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Your search keyword '"G. L. Bashindzhagyan"' showing total 14 results
Start Over Author "G. L. Bashindzhagyan" Topic astrophysics::high energy astrophysical phenomena
14 results on '"G. L. Bashindzhagyan"'

1. An excess of cosmic ray electrons at energies of 300–800 GeV

Author

Joachim Isbert, Alexander D. Panov, Eun-Suk Seo, Jin Chang, M. Christl, T. G. Guzik, G. L. Bashindzhagyan, N. V. Sokolskaya, Wolfgang Schmidt, John W. Watts, J. Wu, John P. Wefel, K. C. Kim, E. N. Kuznetsov, O. Ganel, M. I. Panasyuk, V. I. Zatsepin, H. S. Ahn, and James H. Adams

Subjects
Physics, Multidisciplinary, Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Electron, Astrophysics, Ion, Supernova, Pulsar, Supernova remnant, Astrophysics::Galaxy Astrophysics
Abstract

Galactic cosmic rays consist of protons, electrons and ions, most of which are believed to be accelerated to relativistic speeds in supernova remnants. All components of the cosmic rays show an intensity that decreases as a power law with increasing energy (for example as E(-2.7)). Electrons in particular lose energy rapidly through synchrotron and inverse Compton processes, resulting in a relatively short lifetime (about 10(5) years) and a rapidly falling intensity, which raises the possibility of seeing the contribution from individual nearby sources (less than one kiloparsec away). Here we report an excess of galactic cosmic-ray electrons at energies of approximately 300-800 GeV, which indicates a nearby source of energetic electrons. Such a source could be an unseen astrophysical object (such as a pulsar or micro-quasar) that accelerates electrons to those energies, or the electrons could arise from the annihilation of dark matter particles (such as a Kaluza-Klein particle with a mass of about 620 GeV).

Published
2008
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2. Measuring the deposited energy by the scintillation calorimeter in the ATIC experiment

Author

Wolfgang Schmidt, M. Christl, John W. Watts, A. R. Fazely, V. I. Zatsepin, T. G. Guzik, J. Wu, Alexander D. Panov, O. Ganel, Eun-Suk Seo, M. I. Panasyuk, G. L. Bashindzhagyan, H. S. Ahn, E. N. Kouznetsov, John P. Wefel, N. V. Sokolskaya, Jin Chang, K. C. Kim, James H. Adams, Joachim Isbert, and R. M. Gunashingha

Subjects
Physics, Scintillation, Range (particle radiation), Calorimeter (particle physics), Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Cosmic ray, Bismuth germanate, Spectral line, Nuclear physics, chemistry.chemical_compound, chemistry, Calibration, Particle, High Energy Physics::Experiment, Instrumentation
Abstract

The purpose of the ATIC balloon experiment is to measure the energy spectra of primary cosmic rays with individual charge resolution from protons to iron over the energy range from ∼50 GeV to 200 TeV. The particle energy is measured by a bismuth germanate (BGO) scintillation calorimeter. The procedure of calorimeter calibration is described, in particular, calibration of the temperature dependence of the calorimeter sensitivity using the data of in-flight measurements. A technique for determining the energy deposited in the calorimeter in view of the temperature dependence of its sensitivity is presented. The maximum systematic error in determining the deposited energy by the calorimeter is 10% or less, and the probable error is estimated at 6%.

Published
2008
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3. Enhancing the ATIC charge resolution

Author

Wolfgang Schmidt, V. I. Zatsepin, H. S. Ahn, K. C. Kim, James H. Adams, T. G. Guzik, N. V. Sokolskaya, Joachim Isbert, John W. Watts, A. R. Fazely, K. E. Batkov, J. Wu, Alexander D. Panov, R. M. Gunashingha, Eun-Suk Seo, G. L. Bashindzhagyan, M. I. Panasyuk, E. N. Kouznetsov, O. Ganel, Jin Chang, M. Christl, and John P. Wefel

