromatic photon beam at the SLAC Hybrid Facility, to test the prediction of s channel helicity conservation in inelastic diffraction for t{prime} < 0.4 (GeV/c){sup 2}. In a sample of 1934 events from this reaction, the {rho}{sup 0} decay angular distributions and spin density matrix elements are consistent with s channel helicity conservation. The {pi}{sup +}{pi}{sup {minus}} mass shape displays the same skewing as seen in the reaction {gamma}p {yields} p{pi}{sup +}{pi}{sup {minus}}, and the p{pi}{sup +}{pi}{sup {minus}} mass distribution compares well and scale according to the vector dominance model with that produced in {pi}{sup {plus minus}}p {yields} p{pi}{sup +}{pi}{sup {minus}}. Coherent production of the a{sub 1} meson has been observed through the reaction {nu}Fr {yields} {mu}{sup {minus}}a{sub 1}{sup +}Fr in the Tohoku 1m freon bubble chamber hybrid system. The bubble chamber was exposed to the Fermilab wideband neutrino beam, generated by 800 GeV protons at the Tevatron. The observed rate from the final charged current sample of 1792 events was 1.1 {plus minus} 0.47%, and the a{sub 1} - W coupling is calculated to be f{sup 2}{sub a}/f{sup 2}{sub {rho}} = 5.2 {plus minus} 2.2. A comparison of the cross section and the kinematical parameters with the theoretical predictions of the vector dominance model, gives reasonable agreement with the data. A Monte-Carlo study was performed to check the possibility of detecting the radiative decay of the D*{sub s} in our bubble chamber. Using the most favorable predicted rate through the {phi} branching ratio, it was determined that three times our data sample would be needed for a one {sigma} effect above background.

  6. Universal Parametrization of Thermal Photon Production in Hadronic Matter

    NASA Astrophysics Data System (ADS)

    Heffernan, Matthew; Hohler, Paul; Rapp, Ralf

    2014-09-01

    As the production of photons and dileptons from high-energy collisions is able to provide information on the high temperature and high density phases of nuclear matter, an improved and universal parametrization of the rather involved microscopic calculations is key to honing the theory behind this production. We focus on photon emission rates from hadronic many-body calculations of the in-medium rho spectral function, which includes the effects of baryons and antibaryons. Across a range of temperatures from 0.1 to 0.18 GeV and baryon chemical potentials from 0 to 0.4 GeV, a parametrization of thermal photon rates for energies from 0.2 to 5 GeV is numerically determined through the use of nested fitting methods. This provides a fully functional description of thermal photon production largely within an unprecedented 20% of the calculated values from the spectral function, a significant reduction in error from available parametrizations. The contribution of photons and dileptons from pion-pion bremsstrahlung is evaluated for the importance of its contribution. The functional form, coupled with the comparison to the bremsstrahlung production of thermal photons, will provide a baseline for guiding future studies. As the production of photons and dileptons from high-energy collisions is able to provide information on the high temperature and high density phases of nuclear matter, an improved and universal parametrization of the rather involved microscopic calculations is key to honing the theory behind this production. We focus on photon emission rates from hadronic many-body calculations of the in-medium rho spectral function, which includes the effects of baryons and antibaryons. Across a range of temperatures from 0.1 to 0.18 GeV and baryon chemical potentials from 0 to 0.4 GeV, a parametrization of thermal photon rates for energies from 0.2 to 5 GeV is numerically determined through the use of nested fitting methods. This provides a fully functional description of

  7. High aspect ratio nano-fabrication of photonic crystal structures on glass wafers using chrome as hard mask

    NASA Astrophysics Data System (ADS)

    Nazmul Hossain, Md; Justice, John; Lovera, Pierre; McCarthy, Brendan; O'Riordan, Alan; Corbett, Brian

    2014-09-01

    Wafer-scale nano-fabrication of silicon nitride (Si x N y ) photonic crystal (PhC) structures on glass (quartz) substrates is demonstrated using a thin (30 nm) chromium (Cr) layer as the hard mask for transferring the electron beam lithography (EBL) defined resist patterns. The use of the thin Cr layer not only solves the charging effect during the EBL on the insulating substrate, but also facilitates high aspect ratio PhCs by acting as a hard mask while deep etching into the Si x N y . A very high aspect ratio of 10:1 on a 60 nm wide grating structure has been achieved while preserving the quality of the flat top of the narrow lines. The presented nano-fabrication method provides PhC structures necessary for a high quality optical response. Finally, we fabricated a refractive index based PhC sensor which shows a sensitivity of 185 nm per RIU.

  8. Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals

    NASA Astrophysics Data System (ADS)

    Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

    2016-04-01

    Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for

  9. Radiation hardness test of the Philips Digital Photon Counter with proton beam

    NASA Astrophysics Data System (ADS)

    Barnyakov, M. Yu.; Frach, T.; Kononov, S. A.; Kuyanov, I. A.; Prisekin, V. G.

    2016-07-01

    The Philips Digital Photon Counter (DPC) is a silicon photomultiplier combining Geiger-mode avalanche photodiodes (G-APD) and dedicated readout electronics in the same chip. The DPC is a promising photon sensor for future RICH detectors. A known issue of G-APD is its sensitivity to radiation damage. Two DPC sensors were tested using 800 MeV/c protons. An increase of dark counting rate with proton fluence up to 4 ·1011cm-2 has been measured.

  10. Off-equilibrium photon production during the chiral phase transition

    SciTech Connect

    Michler, Frank; Hees, Hendrik van; Dietrich, Dennis D.; Leupold, Stefan; Greiner, Carsten

    2013-09-15

    In the early stage of ultrarelativistic heavy-ion collisions chiral symmetry is restored temporarily. During this so-called chiral phase transition, the quark masses change from their constituent to their bare values. This mass shift leads to the spontaneous non-perturbative creation of quark–antiquark pairs, which effectively contributes to the formation of the quark–gluon plasma. We investigate the photon production induced by this creation process. We provide an approach that eliminates possible unphysical contributions from the vacuum polarization and renders the resulting photon spectra integrable in the ultraviolet domain. The off-equilibrium photon numbers are of quadratic order in the perturbative coupling constants while a thermal production is only of quartic order. Quantitatively, we find, however, that for the most physical mass-shift scenarios and for photon momenta larger than 1 GeV the off-equilibrium processes contribute less photons than the thermal processes. -- Highlights: •We investigate first-order photon emission arising from the chiral mass shift. •We provide an ansatz eliminating possible unphysical vacuum contributions. •Our ansatz leads to photon spectra being integrable in the ultraviolet domain.

  11. Anisotropy of photon production: initial eccentricity or magnetic field.

    PubMed

    Bzdak, Adam; Skokov, Vladimir

    2013-05-10

    Recent measurements of the azimuthal anisotropy of direct photons in heavy-ion collisions at the energies of Relativistic Heavy Ion Collider show that it is of the same order as the hadronic one. This finding appears to contradict the expected dominance of photon production from a quark-gluon plasma at an early stage of a heavy-ion collision. A possible explanation of the strong azimuthal anisotropy of the photons, given recently, is based on the presence of a large magnetic field in the early phase of a collision. In this Letter, we propose a method to experimentally measure the degree to which a magnetic field in heavy-ion collisions is responsible for the observed anisotropy of photon production. The experimental test proposed in this Letter may potentially change our understanding of the nonequilibrium stage and possible thermalization in heavy-ion collisions. PMID:23705700

  12. Asking for an extra photon in Higgs production at the LHC and beyond

    NASA Astrophysics Data System (ADS)

    Gabrielli, Emidio; Mele, Barbara; Piccinini, Fulvio; Pittau, Roberto

    2016-07-01

    We study the inclusive production of a Higgs boson in association with a high- p T photon at the LHC, detailing the leading-order features of the main processes contributing to the Hγ final state. Requiring an extra hard photon in Higgs production upsets the cross-section hierarchy for the dominant channels. The Hγ inclusive production comes mainly from photons radiated in vector-boson fusion (VBF), which accounts for about 2/3 of the total rate, for p T γ, j > 30 GeV, at leading order. On the other hand, radiating a high- p T photon in the main top-loop Higgs channel implies an extra parton in the final state, which suppresses the production rate by a further α S power. As a result, the Hγ production via top loops at the LHC has rates comparable with the ones arising from either the Htoverline{t} production or the HW ( Z)γ associated production. Then, in order of decreasing cross section, comes the single-top-plus-Higgs channel, followed in turn by the heavy-flavor fusion processes boverline{b}to Hγ and coverline{c}to Hγ . The Hγ production via electroweak loops has just a minor role. At larger c.m. energies, the Htoverline{t}γ channel surpasses the total contribution of top-loop processes. In particular, requiring p T γ, j > 30 GeV at √{S}˜eq 100 TeV, Htoverline{t}γ accounts for about 1 /4 of the inclusive Hγ production at leading order, about half of the total being due to VBF production.

  13. Measurement of prompt photon production in hadronic Z decays

    NASA Astrophysics Data System (ADS)

    Buskulic, D.; Decamp, D.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Mours, B.; Alemany, R.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Pacheco, A.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Lou, J.; Qiao, C.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W.; Atwood, W. B.; Bauerdick, L. A. T.; Blucher, E.; Bonvicini, G.; Bossi, F.; Boudreau, J.; Burnett, T. H.; Drevermann, H.; Forty, R. W.; Hagelberg, R.; Harvey, J.; Haywood, S.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lançon, E.; Lehraus, I.; Lohse, T.; Lusiani, A.; Martinez, M.; Mato, P.; Mattison, T.; Meinhard, H.; Menary, S.; Meyer, T.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Roth, A.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschak, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; Bencheikh, A. M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Pietrzyk, B.; Proriol, J.; Prulhière, F.; Stimpfl, G.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Efthymiopoulos, I.; Kyriakis, A.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rosowsky, A.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Wasserbaech, S.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Campana, P.; Capon, G.; Cerutti, F.; Chiarelli, V.; D'Ettorrepiazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Altoon, B.; Boyle, O.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Turnball, R. M.; Brandl, B.; Braun, O.; Geiges, R.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Nash, J.; Patton, S. J.; Payne, D. G.; Phillips, M. J.; Sedgbeer, J. K.; Tomalin, I. R.; Wright, A. G.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wolf, B.; Aubert, J.-J.; Benchouk, C.; Bernard, V.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Papalexiou, S.; Payre, P.; Qian, Z.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Cowan, G.; Dehning, B.; Dietl, H.; Dydak, F.; Fernandez-Bosman, M.; Frank, M.; Halley, A. W.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Rotscheidt, H.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlein, U.; Stiegler, U.; Denis, R. St.; Takashima, T.; Thomas, J.; Wolf, G.; Bertin, V.; Boucrot, J.; Callot, O.; Chen, X.; Cordier, A.; Davier, M.; Grivas, J.-F.; Heusse, Ph.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Zomer, F.; Abbaneo, D.; Amendolia, S. R.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Focardi, E.; Forti, F.; Giassi, A.; Giorgi, M. A.; Ligabue, F.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Carter, J. M.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Kozanecki, W.; Lemaire, M. C.; Locci, E.; Loucatos, S.; Monnier, E.; Perez, P.; Perrier, F.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Like, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Carney, R. E.; Cartwright, S.; Combley, F.; Hatfield, F.; Reeves, P.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Grupen, C.; Mirabito, L.; Rivera, F.; Schäfer, U.; Ganis, G.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Jared, R. C.; Leclaire, B. W.; Lishka, C.; Pan, Y. B.; Pater, J. R.; Saadi, Y.; Sharma, V.; Schmitt, M.; Shi, Z. H.; Walsh, A. M.; Weber, F. V.; Whitney, M. H.; Wu, Sau Lan; Wu, X.; Zobernig, G.

    1993-03-01

    The production of isolated photons in hadronic Z decays is measured with the ALEPH detector at LEP using a sample of 450 000 hadronic events. The corrected rate is given for several values of the minimum invariant mass squared cut between the photon and the jets. This measurement of final state radiation from the quarks is compared with the predictions of parton shower models JETSET, ARIADNE and HERWIG as well as with the predictions of QCD matrix element calculations.

  14. Systematic studies of the centrality dependence of soft photon production in Au + Au collision with PHENIX

    NASA Astrophysics Data System (ADS)

    Bannier, Benjamin

    2014-11-01

    Since the earliest days of Heavy Ion Physics thermal soft photon radiation emitted during the reaction had been theorized as a smoking gun signal for formation of a quark-gluon plasma and as a tool to characterize its properties. In recent years the existence of excess photon radiation in heavy ion collisions over the expectation from initial hard interactions has been confirmed at both RHIC and LHC energies by PHENIX and ALICE respectively. There the radiation has been found to exhibit elliptic flow v2 well above what can currently be reconciled with a picture of early emission from a plasma phase. During the 2007 and 2010 Au + Au runs PHENIX has measured a high purity sample of soft photons down to pT > 0.4 GeV / c using an external conversion method. We present recent systematic studies by PHENIX from that sample on the centrality dependence of the soft photon yield, and elliptic and triangular flow v2 and v3 in Au + Au collisions which fill in the experimental picture and enable discrimination of competing soft photon production scenarios.

  15. Evaluation of photon production data from neutron-induced reactions

    SciTech Connect

    Fu, C.Y.

    1980-01-01

    The evaluation methods and procedures used for generating the photon production data in the current Evaluated Nuclear Data File (ENDF/B, Version V) are reviewed. There are 42 materials in the General Purpose File of ENDF/B-V that contain data for prompt photon production. Almost all evaluations had substantial experimental data bases, but fewer than half of them employed any of the following evaluation methods. Only a few used theoretical techniques that are sophisticated enough to ensure internal consistency with other particle production data. Comments are made on four evaluation methods: the empirical formalism of Howerton et al., the Troubetzkoy model, the multiparticle Hauser-Feshbach/precompound model, and the Yost method. Critiques are also made on three procedures used for conserving photon energies in neutron capture reactions. The presence of photon production data in the file is useful for studying energy balance, since photon production generally accounts for a large portion of the reaction energy output. Problems found in energy balance checks are discussed. 9 figures, 1 table.

  16. A hard x-ray scanning microprobe for fluorescence imaging and microdiffraction at the advanced photon source

    NASA Astrophysics Data System (ADS)

    Cai, Z.; Lai, B.; Yun, W.; Ilinski, P.; Legnini, D.; Maser, J.; Rodrigues, W.

    2000-05-01

    A hard x-ray scanning microprobe based on zone plate optics and undulator radiation, in the energy region from 6 to 20 keV, has reached a focal spot size (FWHM) of 0.15 μm(v)×0.6 μm(h), and a photon flux of 4×109photons/sec/0.01%BW. Using a slit 44 meters upstream to create a virtual source, a circular beam spot of 0.15 μm in diameter can be obtained with a photon flux of one order of magnitude less. During fluorescence mapping of trace elements in a single human ovarian cell, the microprobe exhibited an imaging sensitivity for Pt (Lα line) of 80 attograms/μm2 for a count rate of 10 counts per second. The x-ray microprobe has been used to map crystallographic strain and multiquantum well thickness in micro-optoelectronic devices produced with the selective area growth technique.

  17. A hard x-ray scanning microprobe for fluorescence imaging and microdiffraction at the Advanced Photon Source

    SciTech Connect

    Cai, L.; Lai, B.; Yun, W.; Ilinski, P.; Legnini, D.; Maser, J.; Rodrigues, W.

    1999-11-02

    A hard x-ray scanning microprobe based on zone plate optics and undulator radiation, in the energy region from 6 to 20 keV, has reached a focal spot size (FWHM) of 0.15 {micro}m (v) x 0.6 {micro}m (h), and a photon flux of 4 x 10{sup 9} photons/sec/0.01%BW. Using a slit 44 meters upstream to create a virtual source, a circular beam spot of 0.15 {micro}m in diameter can be obtained with a photon flux of one order of magnitude less. During fluorescence mapping of trace elements in a single human ovarian cell, the microprobe exhibited an imaging sensitivity for Pt (L{sub a} line) of 80 attograms/{micro}m{sup 2} for a count rate of 10 counts per second. The x-ray microprobe has been used to map crystallographic strain and multiquantum well thickness in micro-optoelectronic devices produced with the selective area growth technique.

  18. The production of a diphoton resonance via photon-photon fusion

    NASA Astrophysics Data System (ADS)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.

    2016-03-01

    Motivated by the recent LHC observation of an excess of diphoton events around an invariant mass of 750 GeV, we discuss the possibility that this is due to the decay of a new scalar or pseudoscalar resonance dominantly produced via photon-photon fusion. We present a precise calculation of the corresponding photon-photon luminosity in the inclusive and exclusive scenarios, and demonstrate that the theoretical uncertainties associated with these are small. In the inclusive channel, we show how simple cuts on the final state may help to isolate the photon-photon induced cross section from any gluon-gluon or vector boson fusion induced contribution. In the exclusive case, that is where both protons remain intact after the collision, we present a precise cross section evaluation and show how this mode is sensitive to the parity of the object, as well as potential CP-violating effects. We also comment on the case of heavy-ion collisions and consider the production of new heavy colourless fermions, which may couple to such a resonance.

  19. Direct Photon Production and Gluon Polarization Measurements in Proton-Proton Collisions at PHENIX

    NASA Astrophysics Data System (ADS)

    Feege, Nils; Phenix Collaboration

    2015-10-01

    Direct photons probe the hard scattering process in proton-proton collisions. The channel that dominates their production in these collisions is ``the inverse QCD Compton effect,'' g + q --> γ + q . Calculating this process requires no photon fragmentation function, which facilitates comparisons between theories and experiments. In polarized p+p collisions, direct photons help determine the proton spin structure. At leading order, the longitudinal double-spin asymmetry ALL is directly proportional to the product of quark and gluon polarizations. The polarized quark distributions are known from polarized lepton-proton scattering experiments. Using them together with ALL measurements allows to access both the magnitude and sign of the polarized gluon distribution. The PHENIX experiment has collected data from polarized p+p collisions at RHIC at center of mass energies of 200 GeV and 500 GeV. This talk presents the status of direct photon cross section measurements and ALL measurements at midrapidity (| η | < 0 . 35) using these data.

  20. Design of Si-photonic structures to evaluate their radiation hardness dependence on design parameters

    NASA Astrophysics Data System (ADS)

    Zeiler, M.; Detraz, S.; Olantera, L.; Pezzullo, G.; Seif El Nasr-Storey, S.; Sigaud, C.; Soos, C.; Troska, J.; Vasey, F.

    2016-01-01

    Particle detectors for future experiments at the HL-LHC will require new optical data transmitters that can provide high data rates and be resistant against high levels of radiation. Furthermore, new design paths for future optical readout systems for HL-LHC could be opened if there was a possibility to integrate the optical components with their driving electronics and possibly also the silicon particle sensors themselves. All these functionalities could potentially be combined in the silicon photonics technology which currently receives a lot of attention for conventional optical link systems. Silicon photonic test chips were designed in order to assess the suitability of this technology for deployment in high-energy physics experiments. The chips contain custom-designed Mach-Zehnder modulators, pre-designed ``building-block'' modulators, photodiodes and various other passive test structures. The simulation and design flow of the custom designed Mach-Zehnder modulators and some first measurement results of the chips are presented.

  1. Photon and hadron production of heavy flavors

    SciTech Connect

    DeJongh, F.

    1993-11-01

    Recent experiments have obtained large clean samples of charmed and bottom hadrons, and have measured both single-quark inclusive cross-sections and quark-antiquark correlations. Predictions for these production properties are available from next-to-leading order QCD. We review recent results from fixed target hadroproduction of charm and bottom, fixed target photoproduction of charm, and production of bottom at proton-antiproton colliders.

  2. A bi-prism interferometer for hard x-ray photons

    SciTech Connect

    Isakovic, A.F.; Siddons, D.; Stein, A.; Warren, J.B.; Sandy, A.R.; Narayanan, M.S.; Ablett, J.M.; Metzler, M. and Evans-Lutterodt, K.

    2010-04-06

    Micro-fabricated bi-prisms have been used to create an interference pattern from an incident hard X-ray beam, and the intensity of the pattern probed with fluorescence from a 30 nm-thick metal film. Maximum fringe visibility exceeded 0.9 owing to the nano-sized probe and the choice of single-crystal prism material. A full near-field analysis is necessary to describe the fringe field intensities, and the transverse coherence lengths were extracted at APS beamline 8-ID-I. It is also shown that the maximum number of fringes is dependent only on the complex refractive index of the prism material.

  3. Method for Developing Descriptions of Hard-to-Price Products: Results of the Telecommunications Product Study

    SciTech Connect

    Conrad, F.; Tonn, B.

    1999-05-01

    This report presents the results of a study to test a new method for developing descriptions of hard-to-price products. The Bureau of Labor Statistics (BLS) is responsible for collecting data to estimate price indices such as the Consumers Price Index (BLS) is responsible for collecting data to estimate price indices such as the Consumers Price Index (CPI). BLS accomplishes this task by sending field staff to places of business to price actual products. The field staff are given product checklists to help them determine whether products found today are comparable to products priced the previous month. Prices for non-comparable products are not included in the current month's price index calculations. A serious problem facing BLS is developing product checklists for dynamic product areas, new industries, and the service sector. It is difficult to keep checklists up-to-date and quite often simply to develop checklists for service industry products. Some people estimates that upwards of 50 % of US economic activity is not accounted for in the CPI

  4. Multimodal hard x-ray nanoprobe facility by nested Montel mirrors aimed for 40nm resolution at Taiwan Photon Source

    NASA Astrophysics Data System (ADS)

    Yin, Gung-Chian; Chang, Shi-Hung; Chen, Bo-Yi; Chen, Huang-Yeh; Lin, Bi-Hsuan; Tseng, Shao-Chin; Lee, Chian-Yao; Wu, Shao-Yun; Tang, Mau-Tsu

    2016-01-01

    The hard X-ray nanoprobe facility at Taiwan Photon Source (TPS) provides multimodal X-ray detections, including XRF, XAS, XEOL, projection microscope, CDI, etc. Resulting from the large numerical aperture obtained by utilizing nested Montel mirrors, the beamline with a moderate length 75 meters can conduct similar performance with those beamlines longer than 100 meters. The mirrors are symmetrically placed with a 45 degrees cut. The beamline optics is thus designed to take the advantage of the symmetry of mirrors such that a round focal spot is accomplished. The size and the divergence of the focus spot are simulated around 40 nm and 6.29 mrad, respectively. The whole facility including the beamline and the stations will be operated under vacuum to preserve the photon coherence as well as to prevent the system from unnecessary environmental interference. A SEM in close cooperation with laser interferometers is equipped to precisely locate the position of the sample. This endstation is scheduled to be commissioned in the fall of 2016.

  5. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    SciTech Connect

    Jungmann-Smith, J. H. Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.; Cartier, S.; Medjoubi, K.

    2015-12-15

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10{sup 4} photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm{sup 2} pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm{sup 2}. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  6. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    NASA Astrophysics Data System (ADS)

    Jungmann-Smith, J. H.; Bergamaschi, A.; Brückner, M.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Medjoubi, K.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G.

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 104 photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm2 pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm2. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  7. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science.

    PubMed

    Jungmann-Smith, J H; Bergamaschi, A; Brückner, M; Cartier, S; Dinapoli, R; Greiffenberg, D; Jaggi, A; Maliakal, D; Mayilyan, D; Medjoubi, K; Mezza, D; Mozzanica, A; Ramilli, M; Ruder, Ch; Schädler, L; Schmitt, B; Shi, X; Tinti, G

    2015-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10(4) photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm(2) pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm(2). Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines. PMID:26724009

  8. Inclusive D*-meson production in two-photon collisions at LEP

    NASA Astrophysics Data System (ADS)

    Sokolov, A. A.

    2002-06-01

    The inclusive production of D*+ is measured by DELPHI in photon-photon collisions at LEP-II energies. The measured cross sections are compatible with the QCD calculations having the contributions from the resolved processes sensitive to the gluon density in photon. The total cross section of the charm quark production in two-photon collisions at LEP-II energies is estimated.

  9. Heavy Meson Production at a Low-Energy Photon Collider

    SciTech Connect

    Asztalos, S

    2004-04-15

    A low-energy {gamma}{gamma} collider has been discussed in the context of a testbed for a {gamma}{gamma} interaction region at the Next Linear Collider(NLC). We consider the production of heavy mesons at such a testbed using Compton-backscattered photons and demonstrate that their production rivals or exceeds those by BELLE, BABAR or LEP where they are produced indirectly via virtual {gamma}{gamma} luminosities.

  10. Study of χc2 production in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Bauer, D. A.; Belcinski, R.; Berg, R. C.; Bingham, H. H.; Buchanan, C. D.; Caldwell, D. O.; Chun, S.-B.; Clark, A. R.; Dahl, O. I.; Daoudi, M.; Eastman, J. J.; Eisner, A. M.; Fairfield, K. H.; Godfrey, G.; Greenbaum, G. S.; Hauptman, J. M.; Hofmann, W.; Holtzapple, R. L.; Khacheryan, S.; Knöpfle, K. T.; Kofler, R. R.; Lambert, D. J.; Layter, J. G.; Lin, W. T.; Loken, S. C.; Lu, A.; Lynch, G. R.; Lys, J. E.; Madaras, R. J.; Marsiske, H.; Masek, G. E.; Miller, E. S.; Nicol, N. A.; Nygren, D. R.; Oyang, Y.-T.; Paar, H. P.; Palounek, A. P. T.; Pellet, D. E.; Ronan, M. T.; Ross, R. R.; Shapiro, G.; Shen, B. C.; Stephens, R. W.; Stevenson, M. L.; Strauss, M. G.; Sullivan, M. K.; Vernon, W.; Wang, E. M.; Wang, Y. X.; Wenzel, W. A.; Yamamoto, H.; Yellin, S. J.; Yost, G. P.; Zapalac, G.; Zeitlin, C.

    1993-03-01

    Two-photon production of the charmonium state χc has been studied by the TPC/Two-Gamma experiment at the SLAC e+e- collider PEP. We observe evidence of the χc2 state in the channel γγ-->χc2, χc2-->γJ/ψ, J/ψ-->l+l- and obtain a value of Γγγ(χc2)=3.4+/-1.7+/-0.9 keV. This is the first observation of the two-photon production of a χc state. Comparison is made with previous experimental results and QCD predictions for Γγγ(χc2).

  11. Meson production in two-photon interactions at LHC energies

    SciTech Connect

    Da Silva, D. T.; Goncalves, V. P.; Sauter, W. K.

    2013-03-25

    The LHC opens a new kinematical regime at high energy, where several questions related to the description of the high-energy regime of the Quantum Chromodynamics (QCD) remain without satisfactory answers. Some open questions are the search for non-q-bar q resonances, the determination of the spectrum of q-bar q states and the identification of states with anomalous {gamma}{gamma} couplings. A possible way to study these problems is the study of meson production in two-photon interactions. In this contribution we calculate the meson production in two-photon interactions at LHC energies considering proton - proton collisions and estimate the total cross section for the production of the mesons {pi}, a, f, {eta} and {chi}.