Subjects
Physics, Atmospheric Science, Photomultiplier, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Advanced Thin Ionization Calorimeter, Detector, Aerospace Engineering, Astronomy and Astrophysics, Cosmic ray, Scintillator, Nuclear physics, Geophysics, Hodoscope, Space and Planetary Science, Ionization, Scintillation counter, General Earth and Planetary Sciences
Abstract

The Advanced Thin Ionization Calorimeter (ATIC) experiment is designed to investigate the charge composition and energy spectra of primary cosmic rays over the energy range from about 10(11) to 10(14) eV during Long Duration Balloon (LDB) flights from McMurdo, Antarctica. Currently, analysis from the ATIC-1 test flight and ATIC-2 science flight is underway and preparation for a second science flight is in progress. Charge identification of the incident cosmic ray is accomplished, primarily, by a pixilated Silicon Matrix detector located at the very top of the instrument. While it has been shown that the Silicon Matrix detector provides good charge identification even in the presence of electromagnetic shower backscatter from tile calorimeter, the detector only measures the charge once. In this paper, we examine use of the top scintillator hodoscope detector to provide a second measure of the cosmic ray charge and, thus, improve the ATIC charge identification. (c) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Published
2008
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4. Elemental energy spectra of cosmic rays from the data of the ATIC-2 experiment

Author

R. M. Gunashingha, G. L. Bashindzhagyan, M. I. Panasyuk, Alexander D. Panov, Wolfgang Schmidt, E. N. Kouznetsov, M. Christl, T. G. Guzik, V. I. Zatsepin, J. P. Wefel, O. Ganel, James H. Adams, K. C. Kim, H. S. Ahn, A. R. Fazely, Jian Wu, Eun-Suk Seo, Joachim Isbert, N. V. Sokolskaya, K. E. Batkov, John W. Watts, and Jin Chang

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Hadron, General Physics and Astronomy, chemistry.chemical_element, Cosmic ray, Alpha particle, Spectral line, Nuclear physics, chemistry, Energy spectrum, Atomic physics, Nuclear Experiment, Helium, Energy (signal processing)
Abstract

This paper reports on the results of measurements performed in the course of the ATIC-2 balloon experiment (2002–2003) for the energy spectra of particles (such as protons; He, C, O, Ne, Mg, Si, and Fe nuclei; and some groups of nuclei) and the all-particle energy spectrum in primary cosmic rays at energies ranging from 50 GeV to 200 TeV. The conclusion is drawn that the energy spectra of protons and helium nuclei differ substantially (the spectrum of protons is steeper) and that the shape of the energy spectra of protons and heavy nuclei cannot be described by a power function.

Published
2007
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5. The energy spectra of heavy nuclei measured by the ATIC experiment

Author

Wolfgang Schmidt, H. S. Ahn, A. R. Fazely, Joachim Isbert, N. V. Sokolskaya, V. I. Zatsepin, Eun-Suk Seo, K. E. Batkov, M. Christl, R. M. Gunasingha, Jin Chang, G. L. Bashindzhagyan, John P. Wefel, Jian Wu, M. I. Panasyuk, James H. Adams, K. C. Kim, Alexander D. Panov, E. N. Kouznetsov, T. G. Guzik, and O. Ganel

Subjects
Physics, Atmospheric Science, High energy, Scattering, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, Aerospace Engineering, Astronomy and Astrophysics, Cosmic ray, Spectral line, Magnetic field, Geophysics, Space and Planetary Science, Ionization, General Earth and Planetary Sciences, Atomic physics, Energy (signal processing)
Abstract

The preliminary energy spectra of heavy nuclei C, O, Ne, Mg, Si, and Fe in the primary cosmic rays measured by the ATIC-2 experiment are presented and compared to previous data and to propagation models. Using previous data to extend the ATIC-2 results for all heavy nuclei to higher energy, the combined spectra can be best fit with diffusion model with weak reacceleration and scattering on random magnetic field with a Kolmogorov spectrum fluctuations becoming dominant at high energy. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

Published
2006
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6. Beam tests of the balloon-borne ATIC experiment