  12. Production of four-prong final states in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Avery, R. E.; Barbaro-Galtieri, A.; Barker, A. R.; Barnes, A. V.; Barnett, B. A.; Bauer, D. A.; Bengtsson, H.-U.; Bintinger, D. L.; Bobbink, G. J.; Bolognese, T. S.; Bross, A. D.; Buchanan, C. D.; Buijs, A.; Caldwell, D. O.; Clark, A. R.; Cowan, G. D.; Crane, D. A.; Dahl, O. I.; Derby, K. A.; Eastman, J. J.; Eberhard, P. H.; Edberg, T. K.; Eisner, A. M.; Enomoto, R.; Erné, F. C.; Fujii, T.; Gary, J. W.; Gorn, W.; Hauptman, J. M.; Hofmann, W.; Huth, J. E.; Hylen, J.; Kamae, T.; Kaye, H. S.; Kees, K. H.; Kenney, R. W.; Kerth, L. T.; Ko, Winston; Koda, R. I.; Kofler, R. R.; Kwong, K. K.; Lander, R. L.; Langeveld, W. G.; Layter, J. G.; Linde, F. L.; Lindsey, C. S.; Loken, S. C.; Lu, A.; Lu, X.-Q.; Lynch, G. R.; Madaras, R. J.; Maeshima, K.; Magnuson, B. D.; Marx, J. N.; Masek, G. E.; Mathis, L. G.; Matthews, J. A.; Maxfield, S. J.; Melnikoff, S. O.; Miller, E. S.; Moses, W.; McNeil, R. R.; Nemethy, P.; Nygren, D. R.; Oddone, P. J.; Paar, H. P.; Park, D. A.; Park, S. K.; Pellett, D. E.; Pripstein, M.; Ronan, M. T.; Ross, R. R.; Rouse, F. R.; Schwitkis, K. A.; Sens, J. C.; Shapiro, G.; Shapiro, M. D.; Shen, B. C.; Slater, W. E.; Smith, J. R.; Steinman, J. S.; Stevenson, M. L.; Stork, D. H.; Strauss, M. G.; Sullivan, M. K.; Takahashi, T.; Thompson, J. R.; Toge, N.; Toutounchi, S.; van Tyen, R.; van Uitert, B.; Vandalen, G. J.; van Daalen Wetters, R. F.; Vernon, W.; Wagner, W.; Wang, E. M.; Wang, Y. X.; Wayne, M. R.; Wenzel, W. A.; White, J. T.; Williams, M. C.; Wolf, Z. R.; Wolf, Z. R.; Yamamoto, H.; Yellin, S. J.; Zeitlin, C.; Zhangj, W.-M.

    1988-01-01

    Results are presented on the exclusive production of four-prong final states in photon-photon collisions from the TPC/Two-Gamma detector at the SLAC e+e- storage ring PEP. Measurement of dE/dx and momentum in the time-projection chamber (TPC) provides identification of the final states 2π+2π-, K+K-π+π-, and 2K+2K-. For two quasireal incident photons, both the 2π+2π- and K+K-π+π- cross sections show a steep rise from threshold to a peak value, followed by a decrease at higher mass. Cross sections for the production of the final states ρ0ρ0, ρ0π+π-, and φπ+π- are presented, together with upper limits for φρ0, φφ, and K*0K¯ *0. The ρ0ρ0 contribution dominates the four-pion cross section at low masses, but falls to nearly zero above 2 GeV. Such behavior is inconsistent with expectations from vector dominance but can be accommodated by four-quark resonance models or by t-channel factorization. Angular distributions for the part of the data dominated by ρ0ρ0 final states are consistent with the production of JP=2+ or 0+ resonances but also with isotropic (nonresonant) production. When one of the virtual photons has mass (m2γ=-Q2≠0), the four-pion cross section is still dominated by ρ0ρ0 at low final-state masses Wγγ and by 2π+2π- at higher mass. Further, the dependence of the cross section on Q2 becomes increasingly flat as Wγγ increases.

  13. Virtual Young's Double Slit Experiment for Hard X-ray Photons

    NASA Astrophysics Data System (ADS)

    Isakovic, Abdel; Evans-Lutterodt, K.; Siddons, D. P.; Stein, A.; Warren, J. B.; Sandy, A.; Narayanan, S.; Metzler, M.

    2010-03-01

    Coherent hard X-ray beams underlie many of the recent advances in X-ray imaging and characterization, and it is crucial to quantify the coherence properties of X-ray beams for further advances. The classic Young's double slit experiment is an accepted method from which one can deduce the transverse coherence length, but unfortunately the double slit experiment is difficult to implement at these wavelengths. Micro-fabricated prisms are used to implement a virtual Young's double slit experiment, and interference fringes are quantified by X-ray fluorescence from a 30 nm Cr film in addition to being recorded with YAG crystal and CCD. The maximum number of fringes in the classical overlap region is comparable to δ/4πβ, the ratio of real to imaginary parts of the X-ray refractive index of the prism material. We have measured the horizontal and vertical transverse coherence lengths at beamline APS 8-ID. We suggest this to be a flexible, easily applied method that can be implemented at X-ray laboratories for both, coherence measurements and interferometric imaging. http://arxiv.org/abs/0910.5524

  14. Comparisons of exact results for the virtual photon contribution to single hard bremsstrahlung in radiative return for e{sup +}e{sup -} annihilation

    SciTech Connect

    Jadach, S.; Ward, B.F.L.; Yost, S.A.

    2006-04-01

    We compare fully differential exact results for the virtual photon correction to single hard photon bremsstrahlung obtained using independent calculations, both for e{sup +}e{sup -} annihilation at high-energy colliders and for radiative return applications. The results are compared using Monte Carlo evaluations of the matrix elements as well as by direct analytical evaluation of certain critical limits. Special attention is given to the issues of numerical stability and the treatment of finite-mass corrections. It is found that agreement on the order of 10{sup -5} or better is obtained over most of the range of hard photon energies, at CMS energies relevant to both high-energy collisions and radiative return experiments.

  15. Coherent Two Photon Production in Superconductor-Semiconductor Heterostructures

    NASA Astrophysics Data System (ADS)

    Baireuther, Paul; Vekhter, Ilya; Schmalian, Jörg

    2012-02-01

    Connecting a thin (direct band gap) p-n junction to a superconductor allows Cooper pairs to tunnel into the junction. This leads to an enhancement of the luminescence at the junction via Cooper pair based radiative recombination[1,2], an effect that has recently been observed experimentally[3]. Due to the proximity-induced Cooper pairs in the junction, anomalous photon production related to coherent two photon processes becomes allowed. Using a simple model for direct band gap luminescence we study a superconductor-p-n-superconductor heterostructure where the two photon state depends on the relative phase between the two superconductors. We investigate to what extend the production rate of entangled photons is controlled by the phase difference between the attached superconductors. [1] E. Hanamura, Phys. Stat. Sol. (b) 234, 166 (2002). [2] Y. Asano, I. Suemune, H. Takayanagi, and E. Hanamura, Phys. Rev. Lett. 103, 187001 (2009). [3] I. Suemune, T. Akazaki, K. Tanaka, M. Jo, K. Uesugi, M. Endo1, H. Kumano, E. Hanamura, H. Takayanagi, M. Yamanishi and H. Kan, Jpn. Journ. of Appl. Phys. 45, 9264 (2006).

  16. Recent developments in the theory of photon-photon collisions

    SciTech Connect

    Brodsky. S.J.

    1984-09-01

    Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references.

  17. Consistent simulation of direct-photon production in hadron collisions including associated two-jet production

    NASA Astrophysics Data System (ADS)

    Odaka, Shigeru; Kurihara, Yoshimasa

    2016-05-01

    We have developed an event generator for direct-photon production in hadron collisions, including associated 2-jet production in the framework of the GR@PPA event generator. The event generator consistently combines γ + 2-jet production processes with the lowest-order γ + jet and photon-radiation (fragmentation) processes from quantum chromodynamics (QCD) 2-jet production using a subtraction method. The generated events can be fed to general-purpose event generators to facilitate the addition of hadronization and decay simulations. Using the obtained event information, we can simulate photon isolation and hadron-jet reconstruction at the particle (hadron) level. The simulation reasonably reproduces measurement data obtained at the large hadron collider (LHC) concerning not only the inclusive photon spectrum, but also the correlation between the photon and jet. The simulation implies that the contribution of the γ + 2-jet is very large, especially in low photon-pT ( ≲ 50 GeV) regions. Discrepancies observed at low pT, although marginal, may indicate the necessity for the consideration of further higher-order processes. Unambiguous particle-level definition of the photon-isolation condition for the signal events is desired to be given explicitly in future measurements.

  18. Production of χc2 mesons in photon-photon collisions at LEP

    NASA Astrophysics Data System (ADS)

    OPAL Collaboration; Ackerstaff, K.; Alexander, G.; Allison, J.; Altekamp, N.; Anderson, K. J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S. F.; Axen, D.; Azuelos, G.; Ball, A. H.; Barberio, E.; Barillari, T.; Barlow, R. J.; Bartoldus, R.; Batley, J. R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S. D.; Blobel, V.; Bloodworth, I. J.; Bobinski, M.; Bock, P.; Böhme, J.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brown, R. M.; Burckhart, H. J.; Burgard, C.; Bürgin, R.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrisman, D.; Ciocca, C.; Clarke, P. E. L.; Clay, E.; Cohen, I.; Conboy, J. E.; Cooke, O. C.; Couyoumtzelis, C.; Coxe, R. L.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; Davis, R.; de Jong, S.; del Pozo, L. A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M. S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I. P.; Eatough, D.; Estabrooks, P. G.; Etzion, E.; Evans, H. G.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A. A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Fürtjes, A.; Futyan, D. I.; Gagnon, P.; Gary, J. W.; Gascon, J.; Gascon-Shotkin, S. M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W. R.; Gingrich, D. M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwé, M.; Hanson, G. G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C. K.; Hartmann, C.; Hauschild, M.; Hawkes, C. M.; Hawkings, R.; Hemingway, R. J.; Herndon, M.; Herten, G.; Heuer, R. D.; Hildreth, M. D.; Hill, J. C.; Hillier, S. J.; Hobson, P. R.; Hocker, A.; Homer, R. J.; Honma, A. K.; Horváth, D.; Hossain, K. R.; Howard, R.; Hüntemeyer, P.; Igo-Kemenes, P.; Imrie, D. C.; Ishii, K.; Jacob, F. R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C. R.; Jovanovic, P.; Junk, T. R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P. I.; Keeler, R. K.; Kellogg, R. G.; Kennedy, B. W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D. S.; Kokott, T. P.; Kolrep, M.; Komamiya, S.; Kowalewski, R. V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G. D.; Lanske, D.; Lauber, J.; Lautenschlager, S. R.; Lawson, I.; Layter, J. G.; Lazic, D.; Lee, A. M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A. W.; Lloyd, S. L.; Loebinger, F. K.; Long, G. D.; Losty, M. J.; Ludwig, J.; Liu, D.; Macchiolo, A.; MacPherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A. J.; Martin, J. P.; Martinez, G.; Mashimo, T.; Mättig, P.; McDonald, W. J.; McKenna, J.; McKigney, E. A.; McMahon, T. J.; McPherson, R. A.; Meijers, F.; Menke, S.; Merritt, F. S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D. J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H. A.; Nellen, B.; Nisius, R.; O'Neale, S. W.; Oakham, F. G.; Odorici, F.; Ogren, H. O.; Oreglia, M. J.; Orito, S.; Pálinkás, J.; Pásztor, G.; Pater, J. R.; Patrick, G. N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J. E.; Pinfold, J.; Plane, D. E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycień , M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S. A.; Rodning, N.; Roney, J. M.; Roscoe, K.; Rossi, A. M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D. R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W. M.; Sarkisyan, E. K. G.; Sbarra, C.; Schaile, A. D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schöning, A.; Schröder, M.; Schumacher, M.; Schwick, C.; Scott, W. G.; Seuster, R.; Shears, T. G.; Shen, B. C.; Shepherd-Themistocleous, C. H.; Sherwood, P.; Siroli, G. P.; Sittler, A.; Skuja, A.; Smith, A. M.; Snow, G. A.; Sobie, R.; Söldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, D.; Ströhmer, R.; Surrow, B.; Talbot, S. D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M. A.; von Törne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trócsányi, Z.; Tsur, E.; Turcot, A. S.; Turner-Watson, M. F.; van Kooten, R.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wäckerle, F.; Wagner, A.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Wells, P. S.; Wermes, N.; White, J. S.; Wilson, G. W.; Wilson, J. A.; Wyatt, T. R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1998-10-01

    We present an observation at LEP of the production of χc2 mesons in the collisions of two quasi-real photons using the OPAL detector. The χc2 mesons are reconstructed in the decay channel χc2-->J/ψ γ-->l+ l- γ (with l = e,μ) using all data taken at e+e- centre-of-mass energies of 91 and 183 GeV, corresponding to integrated luminosities of 167 and 55 pb-1 respectively. The two-photon width of the χc2 is determined to be Γ(χc2-->γγ)=1.76+/-0.47+/- 0.37+/-0.15 keV, where the first error is statistical, the second is systematic and the third comes from branching ratio uncertainties.

  19. Born-approximation and radiative corrections to pair production in photon-photon collisions

    NASA Technical Reports Server (NTRS)

    Gould, Robert J.

    1989-01-01

    Aspects of pair production in photon-photon collisions, which can be of great importance in a variety of astrophysical settings, are examined. In particular, the correction associated with the use of Coulomb rather than plane-wave functions to describe the outgoing e(+) e(-) is evaluated. This is important only in the energy domain near threshold where e(+) e(-) are nonrelativistic, and the effect is evaluated. Because of the extreme simplicity of the nonrelativistic Born limit, the corresponding derivation is briefly outlined using noncovariant perturbation theory. The relative magnitude of the Born correction is comparable to radiative-correction effects. These effects can be evaluated easily in the nonrelativistic limit, and an approximate calculation is outlined.

  20. White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

    SciTech Connect

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  1. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    SciTech Connect

    Benson, C.; Jaski, Y.; Powers, T.; Schmidt, O.; Rossi, E.; Maser, J.

    2007-01-19

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  2. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  3. The Pair Beam Production Spectrum from Photon-Photon Annihilation in Cosmic Voids

    NASA Astrophysics Data System (ADS)

    Schlickeiser, R.; Elyiv, A.; Ibscher, D.; Miniati, F.

    2012-10-01

    Highly beamed relativistic e ±-pair energy distributions result in double photon collisions of the beamed gamma rays from TeV blazars at cosmological distances with the isotropically distributed extragalactic background light (EBL) in the intergalactic medium. The typical energies k 0 ~= 10-7 in units of mec 2 of the EBL are more than 10 orders of magnitude smaller than the observed gamma-ray energies k 1 >= 107. Using the limit k 0 Lt k 1, we demonstrate that the angular distribution of the generated pairs in the lab frame is highly beamed in the direction of the initial gamma-ray photons. For the astrophysically important case of power-law distributions of the emitted gamma-ray beam up to the maximum energy M interacting with Wien-type N(k 0)vpropkq 0exp (- k 0/Θ) soft photon distributions with total number density N 0, we calculate analytical approximations for the electron production spectrum. For distant objects with luminosity distances dL Gt r 0 = (σ T N 0)-1 = 0.49N -1 0 Mpc (with Thomson cross section σ T ), the implied large values of the optical depth τ0 = dL /r 0 indicate that the electron production spectra differ at energies inside and outside the interval [(Θln τ0)-1, τ0/Θ], given the maximum gamma-ray energy M Gt Θ-1. In the case M Gt Θ-1, the production spectrum is strongly peaked near E ~= Θ-1, being exponentially reduced at small energies and decreasing with the steep power law vpropE -1 - p up to the maximum energy E = M - (1/2).

  4. Electroweak radiative corrections to triple photon production at the ILC

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Li, Wei-Hua; Duan, Peng-Fei; Song, Mao; Li, Gang

    2016-07-01

    In this paper, we present the precision predictions for three photon production in the standard model (SM) at the ILC including the full next-to-leading (NLO) electroweak (EW) corrections, high order initial state radiation (h.o.ISR) contributions and beamstrahlung effects. We present the LO and the NLO EW + h.o.ISR + beamstrahlung corrected total cross sections for various colliding energy when √{ s} ≥ 200 GeV and the kinematic distributions of final photons with √{ s} = 500 GeV at ILC, and find that the NLO EW corrections, the h.o.ISR contributions and the beamstrahlung effects are important in exploring the process e+e- → γγγ.

  5. Neutral Higgs boson pair production in photon-photon annihilation in the two Higgs doublet model

    SciTech Connect

    Arhrib, Abdesslam; Benbrik, Rachid; Chen, C.-H.; Santos, Rui

    2009-07-01

    We study double Higgs production in photon-photon collisions as a probe of the new dynamics of Higgs interactions in the framework of two Higgs doublet models. We analyze neutral Higgs bosons production and decay in the fusion processes, {gamma}{gamma}{yields}S{sub i}S{sub j}, S{sub i}=h{sup 0}, H{sup 0}, A{sup 0}, and show that both h{sup 0}h{sup 0} and A{sup 0}A{sup 0} production can be enhanced by threshold effects in the region E{sub {gamma}}{sub {gamma}}{approx_equal}2m{sub H{+-}}. Resonant effects due to the heavy Higgs H{sup 0} can also play a role in the cross section enhancement when it is allowed to decay to two light CP-even h{sup 0} or to two light CP-odd A{sup 0} scalars. We have scanned the allowed parameter space of the two Higgs doublet model and found a vast region of the parameter space where the cross section is 2 orders of magnitude above the standard model cross section. We further show that the standard model experimental analysis can be used to discover or to constrain the two Higgs doublet model parameter space.

  6. Heavy quark production in photon-Pomeron interactions at high energies

    SciTech Connect

    Machado, M. M.; Goncalves, V. P.

    2013-03-25

    The diffractive heavy quark cross sections are estimated considering photon-Pomeron interactions in hadron - hadron at RHIC, Tevatron, and CERN LHC energies. We assume the validity of the hard diffractive factorization and calculate the charm and bottom total cross sections and rapidity distributions using the diffractive parton distribution functions of the Pomeron obtained by the H1 Collaboration at DESY-HERA. Such processes are sensitive to the gluon content of the Pomeron at high energies and are a good place to constrain the behavior of this distribution. We also compare our predictions with those obtained using the dipole model, and verify that these processes are a good test of the different mechanisms for heavy quarks diffractive production at hadron colliders.

  7. Ionizing Photon Production and Escape in Extreme Starbursts: the Case of the Green Peas

    NASA Astrophysics Data System (ADS)

    Jaskot, Anne; Oey, Sally

    2015-08-01

    With similarities to high-redshift galaxies and potential Lyman continuum (LyC) escape, the low-redshift "Green Pea" (GP) galaxies represent an important test of ionizing photon production and feedback in young massive clusters. Using optical spectra and HST ACS emission-line imaging, we evaluate the ionizing sources, optical depths, and spatial variation of ionization in these unusual starbursts. The GPs’ spectra imply young starburst ages and possible low LyC optical depths. However, CLOUDY photoionization and Starburst99 models have difficulty reproducing all of the observed line ratios and suggest a need for additional hard ionizing sources. New ACS observations of four GPs highlight the extreme, compact nature of these bursts and reveal regions of low optical depth that are the likely sites of LyC escape.

  8. Delta-Isobar Production in the Hard Photodisintegration of a Deuteron

    NASA Astrophysics Data System (ADS)

    Granados, Carlos; Sargsian, Misak

    2010-02-01

    Hard photodisintegration of the deuteron in delta-isobar production channels is proposed as a useful process in identifying the quark structure of hadrons and of hadronic interactions at large momentum and energy transfer. The reactions are modeled using the hard re scattering model, HRM, following previous works on hard breakup of a nucleon nucleon (NN) system in light nuclei. Here,quantitative predictions through the HRM require the numerical input of fits of experimental NN hard elastic scattering cross sections. Because of the lack of data in hard NN scattering into δ-isobar channels, the cross section of the corresponding photodisintegration processes cannot be predicted in the same way. Instead, the corresponding NN scattering process is modeled through the quark interchange mechanism, QIM, leaving an unknown normalization parameter. The observables of interest are ratios of differential cross sections of δ-isobar production channels to NN breakup in deuteron photodisintegration. Both entries in these ratios are derived through the HRM and QIM so that normalization parameters cancel out and numerical predictions can be obtained. )

  9. Measurement of the inclusive isolated prompt photon production cross section at the Tevatron using the CDF detector

    SciTech Connect

    Deluca Silberberg, Carolina

    2009-04-01

    require a good understanding of the background, mainly dominated by light mesons (π0 and η) which decay into two very collinear photons. Since these photons are produced within a jet, they tend to be non-isolated in most of the cases, and can be suppressed by requiring the photon candidates to be isolated in the calorimeter. In the case the hard scattered parton hadronizes leaving most of its energy to the meson, the photon produced in the decay will not be surrounded by large energy depositions. To further reduce this remaining isolated background, we present a new technique based on the isolation distribution in the calorimeter. The measured cross section is compared to next-to-leading order (NLO) pQCD calculations, which have been corrected for non-perturbative contributions. This thesis is organized as follows: we start with a brief review of QCD theory and the formalism to calculate cross sections in Chapter 2, where we also introduce the physics of prompt photon production and summarize the current status of the prompt photon phenomenology. Chapter 3 contains a description of the Tevatron and the CDF detector. The experimental measurement is described in Chapter 4, where we provide details on the different datasets used in the measurement, the trigger, and the event selection requirements. Most of this Chapter is devoted to the explanation of the background subtraction method and the determination of the photon signal fraction. The systematic uncertainties on the measurement are evaluated in Chapter 5, while Chapter 6 discusses the final results and the comparison to the theoretical predictions. Finally, the conclusions are presented in Chapter 7.

  10. The Comprehension and Production of Wh-Questions in Deaf and Hard-of-Hearing Children

    ERIC Educational Resources Information Center

    Friedmann, Naama; Szterman, Ronit

    2011-01-01

    Hearing loss during the critical period for language acquisition restricts spoken language input. This input limitation, in turn, may hamper syntactic development. This study examined the comprehension, production, and repetition of Wh-questions in deaf or hard-of-hearing (DHH) children. The participants were 11 orally trained Hebrew-speaking…

  11. Process for casting hard-faced, lightweight camshafts and other cylindrical products

    DOEpatents

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.; Wilson, Rick D.

    1996-01-01

    A process for casting a hard-faced cylindrical product such as an automobile camshaft includes the steps of: (a) preparing a composition formed from a molten base metal and an additive in particle form and having a hardness value greater than the hardness value of the base metal; (b) introducing the composition into a flask containing a meltable pattern of a cylindrical product such as an automobile camshaft to be manufactured and encased in sand to allow the composition to melt the pattern and assume the shape of the pattern within the sand; and (c) rotating the flask containing the pattern about the longitudinal axes of both the flask and the pattern as the molten base metal containing the additive in particle form is introduced into the flask to cause particles of the additive entrained in the molten base metal to migrate by centrifugal action to the radial extremities of the pattern and thereby provide a cylindrical product having a hardness value greater at it's radial extremities than at its center when the molten base metal solidifies.

  12. THE PAIR BEAM PRODUCTION SPECTRUM FROM PHOTON-PHOTON ANNIHILATION IN COSMIC VOIDS

    SciTech Connect

    Schlickeiser, R.; Ibscher, D.; Elyiv, A.; Miniati, F. E-mail: ibscher@tp4.rub.de E-mail: fm@phys.ethz.ch

    2012-10-20

    Highly beamed relativistic e {sup {+-}}-pair energy distributions result in double photon collisions of the beamed gamma rays from TeV blazars at cosmological distances with the isotropically distributed extragalactic background light (EBL) in the intergalactic medium. The typical energies k {sub 0} {approx_equal} 10{sup -7} in units of m{sub e}c {sup 2} of the EBL are more than 10 orders of magnitude smaller than the observed gamma-ray energies k {sub 1} {>=} 10{sup 7}. Using the limit k {sub 0} << k {sub 1}, we demonstrate that the angular distribution of the generated pairs in the lab frame is highly beamed in the direction of the initial gamma-ray photons. For the astrophysically important case of power-law distributions of the emitted gamma-ray beam up to the maximum energy M interacting with Wien-type N(k {sub 0}){proportional_to}k{sup q} {sub 0}exp (- k {sub 0}/{Theta}) soft photon distributions with total number density N {sub 0}, we calculate analytical approximations for the electron production spectrum. For distant objects with luminosity distances d{sub L} >> r {sub 0} = ({sigma} {sub T} N {sub 0}){sup -1} = 0.49N {sup -1} {sub 0} Mpc (with Thomson cross section {sigma} {sub T}), the implied large values of the optical depth {tau}{sub 0} = d{sub L} /r {sub 0} indicate that the electron production spectra differ at energies inside and outside the interval [({Theta}ln {tau}{sub 0}){sup -1}, {tau}{sub 0}/{Theta}], given the maximum gamma-ray energy M >> {Theta}{sup -1}. In the case M >> {Theta}{sup -1}, the production spectrum is strongly peaked near E {approx_equal} {Theta}{sup -1}, being exponentially reduced at small energies and decreasing with the steep power law {proportional_to}E {sup -1-p} up to the maximum energy E = M - (1/2).

  13. Chemical Characterization of Beer Aging Products Derived from Hard Resin Components in Hops (Humulus lupulus L.).

    PubMed

    Taniguchi, Yoshimasa; Yamada, Makiko; Taniguchi, Harumi; Matsukura, Yasuko; Shindo, Kazutoshi

    2015-11-25

    The bitter taste of beer originates from resins in hops (Humulus lupulus L.), which are classified into two subtypes (soft and hard). Whereas the nature and reactivity of soft-resin-derived compounds, such as α-, β-, and iso-α-acids, are well studied, there is only a little information on the compounds in hard resin. For this work, hard resin was prepared from stored hops and investigated for its compositional changes in an experimental model of beer aging. The hard resin contained a series of α-acid oxides. Among them, 4'-hydroxyallohumulinones were unstable under beer storage conditions, and their transformation induced primary compositional changes of the hard resin during beer aging. The chemical structures of the products, including novel polycyclic compounds scorpiohumulinols A and B and dicyclohumulinols A and B, were determined by HRMS and NMR analyses. These compounds were proposed to be produced via proton-catalyzed cyclization reactions of 4'-hydroxyallohumulinones. Furthermore, they were more stable than their precursor 4'-hydroxyallohumulinones during prolonged storage periods. PMID:26507444

  14. Analytical Expressions for the Hard-Scattering Production of Massive Partons

    SciTech Connect

    Wong, Cheuk-Yin

    2016-01-01

    We obtain explicit expressions for the two-particle differential cross section $E_c E_\\kappa d\\sigma (AB \\to c\\kappa X) /d\\bb c d \\bb \\kappa$ and the two-particle angular correlation function \\break $d\\sigma(AB$$ \\to$$ c\\kappa X)/d\\Delta \\phi \\, d\\Delta y$ in the hard-scattering production of massive partons in order to exhibit the ``ridge" structure on the away side in the hard-scattering process. The single-particle production cross section $d\\sigma(AB \\to cX) /dy_c c_T dc_T $ is also obtained and compared with the ALICE experimental data for charm production in $pp$ collisions at 7 TeV at LHC.

  15. Hard x-ray production from high intensity laser solid interactions

    SciTech Connect

    Sefcik, J. A., LLNL

    1998-06-03

    Intense laser (> 10{sup 21} W/cm{sup 2}) driven hard x-ray sources offer a new alternative to conventional electron accelerator bremsstrahlung sources. These laser driven sources offer considerable simplicity in design and cost advantage for multiple axis views and have the potential for much higher spatial and temporal resolution than is achievable with accelerator sources We have begun a series of experiments using the Petawatt Laser system at LLNL to determine the potential of these sources for radiography applications Absolutely calibrated spectra extending to 20 MeV and high resolution radiographs through a {rho}r{>=}150 gm/cm{sup 2} have been obtained The physics of these sources and the scaling relationships and laser technology required to provide the dose levels necessary for radiography applications will be discussed Diagnostics of the laser produced electrons and photons will be addressed

  16. Soft X-ray production by photon scattering in pulsating binary neutron star sources

    NASA Technical Reports Server (NTRS)

    Bussard, R. W.; Meszaros, P.; Alexander, S.

    1985-01-01

    A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

  17. Exclusive production of pp¯π+π- in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Avery, R.E.; Barbaro-Galtieri, A.; Barker, A.R.; Barnett, B.A.; Bauer, D.A.; Bay, A.; Bobbink, G.J.; Buchanan, C.D.; Buijs, A.; Caldwell, D.O.; Chao, H.-Y.; Chun, S.-B.; Clark, A.R.; Cowan, G.D.; Crane, D.A.; Dahl, O.I.; Daoudi, M.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Edberg, T.K.; Eisner, A.M.; Erne, F.C.; Fairfield, K.H.; Hauptman, J.M.; Hofmann, W.; Hylen, J.; Kamae, T.; Kaye, H.S.; Kenney, R.W.; Khacheryan, S.; Kofler, R.R.; Langeveld, W.G.J.; Layter, J.G.; Lin, W.T.; Linde, F.L.; Loken, S.C.; Lynch, G.R.; Madaras, R.J.; Magnuson, B.D.; Masek, G.E.; Mathis, L.G.; Matthews, J.A.J.; Maxfield, S.J.; Miller, E.S.; Moses, W.; Nygren, D.R.; Oddone, P.J.; Paar, H.P.; Park, S.K.; Pellett, D.E.; Pripstein, M.; Ronan, M.T.; Ross, R.R.; Rouse, F.R.; Schwitkis, K.A.; Sens, J.C.; Shapiro, G.; Shen, B.C.; Smith, J.R.; Steinmen, J.S.; Stephens, R.W.; Stevenson, M.L.; Stork, D.H.; Strauss, M.G.; Sullivan, M.K.; Takahashi, T.; Toutouchi, S.; van Tyen, R.; Vernon, W.; Wagner, W.; Wang, E.M.; Wang, Y.-X.; Wenzel, W.A.; Wolf, Z.R.; Yamamoto, H.; Yellin, S.J.; Zeitlin, C.

    1989-11-01

    We report a measurement of the e+e--->e+e-pp¯π+π- process with the TPC/Two-Gamma facility at the PEP e+e- storage ring at SLAC. Forty-five pp¯π+π- events were identified in data corresponding to an integrated e+e- luminosity of 142 pb-1. The cross section for γγ-->pp¯π+π- is given both as a function of the γγ center-of-mass energy Wγγ, with Wγγ between 2.5 and 5.5 GeV, and as a function of the invariant mass squared q2 of one of the photons, with -q2<7 GeV2. This cross section falls much less rapidly with Wγγ than does the cross section for a similar process, γγ-->pp¯. No Δ0Δ¯ 0 production is observed, and only a small fraction of the events at low Wγγ is consistent with γγ-->Δ++Δ¯ --, Δ++p¯π-, or Δ¯ --π+. In an expanded search through the same data, four events compatible with either ΛΛ¯ (Λ-->pπ-) or Σ0Λ¯ (Σ0-->Λγ) production were found.

  18. Direct photon production in high-energy nuclear collisions

    NASA Astrophysics Data System (ADS)

    Peitzmann, T.

    2016-01-01

    Direct photons have always been considered a promising probe for the very early phases of high-energy nuclear collisions. Prompt photons reveal information about the initial state and its possible modifications in nuclei. In this context they should be one of the best probes for effects of gluon saturation. Thermal photons emitted from the produced matter in nuclear collisions carry information on the temperature of the very early phase. In particular a simultaneous measurement of yield and elliptic flow of thermal photons can put strong constraints on the early time dynamics of the system. I review the status of results on direct photon measurements at RHIC and LHC and their interpretation. Prompt photons at high pT are consistent with expectations from NLO pQCD in pp and show no strong nuclear modifications in A-A collisions. Recent analysis at RHIC has shown very intriguing results for lower pT, with high thermal photon yield and strong elliptic flow of direct photons, which are not fully understood theoretically. Also the ALICE experiment at the LHC has measured a high yield of thermal photons. Furthermore I discuss prospects for future measurements of forward direct photons at the LHC.

  19. Growth and Saxitoxin Production by Cylindrospermopsis raciborskii (Cyanobacteria) Correlate with Water Hardness

    PubMed Central

    Carneiro, Ronaldo Leal; Pacheco, Ana Beatriz Furlanetto; Azevedo, Sandra Maria Feliciano de Oliveira e

    2013-01-01

    The cosmopolitan and increasing distribution of Cylindrospermopsis raciborskii can be attributed to its ecophysiological plasticity and tolerance to changing environmental factors in water bodies. In reservoirs in the semi-arid region of Brazil, the presence and common dominance of C. raciborskii have been described in waters that are considered hard. We investigated the response of a Brazilian C. raciborskii strain to water hardness by evaluating its growth and saxitoxin production. Based on environmental data, a concentration of 5 mM of different carbonate salts was tested. These conditions affected growth either positively (MgCO3) or negatively (CaCO3 and Na2CO3). As a control for the addition of cations, MgCl2, CaCl2 and NaCl were tested at 5 or 10 mM, and MgCl2 stimulated growth, NaCl slowed but sustained growth, and CaCl2 inhibited growth. Most of the tested treatments increased the saxitoxin (STX) cell quota after six days of exposure. After 12 days, STX production returned to concentrations similar to that of the control, indicating an adaptation to the altered water conditions. In the short term, cell exposure to most of the tested conditions favored STX production over neoSTX production. These results support the noted plasticity of C. raciborskii and highlight its potential to thrive in hard waters. Additionally, the observed relationship between saxitoxin production and water ion concentrations characteristic of the natural environments can be important for understanding toxin content variation in other harmful algae that produce STX. PMID:23955286

  20. A hard x-ray prototype production exposure station at NSLS

    SciTech Connect

    Johnson, E.D.; Milne, J.C.

    1997-07-01

    Exposures conducted at the NSLS R and D beamline (X-27B) for High Aspect Ratio Precision Manufacture have proven sufficiently successful that the authors are constructing a dedicated hard x-ray exposure beamline. The new beamline (X-14B) provides an exposure field {approximately} 120 mm wide, three times larger than that of X-27B. The scanner is based on the hydraulic system from the X-27B program. It is optimized for planar exposures and takes advantage of the full 525 mm stroke available. Exposures of multiple substrates and masks will be possible, with the fixturing supporting mounting of substrate holders from other groups (ALS, APS, CAMD, and UW). The function of this beamline is to establish a hard x-ray exposure station where manufacturing scale protocols can be developed and ultimately exploited for production runs.

  1. Production of photons in relativistic heavy-ion collisions

    DOE PAGESBeta

    Jean -Francois Paquet; Denicol, Gabriel S.; Shen, Chun; Luzum, Matthew; Schenke, Bjorn; Jeon, Sangyong; Gale, Charles

    2016-04-18

    In this work it is shown that the use of a hydrodynamical model of heavy-ion collisions which incorporates recent developments, together with updated photon emission rates, greatly improves agreement with both ALICE and PHENIX measurements of direct photons, supporting the idea that thermal photons are the dominant source of direct photon momentum anisotropy. The event-by-event hydrodynamical model uses the impact parameter dependent Glasma model (IP-Glasma) initial states and includes, for the first time, both shear and bulk viscosities, along with second-order couplings between the two viscosities. Furthermore, the effect of both shear and bulk viscosities on the photon rates ismore » studied, and those transport coefficients are shown to have measurable consequences on the photon momentum anisotropy.« less

  2. Production of photons in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Paquet, Jean-François; Shen, Chun; Denicol, Gabriel S.; Luzum, Matthew; Schenke, Björn; Jeon, Sangyong; Gale, Charles

    2016-04-01

    In this work it is shown that the use of a hydrodynamical model of heavy-ion collisions which incorporates recent developments, together with updated photon emission rates, greatly improves agreement with both ALICE and PHENIX measurements of direct photons, supporting the idea that thermal photons are the dominant source of direct photon momentum anisotropy. The event-by-event hydrodynamical model uses the impact parameter dependent Glasma model (IP-Glasma) initial states and includes, for the first time, both shear and bulk viscosities, along with second-order couplings between the two viscosities. The effect of both shear and bulk viscosities on the photon rates is studied, and those transport coefficients are shown to have measurable consequences on the photon momentum anisotropy.

  3. Speech Sound Production in Two-Year-Olds who are Hard of Hearing

    PubMed Central

    Ambrose, Sophie E.; Unflat Berry, Lauren M.; Walker, Elizabeth A.; Harrison, Melody; Oleson, Jacob; Moeller, Mary Pat

    2014-01-01

    Purpose The purpose of the study was to 1) compare the speech sound production abilities of 2-year-old children who are hard of hearing (HH) to children with normal hearing (NH), 2) identify sources of risk for individual children who are HH, and 3) determine whether speech sound production skills at age two were predictive of speech sound production skills at age three. Method Seventy children with bilateral, mild-to-severe hearing loss who use hearing aids and 37 age- and SES-matched children with NH participated. Children’s speech sound production abilities were assessed at 2 and 3 years of age. Results At age two, the HH group demonstrated vowel production abilities on par with their NH peers, but weaker consonant production abilities. Within the HH group, better outcomes were associated with hearing aid fittings by 6 months of age, hearing loss of less than 45 dB HL, stronger vocabulary scores, and being female. Positive relationships existed between children’s speech sound production abilities at 2 and 3 years of age. Conclusions Assessment of early speech sound production abilities in combination with demographic, audiologic, and linguistic variables may be useful in identifying HH children who are at risk of delays in speech sound production. PMID:24686852

  4. Photon production from gluon-mediated quark-anti-quark annihilation at confinement

    NASA Astrophysics Data System (ADS)

    Campbell, Sarah

    2015-07-01

    Heavy ion collisions at the BNL Relativistic Heavy Ion Collider produce direct photons at low transverse momentum pT from 1-3 GeV /c , in excess of the p +p spectra scaled by the nuclear overlap factor TA A. These low-pT photons have a large azimuthal anisotropy v2. Theoretical models, including hydrodynamic models, struggle to quantitatively reproduce the large low-pT direct photon excess and v2 in a self-consistent manner. This paper presents a description of the low-pT photon flow as the result of increased photon production from soft-gluon-mediated q -q ¯ interactions as the system becomes color neutral. This production mechanism will generate photons that follow constituent quark number, nq, scaling of v2 with an nq value of 2 for direct photons. χ2 comparisons of the published PHENIX direct photon and identified particle v2 measurements finds that nq scaling applied to the direct photon v2 data prefers the value nq=1.8 and agrees with nq=2 within errors in most cases. The 0-20% and 20-40% Au+Au direct photon data are compared to a coalescence-like Monte Carlo simulation that calculates the direct photon v2 while describing the shape of the direct photon pT spectra in a consistent manner. The simulation, while systematically low compared to the data, is in agreement with the Au+Au measurement at pT less than 3 GeV /c in both centrality bins. Furthermore, this production mechanism predicts that higher order flow harmonics vn in direct photons will follow the modified nq-scaling laws seen in identified hadron vn with an nq value of 2.

  5. Photon-tagged heavy meson production in high energy nuclear collisions

    SciTech Connect

    Kang, Z.B.; Vitev, I.

    2011-07-26

    We study the photon-triggered light and heavy meson production in both p+p and A+A collisions. We find that a parton energy loss approach that successfully describes inclusive hadron attenuation in nucleus-nucleus reactions at RHIC can simultaneously describe well the experimentally determined photon-triggered light hadron fragmentation functions. Using the same framework, we generalize our formalism to study photon-triggered heavy meson production. We find that the nuclear modification of photon-tagged heavy meson fragmentation functions in A+A collision is very different from that of the photon-tagged light hadron case. While photon-triggered light hadron fragmentation functions in A+A collisions are suppressed relative to p+p, photon-triggered heavy meson fragmentation functions can be either enhanced or suppressed, depending on the specific kinematic region. The anticipated smaller energy loss for b-quarks manifests itself as a flatter photon-triggered B-meson fragmentation function compared to that for the D-meson case. We make detailed predictions for both RHIC and LHC energies. We conclude that a comprehensive comparative study of both photon-tagged light and heavy meson production can provide new insights in the details of the jet quenching mechanism.

  6. Photon annd pion production in heavy ion collisions

    SciTech Connect

    Blann, M.

    1989-05-01

    In this paper we describe different formulations for treating the nucleon-nucleon transport physics. These will all be semi-classical treatments; however considerable work has been done considering the relationship between quantal and semi-classical formulations. We discuss additional input specific to calculation of pion and photon yields, and present comparisons between calculated and experimental results, mostly for high energy photons. Conclusions and suggestions for future work are presented in the last section. 65 refs., 7 figs.

  7. The Lyman-continuum photon production efficiency in the high-redshift Universe

    NASA Astrophysics Data System (ADS)

    Wilkins, Stephen M.; Feng, Yu; Di-Matteo, Tiziana; Croft, Rupert; Stanway, Elizabeth R.; Bouwens, Rychard J.; Thomas, Peter

    2016-05-01

    The Lyman-continuum photon production efficiency (ξion) is a critical ingredient for inferring the number of photons available to reionize the intergalactic medium. To estimate the theoretical production efficiency in the high-redshift Universe we couple the BlueTides cosmological hydrodynamical simulation with a range of stellar population synthesis models. We find Lyman-continuum photon production efficiencies of log10(ξion/erg-1 Hz) ≈ 25.1-25.5 depending on the choice of stellar population synthesis model. These results are broadly consistent with recent observational constraints at high-redshift though favour a model incorporating the effects of binary evolution.

  8. Production of heralded pure single photons from imperfect sources using cross-phase-modulation

    SciTech Connect

    Konrad, Thomas; Nock, Michael; Scherer, Artur; Audretsch, Juergen

    2006-09-15

    Realistic single-photon sources do not generate single photons with certainty. Instead they produce statistical mixtures of photons in Fock states |1> and vacuum (noise). We describe how to eliminate the noise in the output of the sources by means of another noisy source or a coherent state and cross-phase-modulation (XPM). We present a scheme that announces the production of pure single photons and thus eliminates the vacuum contribution. This is done by verifying a XPM-related phase shift with a Mach-Zehnder interferometer.

  9. A cascade of e ‑ e + pair production by a photon with subsequent annihilation to a single photon in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Diachenko, M. M.; Novak, O. P.; Kholodov, R. I.

    2016-06-01

    The process of electron–positron pair production by a photon with subsequent annihilation to a single photon in a strong magnetic field has been studied. The general amplitude has been calculated and the process rates have been found in a low Landau levels approximation (resonant and nonresonant cases). The comparison of resonant and nonresonant cases shows a significant excess of the resonant rate. The polarization of the final photon in a strong magnetic field has also been found. It has been shown that polarizations of the initial and final photons are independent except for the case of normal linear polarization of the initial photon.

  10. Effects of the plasma profiles on photon and pair production in ultrahigh intensity laser solid interaction

    SciTech Connect

    Tian, Y. X.; Jin, X. L. Yan, W. Z.; Li, J. Q.; Li, B.; Yu, J. Q.

    2015-12-15

    The model of photon and pair production in strong field quantum electrodynamics is implemented into our 1D3V particle-in-cell code with Monte Carlo algorithm. Using this code, the evolution of the particles in ultrahigh intensity laser (∼10{sup 23} W/cm{sup 2}) interaction with aluminum foil target is observed. Four different initial plasma profiles are considered in the simulations. The effects of initial plasma profiles on photon and pair production, energy spectra, and energy evolution are analyzed. The results imply that one can set an optimal initial plasma profile to obtain the desired photon distributions.

  11. Singular Values of Products of Ginibre Random Matrices, Multiple Orthogonal Polynomials and Hard Edge Scaling Limits

    NASA Astrophysics Data System (ADS)

    Kuijlaars, Arno B. J.; Zhang, Lun

    2014-12-01

    Akemann, Ipsen and Kieburg recently showed that the squared singular values of products of M rectangular random matrices with independent complex Gaussian entries are distributed according to a determinantal point process with a correlation kernel that can be expressed in terms of Meijer G-functions. We show that this point process can be interpreted as a multiple orthogonal polynomial ensemble. We give integral representations for the relevant multiple orthogonal polynomials and a new double contour integral for the correlation kernel, which allows us to find its scaling limits at the origin (hard edge). The limiting kernels generalize the classical Bessel kernels. For M = 2 they coincide with the scaling limits found by Bertola, Gekhtman, and Szmigielski in the Cauchy-Laguerre two-matrix model, which indicates that these kernels represent a new universality class in random matrix theory.

  12. CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation.

    PubMed

    Hahn, C; Weber, G; Märtin, R; Höfer, S; Kämpfer, T; Stöhlker, Th

    2016-04-01

    Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays - such as laser-generated plasmas - is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse. PMID:27131653

  13. CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation

    NASA Astrophysics Data System (ADS)

    Hahn, C.; Weber, G.; Märtin, R.; Höfer, S.; Kämpfer, T.; Stöhlker, Th.

    2016-04-01

    Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays — such as laser-generated plasmas — is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.

  14. Photon and dilepton production in high energy heavy ion collisions

    DOE PAGESBeta

    Sakaguchi, Takao

    2015-05-07

    The recent results on direct photons and dileptons in high energy heavy ion collisions, obtained particularly at RHIC and LHC are reviewed. The results are new not only in terms of the probes, but also in terms of the precision. We shall discuss the physics learned from the results.

  15. J/{psi} plus prompt-photon associated production in two-photon collisions at next-to-leading order

    SciTech Connect

    Klasen, Michael; Kniehl, Bernd A.; Mihaila, Luminita N.; Steinhauser, Matthias

    2005-01-01

    We calculate the cross section of J/{psi} plus prompt-photon inclusive production in {gamma}{gamma} collisions at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD) focusing on direct photoproduction. Apart from direct J/{psi} production, we also include the feed-down from directly produced {chi}{sub cJ} and {psi}{sup '} mesons. We discuss the analytical calculation, in particular the treatment of the various types of singularities and the NRQCD operator renormalization, in some detail. We present theoretical predictions for the future e{sup +}e{sup -} linear collider TESLA, taking into account both brems- and beamstrahlung.

  16. J/ψ plus prompt-photon associated production in two-photon collisions at next-to-leading order

    NASA Astrophysics Data System (ADS)

    Klasen, Michael; Kniehl, Bernd A.; Mihaila, Luminiţa N.; Steinhauser, Matthias

    2005-01-01

    We calculate the cross section of J/ψ plus prompt-photon inclusive production in γγ collisions at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD) focusing on direct photoproduction. Apart from direct J/ψ production, we also include the feed-down from directly produced χcJ and ψ' mesons. We discuss the analytical calculation, in particular the treatment of the various types of singularities and the NRQCD operator renormalization, in some detail. We present theoretical predictions for the future e+e- linear collider TESLA, taking into account both brems- and beamstrahlung.

  17. Exclusive e+e-, di-photon and di-jet production at the Tevatron

    SciTech Connect

    Terashi, Koji; /Rockefeller U.

    2007-05-01

    Results from studies on exclusive production of electron-position pair, di-photon, and dijet production at CDF in proton-antiproton collisions at the Fermilab Tevatron are presented. THe first observation and cross section measurements of exclusive e{sup +}e{sup -} and di-jet production in hadron-hadron collisions are emphasized.

  18. Power-efficient production of photon pairs in a tapered chalcogenide microwire

    SciTech Connect

    Meyer-Scott, Evan Dot, Audrey; Ahmad, Raja; Li, Lizhu; Rochette, Martin; Jennewein, Thomas

    2015-02-23

    Using tapered fibers of As{sub 2}Se{sub 3} chalcogenide glass, we produce photon pairs at telecommunication wavelengths with low pump powers. We found maximum coincidences-to-accidentals ratios of 2.13 ± 0.07 for degenerate pumping with 3.2 μW average power, and 1.33 ± 0.03 for non-degenerate pumping with 1.0 μW and 1.5 μW average power of the two pumps. Our results show that the ultrahigh nonlinearity in these microwires could allow single-photon pumping to produce photon pairs, enabling the production of large entangled states, heralding of single photons after lossy transmission, and photonic quantum information processing with nonlinear optics.

  19. Prompt photon production in p-p collisions

    SciTech Connect

    Cleymans, J.; Quack, E.; Redlich, K.

    1995-07-01

    A systematic study of the inclusive photon cross-section in p-p collisions is presented. The dependence of the {gamma} rates on the renormalization and factorization scales is discussed. A comparison is made with experimental data for centre-of-mass energies ranging from 23 GeV to 1.8 TeV. Predictions of the cross-sections are given for two different sets of structure functions for RHIC and LHC energies.

  20. CT14QED parton distribution functions from isolated photon production in deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Schmidt, Carl; Pumplin, Jon; Stump, Daniel; Yuan, C.-P.

    2016-06-01

    We describe the implementation of quantum electrodynamic (QED) evolution at leading order (LO) along with quantum chromodynamic (QCD) evolution at next-to-leading order (NLO) in the CTEQ-TEA global analysis package. The inelastic contribution to the photon parton distribution function (PDF) is described by a two-parameter ansatz, coming from radiation off the valence quarks, and based on the CT14 NLO PDFs. Setting the two parameters to be equal allows us to completely specify the inelastic photon PDF in terms of the inelastic momentum fraction carried by the photon, p0γ, at the initial scale Q0=1.295 GeV . We obtain constraints on the photon PDF by comparing with ZEUS data [S. Chekanov et al. (ZEUS Collaboration), Phys. Lett. B 687, 16 (2010)] on the production of isolated photons in deep inelastic scattering, e p →e γ +X . For this comparison we present a new perturbative calculation of the process that consistently combines the photon-initiated contribution with the quark-initiated contribution. Comparison with the data allows us to put a constraint at the 90% confidence level of p0γ≲0.14 % for the inelastic photon PDF at the initial scale of Q0=1.295 GeV in the one-parameter radiative ansatz. The resulting inelastic CT14QED PDFs will be made available to the public. In addition, we also provide CT14QEDinc PDFs, in which the inclusive photon PDF at the scale Q0 is defined by the sum of the inelastic photon PDF and the elastic photon distribution obtained from the equivalent photon approximation.

  1. Influence of the magnetic properties and repetitions on the energy product in layered thin film hard soft magnetic nanocomposites

    NASA Astrophysics Data System (ADS)

    Zagardo, David; Beik Mohammadi, Jamileh; Tuggle, Andrew; Mewes, Claudia; Mewes, Tim; Suzuki, Takao; MINT Center Team

    2015-03-01

    Exchange spring composites (hard-soft magnetic composites) are interesting for many applications such as rare-earth free permanent magnets and information storage. One key aspect is the figure of merit, the energy product, also called (BH)max. The system of study is a magnetic nano composite where each bilayer consists of a soft and hard magnetic material of total height of 22 nm. Using micromagnetic simulations we have investigated the influence of different ratios of the volume of the hard and soft layers on the energy product and the number of bilayer repetitions. Our findings indicate that the maximum energy product depends strongly on the volume ratio as well as on the number of repetitions. In addition we have studied the influence of different anisotropy contributions of the hard and soft magnetic layer on the energy product. Finally we have studied the influence of the interlayer exchange coupling on the energy product, which show that strong interlayer exchange coupling is necessary to reach a high energy product.

  2. Electron-positron pair production by ultrarelativistic electrons in a soft photon field

    NASA Technical Reports Server (NTRS)

    Mastichiadis, A.; Marscher, A. P.; Brecher, K.

    1986-01-01

    The fully differential cross section for photon-electron pair production is integrated numerically over phase space. Results are obtained for the astrophysically interesting case in which the interaction between an ultrarelativistic electron and a soft photon results in electron-positron pair production. The positron spectrum is a function of the energies of both the photon and the electron, as well as the angle of interaction. It is found that the energy at which the positron distribution peaks is inversely proportional to the photon energy and independent of the electron energy. The positron spectrum is integrated once more over initial electron energies for a power-law energy distribution of primary electrons. The same procedure is repeated for the recoil particle; it is shown that the peak of the recoil energy distribution depends linearly on the energy of the primary electron. Finally, semianalytical expressions are obtained for the energy losses of the primary electrons.

  3. Enhancing Photon Utilization Efficiency for Astaxanthin Production from Haematococcus lacustris Using a Split-Column Photobioreactor.

    PubMed

    Kim, Z-Hun; Park, Hanwool; Lee, Ho-Sang; Lee, Choul-Gyun

    2016-07-28

    A split-column photobioreactor (SC-PBR), consisting of two bubble columns with different sizes, was developed to enhance the photon utilization efficiency in an astaxanthin production process from Haematococcus lacustris. Among the two columns, only the smaller column of SC-PBR was illuminated. Astaxanthin productivities and photon efficiencies of the SC-PBRs were compared with a standard bubble-column PBR (BC-PBR). Astaxanthin productivity of SC-PBR was improved by 28%, and the photon utilization efficiencies were 28-366% higher than the original BC-PBR. The results clearly show that the effective light regime of SC-PBR could enhance the production of astaxanthin. PMID:27056475

  4. Study of photon emission by electron capture during solar nuclei acceleration. 3: Photon production evaluations

    NASA Technical Reports Server (NTRS)

    Gallegos, A.; Perez-Peraza, J.; Alvarez, M.