Author

H. J. Kim, J. Z. Wang, A. R. Fazely, T. G. Guzik, R. M. Gunasingha, D. Granger, Wolfgang Schmidt, J. Ampe, B. Price, Eun-Suk Seo, N. V. Sokolskaya, John P. Wefel, H. S. Ahn, Sun Kee Kim, M. Stewart, James H. Adams, Alexander D. Panov, O. Ganel, Jian Wu, G. A. Samsonov, Gary L. Case, Joachim Isbert, Jin Chang, Y. J. Han, S. B. Ellison, K. C. Kim, G. L. Bashindzhagyan, R. Gould, M. I. Panasyuk, Yeong-Dae Kwon, D. Wagner, V. I. Zatsepin, R. Sina, A. A. Voronin, and M. Sen

Subjects
Astroparticle physics, Physics, Nuclear and High Energy Physics, Large Hadron Collider, Astrophysics::High Energy Astrophysical Phenomena, Advanced Thin Ionization Calorimeter, Cosmic ray, Bismuth germanate, Radiation length, Calorimeter, Nuclear physics, chemistry.chemical_compound, chemistry, Ultra-high-energy cosmic ray, Nuclear Experiment, Instrumentation
Abstract

The Advanced Thin Ionization Calorimeter (ATIC) balloon-borne experiment is designed to perform cosmic-ray elemental spectra measurement from 50 GeV to 100 TeV for nuclei from hydrogen to iron. These measurements are expected to provide crucial hints about some of the most fundamental questions in astroparticle physics today. ATTIC'S design centers on an 18 radiation length (X(sub Omnicron)) deep bismuth germanate (BGO) calorimeter, preceded by a 0.75 lambda(sub int) graphite target. In September 1999 the ATIC detector was exposed to high-energy beams at CERN's SPS accelerator, within the framework of the development program for the Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS). In December 2000 - January 2001, ATIC flew on the first of a series of long duration balloon (LDB) flights from McMurdo Station, Antarctica. We present here results from the 1999 beam-tests, including energy resolutions for electrons and protons at several beam energies from 100 GeV to 375 GeV, as well as signal linearity and collection efficiency estimates. We show how these results compare with expectations based on simulations, and their expected impacts on mission performance.

Published
2005
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7. Albedo in the ATIC experiment: Measurements and simulations

Author

N. V. Sokolskaya, K. E. Batkov, M. Christl, T. G. Guzik, G. L. Bashindzhagyan, O. Ganel, J. Z. Wang, A. R. Fazely, Jian Wu, K. C. Kim, Joachim Isbert, R. M. Gunasingha, Alexander D. Panov, M. I. Panasyuk, Eun-Suk Seo, Jin Chang, James H. Adams, H. S. Ahn, Wolfgang Schmidt, E. N. Kouznetsov, John P. Wefel, and V. I. Zatsepin

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Backscatter, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Resolution (electron density), Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Albedo, Atomic and Molecular Physics, and Optics, Spectral line, Computational physics, Electric current, Physics::Atmospheric and Oceanic Physics
Abstract

We analyze the characteristics of the albedo, or the backscatter current, which constitutes a background for charge measurements in calorimetric experiments in high-energy cosmic rays. We compare the experimental data obtained in the flights of the ATIC spectrometer with the simulations performed using the GEANT 3.21 code. We discuss the influence of the backscatter on the charge resolution in the ATIC experiment.

Published
2005
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8. The silicon matrix as a charge detector in the ATIC experiment

Author

R. M. Gunasingha, Alexander D. Panov, Jian Wu, H. S. Ahn, A. R. Fazely, V. I. Zatsepin, E. N. Kouznetsov, J. P. Wefel, K. C. Kim, Wolfgang Schmidt, M. Christl, J. Z. Wang, James H. Adams, M. I. Panasyuk, O. Ganel, T. G. Guzik, G. L. Bashindzhagyan, N. V. Sokolskaya, K. E. Batkov, Joachim Isbert, Jin Chang, and Eun-Suk Seo

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Advanced Thin Ionization Calorimeter, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Scintillator, Calorimeter, Nuclear physics, Ionization, Scintillation counter, Nuclear Experiment, Instrumentation
Abstract