    1985-01-01

    Lower limits of photon fluxes were evaluated from electron capture during acceleration in solar flares, because the arbitrary q sub c asterisk assumed in this work evolves very slow with velocity, probably much more slowly than the physical actual situation: in fact, more emission is expected toward the IR region. Nevertheless the authors claim to show that the factibility of sounding acceleration processes, charge evolution processes and physical parameters of the source itself, by the observational analysis of this kind of emissions. For instance, it would be interesting to search observationally, for the predicted flux and energy drift of F sub e ions interacting with the atomic 0 and F sub e of the source matter, or, even more feasible for the X-ray lines at 4.2 keV and 2.624 + 0.003 KeV from Fe and S ions in ionized Fe at T = 10 to the 7th power K respectively, the 418 + or - 2 eV and 20 + or - 4 eV lines of Fe and S in ionized Fe at 5 x 10 to the 6th power K, which are predicted from Fermi acceleration.

  5. Conversion of pesticides to biologically active products on urban hard surfaces.

    PubMed

    Jiang, Weiying; Gan, Jay

    2016-06-15

    Impervious pavements such as concrete are a dominant feature of urban landscapes, but their role in the fate of environmental contaminants is largely ignored. This study considered the case of urban-use pesticides, and demonstrated for the first time that surfaces such as concrete were capable of converting pesticides to other biologically active intermediates. Rapid transformation of pesticides was observed in both bench and field scale setups. Under outdoor conditions, permethrin, a heavily used pyrethroid insecticide, quickly formed 3-phenoxybenzoic acid (3-PBA) that is a known endocrine disruptor, and the level of 3-PBA was >100μg/L in the runoff water even 3months after the treatment. Fipronil, a product used for termite and ant control, was quickly transformed to desulfinyl and sulfone derivatives, with the desulfinyl level exceeding that of parent in the runoff water only 1week after treatment. Fipronil derivatives have aquatic toxicity similar or even greater than the parent fipronil. Direct sampling of deposited particles from residential exterior pavements revealed widespread presence of fipronil sulfone and desulfinyl and demonstrated their in-situ formation and accumulation on concrete. The extensive transformations were likely caused by the alkalinity and metal oxides in concrete and conducive photolytic conditions at the hard surfaces. The study findings highlight the role of urban pavements and urbanization in the geochemical cycling of anthropogenic contaminants. PMID:26971210

  6. Direct photon production of d+A and A+A collisions at RHIC

    SciTech Connect

    Zhang, Benwei; Vitev, Ivan

    2008-01-01

    Direct photon productions in minimum bias d+Cu and d+Au and central Cu+Cu and Au+Au at center of mass energies {radical}s = 62.4 GeV and 200GeV at RHIC are investigated systematically by taking into account jet quenching effect, medium-induced photon bremsstrahlung and jet-photon conversion in the hot QGP as well as known cold nuclear matter effects such as the isospin effect, the Cronin effect, shadowing effect, EMC effect and cold nuclear matter energy loss. It is shown that at high p{sub T} the nuclear modification factor for direct photon R{sub AA}(p{sub T}) is suppressed and dominated by cold nuclear matter effects, and there is no large enhancement due to medium-induced photon bremsstrahlung and jet-photon conversion in the hot QGP. Comparison of numerical simulations with experimental data rules out large Cronin enhancement and incoherent photon emission in medium, though large error bars in currently experimental data can not provide tight constraints on other nuclear matter effects.

  7. Can neutrino-induced photon production explain the low energy excess in MiniBooNE?

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Serot, Brian D.

    2013-02-01

    This report summarizes our study of Neutral Current (NC)-induced photon production in MiniBooNE, as motivated by the low energy excess in this experiment [A.A. Aquilar-Arevalo et al., MiniBooNE Collaboration, Phys. Rev. Lett. 98 (2007) 231801; A.A. Aquilar-Arevalo et al., MiniBooNE Collaboration, Phys. Rev. Lett. 103 (2009) 111801]. It was proposed that NC photon production with two anomalous photon-Z boson-vector meson couplings might explain the excess. However, our computed event numbers in both neutrino and antineutrino runs are consistent with the previous MiniBooNE estimate that is based on their pion production measurement. Various nuclear effects discussed in our previous works, including nucleon Fermi motion, Pauli blocking, and the Δ resonance broadening in the nucleus, are taken into account. Uncertainty due to the two anomalous terms and nuclear effects are studied in a conservative way.

  8. Kirkpatrick-Baez mirrors to focus hard X-rays in two dimensions as fabricated, tested and installed at the Advanced Photon Source.

    PubMed

    Kujala, Naresh; Marathe, Shashidhara; Shu, Deming; Shi, Bing; Qian, Jun; Maxey, Evan; Finney, Lydia; Macrander, Albert; Assoufid, Lahsen

    2014-07-01

    The micro-focusing performance for hard X-rays of a fixed-geometry elliptical Kirkpatrick-Baez (K-B) mirrors assembly fabricated, tested and finally implemented at the micro-probe beamline 8-BM of the Advanced Photon Source is reported. Testing of the K-B mirror system was performed at the optics and detector test beamline 1-BM. K-B mirrors of length 80 mm and 60 mm were fabricated by profile coating with Pt metal to produce focal lengths of 250 mm and 155 mm for 3 mrad incident angle. For the critical angle of Pt, a broad bandwidth of energies up to 20 keV applies. The classical K-B sequential mirror geometry was used, and mirrors were mounted on micro-translation stages. The beam intensity profiles were measured by differentiating the curves of intensity data measured using a wire-scanning method. A beam size of 1.3 µm (V) and 1.2 µm (H) was measured with monochromatic X-rays of 18 keV at 1-BM. After installation at 8-BM the measured focus met the design requirements. In this paper the fabrication and metrology of the K-B mirrors are reported, as well as the focusing performances of the full mirrors-plus-mount set-up at both beamlines. PMID:24971959

  9. Preliminary effects of water hardness on triactinomyxon production and development from eastern tubifex worms infected with Myxobolus cerebralis

    USGS Publications Warehouse

    Waldrop, Thomas B.; Densmore, Christine; Blazer, Vicki; Smith, Dave; Schill, Bane

    1999-01-01

    Whirling disease is caused by Myxobolus cerebralis and requires an intermediate oligochaete host identified as Tubifex tubifex (Wolf, Markiw, and Hiltunen, 1986). M. cerebralis spores ingested by the tubifex worms develop into triactinomyxons (tams) that are eventually released into the water column to infect salmonid fish. There may be many environmental parameters, biotic or abiotic, that may affect the development of waterborne tams in eastern tubifex worms. This study will focus on one of those environmental parameters, total water hardness. Total water hardness is defined as the concentration of calcium and magnesium in a water sample expressed in milligrams per liter of equivalent CACO3 (Boyd, 1990). This study will address whether different levels of water hardness affect the development and production of tams released by infected tubifex worms.

  10. Recent results on D decays and lepton, photon, (and hadron) production of charm

    SciTech Connect

    Nash, T.

    1983-09-01

    After a brief introduction to the experiments with results included in this review, we will discuss, in turn, production of psi and psi', production of open charm in lepton and photon beams, D decays, and give a brief token mention of recent hadroproduction results. Emphasis will be on results reported since the Paris conference (August, 1982), but we will try to include all results since the last Lepton Photon Conference at Bonn (August, 1981) as well as earlier results when necessary for comparison. 42 references.

  11. Gluon versus photon production of a 750 GeV diphoton resonance

    NASA Astrophysics Data System (ADS)

    Csáki, Csaba; Hubisz, Jay; Lombardo, Salvator; Terning, John

    2016-05-01

    The production mechanism of a 750 GeV diphoton resonance, either via gluon or photon fusion, can be probed by studying kinematic observables in the diphoton events. We perform a detector study of the two production modes of a hypothetical scalar or tensor diphoton resonance in order to characterize the features of the two scenarios. The nature of the resonance production can be determined from the jet multiplicity, the jet and diphoton rapidities, the rate of central pseudorapidity gaps, or the possible detection of forward protons from elastic photoproduction for events in the signal region. Kinematic distributions for both signals and expected irreducible diphoton background events are provided for comparison along with a study of observables useful for distinguishing the two scenarios at an integrated luminosity of 20 fb-1 . We find that decay photons from a 750 GeV scalar resonance have a preference for acceptance in the central detector barrel, while background events are more likely to give accepted photons in the detector end caps. This disfavors the interpretation of the large number of excess events found by the Run-2 CMS diphoton search with one photon detected in the end cap as a wide spin-0 resonance signal. However, one expects more end cap photons in the case of spin-2 resonance.

  12. Photon-photon collisions

    SciTech Connect

    Burke, D.L.

    1982-10-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e..gamma.. scattering. Considerable work has now been accumulated on resonance production by ..gamma gamma.. collisions. Preliminary high statistics studies of the photon structure function F/sub 2//sup ..gamma../(x,Q/sup 2/) are given and comments are made on the problems that remain to be solved.

  13. Search for two-photon production of f{sub J}(2220)/{xi}(2230) at CLEO

    SciTech Connect

    Galik, Richard S.

    1997-05-20

    We use the CLEO detector at the Cornell e{sup +}e{sup -} storage ring, CESR, to search for the two-photon production of the glueball candidate f{sub J}(2220) in its decay to K{sub s}K{sub s}. We present a restrictive upper limit on the product of the two-photon partial width and the K{sub s}K{sub s} branching fraction, {gamma}{sub {gamma}}{sub {gamma}}{center_dot}B{sub K{sub s}}{sub K{sub s}} for this narrow resonance. We use this limit to calculate a lower limit on the stickiness, which is a measure of the two-gluon coupling relative to the two-photon coupling. This limit on stickiness indicates that the f{sub J}(2220) has substantial glueball content.

  14. Exclusive production of K+K-π+π- in photon-photon collisions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Armitage, J. C.; Bakken, J. A.; Barbaro-Galtieri, A.; Barker, A. R.; Barnes, A. V.; Barnett, B. A.; Bengtsson, H.-U.; Bintinger, D. L.; Blumenfeld, B. J.; Bobbink, G. J.; Bross, A. D.; Buchanan, C. D.; Buijs, A.; Cain, M. P.; Caldwell, D. O.; Chamberlain, O.; Chien, C.-Y.; Clark, A. R.; Cordier, A.; Dahl, O. I.; Day, C. T.; Derby, K. A.; van Driel, M. A.; Eberhard, P. H.; Eisner, A. M.; Erné, F. C.; Fancher, D. L.; Fujii, H.; Fujii, T.; Gabioud, B.; Gary, J. W.; Gorn, W.; Hadley, N. J.; Hauptman, J. M.; Hofmann, W.; Huth, J. E.; Hylen, J.; Joshi, U. P.; Kamae, T.; Kaye, H. S.; Kees, K. H.; Kenney, R. W.; Kerth, L. T.; Ko, Winston; Koda, R. I.; Kofler, R. R.; Kwong, K. K.; Lander, R. L.; Langeveld, W. G.; Layter, J. G.; Linde, F. L.; Lindsey, C. S.; Loken, S. C.; Lu, A.; Lu, X.-Q.; Lynch, G. R.; Madansky, L.; Madaras, R. J.; Maeshima, K.; Magnuson, B. D.; Marx, J. N.; Maruyama, K.; Masek, G. E.; Matthews, J. A.; Melnikoff, S. O.; Miller, E. S.; Moses, W.

    1985-06-01

    We report a measurement of the reaction γγ-->K+K-π+π- in both tagged and untagged events at PEP. The cross section rises with invariant γγ mass to about 15 nb at 2 GeV and falls slowly at higher masses. We find clear evidence for the processes γγ-->φπ+π- and γγ-->K*0(892)Kπ. Upper limits (95% C.L.) of 1.5 and 5.7 nb in the mass range from 1.7 to 3.7 GeV are obtained for φρ0 and K*0K¯*0 production, respectively.

  15. Double vector meson production in photon-hadron interactions at hadronic colliders

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Moreira, B. D.; Navarra, F. S.

    2016-07-01

    In this paper we analyze the double vector meson production in photon-hadron (γ h) interactions at pp / pA / AA collisions and present predictions for the ρ ρ , J/Ψ J/Ψ , and ρ J/Ψ production considering the double scattering mechanism. We estimate the total cross sections and rapidity distributions at LHC energies and compare our results with the predictions for the double vector meson production in γ γ interactions at hadronic colliders. We present predictions for the different rapidity ranges probed by the ALICE, ATLAS, CMS, and LHCb Collaborations. Our results demonstrate that the ρ ρ and J/Ψ J/Ψ production in PbPb collisions is dominated by the double-scattering mechanism, while the two-photon mechanism dominates in pp collisions. Moreover, our results indicate that the analysis of the ρ J/Ψ production at LHC can be useful to constrain the double-scattering mechanism.

  16. Di-photon and photon + b/c production cross sections at Ecm = 1.96- TeV

    SciTech Connect

    Gajjar, Anant; /Liverpool U.

    2005-05-01

    Measurements of the di-photon cross section have been made in the central region and are found to be in good agreement with NLO QCD predictions. The cross section of events containing a photon and additional heavy flavor jet have also been measured, as well as the ratio of photon + b to photon + c. The statistically limited sample shows good agreement with Leading Order predictions.

  17. Further Results on the Production of Neutral Mesons by Photons

    DOE R&D Accomplishments Database

    Panofsky, W. K. H.; Steinberger, J.; Steller, J.

    1951-10-01

    Further measurements have been made on the photoproduction of neutral mesons using the gamma-gamma coincidence technique. New data have been obtained on the gamma-gamma correlation curves in beryllium. The angular distribution of the photo mesons in Be has been determined and found to be strongly peaked forward. The dependence on the atomic number A of production has been found to obey an A{sup 2/3} law. Some data obtained for production in hydrogen show that the pi-zero and pi-plus production cross sections are comparable and that the pi-zero excitation curve starts more slowly from threshold than does the pi-plus photo excitation curve.

  18. Photon-photon collisions

    SciTech Connect

    Brodsky, S.J.

    1988-07-01

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of ..gamma gamma.. physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive ..gamma gamma.. reactions at high momentum transfer. 73 refs., 12 figs.

  19. Abstracts of computer programs and data libraries pertaining to photon production data

    SciTech Connect

    White, J.E.; Manneschmidt, J.B.; Finch, S.Y.; Dickens, J.K.

    1998-06-01

    Abstracts, or descriptions, of computer programs and data libraries pertaining to Photon Production Data (Measurements, Evaluations and Calculations) maintained in the collections of the Radiation Safety Information Computational Center, Oak Ridge, Tennessee USA and at the OECD/NEA Data Bank, Paris, are collected in this document.

  20. New evaluation of photon production for JEFF-3

    NASA Astrophysics Data System (ADS)

    Ravaux, S.; Bernard, D.; Santamarina, A.

    2013-03-01

    In this work, new gamma production evaluations are proposed for JEFF-3 for crucial nuclei for power reactors and Jules Horowitz Reactor: Fe, Ag, In, Cd and Gd. We specifically work on two nuclear reactions: the inelastic scattering and the radiative capture. We performed gamma production multiplicities, angular distributions and energy spectrum for incident neutron energies between 10-11 and 20 MeV by simulating the whole intranuclear gamma cascade. For this simulation, the discrete part of the nuclei level schemes came from the RIPL2.0 library and the latest EGAF measurements carried out at Budapest facility. The EGAF measurements are available in the adopted IAEA library. The continuum level scheme part has been estimated with a level density model: the Gilbert-Cameron model and a strength function model: the Generalized Lorentzian model. Then, the gamma cascade has been simulated using TALYS which is a nuclear reaction modeling code.

  1. Growth of optical-quality anthracene crystals doped with dibenzoterrylene for controlled single photon production

    SciTech Connect

    Major, Kyle D. Lien, Yu-Hung; Polisseni, Claudio; Grandi, Samuele; Kho, Kiang Wei; Clark, Alex S.; Hwang, J.; Hinds, E. A.

    2015-08-15

    Dibenzoterrylene (DBT) molecules within a crystalline anthracene matrix show promise as quantum emitters for controlled, single photon production. We present the design and construction of a chamber in which we reproducibly grow doped anthracene crystals of optical quality that are several mm across and a few μm thick. We demonstrate control of the DBT concentration over the range 6–300 parts per trillion and show that these DBT molecules are stable single-photon emitters. We interpret our data with a simple model that provides some information on the vapour pressure of DBT.

  2. Rapidity correlations and {Delta}G from prompt photon plus jet production in polarized pp collisions

    SciTech Connect

    Sanghyeon Chang; Claudio Coriano; L. E. Gordon

    1997-09-01

    A study of prompt photon plus associated jet production is performed at next-to-leading order (O({alpha}{alpha}{sub s}{sup 2})) in QCD at {radical}S=200--500 GeV, appropriate for the RHIC polarized {rvec p}{rvec p} collider experiment. Momentum correlations between the jet and photon are examined and the utility of the process as a method for constraining the size and shape of the polarized gluon density of the proton {Delta}G is examined.

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

    NASA Astrophysics Data System (ADS)

    Manko, A. Yu.; Shulyakovsky, R. G.

    2016-03-01

    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.

  4. Z{gamma}{gamma} production with leptonic decays and triple photon production at next-to-leading order QCD

    SciTech Connect

    Bozzi, G.; Campanario, F.; Rauch, M.; Zeppenfeld, D.

    2011-10-01

    We present a calculation of the O({alpha}{sub s}) QCD corrections to the production of a Z boson in association with two photons and to triple-photon production at hadron colliders. All final-state photons are taken as real. For the Z boson, we consider the decays both into charged leptons and into neutrinos including all off-shell effects. Numerical results are obtained via a Monte Carlo program based on the structure of the VBFNLO program package. This allows us to implement general cuts and distributions of the final-state particles. We find that the next-to-leading order QCD corrections are sizable and significantly exceed the expectations from a scale variation of the leading-order result. In addition, differential distributions of important observables change considerably. The prediction of two-photon-associated Z production with Z decays into neutrinos from the charged-lepton rate works well, once we use an additional cut on the invariant mass of the charged-lepton pair.

  5. Nonclassical photon pair production in a voltage-biased Josephson junction.

    PubMed

    Leppäkangas, Juha; Johansson, Göran; Marthaler, Michael; Fogelström, Mikael

    2013-06-28

    We investigate electromagnetic radiation emitted by a small voltage-biased Josephson junction connected to a superconducting transmission line. At frequencies below the well-known emission peak at the Josephson frequency (2eV/h), extra radiation is triggered by quantum fluctuations in the transmission line. For weak tunneling couplings and typical Ohmic transmission lines, the corresponding photon-flux spectrum is symmetric around half the Josephson frequency, indicating that the photons are predominately created in pairs. By establishing an input-output formalism for the microwave field in the transmission line, we give further evidence for this nonclassical photon pair production, demonstrating that it violates the classical Cauchy-Schwarz inequality for two-mode flux cross correlations. In connection to recent experiments, we also consider a stepped transmission line, where resonances increase the signal-to-noise ratio. PMID:23848913

  6. Perspetives of study the direct photon production process at FAIR energy

    NASA Astrophysics Data System (ADS)

    Skachkova, A. N.; Skachkov, N. B.

    2015-11-01

    The modeling of high energy photons production in collisions of antiproton beam having E beam = 15 GeV with the proton target pp→ γ + {ptX} is done using the event sample simulated by PYTHIA6 generator. Such energy is high enough to consider this collision as a relativistic one and being caused by parton-parton scattering. The distribution of the set of kinematic variables and cuts which can be useful for getting the information about proton structure in the available kinematic region is obtained. The contributions of fake photons which can appear from the hadron decays as well as of the background caused by the minimum bias events and other QCD processes are estimated. The set of cuts which can be useful for separation of signal events containing the direct photons from background events is proposed.

  7. Validation of method for enhanced production of red-shifted bioluminescent photons in vivo

    NASA Astrophysics Data System (ADS)

    Dragavon, Joe; Blazquez, Samantha; Rogers, Kelly L.; Samson, Chelsea; Tournebize, Régis; Shorte, Spencer

    2011-02-01

    Bioluminescence Imaging (BLI) is an increasingly useful and applicable technique that allows for the non-invasive observation of biological events in intact living organisms, ranging from single cells to small rodents. Though the photon production occurs within the host, significant exposure times can be necessary due to the low photon flux compared to fluorescence imaging. The optical absorption spectrum of haemoglobin strongly overlaps most bioluminescent emission spectra, greatly attenuating the total detectable photons in animal models. We have developed and validated a technique that is able to red-shift the bioluminescent photons to the more desirable optical region of > 650 nm, a region of minimal absorbance by hemoglobin. This red-shift occurs by using bioluminescence as an internal light source capable of exciting a fluorophore, such as a fluorescent protein or a quantum dot, that emits in the red. Interestingly, in the absence of an absorber, this excitation can occur over substantial distances (microns to centimeters), far exceeding distances associated to, and thereby precluding, resonance energy transfer phenomena. We show this novel technique yields a substantial increase in the number of red photons for in vitro and ex vivo conditions, suggesting eventually utility for in vivo studies on, for example, intact living mice.

  8. Inclusive photon production at forward rapidities in pp collisions at LHC energies with the ALICE experiment

    NASA Astrophysics Data System (ADS)

    Sudipan De for the ALICE collaboration

    2016-04-01

    Measurements of multiplicity and pseudorapidity distributions of particles produced in pp collisions are important for the study of particle production mechanisms and to obtain baseline distributions to be compared with those from heavy-ion collisions. The inclusive photon measurements (dominated by π0 decays) are complementary to the charged particle measurements. The present work focuses on the forward rapidity region with comparisons to different models such as PYTHIA and PHOJET. We report the measurements of multiplicity and pseudorapidity distributions of inclusive photons using the ALICE Photon Multiplicity Detector (PMD) at forward rapidities (2.3 < η < 3.9) in pp collisions at = 0.9, 2.76 and 7 TeV. It is observed that the photon multiplicity distributions are well described by negative binomial distributions (NBD). Multiplicity distributions are studied in terms of KNO variables for each energy. It is shown that the increase in the average photon multiplicity as a function of beam energy is compatible with both a logarithmic and power law dependence. The results are compared to different model predictions. These models reproduce experimental results at lower energy while they are not accurate at higher energies.

  9. Anomalous soft photon production from the induced currents in Dirac sea

    NASA Astrophysics Data System (ADS)

    Loshaj, Frasher; Kharzeev, Dmitri

    2013-10-01

    The propagation of a high energy quark distrurbs the confining vacuum inducing the currents in Dirac sea. Since quarks possess electric charge, these induced vacuum currents act as a source of soft photon radiation. This can lead to the enhancement of the soft photon production above the expectations based on the charged hadron yields and the Low theorem. We illustrate the phenomenon by using the exactly soluble 1 + 1 dimensional massless Abelian gauge model that shares with QCD all of the ingredients involved in this mechanism: confinement, chiral symmetry breaking, axial anomaly, and the periodic θ-vacuum. We show that the propagating quark throughout the process of hadronization induces in the vacuum charged transition currents that lead to a strong resonant enhancement of the soft photon yield; the Low theorem however remains accurate in the limit of very soft momenta. We then construct on the basis of our result a simple phenomenological model and apply it to the soft photon production in the fragmentation of jets produced in Z0 decays. We find a qualitative agreement with the recent result from the DELPHI Collaboration.

  10. Anomalous soft photon production from the induced currents in Dirac sea

    NASA Astrophysics Data System (ADS)

    Kharzeev, Dmitri E.; Loshaj, Frashër

    2014-04-01

    The propagation of a high-energy quark disturbs the confining QCD vacuum inducing the currents in Dirac sea. Since quarks possess electric charge, these induced vacuum quark currents act as a source of soft photon radiation. This can lead to the enhancement of the soft photon production above the expectations based on the charged hadron yields and the Low theorem. We illustrate the phenomenon by using the exactly soluble 1+1 dimensional massless Abelian gauge model that shares with QCD all of the ingredients involved in this mechanism: confinement, chiral symmetry breaking, axial anomaly, and the periodic θ vacuum. We show that the propagating quark throughout the process of hadronization induces in the vacuum charged transition currents that lead to a strong resonant enhancement of the soft photon yield; the Low theorem, however, remains accurate in the limit of very soft momenta. We then construct on the basis of our result a simple phenomenological model and apply it to the soft photon production in the fragmentation of jets produced in Z0 decays. We find a qualitative agreement with the recent result from the DELPHI Collaboration.

  11. Non-factorizable photonic corrections to resonant production and decay of many unstable particles

    NASA Astrophysics Data System (ADS)

    Dittmaier, Stefan; Schwan, Christopher

    2016-03-01

    Electroweak radiative corrections to the production of high-multiplicity final states with several intermediate resonances in most cases can be sufficiently well described by the leading contribution of an expansion about the resonance poles. In this approach, also known as pole approximation, corrections are classified into separately gauge-invariant factorizable and non-factorizable corrections, where the former can be attributed to the production and decay of the unstable particles on their mass shell. The remaining non-factorizable corrections are induced by the exchange of soft photons between different production and decay subprocesses. We give explicit analytical results for the non-factorizable photonic virtual corrections to the production of an arbitrary number of unstable particles at the one-loop level and, thus, present an essential building block in the calculation of next-to-leading-order electroweak corrections in pole approximation. The remaining virtual factorizable corrections can be obtained with modern automated one-loop matrix-element generators, while the evaluation of the corresponding real photonic corrections can be evaluated with full matrix elements by multi-purpose Monte Carlo generators. Our results can be easily modified to non-factorizable QCD corrections, which are induced by soft-gluon exchange.

  12. Dilepton and photon production in the presence of a nontrivial Polyakov loop

    NASA Astrophysics Data System (ADS)

    Hidaka, Yoshimasa; Lin, Shu; Pisarski, Robert D.; Satow, Daisuke

    2015-10-01

    We calculate the production of dileptons and photons in the presence of a nontrivial Polyakov loop in QCD. This is applicable to the semi-Quark Gluon Plasma (QGP), at temperatures above but near the critical temperature for deconfinement. The Polyakov loop is small in the semi-QGP, and near unity in the perturbative QGP. Working to leading order in the coupling constant of QCD, we find that there is a mild enhancement, ˜ 20%, for dilepton production in the semi-QGP over that in the perturbative QGP. In contrast, we find that photon production is strongly suppressed in the semi-QGP, by about an order of magnitude, relative to the perturbative QGP. In the perturbative QGP photon production contains contributions from 2 → 2 scattering and collinear emission with the Landau-Pomeranchuk-Migdal (LPM) effect. In the semi-QGP we show that the two contributions are modified differently. The rate for 2 → 2 scattering is suppressed by a factor which depends upon the Polyakov loop. In contrast, in an SU( N ) gauge theory the collinear rate is suppressed by 1 /N , so that the LPM effect vanishes at N = ∞. To leading order in the semi-QGP at large N , we compute the rate from 2 → 2 scattering to the leading logarithmic order and the collinear rate to leading order.

  13. Direct photon production at 0.5 TeV/c

    SciTech Connect

    Zutshi, V.

    1995-04-01

    The authors present data from Fermilab experiment E706 on high P{sub T} direct photon production in hadronic collisions. The experimental apparatus of E706 was optimized for a precision study of large P{sub T} direct photon and associated jet production. It consists of a large liquid argon calorimeter with a finely segmented electromagnetic section, a charge particle spectrometer using silicon vertex detectors in the target region and proportional wire chambers and drift tubes downstream of the analysis magnet. Results are presented for 0.5 TeV/c positive and negative beams incident on Be, Cu and Hydrogen targets. Comparisons of these data to NLL QCD theory will be presented.

  14. Double Spin Asymmetry ALT in the Production of Photons, Hadrons, and Jets

    NASA Astrophysics Data System (ADS)

    Pitonyak, Daniel

    We calculate the double spin asymmetry (DSA) ALT in proton-proton (pp) collisions for the production of photons, hadrons, and jets in the collinear twist-3 framework. These processes allows us for the first time to access a complete set of collinear twist-3 functions. We also give numerical estimates for the asymmetries of which photon production shows the most promise of a measurable effect. Furthermore, we comment on how these asymmetries would allow us to probe the gluon helicity down to as of yet unexplored x values, remark on the importance of these effects in determining the evolution of the Efremov-Teryaev-Qiu-Sterman (ETQS) function TF(x, x), and discuss their usefulness in resolving the true mechanism behind the large transverse single spin asymmetries (SSAs) measured in pp collisions.

  15. Vacuum ultraviolet of hydrogenated amorphous carbons. II. Small hydrocarbons production in Photon Dominated Regions

    NASA Astrophysics Data System (ADS)

    Alata, I.; Jallat, A.; Gavilan, L.; Chabot, M.; Cruz-Diaz, G. A.; Munoz Caro, G. M.; Béroff, K.; Dartois, E.

    2015-12-01

    Context. Hydrogenated amorphous carbons (a-C:H) are a major component of the carbonaceous solids present in the interstellar medium. The production and existence of these grains is connected in particular with the balance between their photolysis, radiolysis, and hydrogenation. During grain processing, H2 and other small organic molecules, radicals, and fragments are released into the gas phase. Aims: We perform photolytic experiments on laboratory produced interstellar a-C:H analogues to monitor and quantify the release of species and compare to relevant observations in the interstellar medium. Methods: Hydrogenated amorphous carbon analogues at low temperature are exposed to ultraviolet (UV) photons, under ultra-high vacuum conditions. The species produced are monitored using mass spectrometry and post irradiation temperature-programmed desorption. Additional experiments are performed using deuterated analogues and the species produced are unambiguously separated from background contributions. We implement the laboratory measured yields for the released species in a time dependent model to investigate the effect of the UV photon irradiation of hydrogenated amorphous carbons in a photon dominated region, and estimate the associated time scale. Results: The UV photolysis of hydrogenated amorphous carbons leads to the production of H2 molecules and small hydrocarbons. The model shows that the photolytic evolution of a-C:Hs in photon dominated regions, such as the Horsehead Nebula, can raise the abundance of carbonaceous molecules by several orders of magnitude at intermediate visual extinctions, i.e., after the C+ maximum and before the dense cloud conditions prevail where models generally show a minimum abundance for such carbonaceous species. The injection time peak ranges from a thousand to ten thousand years in the models, considering only the destruction of such grains and no re-hydrogenation. This time scale is consistent with the estimated advection front of

  16. Dark-photon searches via Higgs-boson production at the LHC

    NASA Astrophysics Data System (ADS)

    Biswas, Sanjoy; Gabrielli, Emidio; Heikinheimo, Matti; Mele, Barbara

    2016-05-01

    Dark photons γ ¯ mediating long-range forces in a dark sector are predicted by various new physics scenarios, and are being intensively searched for in experiments. We extend a previous study of a new discovery process for dark photons proceeding via Higgs-boson production at the LHC. Thanks to the nondecoupling properties of the Higgs boson, BR (H →γ γ ¯ ) values up to a few percent are possible for a massless dark photon, even for heavy dark-sector scenarios. The corresponding signature consists (for a Higgs boson at rest) of a striking monochromatic photon with energy Eγ=mH/2 , and a similar amount of missing energy. We perform a model-independent analysis at the LHC of both the gluon-fusion and vector-boson fusion (VBF) Higgs production mechanisms at 14 TeV, including parton-shower effects, and updating our previous parton-level analysis at 8 TeV in the gluon-fusion channel by a more realistic background modeling. We find that a 5 σ sensitivity can be reached in the gluon-fusion channel for BR (H →γ γ ¯)≃0.1 % with an integrated luminosity of L ≃300 fb-1. The corresponding VBF reach is instead restricted to 1%. Such decay rates can be naturally obtained in dark-photon scenarios arising from unbroken U (1 )F models explaining the origin and hierarchy of the Yukawa couplings, strongly motivating the search for this exotic Higgs decay at the LHC.

  17. Production of [ital Z]-Higgs boson pairs at photon linear colliders

    SciTech Connect

    Eboli, O.J.P. ); Gonzalez-Garcia, M.C. ); Novaes, S.F. )

    1994-09-01

    We study the associated production of [ital Z] and standard model Higgs bosons in high energy [gamma][gamma] collisions with the photons originating from Compton laser backscattering. According to our results, within the framework of the standard model, this process will give rise only to very few events for a yearly integrated luminosity of 10 fb[sup [minus]1], even at very high energies.

  18. Weak Pion and Photon Production from Nuclei in a Chiral Effective Field Theory (Update)

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Serot, Brian D.

    2011-04-01

    Neutrino-induced pion and photon production from nucleons and nuclei are important for the interpretation of neutrino-oscillation experiments. [A. A. Aquilar-Arevalo et al. (MiniBooNE Collaboration), Phys. Rev. Lett. 100, 032301 (2008)]. We have been working on these problems in a Lorentz-covariant effective field theory (known as QHD EFT), which contains nucleons, pions, Deltas (Δ), isoscalar scalar (σ) and vector (ω) fields, and isovector vector (ρ) fields and has nonlinear chiral symmetry built in. Here we update our results on weak pion and photon production from nuclei, including both incoherent and coherent scattering. Connections between our results and the background analysis from MiniBooNE will be presented. In particular, coherent production of photons will be emphasized, and the possible relevance to the low-energy excess events at MiniBooNE will be explored. To justify our approximation scheme, we compare our results with data for inclusive electron scattering off nuclei up to the Δ peak and with coherent photoproduction of pions. Finally, we focus on the approximation scheme used and discuss the important Δ dynamics in the medium. An interesting mechanism to generate the Δ's spin-orbit coupling in the nucleus will be introduced, together with its possible consequences. Supported in part by the Department of Energy under Contract No. DE-FG02-87ER40365.

  19. Vector meson and associated strangeness production using a linearly polarized photon beam at Jefferson Lab

    SciTech Connect

    Philip L. Cole

    2004-09-01

    The set of experiments forming the g8a run took place in the summer of 2001 in Hall B of Jefferson Lab. The g8a run was the commissioning experiment for the linearly-polarized photon beam at CLAS. The aim of these experiments is to improve the understanding of the underlying symmetry of the quark degrees of freedom in the nucleon, the nature of the parity exchange between the incident photon and the target nucleon, and the mechanism of associated strangeness production in electromagnetic reactions. A beam of tagged and collimated linearly polarized photons (energy range 1.8-2.2 GeV) in conjunction with the large solid angle coverage of CLAS make possible the extraction of the differential cross-sections and polarization observables for the photoproduction of vector mesons and kaons. The reaction channels are under investigation to search for possibly missing nucleon resonances. An overview of the experiment and preliminary results on the measurement of the photon asymmetries of the aforementioned reactions will be presented in this paper.

  20. Probing the Small-x Gluon Tomography in Correlated Hard Diffractive Dijet Production in Deep Inelastic Scattering.

    PubMed

    Hatta, Yoshitaka; Xiao, Bo-Wen; Yuan, Feng

    2016-05-20

    We investigate the close connection between the quantum phase space Wigner distribution of small-x gluons and the color dipole scattering amplitude, and we propose studying it experimentally in the hard diffractive dijet production at the planned electron-ion collider. The angular correlation between the nucleon recoiled momentum and the dijet transverse momentum probes the nontrivial correlation in the phase space Wigner distribution. This experimental study not only provides us with three-dimensional tomographic pictures of gluons inside high energy protons-it gives a unique and interesting signal for the small-x dynamics with QCD evolution effects. PMID:27258865

  1. Measurement of inclusive isolated prompt photon production at center of mass energy = 7 TeV with the ATLAS

    NASA Astrophysics Data System (ADS)

    Hance, Michael

    Prompt photons at hadron colliders are useful probes of perturbative quantum chromodynamics (pQCD), and are also found in signatures of new physics. A precise measurement of prompt photon production is both a useful test of theoretical models as well as an important step towards understanding final states that contain energetic photons. This thesis presents a measurement of the inclusive isolated prompt photon production cross section in proton-proton collisions at a center-of-mass energy of s = 7 TeV. The data are collected with the ATLAS detector at the Large Hadron Collider, and correspond to 35 pb-1 of integrated luminosity. The measurement is made in four photon pseudorapidity (etagamma) regions: 0 ≤ |etagamma| < 0.6; 0.6 ≤ |etagamma| < 1.37; 1.52 ≤ |eta gamma| < 1.81; and 1.81 ≤ |etagamma| < 2.37; and covers photon transverse energies ( EgT ) in the range 15 GeV ≤ EgT < 400 GeV. Photon candidates are reconstructed and identified through the use of the ATLAS calorimeter and tracking systems. The residual background, primarily from neutral meson decays, is estimated using in-situ techniques based on observed distributions of the total transverse energy in a narrow cone around the photon candidate. The measurements are compared to predictions from next-to-leading order pQCD calculations, with good agreement for photon transverse energies greater than 25 GeV.

  2. Field-induced decay of the quantum vacuum: Visualizing pair production in a classical photonic system

    SciTech Connect

    Longhi, S.

    2010-02-15

    The phenomenon of vacuum decay, that is, electron-positron pair production due to the instability of the quantum electrodynamics vacuum in an external field, is a remarkable prediction of Dirac theory whose experimental observation is still lacking. Here a classic wave optics analog of vacuum decay, based on light propagation in curved waveguide superlattices, is proposed. This photonic analog enables a simple and experimentally accessible visualization in space of the process of pair production as breakup of an initially negative-energy Gaussian wave packet, representing an electron in the Dirac sea, under the influence of an oscillating electric field.

  3. Analysis of Charged Particle/Photon Correlations in Hadronic Multiparticle Production

    SciTech Connect

    Bjorken, James

    2003-05-23

    In order to analyze data on joint charged-particle/photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency corrections and the details of the modeling of the primary pion production, and sensitivity to the production of DCC, as opposed to the generic, binomial-distribution partition of pions into charged and neutral species. The relevant formalism is developed and tested in Monte-Carlo simulations of the MiniMax experimental conditions.

  4. Atom detection and photon production in a scalable, open, optical microcavity.

    PubMed

    Trupke, M; Goldwin, J; Darquié, B; Dutier, G; Eriksson, S; Ashmore, J; Hinds, E A

    2007-08-10

    A microfabricated Fabry-Perot optical resonator has been used for atom detection and photon production with less than 1 atom on average in the cavity mode. Our cavity design combines the intrinsic scalability of microfabrication processes with direct coupling of the cavity field to single-mode optical waveguides or fibers. The presence of the atom is seen through changes in both the intensity and the noise characteristics of probe light reflected from the cavity input mirror. An excitation laser passing transversely through the cavity triggers photon emission into the cavity mode and hence into the single-mode fiber. These are first steps toward building an optical microcavity network on an atom chip for applications in quantum information processing. PMID:17930821

  5. Constraints on Ionizing Photon Production from the Large-scale Lyα Forest

    NASA Astrophysics Data System (ADS)

    Pontzen, Andrew; Bird, Simeon; Peiris, Hiranya; Verde, Licia

    2014-09-01

    Recent work has shown that the z ~= 2.5 Lyα forest on large scales encodes information about the galaxy and quasar populations that keep the intergalactic medium photoionized. We present the first forecasts for constraining the populations with data from current and next-generation surveys. At a minimum, the forest should tell us whether galaxies or, conversely, quasars dominate the photon production. The number density and clustering strength of the ionizing sources might be estimated to sub-10% precision with a DESI-like survey if degeneracies (e.g., with the photon mean-free-path, small-scale clustering power normalization, and potentially other astrophysical effects) can be broken by prior information. We demonstrate that when inhomogeneous ionization is correctly handled, constraints on dark energy do not degrade.

  6. Measurement of inclusive charm production in two-photon collisions at LEP

    NASA Astrophysics Data System (ADS)

    Stone, Alan L., Jr.

    The cross section of inclusive charm production in two- photon collisions s(e+e--->e +e- ccX) is measured at the Large Electron Positron (LEP) collider at the European Center for Nuclear and Particle Physics (CERN). The data was obtained with the L3 detector at the center-of-mass energy of 91 GeV (LEP1) and for the first time at the center-of-mass energies from 130-183 GeV (LEP2). Charmed hadrons are identified by electrons and muons from semileptonic decays. The measured cross section agrees with next-to-leading order (NLO) QCD calculations. The direct process gg-->cc is found to be insufficient to describe the data. The measured cross section values and event distributions require contributions from resolved processes, which are sensitive to the gluon density in the photon.

  7. Industrial-scale spray layer-by-layer assembly for production of biomimetic photonic systems.

    PubMed

    Krogman, K C; Cohen, R E; Hammond, P T; Rubner, M F; Wang, B N

    2013-12-01

    Layer-by-layer assembly is a powerful and flexible thin film process that has successfully reproduced biomimetic photonic systems such as structural colour. While most of the seminal work has been carried out using slow and ultimately unscalable immersion assembly, recent developments using spray layer-by-layer assembly provide a platform for addressing challenges to scale-up and manufacturability. A series of manufacturing systems has been developed to increase production throughput by orders of magnitude, making commercialized structural colour possible. Inspired by biomimetic photonic structures we developed and demonstrated a heat management system that relies on constructive reflection of near infrared radiation to bring about dramatic reductions in heat content. PMID:24263056

  8. CONSTRAINTS ON IONIZING PHOTON PRODUCTION FROM THE LARGE-SCALE Lyα FOREST

    SciTech Connect

    Pontzen, Andrew; Peiris, Hiranya; Bird, Simeon; Verde, Licia

    2014-09-10

    Recent work has shown that the z ≅ 2.5 Lyα forest on large scales encodes information about the galaxy and quasar populations that keep the intergalactic medium photoionized. We present the first forecasts for constraining the populations with data from current and next-generation surveys. At a minimum, the forest should tell us whether galaxies or, conversely, quasars dominate the photon production. The number density and clustering strength of the ionizing sources might be estimated to sub-10% precision with a DESI-like survey if degeneracies (e.g., with the photon mean-free-path, small-scale clustering power normalization, and potentially other astrophysical effects) can be broken by prior information. We demonstrate that when inhomogeneous ionization is correctly handled, constraints on dark energy do not degrade.

  9. Geometrical scaling of direct-photon production in hadron collisions from RHIC to the LHC

    SciTech Connect

    Klein-Boesing, Christian; McLerran, L.

    2014-05-27

    Geometric scaling is a property of hadronic interactions predicted by theories of gluon saturation and expressing rates in terms of dimensionless ratios of transverse momentum to the saturation momentum. In this paper we consider production of photons in pp, dAu and AuAu collisions at √sNN= 200 GeV (RHIC) and in PbPb collisions at √sNN= 2760 GeV (LHC) and show that the yield of direct photons in the transverse momentum range 1 GeV

  10. Production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

    PubMed

    Melville, G; Meriarty, H; Metcalfe, P; Knittel, T; Allen, B J

    2007-09-01

    The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. The production of Ac-225 has been achieved using bremsstrahlung photons from an 18 MV medical linear accelerator (linac) to bombard a Ra-226 target. A linac dose of 2800 Gy produced about 64 microCi of Ra-225, which decays to Ac-225. This result, while consistent with the theoretical calculations, is far too low to be of practical use. A more powerful linac is required that runs at a higher current, longer pulse length and higher frequency for practical production. This process could also lead to the reduction of the nuclear waste product Ra-226. PMID:17532223

  11. Magneto-sonoluminescence and its signatures in photon and dilepton production in relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Başar, Gökçe; Kharzeev, Dmitri E.; Shuryak, Edward V.

    2014-07-01

    The matter produced in the early stages of heavy ion collisions consists mostly of gluons, and is penetrated by the coherent magnetic field produced by spectator nucleons. The fluctuations of gluonic matter in an external magnetic field couple to real and virtual photons through virtual quark loops. We study the resulting contributions to photon and dilepton production that stem from the fluctuations of the stress tensor Tμν in the background of a coherent magnetic field B ⃗. Our study extends significantly the earlier work [G. Basar, D. E. Kharzeev, and V. Skokov, Phys. Rev. Lett. 109, 202303 (2012), 10.1103/PhysRevLett.109.202303], in which only the fluctuations of the trace of the stress tensor Tμμ were considered (the coupling of Tμμ to electromagnetic fields is governed by the scale anomaly). In the present paper we derive more general relations using the operator product expansion (OPE). We also extend the previous study to the case of dileptons, which offers the possibility to discriminate between various production mechanisms. Among the phenomena that we study are magneto-sonoluminescence [MSL, the interaction of magnetic field B ⃗(x,t) with the sound perturbations of the stress tensor δTμν(x ,t)] and magneto-thermoluminescence [MTL, the interaction of B⃗(x,t) with smooth average ]. We calculate the rates of these process and find that they can dominate the photon and dilepton production at early stages of heavy ion collisions. We also point out the characteristic signatures of MSL and MTL that can be used to establish their presence and to diagnose the produced matter.

  12. The mystery of spectral breaks: Lyman continuum absorption by photon-photon pair production in the Fermi GeV spectra of bright blazars

    SciTech Connect

    Stern, Boris E.; Poutanen, Juri E-mail: juri.poutanen@utu.fi

    2014-10-10

    We re-analyze Fermi/LAT γ-ray spectra of bright blazars using the new Pass 7 version of the detector response files and detect breaks at ∼5 GeV in the rest-frame spectra of 3C 454.3 and possibly also 4C +21.35, associated with the photon-photon pair production absorption by the He II Lyman continuum (LyC). We also detect significant breaks at ∼20 GeV associated with hydrogen LyC in both the individual spectra and the stacked redshift-corrected spectrum of several bright blazars. The detected breaks in the stacked spectra univocally prove that they are associated with atomic ultraviolet emission features of the quasar broad-line region (BLR). The dominance of the absorption by the hydrogen Ly complex over He II, a small detected optical depth, and break energy consistent with head-on collisions with LyC photons imply that the γ-ray emission site is located within the BLR, but most of the BLR emission comes from a flat disk-like structure producing little opacity. Alternatively, the LyC emission region size might be larger than the BLR size measured from reverberation mapping, and/or the γ-ray emitting region is extended. These solutions would resolve the long-standing issue of how the multi-hundred GeV photons can escape from the emission zone without being absorbed by softer photons.

  13. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  14. Photon emission and pair production in the interaction of ultra-intense lasers with electrons

    NASA Astrophysics Data System (ADS)

    Jirka, Martin; Klimo, Ondrej; Bulanov, Sergei; Weber, Stefan

    2015-11-01

    With the advent of 10 PW laser facilities, new regimes of laser-matter interaction are opening since QED effects come into play. Due to the radiation reaction which takes place in ultra-intense laser-matter interactions, charged particles lose their energy by emitting high-energy photons. These photons can in the strong laser field create electron-positron pairs via Breit-Wheeler process. One possible interaction scenario leading to efficient generation of pairs is the interaction of two colliding laser pulses with an electron target lying in the common focal spot. In our PIC simulations, gamma-ray photon emission and pair production are studied for different laser wavelengths, intensities and both laser polarization. According to our results, linearly polarized laser pulses seem to be more convenient for efficient pair creation. The role of ions contained in the target and its density are also assessed. Results are compared with the different interaction configuration when the energetic electron bunch interacts with one counter-propagating laser pulse. This research has been partially supported by the Czech Science Foundation (Project No. 15-02964S).

  15. Search for anomalous production of events with a high energy lepton and photon at the Tevatron

    SciTech Connect

    Loginov, Andrey Borisovich; /Moscow, ITEP

    2006-01-01

    We present results of a search for the anomalous production of events containing a high-transverse momentum charged lepton ({ell}, either e or {mu}) and photon ({gamma}), accompanied by missing transverse energy (E{sub T}), and/or additional leptons and photons, and jets (X). We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb{sup -1}, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 {ell}{gamma}E{sub T} events versus a standard model expectation of 37.3 {+-} 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 {+-} 0.7 events (corresponding to a 2.7 {sigma} effect), is not supported by the new data. In the signature of {ell}{ell}{gamma} + X we observe 31 events versus an expectation of 23.0 {+-} 2.7 events. In this sample we find no events with an extra photon or E{sub T} and so find no events like the one ee{gamma}{gamma} E{sub T} event observed in Run I.

  16. Hard Surface Biocontrol in Hospitals Using Microbial-Based Cleaning Products

    PubMed Central

    Vandini, Alberta; Temmerman, Robin; Frabetti, Alessia; Caselli, Elisabetta; Antonioli, Paola; Balboni, Pier Giorgio; Platano, Daniela; Branchini, Alessio; Mazzacane, Sante

    2014-01-01

    Background Healthcare-Associated Infections (HAIs) are one of the most frequent complications occurring in healthcare facilities. Contaminated environmental surfaces provide an important potential source for transmission of many healthcare-associated pathogens, thus indicating the need for new and sustainable strategies. Aim This study aims to evaluate the effect of a novel cleaning procedure based on the mechanism of biocontrol, on the presence and survival of several microorganisms responsible for HAIs (i.e. coliforms, Staphyloccus aureus, Clostridium difficile, and Candida albicans) on hard surfaces in a hospital setting. Methods The effect of microbial cleaning, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium, in comparison with conventional cleaning protocols, was evaluated for 24 weeks in three independent hospitals (one in Belgium and two in Italy) and approximately 20000 microbial surface samples were collected. Results Microbial cleaning, as part of the daily cleaning protocol, resulted in a reduction of HAI-related pathogens by 50 to 89%. This effect was achieved after 3–4 weeks and the reduction in the pathogen load was stable over time. Moreover, by using microbial or conventional cleaning alternatively, we found that this effect was directly related to the new procedure, as indicated by the raise in CFU/m2 when microbial cleaning was replaced by the conventional procedure. Although many questions remain regarding the actual mechanisms involved, this study demonstrates that microbial cleaning is a more effective and sustainable alternative to chemical cleaning and non-specific disinfection in healthcare facilities. Conclusions This study indicates microbial cleaning as an effective strategy in continuously lowering the number of HAI-related microorganisms on surfaces. The first indications on the actual level of HAIs in the trial hospitals monitored on a continuous basis are very promising, and may pave the

  17. D0 results on diphoton direct production and double parton interactions in photon + 3 jet events

    SciTech Connect

    Sawyer, Lee; /Louisiana Tech. U.

    2010-01-01

    We report the measurement of differential diphoton direct production cross sections and a study of photon + 3-jet events with double parton (DP) interactions, based on data taken with the D0 experiment at the Fermilab Tevatron proton-antiproton collider. We measure single differential cross sections as a function of the diphoton mass, the transverse momentum of the diphoton system, the azimuthal angle between the photons, and the polar scattering angle of the photons. In addition, we measure double differential cross sections considering the last three kinematic variables in three diphoton mass bins. The results are compared with different perturbative QCD predictions and event generators. We have used a sample of photon + 3-jet events collected by the D0 experiment with an integrated luminosity of about 1 fb{sup -1} to determine the fraction of events with double parton scattering (f{sub DP}) in a single p{bar p} collision at {radical}s = 1.96 TeV. The DP fraction and effective cross section ({sigma}{sub eff}), a process-independent scale parameter related to the parton density inside the nucleon, are measured in three intervals of the second (ordered in p{sub T}) jet transverse momentum p{sub T}{sup jet2} within the range 15 < p{sub T}{sup jet} < 30 GeV. In this range, f{sub DP} varies between 0.23 < f{sub DP} < 0.47, while {sigma}{sub eff} has the average value {sigma}{sub eff}{sup ave} = 16.4 {+-} 0.3(stat) {+-} 2.3(syst) mb.

  18. Photon-photon collisions

    SciTech Connect

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  19. ConnesFusionTensorProduct/Photon GluonFusion in Mitochondria

    NASA Astrophysics Data System (ADS)

    Wh-Maksoed, Prodi Of Physics Ui, Depok 16415-Indonesia; Ssi, Wh-Maksoed

    2016-05-01

    As in AJ Wassermann distinguished of classical invariant theory & quantum invariant theory subfactor, in S. Palcoux:``From Neveu-Schwarz Subfactors & Connes Fusion'' described the subfactor theory & Witt-algebra whereas Andreas Thom's explanation about ConnesFusionTensorProduct/CFTP related Connes fusion to composition of homomorphism (i). classical tensor product O-X adds the changes,(ii). Relative tensor product H-X preserve the changes. For photonGluonFusion/PGF defined:''photon is the gauge boson of QED, the simplest of all boson'' devotes to CFT as ``quantum field theory which are invariant under conformal transformation & in 2D there are infinite dimensional algebra. Alain Connes states theirselves Connes fusion as ``associative tensor operation'' to be in coincidences with ``their dynamic behavior driven by the balance in mitochondrial fusion & fission (Carveney, 2007) from Peter Alexander Williams: ``Retinal neuronal remodeling in a model of Optic Atrophy'', Dec, 2011. Great acknowledged to the VicePresident of the R.I, HE.Mr. Drs. M. JUSUF KALLA.

  20. A phenomenological study of photon production in low energy neutrino nucleon scattering

    SciTech Connect

    Jenkins, James P; Goldman, Terry J

    2009-01-01

    Low energy photon production is an important background to many current and future precision neutrino experiments. We present a phenomenological study of t-channel radiative corrections to neutral current neutrino nucleus scattering. After introducing the relevant processes and phenomenological coupling constants, we will explore the derived energy and angular distributions as well as total cross-section predictions along with their estimated uncertainties. This is supplemented throughout with comments on possible experimental signatures and implications. We conclude with a general discussion of the analysis in the context of complimentary methodologies. This is based on a talk presented at the DPF 2009 meeting in Detroit MI.

  1. Dynamic control of photosynthetic photon flux for lettuce production in CELSS

    NASA Technical Reports Server (NTRS)

    Chun, C.; Mitchell, C. A.