The Advanced Thin Ionization Calorimeter (ATIC) was built for series of long- duration balloon flights in Antarctica. Its main goal is to measure energy spectra of cosmic ray nuclei from protons up to iron nuclei over a wide energy range from 30 GeV up to 100 TeV. The ATIC balloon experiment had its first, test flight that lasted for 16 days from 28 Dec 2000 to 13 Jan 2OO1 around the continent. The ATIC spectrometer consists of a fully active BGO calorimeter, scintillator hodoscopes and a silicon matrix. The silicon matrix, consisting of 4480 pixels, was used as a charge detector in the experiment. About 25 million cosmic ray events were detected during the flight. In the paper, the charge spectrum obtained with the silicon matrix is analyzed.

Published
2004
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9. [Untitled]

Author

M. Merkin, M. I. Panasyuk, G. L. Bashindzhagyan, V. I. Zatsepin, G. A. Samsonov, J. H. Adams, N. V. Sokolskaya, and L.A. Khein

Subjects
Range (particle radiation), Materials science, Spectrometer, Calorimeter (particle physics), Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Detector, Resolution (electron density), Cosmic ray, Charge (physics), Astrophysics::Cosmology and Extragalactic Astrophysics, Spectral line, Nuclear physics, Instrumentation
Abstract

The characteristics of the silicon matrix which is the main charge detector in the ATIC balloon experiment are reported. The ATIC spectrometer was designed to measure the elemental composition and energy spectra of primary cosmic rays in an energy range of 1010to 1013eV with individual charge resolution from protons to iron under high albedo conditions from the calorimeter.

Published
2001
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10. Measurement of Leading Particle Effects in Decays ofZ0Bosons into Light Flavors

Author

T. W. Reeves, A. Chou, K.C. Moffeit, R. Dubois, S. R. Smith, H. A. Neal, S. Fahey, P.L. Reinertsen, A. Sugiyama, J. M. Yamartino, C. Y. Prescott, L. S. Rochester, Stephen Watts, R. R. Kofler, J. Quigley, J. Wyss, Michael J. Fero, E. R. Weiss, C. H. Park, Bruce Schumm, D. Su, T. Bolton, M. Dima, Stephen Robert Wagner, B. N. Ratcliff, A. Lu, C. Simopoulos, M. Cavalli-Sforza, B. T. Meadows, P. E. Stamer, M.B. Barakat, M. E. Huffer, C. C. Young, J. Yashima, J. D. Turk, V. V. Serbo, N.J. Allen, R.D. Elia, G. E. Gladding, J. Schwiening, A. I. Trandafir, M. Piccolo, Gilbert Shapiro, R. E. Cassell, P.E. Rensing, R. H. Schindler, R. Verdier, E. L. Hart, T. Nagamine, M. Kalelkar, T. Schalk, G. L. Bashindzhagyan, C. Vannini, E. Etzion, A. Hasan, M. Carpinelli, Michael H. Shaevitz, A. Szumilo, M. Loreti, B. Bolen, T. H. Burnett, W. J. Wisniewski, M. Langston, J. A. Coller, S. Manly, O. Bardon, F. E. Taylor, J. R. Bogart, D. Aston, S. J. Yellin, A. Calcaterra, K. Hasuko, R. Prepost, P.F. Jacques, R. Kroeger, D. Calloway, S. Sen, G. H. Zapalac, R. K. Yamamoto, N.M. Krishna, A. P. Waite, X. Yang, D. C. Williams, S. J. Hedges, O. H. Saxton, M. Nussbaum, R. Cowan, K. T. Pitts, Shiro Suzuki, Timothy Barklow, Piero Giorgio Verdini, X. Liu, S. S. Hertzbach, R. W. Zdarko, M.E. King, J. J. Russell, S. Willocq, A. S. Johnson, R. Steiner, H. R. Band, L.S. Osborne, Rino Castaldi, H. O. Cohn, K. Furuno, Giancarlo Mantovani, W. W. Ash, R. Messner, S. Gonzalez, M. D. Hildreth, V. Cook, K.D. Shmakov, Yukio Hasegawa, H. Hwang, H. L. Lynch, J. S. Whitaker, Alberto Benvenuti, R. Ben-David, G. D. Punkar, R. de Sangro, E. Vella, R. A. Johnson, J. E. Brau, A. W. Weidemann, J. Zhou, H. Kawahara, G. B. Word, D. G. Coyne, Henry W. Kendall, D. J. Sherden, C. Fan, J.P. Venuti, D. J. Jackson, Fred Wickens, D. W. G. S. Leith, C.J.S. Damerell, R. J. Wilson, A. O. Bazarko, Martin Breidenbach, R. Cotton, Yongduk Kim, C. Baltay, E. W. Hughes, J. A. Lauber, H. Masuda, S. H. Williams, J. Ma, Minghui Liu, D. Onoprienko, G. Blaylock, B. Camanzi, G. M. Bilei, G. R. Bower, R. S. Panvini, D. Falciai, G. Crawford, M. Swartz, James Shank, Andrea Castro, Wit Busza, F. Suekane, P. C. Rowson, J. A. Jaros, P.J. Dervan, H. Yuta, D. O. Caldwell, Thomas W. Markiewicz, T. Gillman, E. Church, T. Junk, J. L. Harton, S. Narita, Tadayuki Takahashi, J. P. Fernandez, P. M. Mockett, G. Baranko, M. B. Smy, Y. Iwasaki, K.G. Baird, David A. Williams, J. Huber, T. L. Usher, S. L. White, A. K. McKemey, R. King, R.J. Plano, I. Karliner, M. G. Strauss, Dominik Müller, H. Park, T. Maruyama, Y. Ohnishi, B. I. Eisenstein, D. N. Dong, J. A. Snyder, A. Lath, I. M. Peruzzi, E. Mazzucato, A.B. d'Oliveira, E. Torrence, H. J. Kang, Roberto Dell'Orso, J. Va'vra, J.J. Reidy, N. B. Sinev, D. L. Wagner, V. Lia, U. Nauenberg, D. L. Burke, W. M. Bugg, P. N. Burrows, Dario Bisello, T.J. Pavel, R. Frey, J. R. Johnson, R. Kajikawa, H. M. Steiner, T. Akagi, L. Piemontese, T. B. Moore, Enrico Pieroni, J. F. Labs, G. Mancinelli, P.Y.C. Du, M. Daoudi, K. Abe, and M. Woods