    1996-01-01

    A new dynamic control of photosynthetic photon flux (PPF) was tested using lettuce canopies growing in the Minitron II plant-growth/canopy gas-exchange system. Canopy photosynthetic rates (Pn) were measured in real time and fedback for further environment control. Pn can be manipulated by changing PPF, which is a good environmental parameter for dynamic control of crop production in a Controlled Ecological Life-Support Systems CELSS. Decision making that combines empirical mathematical models with rule sets developed from recent experimental data was tested. With comparable yield indices and potential for energy savings, dynamic control strategies will contribute greatly to the sustainability of space-deployed CELSS.

  2. Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF

    SciTech Connect

    Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2009-10-01

    The authors present results of a search for anomalous production of two photons together with an electron, muon, {tau} lepton, missing transverse energy, or jets using p{bar p} collision data from 1.1-2.0 fb{sup -1} of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs for new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.

  3. Origin of the kT smearing in direct photon production

    NASA Astrophysics Data System (ADS)

    Lai, Hung-Liang; Li, Hsiang-Nan

    1998-12-01

    We show that the Sudakov factor from the resummation of double logarithms ln(s/k2T) contained in the distribution functions is responsible for the kT smearing mechanism employed in the next-to-leading-order QCD (αα2s) calculations of direct photon production. s is the center-of-mass energy, and kT the transverse momentum carried by a parton in a colliding hadron. This factor exhibits the appropriate s-dependent Gaussian width in kT, such that our predictions are in good agreement with experimental data.

  4. Exclusive vector meson production with a leading neutron in photon-hadron interactions at hadronic colliders

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Moreira, B. D.; Navarra, F. S.; Spiering, D.

    2016-07-01

    In this paper, we study leading neutron production in photon-hadron interactions that take place in p p and p A collisions at large impact parameters. Using a model that describes the recent leading neutron data at HERA, we consider exclusive vector meson production in association with a leading neutron in p p /p A collisions at RHIC and LHC energies. The total cross sections and rapidity distributions of ρ , ϕ , and J /Ψ produced together with a leading neutron are computed. Our results indicate that the study of these processes is feasible and that it can be used to improve the understanding of leading neutron processes and of exclusive vector meson production.

  5. Center of mass energy and system-size dependence of photon production at forward rapidity at RHIC

    SciTech Connect

    STAR Collaboration; Abelev, Betty

    2010-07-05

    We present the multiplicity and pseudorapidity distributions of photons produced in Au+Au and Cu+Cu collisions at {radical}s{sub NN} = 62.4 and 200 GeV. The photons are measured in the region -3.7 < {eta} < -2.3 using the photon multiplicity detector in the STAR experiment at RHIC. The number of photons produced per average number of participating nucleon pairs increases with the beam energy and is independent of the collision centrality. For collisions with similar average numbers of participating nucleons the photon multiplicities are observed to be similar for Au+Au and Cu+Cu collisions at a given beam energy. The ratios of the number of charged particles to photons in the measured pseudorapidity range are found to be 1.4 {+-} 0.1 and 1.2 {+-} 0.1 for {radical}s{sub NN} = 62.4 GeV and 200 GeV, respectively. The energy dependence of this ratio could reflect varying contributions from baryons to charged particles, while mesons are the dominant contributors to photon production in the given kinematic region. The photon pseudorapidity distributions normalized by average number of participating nucleon pairs, when plotted as a function of {eta} - ybeam, are found to follow a longitudinal scaling independent of centrality and colliding ion species at both beam energies.

  6. One-sided imaging of large, dense objects using the 511 keV photons from induced pair production

    SciTech Connect

    Tavora, L.M.; Gilboy, W.B.; Morton, E.J.; Morgado, R.E.; Estep, R.J.; Rawool-Sullivan, M.

    1998-03-01

    The use of annihilation photons from photon-induced electron-positron pair production as a means of inspecting objects when only one side is accessible is described. The Z2 dependence of the pair production cross section and the high penetration of 511 keV photons suggest that this method should be capable of localizing high Z materials in lower Z matrices. The experimental results for the dependence of the back streaming photon yield on Z indicate that dynamic ranges of the order of 20 may be obtained for materials with 4 < Z < 82. Results for point to point images obtained in line scans of representative geometries are also shown. Simulation studies based on the EGS4 Monte Carlo code were also performed and their results show an agreement with experimental data of the order of 5%.

  7. Measurement of direct photon production in p+p collisions at sqrt[s] = 200 GeV.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Jamel, A; Alexander, J; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Averbeck, R; Awes, T C; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Bazilevsky, A; Belikov, S; Bjorndal, M T; Boissevain, J G; Borel, H; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Comets, M P; Constantin, P; Csanád, M; Csörgo, T; Cussonneau, J P; d'Enterria, D; Das, K; David, G; Deák, F; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drachenberg, J L; Drapier, O; Drees, A; Durum, A; Dutta, D; Dzhordzhadze, V; Efremenko, Y V; En'yo, H; Espagnon, B; Esumi, S; Fields, D E; Finck, C; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fung, S-Y; Gadrat, S; Germain, M; Glenn, A; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Perdekamp, M Grosse; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hasuko, K; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hidas, P; Hiejima, H; Hill, J C; Hobbs, R; Holzmann, W; Homma, K; Hong, B; Hoover, A; Horaguchi, T; Ichihara, T; Ikonnikov, V V; Imai, K; Inaba, M; Inuzuka, M; Isenhower, D; Isenhower, L; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kaneta, M; Kang, J H; Katou, K; Kawabata, T; Kazantsev, A V; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D J; Kim, E; Kim, G-B; Kim, H J; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Kohara, R; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kunde, G J; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Le Bornec, Y; Lebedev, A; Leckey, S; Lee, D M; Leitch, M J; Leite, M A L; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Masui, H; Matathias, F; Matsumoto, T; McCain, M C; McGaughey, P L; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mukhopadhyay, D; Muniruzzaman, M; Nagamiya, S; Nagle, J L; Nakamura, T; Newby, J; Nyanin, A S; Nystrand, J; O'brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, H; Okada, K; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Penev, V; Peng, J-C; Pereira, H; Peresedov, V; Pierson, A; Pinkenburg, C; Pisani, R P; Purschke, M L; Purwar, A K; Qualls, J M; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosendahl, S S E; Rosnet, P; Rykov, V L; Ryu, S S; Saito, N; Sakaguchi, T; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shimomura, M; Sickles, A; Silva, C L; Silvermyr, D; Sim, K S; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagi, S; Takagui, E M; Taketani, A; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Taranenko, A; Tarján, P; Thomas, T L; Togawa, M; Tojo, J; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tydesjö, H; Tyurin, N; Uam, T J; Velkovska, J; Velkovsky, M; Veszprémi, V; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Willis, N; Wohn, F K; Woody, C L; Xie, W; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L; Zong, X; Van Hecke, H W

    2007-01-01

    Cross sections for midrapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported for transverse momenta of 3 < pT < 16 GeV/c. Next-to-leading order perturbative QCD (pQCD) describes the data well for pT >5 GeV/c, where the uncertainties of the measurement and theory are comparable. We also report on the effect of requiring the photons to be isolated from parton jet energy. The observed fraction of isolated photons is well described by pQCD for pT >7 GeV/c. PMID:17358469

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

    NASA Astrophysics Data System (ADS)

    Asakawa, Eri; Harada, Daisuke; Kanemura, Shinya; Okada, Yasuhiro; 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→hh and γγ→hh, where h is the (lightest) Higgs boson and g and γ 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+e-→hhZ and γγ→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→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.

  9. 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.

  10. Anomalous photon-gauge boson coupling contribution to the exclusive vector boson pair production from two photon exchange in pp collisions at 13 TeV

    SciTech Connect

    Martins, D. E.; Vilela Pereira, A.; Sá Borges, J.; Rebello Teles, P.

    2015-04-10

    We study the W and Z pair production from two-photon exchange in proton-proton collisions at the LHC in order to evaluate the contributions of anomalous photon-gauge boson couplings, that simulates new particles and couplings predicted in many Standard Model (SM) extensions. The experimental results of W{sup +} W{sup −} exclusive production (pp → pW{sup +}W{sup −} p) at 7 TeV from the CMS collaboration [1] updates the experimental limits on anomalous couplings obtained at the Large Electron-Positron Collider (LEP). This motivates our present analysis hopefully anticipating the expected results using the Precision Proton Spectrometer (PPS) to be installed as part of CMS. In this work, we consider the W{sup +}W{sup −} exclusive production to present the p{sub T} distribution of the lepton pair corresponding to the SM signal with p{sub T} (e, μ) > 10 GeV. Next, we consider the photon-gauge boson anomalous couplings by calculating, from the FPMC and MadGraph event generators, the process γγ → W{sup +}W{sup −} from a model with gauge boson quartic couplings, by considering a 1 TeV scale for new physical effects. We present our results for an integrated luminosity of 5 fb{sup −1} at center-of-mass energy of 7 TeV and for an integrated luminosity of 100 fb{sup −1} at 13 TeV. We present our preliminary results for Z pair exclusive production from two-photon exchange with anomalous couplings, where the ZZγγ quartic coupling is absent in the SM. We calculate the total cross section for the exclusive process and present the four lepton invariant mass distribution. Finally we present an outlook for the present analysis.

  11. Spin effects in hard collision processes

    SciTech Connect

    Ranft, G.; Ranft, J.

    1984-05-01

    Questions of conservation and nonconservation of parity in phenomena associated with particle spin are reviewed. The main attention is concentrated on the production of hadrons, jets, and photons with large momentum transfer and the production of lepton pairs. The mechanisms of the hard-scattering subprocess include exchange of W/sup + -/ and Z/sup 0/ mesons, QCD and QED, and also interference between QCD and the weak interactions and between QED and the weak interactions. Effective cross sections of hard scattering processes are calculated, a factorization of the hadron--hadron scattering cross section is proposed, and the possible types of spin effects manifested in the hadronic subprocesses are classified and discussed. The properties of the polarized proton distributions and polarized structure functions are given in two appendices.

  12. Reconsideration of the inclusive prompt photon production at the LHC with kT-factorization

    NASA Astrophysics Data System (ADS)

    Lipatov, A. V.; Malyshev, M. A.

    2016-08-01

    We reconsider the inclusive production of isolated prompt photons in p p collisions at the LHC energies in the framework of kT-factorization approach. Our analysis is based on the O (α αs) off-shell (depending on the transverse momenta of initial quarks and gluons) production amplitudes of q*g*→γ q and q*q¯*→γ g partonic subprocesses and transverse momentum dependent (or unintegrated) quark and gluon densities in a proton, which are chosen in accordance with the Kimber-Martin-Ryskin prescription. We show that the subleading high-order O (α αs2) contributions, not covered by the noncollinear evolution of parton densities, are important to describe latest LHC data.

  13. Analysis of charged-particle{endash}photon correlations in hadronic multiparticle production

    SciTech Connect

    MiniMax Collaboration

    1997-05-01

    In order to analyze data on joint charged-particle{endash}photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency corrections and the details of the modeling of the primary pion production, and sensitivity to the production of DCC, as opposed to the generic, binomial-distribution partition of pions into charged and neutral species. The relevant formalism is developed and tested in Monte Carlo simulations of the MiniMax experimental conditions. {copyright} {ital 1997} {ital The American Physical Society}

  14. Heavy ion precompound phenomena: A glance at hard gamma and subthreshold pion production

    SciTech Connect

    Blann, M.; Remington, B.A.

    1987-08-01

    We test a relaxation model based on two body nucleon-nucleon scattering processes to interpret phenomena observed in heavy ion reactions. We use the Boltzmann master equation to accomplish this. By assuming that the projectile nucleons share the total excitation with equal a-priori probability of all configurations, we are able to reproduce several sets of neutron spectra from /sup 20/Ne and /sup 12/C induced reactions on /sup 165/Ho. With no additional free parameters our model successfully reproduces subthreshold pion production cross sections, high energy ..gamma..-ray spectra, and angular distributions of high energy ..gamma..-rays. 40 refs., 12 figs., 2 tabs.

  15. First measurement of Z/γ* production in compton scattering of quasi-real photons

    NASA Astrophysics Data System (ADS)

    OPAL Collaboration; Abbiendi, G.; Ackerstaff, K.; Alexander, G.; Allison, J.; Altekamp, N.; Anderson, K. J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S. F.; Axen, D.; Azuelos, G.; Ball, A. H.; Barberio, E.; Barlow, R. J.; Bartoldus, R.; Batley, J. R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S. D.; Blobel, V.; Bloodworth, I. J.; Bobinski, M.; Bock, P.; Böhme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R. M.; Burckhart, H. J.; Burgard, C.; Bürgin, R.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrisman, D.; Ciocca, C.; Clarke, P. E. L.; Clay, E.; Cohen, I.; Conboy, J. E.; Cooke, O. C.; Couyoumtzelis, C.; Coxe, R. L.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; Davis, R.; de Jong, S.; del Pozo, L. A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M. S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I. P.; Eatough, D.; Estabrooks, P. G.; Etzion, E.; Evans, H. G.; Fabbri, F.; Fanti, M.; Faust, A. A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Fürtjes, A.; Futyan, D. I.; Gagnon, P.; Gary, J. W.; Gascon, J.; Gascon-Shotkin, S. M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W. R.; Gingrich, D. M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwé, M.; Hanson, G. G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C. K.; Hartmann, C.; Hauschild, M.; Hawkes, C. M.; Hawkings, R.; Hemingway, R. J.; Herndon, M.; Herten, G.; Heuer, R. D.; Hildreth, M. D.; Hill, J. C.; Hillier, S. J.; Hobson, P. R.; Hocker, A.; Homer, R. J.; Honma, A. K.; Horváth, D.; Hossain, K. R.; Howard, R.; Hüntemeyer, P.; Igo-Kemenes, P.; Imrie, D. C.; Ishii, K.; Jacob, F. R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C. R.; Jovanovic, P.; Junk, T. R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P. I.; Keeler, R. K.; Kellogg, R. G.; Kennedy, B. W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D. S.; Kokott, T. P.; Kolrep, M.; Komamiya, S.; Kowalewski, R. V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G. D.; Lanske, D.; Lauber, J.; Lautenschlager, S. R.; Lawson, I.; Layter, J. G.; Lazic, D.; Lee, A. M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A. W.; Lloyd, S. L.; Loebinger, F. K.; Long, G. D.; Losty, M. J.; Ludwig, J.; Liu, D.; Macchiolo, A.; MacPherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A. J.; Martin, J. P.; Martinez, G.; Mashimo, T.; Mättig, P.; McDonald, W. J.; McKenna, J.; McKigney, E. A.; McMahon, T. J.; McPherson, R. A.; Meijers, F.; Menke, S.; Merritt, F. S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D. J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H. A.; Nellen, B.; Nisius, R.; O'Neale, S. W.; Oakham, F. G.; Odorici, F.; Ogren, H. O.; Oreglia, M. J.; Orito, S.; Pálinkás, J.; Pásztor, G.; Pater, J. R.; Patrick, G. N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J. E.; Pinfold, J.; Plane, D. E.; Poffenberger, P.; Polok, J.; Przybycień , M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S. A.; Rodning, N.; Roney, J. M.; Roscoe, K.; Rossi, A. M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D. R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W. M.; Sarkisyan, E. K. G.; Sbarra, C.; Schaile, A. D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schöning, A.; Schröder, M.; Schumacher, M.; Schwick, C.; Scott, W. G.; Seiler, T.; Seuster, R.; Shears, T. G.; Shen, B. C.; Shepherd-Themistocleous, C. H.; Sherwood, P.; Siroli, G. P.; Sittler, A.; Skuja, A.; Smith, A. M.; Snow, G. A.; Sobie, R.; Söldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, D.; Ströhmer, R.; Surrow, B.; Talbot, S. D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M. A.; von Törne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trócsányi, Z.; Tsur, E.; Turcot, A. S.; Turner-Watson, M. F.; van Kooten, R.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wäckerle, F.; Wagner, A.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Wells, P. S.; Wermes, N.; White, J. S.; Wilson, G. W.; Wilson, J. A.; Wyatt, T. R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1998-10-01

    We report the first observation of Z/γ* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e--->e+e- Z/γ*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/γ* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/γ* branching ratio to hadrons to be (0.9+/-0.3+/-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)eγ* production, this product is found to be (4.1+/-1.6+/-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.

  16. Investigation of a photon counting avalanche photodiode from Hamamatsu photonics

    NASA Astrophysics Data System (ADS)

    Britvitch, I.; Musienko, Y.; Renker, D.

    2006-11-01

    Multi-cell avalanche photodiodes (APDs) operating in Geiger mode have been shown to be a very promising alternative to photomultiplier tubes for the detection of single photons at room temperature. Like a photomultiplier they have high gain and a fast rise time and they are insensitive to pickup. Beyond it they operate in high magnetic fields, are compact and need a relatively low bias voltage. It is expected that the MOS production technique makes them cheap. Recently PSI and Hamamatsu Photonics worked together for the development of a radiation-hard APD for CMS ECAL and had very good success. The development continued based on a similar design for a photon counting multielement Geiger-mode APD with an area of 1×1 mm 2. The properties of this device have been measured and will be reported.

  17. Singular Values for Products of Complex Ginibre Matrices with a Source: Hard Edge Limit and Phase Transition

    NASA Astrophysics Data System (ADS)

    Forrester, Peter J.; Liu, Dang-Zheng

    2016-05-01

    The singular values squared of the random matrix product {Y = {Gr G_{r-1}} ldots G1 (G0 + A)}, where each {Gj} is a rectangular standard complex Gaussian matrix while A is non-random, are shown to be a determinantal point process with the correlation kernel given by a double contour integral. When all but finitely many eigenvalues of A* A are equal to bN, the kernel is shown to admit a well-defined hard edge scaling, in which case a critical value is established and a phase transition phenomenon is observed. More specifically, the limiting kernel in the subcritical regime of {0 < b < 1} is independent of b, and is in fact the same as that known for the case b = 0 due to Kuijlaars and Zhang. The critical regime of b = 1 allows for a double scaling limit by choosing {{b = (1 - τ/√{N})^{-1}}}, and for this the critical kernel and outlier phenomenon are established. In the simplest case r = 0, which is closely related to non-intersecting squared Bessel paths, a distribution corresponding to the finite shifted mean LUE is proven to be the scaling limit in the supercritical regime of {b > 1} with two distinct scaling rates. Similar results also hold true for the random matrix product {Tr T_{r-1} ldots T1 (G0 + A)}, with each {Tj} being a truncated unitary matrix.

  18. Direct photon production in Pb-Pb collisions at √{sNN} = 2.76 TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaraz, J. R. M.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Böttger, S.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.

    2016-03-01

    Direct photon production at mid-rapidity in Pb-Pb collisions at √{sNN} = 2.76 TeV was studied in the transverse momentum range 0.9 Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e- pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0-20%, 20-40%, and 40-80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT ≳ 5 GeV / c. Direct photon spectra down to pT ≈ 1 GeV / c could be extracted for the 20-40% and 0-20% centrality classes. The significance of the direct photon signal for 0.9 photon production in heavy-ion collisions agree with the data within uncertainties.

  19. Study of π0 pair production in single-tag two-photon collisions

    NASA Astrophysics Data System (ADS)

    Masuda, M.; Uehara, S.; Watanabe, Y.; Nakazawa, H.; Abdesselam, A.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Atmacan, H.; Aulchenko, V.; Aushev, T.; Babu, V.; Badhrees, I.; Bakich, A. M.; Barberio, E.; Behera, P.; Bhuyan, B.; Biswal, J.; Bobrov, A.; Bonvicini, G.; Bozek, A.; Bračko, M.; Browder, T. E.; Červenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Cho, K.; Chobanova, V.; Choi, S.-K.; Choi, Y.; Cinabro, D.; Dalseno, J.; Danilov, M.; Dash, N.; Dingfelder, J.; Doležal, Z.; Drásal, Z.; Dutta, D.; Eidelman, S.; Epifanov, D.; Farhat, H.; Fast, J. E.; Ferber, T.; Fulsom, B. G.; Gaur, V.; Gabyshev, N.; Garmash, A.; Gillard, R.; Giordano, F.; Glattauer, R.; Goh, Y. M.; Goldenzweig, P.; Golob, B.; Haba, J.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hou, W.-S.; Iijima, T.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Jaegle, I.; Joffe, D.; Joo, K. K.; Julius, T.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kim, D. Y.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. H.; Kim, Y. J.; Ko, B. R.; Korpar, S.; Križan, P.; Krokovny, P.; Kumita, T.; Kuzmin, A.; Kwon, Y.-J.; Lange, J. S.; Lee, D. H.; Lee, I. S.; Li, C.; Li, L.; Li, Y.; Libby, J.; Liventsev, D.; Lukin, P.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Mohanty, S.; Moll, A.; Moon, H. K.; Mori, T.; Mussa, R.; Nakano, E.; Nakao, M.; Nanut, T.; Natkaniec, Z.; Nayak, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Pakhlov, P.; Pakhlova, G.; Pal, B.; Park, C. W.; Park, H.; Pedlar, T. K.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Rauch, J.; Ribežl, E.; Ritter, M.; Rostomyan, A.; Sandilya, S.; Santelj, L.; Sanuki, T.; Sato, Y.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Seon, O.; Sevior, M. E.; Shebalin, V.; Shen, C. P.; Shibata, T.-A.; Shiu, J.-G.; Shwartz, B.; Simon, F.; Sohn, Y.-S.; Sokolov, A.; Solovieva, E.; Starič, M.; Sumihama, M.; Sumiyoshi, T.; Tamponi, U.; Tanida, K.; Teramoto, Y.; Uglov, T.; Unno, Y.; Uno, S.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vinokurova, A.; Vorobyev, V.; Vossen, A.; Wagner, M. N.; Wang, C. H.; Wang, M.-Z.; Wang, P.; Williams, K. M.; Won, E.; Yamaoka, J.; Yamashita, Y.; Yashchenko, S.; Ye, H.; Yusa, Y.; Zhang, C. C.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.; Belle Collaboration

    2016-02-01

    We report a measurement of the differential cross section of π0 pair production in single-tag two-photon collisions, γ*γ →π0π0, in e+e- scattering. The cross section is measured for Q2 up to 30 GeV2, where Q2 is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV

  20. Photon production from the scattering of axions out of a solenoidal magnetic field

    SciTech Connect

    Guendelman, Eduardo I.; Shilon, Idan; Cantatore, Giovanni; Zioutas, Konstantin E-mail: silon@bgu.ac.il E-mail: Konstantin.Zioutas@cern.ch

    2010-06-01

    We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D δ-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. Comparison between the 2D conversion probabilities for QCD inspired axions and those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect is made using an averaging prescription procedure of the 1D case. We also consider scattering at a resonance E{sub axion} ∼ m{sub axion}, which corresponds to the scattering from a δ-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem.

  1. Inclusive J/psi production in two-photon collisions at LEP II with the DELPHI detector

    NASA Astrophysics Data System (ADS)

    Chapkine, Mikhail

    2002-06-01

    Inclusive J/psi production in photon-photon collisions has been observed by the DELPHI collaboration at LEP II beam energies. A clean signal from the reaction gamma][gamma [right arrow] J/psi + X is seen. Number of observed events, N(J/psi [right arrow] mu]+[mu-) = 36 plus-or-minus 7 for the integrated luminosity 617 pb-1, yielding a cross section of sigma](J/[psi [right arrow] mu]+[mu-) = 25.2 plus-or-minus 10.2 pb. Based on a study of the event shapes of different types of gamma][gamma processes in the PYTHIA program, we conclude that (74plus-or-minus22)% of the observed J/psi events are due to the 'resolved' photons, the dominant contribution of which is evidently a single color-octet gluon within the photon.

  2. High Transverse Momentum Direct Photon Production at Fermilab Fixed-Target Energies

    SciTech Connect

    Apanasevich, Leonard

    2005-05-01

    This thesis describes a study of the production of high transverse momentum direct photons and {pi}{sup 0} mesons by proton beams at 530 and 800 GeV/c and {pi}{sup -} beams at 515 GeV/c incident on beryllium, copper, and liquid hydrogen targets. The data were collected by Fermilab experiment E706 during the 1990 and 1991-92 fixed target runs. The apparatus included a large, finely segmented lead and liquid argon electromagnetic calorimeter and a charged particle spectrometer featuring silicon strip detectors in the target region and proportional wire chambers and drift tubes downstream of a large aperture analysis magnet. The inclusive cross sections are presented as functions of transverse momentum and rapidity. The measurements are compared with next-to-leading order perturbative QCD calculations and to results from previous experiments.

  3. Large delay-bandwidth product and tuning of slow light pulse in photonic crystal coupled waveguide.

    PubMed

    Baba, Toshihiko; Kawaaski, Takashi; Sasaki, Hirokazu; Adachi, Jun; Mori, Daisuke

    2008-06-01

    This paper reports two advances in a slow light device consisting of chirped photonic crystal slab coupled waveguide on SOI substrate. One is concerning the delay-bandwidth product, indicating the buffering capacity of the device. We experimentally evaluated a record high value of 57 (a 40 ps delay and a 1.4 THz bandwidth). We also observed ~1 ps wide optical pulse transmission in the cross-correlation measurement. Regarding the pulse as a signal and considering the broadening of the pulse width due to the imperfect dispersion compensation in the device, storage of more than 12 signal bits was confirmed. The other is a wide-range tuning of the pulse delay. We propose a technique for externally controlling the chirping to permit variable delay. We demonstrate tuning of the pulse delay up to 23 ps, corresponding to a ~7 mm extension of the free space length. PMID:18545637

  4. /J/ψ plus dijet associated production in two-photon collisions

    NASA Astrophysics Data System (ADS)

    Klasen, M.; Kniehl, B. A.; Mihaila, L.; Steinhauser, M.

    2001-08-01

    We study the production of a J/ ψ meson in association with one or two jets in γγ collisions concentrating on the direct-photon contribution, which is expected to be dominant for large J/ ψ-meson transverse momentum and/or large dijet invariant mass. We work at leading order in the factorization formalism of nonrelativistic QCD and include all relevant colour-octet processes. We present distributions in J/ ψ-meson transverse momentum and rapidity appropriate for CERN LEP2, a future e+e- linear collider, and a possible γγ collider mode of the latter. In the case of the e+e- linear collider, we assume the beamstrahlung spectrum appropriate for DESY TESLA.

  5. Long-term monitoring of fleshy fruit and hard mast production and seasonal bird distribution at the Savannah River Site, South Carolina.

    SciTech Connect

    Greenberg, Cathryn, H.; Levey, Douglas J.

    2009-06-15

    A final report of Fruit and hard mast production in five habitat types at SRS with a comparison of fruit consumption by fledgling versus adult birds at SRS and Relative importance of fruit, seeds, and insects in the diets of overwintering birds at SRS.