Subjects
Quark, Physics, Antiparticle, Particle physics, Meson, Astrophysics::High Energy Astrophysical Phenomena, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Hadron, General Physics and Astronomy, Elementary particle, Quarkonium, Nuclear physics, Particle decay, High Energy Physics::Experiment, Boson
Abstract

We present evidence for leading particle production in hadronic decays of the Z{sup 0} boson to light-flavor jets. A polarized electron beam was used to tag quark and antiquark jets, and a vertex detector was employed to reject heavy-flavor events. Charged hadrons were identified with a Cherenkov ring imaging detector. In the quark jets, more high-momentum p, L, K{sup -}, and {bar K}{sup *0} were observed than their antiparticles, and vice versa for antiquark jets, providing direct evidence that the higher-momentum particles in jets are more likely to carry the primary quark or antiquark from the Z{sup 0} decay, and that s{bar s} production is suppressed in fragmentation. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997
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11. Fine structure in the cosmic ray electron spectrum measured by the ATIC-2 and ATIC-4 experiments

Author

N. V. Sokolskaya, Joachim Isbert, Jin Chang, John W. Watts, K. C. Kim, Evgeny Postnikov, M. Christl, James H. Adams, V. I. Zatsepin, Eun-Suk Seo, G. L. Bashindzhagyan, J. P. Wefel, M. I. Panasyuk, T. G. Guzik, Alexander D. Panov, E. N. Kouznetsov, H. S. Ahn, and J. Wu

Subjects
Nuclear physics, Physics, Range (particle radiation), Astrophysics::High Energy Astrophysical Phenomena, Spectrum (functional analysis), Hadron, General Physics and Astronomy, Cosmic ray, Electron, Anomaly (physics), Experimental data processing, Fermi Gamma-ray Space Telescope
Abstract

A strong anomaly in form of a wide peak in the energy range 300–800 GeV was discovered in the first measurements of the electron spectrum in the energy range from 20 GeV to 3 TeV by the balloon-borne experiment ATIC [1]. The experimental data processing and analysis of the electron spectrum with different criteria for selection of electrons completely independent of the results reported in [1] is employed in the present paper. New independent analysis generally confirms the results of [1] but shows that the spectrum in the region of the anomaly is represented by a number of narrow peaks. Measured spectrum is compared to the spectrum of [1] and to the spectrum of the Fermi/LAT experiment.

Published
2011
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12. Observation of isolated high-E-T photons in photoproduction at HERA

Author

M. Zachara, R.C.E. Devenish, Q. Zhu, H.-P. Jakob, R. L. Saunders, Danuta Kisielewska, T. Massam, G. Laurenti, B. Mellado, K. Umemori, R. Brugnera, V. A. Kuzmin, D. C. Bailey, M. Kuze, N. Pavel, P.M. Kooijman, M. St-Laurent, D.C. Williams, C. Youngman, A. H. Walenta, Ta Romanowski, F. Dal Corso, M.E. Hayes, L. Iannotti, Antonino Zichichi, R. Loveless, C. Coldewey, J. Shulman, T. Fusayasu, Juan Terron, M. Kasprzak, C.R. Sampson, Jeffrey T. Rahn, Marcel Vreeswijk, R. Ullmann, V.A. Noyes, O. Schwarzer, Helen F Heath, D.D. Reeder, J. Del Peso, C. Rembser, N. A. McCubbin, P. Giusti, Gm Levman, Marco Schioppa, S. Magill, N.C. Brummer, P. G. Pelfer, S.H. An, G. Drews, W.F. Badgett, A.S. Proskuryakov, J. Hartmann, C. Voci, M. Wodarczyk, D. S. Waters, K. Homma, Cristiana Peroni, R. J. Cashmore, K. Yamauchi, M. Y. Pac, W. Hain, C. M. Ginsburg, A. Meyer-Larsen, U. Wollmer, J.J. Ryan, Richard Hall-Wilton, M. Derrick, T. Tymieniecka, S. Ritz, M. Roco, M.A.J. Botje, N. Cartiglia, J. Stamm, B. Foster, U. Kötz, Jonathan Butterworth, S. Yamada, M. C. Petrucci, A. Pesci, H. Kowalski, U. Fricke, S. Mattingly, A. Caldwell, A. Bertolin, Silvia Maselli, N. Gendner, D. Simmons, M. L. Utley, H. Zhang, J. F. Martin, A. Nigro, Fernando Barreiro, Mauro Morandin, Z. Jakubowski, R. S. Orr, F. Palmonari, S. Wölfle, Amedeo Staiano, U. F. Katz, O. Ruske, M. Pfeiffer, M. Brkic, Yuji Yamazaki, D. Horstmann, N. H. Brook, V. L. Harris, Rosario Nania, Sung Keun Park, John Hart, T. Tsurugai, J.T. Bromley, J. Breitweg, F. Ricci, R. J. Nowak, H. F.W. Sadrozinski, Giuseppe Levi, H. Park, Kenneth Long, J. Y. Kim, G. Bari, D. Filges, C. L. Kim, A.F. Whitfield, D. Hasell, G. D'Agostini, R. Kerger, K. Jelen, Matthias Kasemann, A. Prinias, J. F. de Trocóniz, L. Zawiejski, Roberto Cirio, Elisabetta Gallo, A. Bruni, L.K. Gladilin, S. W. Nam, W.R. Frisken, R. Pawlak, F. Selonke, Pietro Antonioli, Luisa Cifarelli, Neville Harnew, E. Hilger, J. Repond, P.B. Straub, D. Piccioni, W. Koch, D.S. Hanna, J.J. Engelen, T. Y. Ling, P. B. Kaziewicz, L. Lamberti, T. Yamashita, M. Löwe, Thomas Trefzger, F. Pelucchi