  6. Radiation hardness tests and characterization of the CLARO-CMOS, a low power and fast single-photon counting ASIC in 0.35 micron CMOS technology

    NASA Astrophysics Data System (ADS)

    Fiorini, M.; Andreotti, M.; Baldini, W.; Calabrese, R.; Carniti, P.; Cassina, L.; Cotta Ramusino, A.; Giachero, A.; Gotti, C.; Luppi, E.; Maino, M.; Malaguti, R.; Pessina, G.; Tomassetti, L.

    2014-12-01

    The CLARO-CMOS is a prototype ASIC that allows fast photon counting with 5 ns peaking time, a recovery time to baseline smaller than 25 ns, and a power consumption of less than 1 mW per channel. This chip is capable of single-photon counting with multi-anode photomultipliers and finds applications also in the read-out of silicon photomultipliers and microchannel plates. The prototype is realized in AMS 0.35 micron CMOS technology. In the LHCb RICH environment, assuming 10 years of operation at the nominal luminosity expected after the upgrade in Long Shutdown 2 (LS2), the ASIC must withstand a total fluence of about 6×1012 1 MeV neq /cm2 and a total ionizing dose of 400 krad. A systematic evaluation of the radiation effects on the CLARO-CMOS performance is therefore crucial to ensure long term stability of the electronics front-end. The results of multi-step irradiation tests with neutrons and X-rays up to the fluence of 1014 cm-2 and a dose of 4 Mrad, respectively, are presented, including measurement of single event effects during irradiation and chip performance evaluation before and after each irradiation step.

  7. Direct Photon and Neutral Pion Production in pp and Pb-Pb Collisions Measured with the ALICE Experiment at LHC

    NASA Astrophysics Data System (ADS)

    Peressounko, D.

    2015-06-01

    Measurements of direct photon and neutral pion production in heavy-ion collisions provide a comprehensive set of observables characterizing properties of the hot QCD medium. Direct photons provide means to test the initial stage of an AA collision and carry information about the temperature and space-time evolution of the hot medium. Neutral pion suppression probes the parton energy loss in the hot medium. Measurements of neutral meson spectra in pp collisions at LHC energies √ {s} = 0.9, ; 2.76, ; 7 ; {textrm{TeV}} serve as a reference for heavy-ion collisions and also provide valuable input data for parameterization of the QCD parton Fragmentation Functions. In this talk, results from the ALICE experiment on direct photon and neutral pion production in pp and Pb-Pb collisions are summarized.

  8. Hard-pan soils - Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hard pans, hard layers, or compacted horizons, either surface or subsurface, are universal problems that limit crop production. Hard layers can be caused by traffic or soil genetic properties that result in horizons with high density or cemented soil particles; these horizons have elevated penetrati...

  9. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure. PMID:1511554

  10. Dilepton and/or photon production in heavy ion collisions and the QCD phase transition

    SciTech Connect

    Hung, C.M.; Shuryak, E.V.

    1997-07-01

    We study the electromagnetic production from highly excited hadronic matter created in heavy ion collisions. The rates include the usual lowest order processes in quark-gluon plasma plus the usual reactions in the hadronic phase, related with {rho},a{sub 1} mesons. The space-time integration is done using a hydrodynamical model. Conventional {bar q}q ({pi}{sup +}{pi}{sup {minus}}) annihilation in quark-gluon plasma and hadronic phase cannot explain the observed dilepton spectrum, especially that by the CERES experiment at CERN. A decreased {rho} mass can account for the observed effect, provided it shifts into the region of 0.4{endash}0.5 GeV near the phase transition. In order to test this hypothesis one should also look at the chiral partner of {rho}, the axial a{sub 1} meson: its mass must then behave similarly. Its decay a{sub 1}{r_arrow}{pi}e{sup +}e{sup {minus}} populates the low mass region seen in the same experiment. The results for direct photon production are below the current WA80 experimental bounds, for all variants considered. {copyright} {ital 1997} {ital The American Physical Society}

  11. Analysis of the components of hard resin in hops (Humulus lupulus L.) and structural elucidation of their transformation products formed during the brewing process.

    PubMed

    Taniguchi, Yoshimasa; Taniguchi, Harumi; Yamada, Makiko; Matsukura, Yasuko; Koizumi, Hideki; Furihata, Kazuo; Shindo, Kazutoshi

    2014-11-26

    The resins from hops (Humulus lupulus L.), which add the bitter taste to beer, are classified into two main sub-fractions, namely, soft and hard resins. α- and β-Acids in soft resin and their transformation during the wort boiling process are well-studied; however, other constituents in resins, especially hard resin, have been unidentified. In this study, we identified humulinones and hulupones as soft-resin components, in addition to 4'-hydroxyallohumulinones and tricyclooxyisohumulones A and B as hard-resin components. These compounds are all oxidation products derived from α- or β-acids. We also investigated compositional changes in the hard resin during the wort boiling process, which has a significant effect on the taste of the beer, by using model boiling experiments. The major changes were identified to be isomerization of 4'-hydroxyallohumulinones into 4'-hydroxyallo-cis-humulinones, followed by decomposition into cis-oxyhumulinic acids. These findings will be helpful in systematically evaluating and optimizing the effect of the hard resin on beer quality. PMID:25354357

  12. Polarization observables in hard rescattering mechanism of deuteron photodisintegration

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak M.

    2004-05-01

    Polarization properties of high energy photodisintegration of the deuteron are studied within the framework of the hard rescattering mechanism (HRM). In HRM, a quark of one nucleon knocked-out by the incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with high relative momentum. Summation of all relevant quark rescattering amplitudes allows us to express the scattering amplitude of the reaction through the convolution of a hard photon-quark interaction vertex, the large angle p-n scattering amplitude and the low momentum deuteron wave function. Within HRM, it is demonstrated that the polarization observables in hard photodisintegration of the deuteron can be expressed through the five helicity amplitudes of NN scattering at high momentum transfer. At 90° CM scattering HRM predicts the dominance of the isovector channel of hard pn rescattering, and it explains the observed smallness of induced, Py and transfered, Cx polarizations without invoking the argument of helicity conservation. Namely, HRM predicts that Py and Cx are proportional to the φ5 helicity amplitude which vanishes at θcm=90° due to symmetry reasons. HRM predicts also a nonzero value for Cz in the helicity-conserving regime and a positive Σ asymmetry which is related to the dominance of the isovector channel in the hard reinteraction. We extend our calculations to the region where large polarization effects are observed in pp scattering as well as give predictions for angular dependences.

  13. Resonance formation in photon-photon collisions

    SciTech Connect

    Gidal, G.

    1988-08-01

    Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the ..gamma gamma..* production of spin-one resonances. 37 refs., 17 figs., 5 tabs.

  14. Soft X-Ray Irradiation of Methanol Ice: Formation of Products as a Function of Photon Energy

    NASA Astrophysics Data System (ADS)

    Chen, Y.-J.; Ciaravella, A.; Muñoz Caro, G. M.; Cecchi-Pestellini, C.; Jiménez-Escobar, A.; Juang, K.-J.; Yih, T.-S.

    2013-12-01

    Pure methanol ices have been irradiated with monochromatic soft X-rays of 300 and 550 eV close to the 1s resonance edges of C and O, respectively, and with a broadband spectrum (250-1200 eV). The infrared (IR) spectra of the irradiated ices show several new products of astrophysical interest such as CH2OH, H2CO, CH4, HCOOH, HCOCH2OH, CH3COOH, CH3OCH3, HCOOCH3, and (CH2OH)2, as well as HCO, CO, and CO2. The effect of X-rays is the result of the combined interactions of photons and electrons with the ice. A significant contribution to the formation and growth of new species in the CH3OH ice irradiated with X-rays is given by secondary electrons, whose energy distribution depends on the energy of X-ray photons. Within a single experiment, the abundances of the new products increase with the absorbed energy. Monochromatic experiments show that product abundances also increase with the photon energy. However, the abundances per unit energy of newly formed species show a marked decrease in the broadband experiment as compared to irradiations with monochromatic photons, suggesting a possible regulatory role of the energy deposition rate. The number of new molecules produced per absorbed eV in the X-ray experiments has been compared to those obtained with electron and ultraviolet (UV) irradiation experiments.

  15. Absorption of gamma-ray photons in a vacuum neutron star magnetosphere: I. Electron-positron pair production

    SciTech Connect

    Istomin, Ya. N. Sob'yanin, D. N.

    2011-10-15

    The production of electron-positron pairs in a vacuum neutron star magnetosphere is investigated for both low (compared to the Schwinger one) and high magnetic fields. The case of a strong longitudinal electric field where the produced electrons and positrons acquire a stationary Lorentz factor in a short time is considered. The source of electron-positron pairs has been calculated with allowance made for the pair production by curvature and synchrotron photons. Synchrotron photons are shown to make a major contribution to the total pair production rate in a weak magnetic field. At the same time, the contribution from bremsstrahlung photons may be neglected. The existence of a time delay due to the finiteness of the electron and positron acceleration time leads to a great reduction in the electron-positron plasma generation rate compared to the case of a zero time delay. The effective local source of electron-positron pairs has been constructed. It can be used in the hydrodynamic equations that describe the development of a cascade after the absorption of a photon from the cosmic gamma-ray background in a neutron star magnetosphere.

  16. Measurement of the Isolated Prompt Photon Production Cross Section in pp Collisions at {radical}(s)=7 TeV

    SciTech Connect

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Eroe, J.; Fabjan, C.; Friedl, M.; Fruehwirth, R.; Ghete, V. M.; Hammer, J.; Haensel, S.; Hartl, C.; Hoch, M.; Hoermann, N.; Hrubec, J.; Jeitler, M.; Kasieczka, G.; Kiesenhofer, W.

    2011-02-25

    The differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy E{sub T}{sup {gamma}} in pp collisions at {radical}(s)=7 TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9 pb{sup -1}. Photons are required to have a pseudorapidity |{eta}{sup {gamma}}|<1.45 and E{sub T}{sup {gamma}}>21 GeV, covering the kinematic region 0.006

  17. Measurement of the Differential Cross Section for Isolated Prompt Photon Production in pp Collisions at 7 TeV

    SciTech Connect

    Chatrchyan, S.; et al.,

    2011-09-01

    A measurement of the differential cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data sample corresponds to an integrated luminosity of 36 inverse picobarns recorded by the CMS detector at the LHC. The measurement covers the pseudorapidity range |eta|<2.5 and the transverse energy range 25 < ET < 400 GeV, corresponding to the kinematic region 0.007 < xT < 0.114. Photon candidates are identified with two complementary methods, one based on photon conversions in the silicon tracker and the other on isolated energy deposits in the electromagnetic calorimeter. The measured cross section is presented as a function of ET in four pseudorapidity regions. The next-to-leading-order perturbative QCD calculations are consistent with the measured cross section.

  18. Modelling gamma-ray photon emission and pair production in high-intensity laser–matter interactions

    SciTech Connect

    Ridgers, C.P.; Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX ; Kirk, J.G.; Duclous, R.; Blackburn, T.G.; Brady, C.S.; Bennett, K.; Arber, T.D.; Bell, A.R.; Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX

    2014-03-01

    In high-intensity (>10{sup 21} Wcm{sup −2}) laser–matter interactions gamma-ray photon emission by the electrons can strongly affect the electron's dynamics and copious numbers of electron–positron pairs can be produced by the emitted photons. We show how these processes can be included in simulations by coupling a Monte Carlo algorithm describing the emission to a particle-in-cell code. The Monte Carlo algorithm includes quantum corrections to the photon emission, which we show must be included if the pair production rate is to be correctly determined. The accuracy, convergence and energy conservation properties of the Monte Carlo algorithm are analysed in simple test problems.

  19. Measurement of the Isolated Prompt Photon Production Cross Section in pp Collisions at sqrt(s) = 7 TeV

    SciTech Connect

    Khachatryan, Vardan; et al.

    2011-02-01

    The differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy E_T-gamma in pp collisions at sqrt(s)=7 TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9 inverse picobarns. Photons are required to have a pseudorapidity |eta_gamma|<1.45 and E_T-gamma > 21 GeV, covering the kinematic region 0.006 < x_T < 0.086. The measured cross section is found to be in agreement with next-to-leading-order perturbative QCD calculations.

  20. Ten years of photonics education at the college level in Ontario: results and by-products

    NASA Astrophysics Data System (ADS)

    Nantel, Marc

    2010-08-01

    In 2000, there was no way for an Ontario student to obtain a credential in optics, laser or photonics without going through graduate school. This was in, arguably, the world-leading jurisdiction in photonics-enabled telecommunications industry. To alleviate this problem and supply the job market with highly-qualified people in the field of optics and photonics, the Ontario Centres of Excellence - then as Photonics Research Ontario - partnered with Algonquin College (Ottawa) and Niagara College (Welland) to establish over the past decade a suite of programs: a 1-year Certificate in Advanced Lasers, a 2-year Diploma for Photonics Engineering Technician, a 3-year Diploma for Photonics Engineering Technologists and a 4-year Bachelor of Applied Technology - Photonics. Much has been learnt along the way - the crucial need for industrial partner and government support, for example - and many course corrections had to be made (telecom bust, anyone?). The author will share the results of this 10-year journey so far, the lessons learnt, and a view to the next ten years for these programs and photonics education in Ontario in general.

  1. Electro-magnetic physics studies at RHIC: Neutral pion production, direct photon HBT, photon elliptic flow in gold-gold collisions at sqrt(s_NN) = 200 GeV and the Muon Telescope Detector simulation

    NASA Astrophysics Data System (ADS)

    Lin, Guoji

    Electro-magnetic (E&M) probes such as direct photons and muons (mu) are important tools to study the properties of the extremely hot and dense matter created in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). In this thesis, several topics of E&M physics will be addressed, including neutral pion (pi0) production, direct photon HBT, and photon elliptic flow (v2) in Au+Au collisions at sNN = 200 GeV. A discussion on the simulation study of the new Muon Telescope Detector (MTD) will also be presented. The pi0 production is a fundamental measurement of hadron production and prerequisite for the background study of direct photons. Neutral pions are reconstructed using the photons detected by the STAR Barrel Electro-magnetic Calorimeter (BEMC) and the Time Projection Chamber (TPC). Spectra of pi 0 are measured at transverse momentum 1 < pT < 12 GeV/c near mid-rapidity (0 < eta < 0.8) in 200 GeV Au+Au collisions. The spectra and nuclear modification factors RCP and RAA are compared to earlier pi+/- and pi0 results. Direct photon Hanbury-Brown and Twiss (HBT) correlations can reveal information of the system size throughout the whole collision. A first attempt of direct photon HBT study at RHIC in 200 GeV Au+Au collisions is done using photons detected by the STAR BEMC and TPC. All unknown correlation at small Qinv is observed, whose magnitude is much larger than the expected HBT signal, and possible causes of the correlation will be discussed. Direct photon elliptic flow (v2) at intermediate to high pT is sensitive to the source of direct photon production. Results of inclusive photon v2 in 200 GeV Au+Au collisions are presented. The v2 of pi0 decay photons is calculated from the previously published pi results. The comparison between inclusive and decay photon v 2 indicates that direct photon v2 is small. A new large-area Muon Telescope Detector at mid-rapidity at RHIC is proposed and under investigation, using the Long-strip Multi-Gap Resistive Plate

  2. Direct photon production in d+Au collisions at sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Adler, S. S.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Al-Jamel, A.; Alexander, J.; Angerami, A.; Aoki, K.; Apadula, N.; Aphecetche, L.; Aramaki, Y.; Armendariz, R.; Aronson, S. H.; Asai, J.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Batsouli, S.; Baublis, V.; Bauer, F.; Baumann, C.; Bazilevsky, A.; Belikov, S.; Belmont, R.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Bickley, A. A.; Bjorndal, M. T.; Blau, D. S.; Boissevain, J. G.; Bok, J. S.; Borel, H.; Boyle, K.; Brooks, M. L.; Brown, D. S.; Bruner, N.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J. M.; Butsyk, S.; Camacho, C. M.; Camard, X.; Campbell, S.; Caringi, A.; Chand, P.; Chang, B. S.; Chang, W. C.; Charvet, J.-L.; Chen, C.-H.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Churyn, A.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cobigo, Y.; Cole, B. A.; Comets, M. P.; Conesa del Valle, Z.; Connors, M.; Constantin, P.; Csanád, M.; Csörgő, T.; Cussonneau, J. P.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; David, G.; Dayananda, M. K.; Deák, F.; Delagrange, H.; Denisov, A.; d'Enterria, D.; Deshpande, A.; Desmond, E. J.; Devismes, A.; Dharmawardane, K. V.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drachenberg, J. L.; Drapier, O.; Drees, A.; Drees, K. A.; Dubey, A. K.; Durham, J. M.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'yo, H.; Espagnon, B.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fields, D. E.; Finck, C.; Finger, M.; Finger, M., Jr.; Fleuret, F.; Fokin, S. L.; Fox, B. D.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fung, S.-Y.; Fusayasu, T.; Gadrat, S.; Garishvili, I.; Germain, M.; Glenn, A.; Gong, H.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gunji, T.; Gustafsson, H.-Å.; Hachiya, T.; Hadj Henni, A.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Hanks, J.; Hansen, A. G.; Hartouni, E. P.; Haruna, K.; Harvey, M.; Haslum, E.; Hasuko, K.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Heuser, J. M.; Hidas, P.; Hiejima, H.; Hill, J. C.; Hobbs, R.; Hohlmann, M.; Holzmann, W.; Homma, K.; Hong, B.; Hoover, A.; Horaguchi, T.; Hornback, D.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Ikonnikov, V. V.; Imai, K.; Imrek, J.; Inaba, M.; Inuzuka, M.; Isenhower, D.; Isenhower, L.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Ivanischev, D.; Iwanaga, Y.; Jacak, B. V.; Jia, J.; Jiang, X.; Jin, J.; Jinnouchi, O.; Johnson, B. M.; Johnson, S. C.; Jones, T.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kaneta, M.; Kang, J. H.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Katou, K.; Kawabata, T.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kelly, S.; Kempel, T.; Khachaturov, B.; Khanzadeev, A.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, E.-J.; Kim, E. J.; Kim, G.-B.; Kim, H. J.; Kim, S. H.; Kim, Y.-J.; Kinney, E.; Kiriluk, K.; Kiss, Á.; Kistenev, E.; Kiyomichi, A.; Klay, J.; Klein-Boesing, C.; Kleinjan, D.; Kobayashi, H.; Kochenda, L.; Kochetkov, V.; Kohara, R.; Komkov, B.; Konno, M.; Koster, J.; Kotchetkov, D.; Kozlov, A.; Král, A.; Kravitz, A.; Kroon, P. J.; Kuberg, C. H.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Layton, D.; Lebedev, A.; Le Bornec, Y.; Leckey, S.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Lenzi, B.; Li, X.; Li, X. H.; Lichtenwalner, P.; Liebing, P.; Lim, H.; Linden Levy, L. A.; Liška, T.; Litvinenko, A.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mannel, E.; Mao, Y.; Martinez, G.; Mašek, L.; Masui, H.; Matathias, F.; Matsumoto, T.; McCain, M. C.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; Means, N.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mikeš, P.; Miki, K.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mishra, G. C.; Mishra, M.; Mitchell, J. T.; Mohanty, A. K.; Moon, H. J.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moss, J. M.; Moukhanova, T. V.; Mukhopadhyay, D.; Muniruzzaman, M.; Murakami, T.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Nouicer, R.; Nyanin, A. S.; Nystrand, J.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Oka, M.; Okada, K.; Onuki, Y.; Oskarsson, A.; Otterlund, I.; Ouchida, M.; Oyama, K.; Ozawa, K.; Pak, R.; Pal, D.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J.; Park, S. K.; Park, W. J.; Pate, S. F.; Pei, H.; Penev, V.; Peng, J.-C.; Pereira, H.; Peresedov, V.; Peressounko, D. Yu.; Petti, R.; Pierson, A.; Pinkenburg, C.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Qualls, J. M.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reuter, M.; Reygers, K.; Riabov, V.; Riabov, Y.; Richardson, E.; Roach, D.; Roche, G.; Rolnick, S. D.; Romana, A.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rosnet, P.; Rukoyatkin, P.; Ružička, P.; Rykov, V. L.; Ryu, S. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakashita, K.; Samsonov, V.; Sanfratello, L.; Sano, S.; Santo, R.; Sato, H. D.; Sato, S.; Sato, T.; Sawada, S.; Schutz, Y.; Sedgwick, K.; Seele, J.; Seidl, R.; Semenov, A. Yu.; Semenov, V.; Seto, R.; Sharma, D.; Shea, T. K.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Suire, C.; Sukhanov, A.; Sullivan, J. P.; Sziklai, J.; Takagi, S.; Takagui, E. M.; Taketani, A.; Tanabe, R.; Tanaka, K. H.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarján, P.; Themann, H.; Thomas, D.; Thomas, T. L.; Togawa, M.; Toia, A.; Tojo, J.; Tomášek, L.; Tomita, Y.; Torii, H.; Towell, R. S.; Tram, V.-N.; Tserruya, I.; Tsuchimoto, Y.; Tydesjö, H.; Tyurin, N.; Uam, T. J.; Vale, C.; Valle, H.; van Hecke, H. W.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Velkovsky, M.; Vértesi, R.; Veszprémi, V.; Vinogradov, A. A.; Virius, M.; Volkov, M. A.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Wei, F.; Wei, R.; Wessels, J.; White, S. N.; Willis, N.; Winter, D.; Wohn, F. K.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xie, W.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; You, Z.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zhang, C.; Zhou, S.; Zimányi, J.; Zolin, L.; Zong, X.

    2013-05-01

    Direct photons have been measured in sNN=200 GeV d+Au collisions at midrapidity. A wide pT range is covered by measurements of nearly real virtual photons (1photons (5photons in d+Au collisions over the scaled p+p cross section is consistent with unity. Theoretical calculations assuming standard cold-nuclear-matter effects describe the data well for the entire pT range. This indicates that the large enhancement of direct photons observed in Au+Au collisions for 1.0

  3. New physics searches with Higgs-photon associated production at the Higgs factory

    NASA Astrophysics Data System (ADS)

    Ren, Hong-Yu

    2015-11-01

    A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e+ e- →γh could be a useful channel for new physics. We express new physics model-independently in the effective Lagrangian approach, and find that the new physics effects of γh have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculate for the first time the 95% confidence level(CL) bounds of γh at the Higgs factory, and prove that γh is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run. Supported by National Natural Science Foundation of China (11275102) and Tsinghua Scholarship for Overseas Graduate Studies

  4. Indirect dark matter signatures in the cosmic dark ages. II. Ionization, heating, and photon production from arbitrary energy injections

    NASA Astrophysics Data System (ADS)

    Slatyer, Tracy R.

    2016-01-01

    Any injection of electromagnetically interacting particles during the cosmic dark ages will lead to increased ionization, heating, production of Lyman-α photons and distortions to the energy spectrum of the cosmic microwave background, with potentially observable consequences. In this paper we describe numerical results for the low-energy electrons and photons produced by the cooling of particles injected at energies from keV to multi-TeV scales, at arbitrary injection redshifts (but focusing on the post-recombination epoch). We use these data, combined with existing calculations modeling the cooling of these low-energy particles, to estimate the resulting contributions to ionization, excitation and heating of the gas, and production of low-energy photons below the threshold for excitation and ionization. We compute corrected deposition-efficiency curves for annihilating dark matter, and demonstrate how to compute equivalent curves for arbitrary energy-injection histories. These calculations provide the necessary inputs for the limits on dark matter annihilation presented in the accompanying paper I, but also have potential applications in the context of dark matter decay or deexcitation, decay of other metastable species, or similar energy injections from new physics. We make our full results publicly available at http://nebel.rc.fas.harvard.edu/epsilon, to facilitate further independent studies. In particular, we provide the full low-energy electron and photon spectra, to allow matching onto more detailed codes that describe the cooling of such particles at low energies.

  5. Composite organic-inorganic butterfly scales: production of photonic structures with atomic layer deposition.

    PubMed

    Gaillot, Davy P; Deparis, Olivier; Welch, Victoria; Wagner, Brent K; Vigneron, Jean Pol; Summers, Christopher J

    2008-09-01

    Recent advances in the photonics and optics industries have produced great demand for ever more sophisticated optical devices, such as photonic crystals. However, photonic crystals are notoriously difficult to manufacture. Increasingly, therefore, researchers have turned towards naturally occurring photonic structures for inspiration and a wide variety of elaborate techniques have been attempted to copy and harness biological processes to manufacture artificial photonic structures. Here, we describe a simple, direct process for producing an artificial photonic device by using a naturally occurring structure from the wings of the butterfly Papilio blumei as a template and low-temperature atomic layer deposition of TiO2 to create a faithful cast of the structure. The optical properties of the organic-inorganic diffraction structures produced are assessed by normal-incidence specular reflectance and found to be well described by multilayer computation method using a two-dimensional photonic crystal model. Depending on the structural integrity of the initially sealed scale, it was found possible not only to replicate the outer but also the inner and more complex surfaces of the structure, each resulting in distinct multicolor optical behavior as revealed by experimental and theoretical data. In this paper, we also explore tailoring the process to design composite skeleton architectures with desired optical properties and integrated multifunctional (mechanical, thermal, optical, fluidic) properties. PMID:18851080

  6. Lightest Higgs boson production at photon colliders in the two Higgs doublet model type III

    SciTech Connect

    Martinez, R.; Rodriguez, J.-Alexis; Milanes, D.A.

    2005-08-01

    The branching ratios of the lightest CP-even Higgs boson h{sup 0} are calculated in the framework of the general two higgs doublet model. Different scenarios are presented taking into account constraints on the flavor changing neutral currents factors obtained in previous works. Plausible scenarios where appear flavor changing processes at tree level like bs and tc are analyzed for relevant parameters. The loop-induced Higgs couplings to photon pairs can be tested with a photon collider. The number of events of h{sup 0} as a resonance in photon colliders are calculated taking into account its corresponding background signal at TESLA, CLIC, and NLC.

  7. Molecular markers linked to genes important for Hard Winter Wheat production and marketing in the U.S. Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biotic stresses including diseases [leaf, stem and stripe rusts, and wheat streak mosaic virus (WSMV)] and insects [greenbug (GB), Hessian fly (Hf), Russian wheat aphid (RWA) and wheat curl mite (WCM)] significantly affect grain yield and end-use quality of hard winter wheat (HWW, Triticum aestivum ...

  8. National Survey on Telephone Services and Products: The Views of Deaf and Hard-of-Hearing People.

    ERIC Educational Resources Information Center

    Bowe, Frank G.

    1991-01-01

    A national survey of 128 deaf and hard-of-hearing adults aged 18 to 70 years found a willingness to pay as much as $15 per month for new telephone-based information services. The most desired services were "enhanced 911," fire, police, and other life/safety services. Subjects also wanted such a network equipped with speech recognition…

  9. $H \\to \\gamma\\gamma$ search and direct photon pair production differential cross section

    SciTech Connect

    Bu, Xuebing

    2010-06-01

    context of the particular fermiophobic Higgs model. The corresponding results have reached the same sensitivity as a single LEP experiement, setting a lower limit on the fermiophobic Higgs of Mhf > 102.5 GeV (Mhf > 107.5 GeV expected). We are slightly below the combined LEP limit (Mhf > 109.7 GeV). We also provide access to the Mhf > 125 GeV region which was inaccessible at LEP. During the study, we found the major and irreducible background direct γγ (DPP) production is not well modelled by the current theoretical predictions: RESBOS, DIPHOX or PYTHIA. There is ~20% theoretical uncertainty for the predicted values. Thus, for our Higgs search, we use the side-band fitting method to estimate DPP contribution directly from the data events. Furthermore, DPP production is also a significant background in searches for new phenomena, such as new heavy resonances, extra spatial dimensions, or cascade decays of heavy new particles. Thus, precise measurements of the DPP cross sections for various kinematic variables and their theoretical understanding are extremely important for future Higgs and new phenomena searches. In this thesis, we also present a precise measurement of the DPP single differential cross sections as a function of the diphoton mass, the transverse momentum of the diphoton system, the azimuthal angle between the photons, and the polar scattering angle of the photons, as well as the double differential cross sections considering the last three kinematic variables in three diphoton mass bins, using 4.2 fb-1 data. These results are the first of their kind at D0 Run II, and in fact the double differential measurements are the first of their kind at Tevatron. The results are compared with different perturbative QCD predictions and event generators.

  10. Perturbative QCD analysis of pion and kaon form factors and pair production in photon-photon collisions using a frozen coupling constant

    SciTech Connect

    Ji Chuengryong ); Amiri, F. )

    1990-12-01

    Within the framework of leading-order perturbative QCD and using a frozen coupling constant, we calculate the pion and kaon form factors and the cross section of pion and kaon pair production in two-photon collisions. We use the same frozen coupling constant as taken in the nucleon Dirac-form-factor analysis and find that the results for the {pi} and {ital K} form factors, the reactions {gamma}{gamma}{r arrow}{pi}{sup +}{pi}{sup {minus}},{ital K}{sup +}{ital K}{sup {minus}}, and the proton Dirac form factor are in fair agreement with the available experimental data. The cutoff value of the frozen coupling constant used in our analysis is consistent with the theoretical estimation presented by Cornwall.

  11. Hard X-ray total scattering study on the structure of Si-dopped ferric oxyhydroxides and products of their transformation

    NASA Astrophysics Data System (ADS)

    Pieczara, Gabriela; Borkiewicz, Olaf; Manecki, Maciej; Rzepa, Grzegorz

    2016-04-01

    Here we report the results of a detailed structural investigation, using synchrotron-based pair distribution function analyses (PDF) and high-resolution X-ray diffraction (HR-XRD), on a series of Si-bearing synthetic analogues of ferrihydrite with a range of Si/Fe ratio relevant to geological environments and on products of their thermal transformation. Hard X-ray total scattering data suitable for PDF analyses have been collected at the PDF-dedicated beamline 11-ID-B and the HR-XRD data at beamline 11-BM of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Ferrihydrite is a poorly crystalline, nano-sized hydrous ferric oxyhydroxide with a nominal/ideal formula Fe5HO8•4H2O. Its chemical composition however, can vary significantly and the atomic structure is yet to be fully understood despite multitude of structural studies undertaken over the past two decades (Michel et al., 2007; Manceau, 2009). One of the most commonly discussed and still unsettled contention points regarding the structural arrangements of ferrihydrite is related to the presence or absence of tetraherdally coordinated iron(III) within its structure. The majority of experimental work carried out to date focused on pure, synthetic ferrihydrite analogues with chemical composition close to ideal/nominal. This approach is clearly a significant oversimplification of natural ferrihydrite which always contains substantial amounts of admixtures, with Si, C, P, As, Ca, S and Al being the most common. One of the most important and the most commonly encountered impurities is Si, in the form of silicate ion that has strong affinity for ferrihydrite. SiO2content in natural ferrihydrites can vary substantially but generally falls with the range of 2.6-31.5 wt% (Cismasu et al., 2011). In certain environments however, such as modern seafloor hydrothermal vents, higher Si/Fe ratios (up to ca. 3) have been reported (Sun et al., 2013). The results of previous reports indicate that silicate

  12. Particle acceleration and production of energetic photons in SN1987A

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.; Stanev, Todor; Harding, Alice

    1987-01-01

    A pulsar wind model for the acceleration of particles in SN1987A is discussed. The expected photon flux is investigated in terms of the spectrum of parent protons and electrons, the nature of the region in which they propagate after acceleration, and the magnetic field and radiation environment which determines the subsequent fate of produced photons. The model is found to produce observable signals if the spin period of the pulsar is 10 ms or less.

  13. Next Generation Endstation for Concurrent Measurements of Charged Products and Photons in LCLS FEL Experiments

    NASA Astrophysics Data System (ADS)

    Osipov, T.; Rolles, D.; Bostedt, C.; Castagna, J.-C.; Hartmann, R.; Bozek, J. D.; Schlichting, I.; Strüder, L.; Ullrich, J.; Berrah, N.

    2012-11-01

    We are designing and building the next generation multi-purpose instrumentation especially adapted to accommodate unique large-area, single-photon counting pnCCD detectors together with advanced many-particle ion and electron imaging spectrometers (reaction microscope, REMI; velocity map imaging, VMI; magnetic bottle) for simultaneous detection of scattered and fluorescent photons and charged particles in experiments at the LCLS FEL.

  14. Soft photon production in central 200 GeV/nucleon {sup 32}S + Au collisions

    SciTech Connect

    Aggarwal, M.M.; Bhatia, V.S.; Mittra, I.S.; Angelis, A.L.; Doenni, P.; Durieux, E.; Foka, P.; Izycki, M.; Kalechofsky, H.; Martin, M.; Naef, H.; Rosselet, L.; Rubio, J.M.; Solomey, N.; Ster, A.; Antonenko, V.; Fokin, S.; Ippolitov, M.; Karadjev, K.; Lebedev, A.; Manko, V.; Nikolaev, S.; Vinogradov, A.; Awes, T.C.; Obenshain, F.E.; Plasil, F.; Saini, S.; Young, G.R.; Badyal, S.K.; Devanand, L.; Kachroo, S.; Rao, N.K.; Sambyal, S.S.; Barlag, C.; Blume, C.; Bock, D.; Bohne, E.; Bucher, D.; Claussen, A.; Clewing, G.; Glasow, R.; Hartig, M.; Hoelker, G.; Kampert, K.; Langheinrich, J.; Peitzmann, T.; Santo, R.; Stueken, D.; Weber, S.; Bhalla, K.B.; Gupta, S.K.; Kumar, V.; Lokanathan, S.; Mookerjee, S.; Raniwala, S.; Buijs, A.; Geurts, F.; Kamermans, R.; Twenhoefel, C.; van Eijndhoven, N.; van Heeringen, E.; Chattopadhyay, S.; Das, A.C.; Dutta Majumdar, M.R.; Ganti, M.S.; Ghosh, T.K.; Nayak, S.K.; Sinha, B.C.; Trivedi, M.D.; Viyogi, Y.P.; Garpman, S.; Gustafsson, H.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Soederstroem, K.; Stenlund, E.; Gutbrod, H.H.; Kolb, B.W.; Langbein, I.; Purschke, M.; Roters, B.; Schmidt, H.R.; Sorensen, S.P.; Steinhaeuser, P.; Xiaochun, H.; Loehner, H.; Siemssen, R.; Slegt, S.

    1997-08-01

    Inclusive photons of low transverse momenta have been measured in 200 GeV/nucleon {sup 32}S+Au collisions at the CERN SPS. Data were taken in the WA93 experiment using a small acceptance BGO detector with longitudinal segmentation. The results are compared to WA80 measurements for the same system and results from hadron decay calculations. An excess of soft photons over the expectations from neutral meson decays is observed. {copyright} {ital 1997} {ital The American Physical Society}

  15. Spin structure of spin-1/2 baryon and spinless meson production amplitudes in photonic and hadronic reactions

    SciTech Connect

    Nakayama, K.; Love, W.G.

    2005-09-01

    The most general spin structures of the spin-1/2 baryon and spinless meson production operator for both photon and nucleon induced reactions are derived from the partial-wave expansions of these reaction amplitudes. The present method provides the coefficients multiplying each spin operator in terms of the partial-wave matrix elements. The result should be useful in studies of these reactions based on partial-wave analyses, especially, when spin observables are considered.

  16. Estimate of massive-dimuon production via a Drell-Yan-type process in two-photon collisions

    SciTech Connect

    Sajjad Zahir, M.

    1981-11-01

    This paper presents a theoretical analysis and numerical estimate of the production of massive ..mu../sup +/..mu../sup -/+hadrons in ..gamma gamma.. collision. Although, from the theoretical point of view, the process might have some interesting possibilities, the numerical estimates show that the cross section is too small to be measured with nearly on-shell high-energy photons from either doubly tagged or untagged electrons considering the luminosity of the new generation of machines.

  17. Measurement of identified and inclusive photon second-harmonic parameter and implications for direct photon production in [FORMULA: SEE TEXT] Au+Au.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kaneta, M; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-01-27

    The azimuthal distribution of identified pi0 and inclusive photons has been measured in [FORMULA: SEE TEXT] Au+Au collisions with the PHENIX experiment at the Relativistic Heavy-Ion Collider (RHIC). The second-harmonic parameter (nu2) was measured to describe the observed anisotropy of the azimuthal distribution. The measured inclusive photon is consistent with the value expected for the photons from hadron decay and is also consistent with the lack of direct photon signal over the measured pT range 1-6 GeV/c. An attempt is made to extract nu2 of direct photons. PMID:16486688

  18. Hard breakup of two nucleons from the He3 nucleus

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak M.; Granados, Carlos

    2009-07-01

    We investigate a large angle photodisintegration of two nucleons from the He3 nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard nucleon-nucleon scattering, the HRM allows the expression of the amplitude of a two-nucleon breakup reaction through the convolution of photon-quark scattering, NN hard scattering amplitude, and nuclear spectral function, which can be calculated using a nonrelativistic He3 wave function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for NN scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as s-11. Second, the s11 weighted cross section will have the shape of energy dependence similar to that of s10 weighted NN elastic scattering cross section. Also one predicts an enhancement of the pp breakup relative to the pn breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn breakup cross sections. This is due to the fact that the same-helicity pp-component is strongly suppressed in the ground state wave function of He3. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer NN breakup reactions for circularly polarized photons. For the pp breakup this asymmetry is predicted to be zero while for the pn it is close to (2)/(3).

  19. Early Run 2 Hard QCD Results from the ATLAS Collaboration

    NASA Astrophysics Data System (ADS)

    Orlando, Nicola

    2016-07-01

    We provide an overview of hard QCD results based on data collected with the ATLAS detector in proton-proton collision at √s = 13 TeV at the Large Hadron Collider. The production of high transverse momentum jets, photons and photon-pairs were studied; the inclusive jet cross section is found to agree well with the prediction of perturbative QCD calculations performed at next-to-leading accuracy. The production cross sections for W and Z bosons in their e and μ decays was measured; in general, agreement is found with the expectation of next-to-next-to leading order QCD calculations and interesting sensitivities to the proton structure functions are already observed. The top production cross sections were measured in different top decay channels and found to agree with the state of the art QCD predictions.

  20. Must "Hard Problems" Be Hard?

    ERIC Educational Resources Information Center

    Kolata, Gina

    1985-01-01

    To determine how hard it is for computers to solve problems, researchers have classified groups of problems (polynomial hierarchy) according to how much time they seem to require for their solutions. A difficult and complex proof is offered which shows that a combinatorial approach (using Boolean circuits) may resolve the problem. (JN)

  1. Hard π0 and η production in S+Au nuclear collisions at SPS energies and possible signature of quark-gluon plasma

    NASA Astrophysics Data System (ADS)

    Tarasov, Yu. A.

    1998-11-01

    Hard π0 and η production is investigated in Landau and Bjorken hydrodynamical models taking into account great number of hadronic resonances (16 and 42) in hadronic phase. We consider two different scenario: with quark-gluon plasma (QGP) formation and with only hadronic gas one without QGP. The Cronin effect and hard direct pions emission are taken into account. It is shown that these two scenario give similar p⊥ spectra which agrees with experimental data obtained by WA80 collaboration. Therefore we conclude that from hadronic spectra it is difficult to extract the proof of QGP formation. However we calculate also the η/π0 ratio. We show that this value agrees with experiment only for scenario with QGP and phase transition to hadrons. The hadronic gas scenario without QGP disagrees with experimental data.

  2. Multi-photon production in e+e- collisions at sqrt(s)=183 GeV

    NASA Astrophysics Data System (ADS)

    OPAL Collaboration; Ackerstaff, K.; Alexander, G.; Allison, J.; Altekamp, N.; Anderson, K. J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S. F.; Axen, D.; Azuelos, G.; Ball, A. H.; Barberio, E.; Barlow, R. J.; Bartoldus, R.; Batley, J. R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S. D.; Blobel, V.; Bloodworth, I. J.; Bobinski, M.; Bock, P.; Böhme, J.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brown, R. M.; Burckhart, H. J.; Burgard, C.; Bürgin, R.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrisman, D.; Ciocca, C.; Clarke, P. E. L.; Clay, E.; Cohen, I.; Conboy, J. E.; Cooke, O. C.; Couyoumtzelis, C.; Coxe, R. L.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; Davis, R.; de Jong, S.; del Pozo, L. A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M. S.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I. P.; Eatough, D.; Estabrooks, P. G.; Etzion, E.; Evans, H. G.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A. A.; Fiedler, F.; Fierro, M.; Fischer, H. M.; Fleck, I.; Folman, R.; Fürtjes, A.; Futyan, D. I.; Gagnon, P.; Gary, J. W.; Gascon, J.; Gascon-Shotkin, S. M.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W. R.; Gingrich, D. M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwé, M.; Hanson, G. G.; Hansroul, M.; Hapke, M.; Hargrove, C. K.; Hartmann, C.; Hauschild, M.; Hawkes, C. M.; Hawkings, R.; Hemingway, R. J.; Herndon, M.; Herten, G.; Heuer, R. D.; Hildreth, M. D.; Hill, J. C.; Hillier, S. J.; Hobson, P. R.; Hocker, A.; Homer, R. J.; Honma, A. K.; Horváth, D.; Hossain, K. R.; Howard, R.; Hüntemeyer, P.; Igo-Kemenes, P.; Imrie, D. C.; Ishii, K.; Jacob, F. R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C. R.; Jovanovic, P.; Junk, T. R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P. I.; Keeler, R. K.; Kellogg, R. G.; Kennedy, B. W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D. S.; Kokott, T. P.; Kolrep, M.; Komamiya, S.; Kowalewski, R. V.; Kress, T.; Krieger, P.; von Krogh, J.; Kyberd, P.; Lafferty, G. D.; Lanske, D.; Lauber, J.; Lautenschlager, S. R.; Lawson, I.; Layter, J. G.; Lazic, D.; Lee, A. M.; Lefebvre, E.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A. W.; Lloyd, S. L.; Loebinger, F. K.; Long, G. D.; Losty, M. J.; Ludwig, J.; Liu, D.; Macchiolo, A.; MacPherson, A.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A. J.; Martin, J. P.; Martinez, G.; Mashimo, T.; Mättig, P.; McDonald, W. J.; McKenna, J.; McKigney, E. A.; McMahon, T. J.; McPherson, R. A.; Meijers, F.; Menke, S.; Merritt, F. S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D. J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H. A.; Nellen, B.; Nisius, R.; O'Neale, S. W.; Oakham, F. G.; Odorici, F.; Ogren, H. O.; Oreglia, M. J.; Orito, S.; Pálinkás, J.; Pásztor, G.; Pater, J. R.; Patrick, G. N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J. E.; Pinfold, J.; Plane, D. E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycień , M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S. A.; Rodning, N.; Roney, J. M.; Roscoe, K.; Rossi, A. M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D. R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W. M.; Sarkisyan, E. K. G.; Sbarra, C.; Schaile, A. D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schöning, A.; Schorner, T.; Schröder, M.; Schumacher, M.; Schwick, C.; Scott, W. G.; Seuster, R.; Shears, T. G.; Shen, B. C.; Shepherd-Themistocleous, C. H.; Sherwood, P.; Siroli, G. P.; Sittler, A.; Skuja, A.; Smith, A. M.; Snow, G. A.; Sobie, R.; Söldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, D.; Ströhmer, R.; Tafirout, R.; Talbot, S. D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M. A.; von Törne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trócsányi, Z.; Tsur, E.; Turcot, A. S.; Turner-Watson, M. F.; van Kooten, R.; Vannerem, P.; Verzocchi, M.; Vikas, P.; Voss, H.; Wäckerle, F.; Wagner, A.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Wells, P. S.; Wermes, N.; White, J. S.; Wilson, G. W.; Wilson, J. A.; Wyatt, T. R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1998-10-01

    The process e+e--->γγ(γ) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 56.2 pb-1 taken at a centre-of-mass energy of 183 GeV. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Λ+> 233 GeV and Λ-> 265 GeV as well as a mass limit for an excited electron, Me*> 227 GeV assuming equal e*eγ and eeγ couplings. No evidence for resonance production is found in the invariant mass spectrum of photon pairs. Limits are obtained for the cross-section times branching ratio for a resonance decaying into two photons.

  3. Measurements of the Differential Cross Sections for the Inclusive Production of a Photon and Heavy Flavor Jet

    SciTech Connect

    Duggan, Daniel; /Florida State U.

    2009-04-01

    This thesis presents the first measurement of the differential production cross section of a heavy flavor (bottom or charm) jet and direct photon at the Fermilab Tevatron. These measurements were performed using data recorded with the D0 detector from proton-antiproton collisions at a center of mass energy of {radical}s = 1.96 TeV. These results probe a kinematic range for the photon transverse momentum of 30 < p{sub T}{sup {gamma}} < 150 GeV and rapidity of |y{sup {gamma}}| < 1.0 and for jet transverse momentum p{sub T}{sup jet} > 15 GeV and rapidity of |y{sup jet}| < 0.8. These results are compared to next-to-leading-order theoretical calculations.

  4. Photon and η production in p + Pb and p + C collisions at √{sNN}=17.4 GeV

    NASA Astrophysics Data System (ADS)

    Aggarwal, M. M.; Ahammed, Z.; Angelis, A. L. S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T. C.; Baba, P. V. K. S.; Badyal, S. K.; Bathe, S.; Batiounia, B.; Baumann, C.; Bernier, T.; Bhalla, K. B.; Bhatia, V. S.; Blume, C.; Bucher, D.; Büsching, H.; Carlén, L.; Chattopadhyay, S.; Decowski, M. P.; Delagrange, H.; Donni, P.; Dutta Majumdar, M. R.; El Chenawi, K.; Dubey, A. K.; Enosawa, K.; Fokin, S.; Frolov, V.; Ganti, M. S.; Garpman, S.; Gavrishchuk, O.; Geurts, F. J. M.; Ghosh, T. K.; Glasow, R.; Guskov, B.; Gustafsson, H. Å.; Gutbrod, H. H.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Karadjev, K.; Karpio, K.; Kolb, B. W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kurata, M.; Lebedev, A.; Löhner, H.; Luquin, L.; Mahapatra, D. P.; Manko, V.; Martin, M.; Martínez, G.; Maximov, A.; Miake, Y.; Mishra, G. C.; Mohanty, B.; Mora, M.-J.; Morrison, D.; Mukhanova, T.; Mukhopadhyay, D. S.; Naef, H.; Nandi, B. K.; Nayak, S. K.; Nayak, T. K.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nilsson, P.; Nishimura, S.; Nomokonov, P.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Pavliouk, S.; Peitzmann, T.; Peressounko, D.; Petracek, V.; Phatak, S. C.; Pinganaud, W.; Plasil, F.; Purschke, M. L.; Rak, J.; Rammler, M.; Raniwala, R.; Raniwala, S.; Rao, N. K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Roy, C.; Rubio, J. M.; Sambyal, S. S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.-R.; Schutz, Y.; Shabratova, G.; Shah, T. H.; Sibiriak, I.; Siemiarczuk, T.; Silvermyr, D.; Sinha, B. C.; Slavine, N.; Söderström, K.; Sood, G.; Sørensen, S. P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Sumbera, M.; Svensson, T.; Tsvetkov, A.; Tykarski, L.; Pijll, E. C. v. d.; v. Eijndhoven, N.; v. Nieuwenhuizen, G. J.; Vinogradov, A.; Viyogi, Y. P.; Vodopianov, A.; Vörös, S.; Wysłouch, B.; Young, G. R.

    2013-01-01

    Measurements of direct photon production in p + Pb and p + C collisions at √{sNN}=17.4 GeV are presented. Upper limits on the direct photon yield as a function of pT are derived and compared to the results for Pb + Pb collisions at √{sNN}=17.3 GeV. The production of the η meson, which is an important input to the direct photon signal extraction, has been determined in the η→2γ channel for p + C collisions at √{sNN}=17.4 GeV.

  5. A Numerical Study of Material Parameter Sensitivity in the Production of Hard Metal Components Using Powder Compaction

    NASA Astrophysics Data System (ADS)

    Andersson, Daniel C.; Lindskog, Per; Staf, Hjalmar; Larsson, Per-Lennart

    2014-06-01

    Modeling of hard metal powder inserts is analyzed based on a continuum mechanics approach. In particular, one commonly used cutting insert geometry is studied. For a given advanced constitutive description of the powder material, the material parameter space required to accurately model the mechanical behavior is determined. These findings are then compared with the corresponding parameter space that can possibly be determined from a combined numerical/experimental analysis of uniaxial die powder compaction utilizing inverse modeling. The analysis is pertinent to a particular WC/Co powder and the finite element method is used in the numerical investigations of the mechanical behavior of the cutting insert.

  6. Detector for high-energy photon backscatter

    NASA Astrophysics Data System (ADS)

    Silver, Michael D.; Erker, Joseph W.; Duncan, Michael Z.; Hartford, Thomas J.; Sivers, E. A.; Hopkinson, James F.

    1993-12-01

    High energy photon backscatter uses pair production to probe deep beneath surfaces with single side accessibility or to image thick, radiographically opaque objects. At the higher photon energies needed to penetrate thick and/or highly attenuating objects, Compton backscatter becomes strongly forward peaked with relatively little backscatter flux. Furthermore, the downward energy shift of the backscattered photon makes it more susceptible to attenuation on its outbound path. Above 1.022 MeV, pair production is possible; at about 10 MeV, pari production crosses over Compton scatter as the dominant x-ray interaction mechanism. The backscattered photons can be hard x rays from the bremsstrahlung of the electrons and positrons or 0.511 MeV photons from the annihilation of the positron. Monte Carlo computer simulations of such a backscatter system were done to characterize the output signals and to optimize a high energy detector design. This paper touches on the physics of high energy backscatter imaging and describes at some length the detector design for tomographic and radiographic imaging.

  7. Photosensitized Singlet Oxygen Production upon Two-Photon Excitation of Single-Walled Carbon Nanotubes and Their Functionalized Analogs

    PubMed Central

    Gandra, Naveen; Chiu, Pui Lam; Li, Wenbing; Anderson, Yolanda R.; Mitra, Somenath; He, Huixin; Gao, Ruomei

    2009-01-01

    Single-walled carbon nanotubes (SWNTs) functionalized with -COOH (along with some sulphonation and nitration), and/or modified with chitosan were prepared and tested for their singlet oxygen (1O2) production. The emission from 1O2 observed upon SWNT irradiation at 532 nm was due to a two-photon process, while 1O2 production via excitation at 355 nm occurred through a conventional one-photon pathway. The relative quantum yield of 1O2 production at excitation wavelength of 532 nm was found to be 0.00, 0.07-0.13 and 0.24-0.54 for highly-functionalized, partially-functionalized and non-functionalized SWNT samples respectively. The nanotube-mediated generation of 1O2 may find applications in both targeted destruction of tumor cells and selective degradation of drug molecules. Our research provides a practical approach to modulate the production of reactive oxygen species from SWNTs via surface functionalization/modification. PMID:20046942

  8. Systematization of the yields of products of photonuclear reactions on enriched-tin targets at the bremsstrahlung-photon endpoint energy of 4.5 GeV

    SciTech Connect

    Balabekyan, A. R.

    2008-11-15

    Yields of photonuclear-reaction products formed in targets from separated tin isotopes under the effect of beams of bremsstrahlung photons whose endpoint energy is 4.5 GeV were investigated. The systematization performed on this basis revealed an isoscaling character of the behavior of the production yields for various regions of reaction-product masses.

  9. Exclusive photon-photon production of muon pairs in proton-proton collisions at sqrt(s) = 7 TeV

    SciTech Connect

    Chatrchyan, Serguei; Khachatryan, Vardan; Sirunyan, Albert M.; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; /Yerevan Phys. Inst. /Vienna, OAW /Minsk, High Energy Phys. Ctr. /Antwerp U., WISINF /Vrije U., Brussels /Brussels U. /Gent U. /Louvain U. /UMH, Mons /Rio de Janeiro, CBPF /Rio de Janeiro State U.

    2011-11-01

    A measurement of the exclusive two-photon production of muon pairs in proton-proton collisions at {radical}s = 7 TeV, pp {yields} p{mu}{sup +}{mu}{sup -}p, is reported using data corresponding to an integrated luminosity of 40 pb{sup -1}. For muon pairs with invariant mass greater than 11.5 GeV, transverse momentum p{sub T}({mu}) > 4 GeV and pseudorapidity |{eta}({mu})| < 2.1, a fit to the dimuon p{sub T}({mu}{sup +}{mu}{sup -}) distribution results in a measured cross section of {sigma}(p {yields} p{mu}{sup +}{mu}{sup -}) = 3.38{sub -0.55}{sup +0.58}(stat.) {+-} 0.16(syst.) {+-} 0.14(lumi.) pb, consistent with the theoretical prediction evaluated with the event generator LPAIR. The ratio to the predicted cross section is 0.83{sub -0.13}{sup +0.14}(stat.) {+-} 0.04(syst.) {+-} 0.03(lumi.). The characteristic distributions of the muon pairs produced via {gamma}{gamma} fusion, such as the muon acoplanarity, the muon pair invariant mass and transverse momentum agree with those from the theory.

  10. Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Lar'kin, A.; Uryupina, D.; Ivanov, K.; Savel'ev, A.; Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Spohr, K.; Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T.

    2014-09-01

    By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition.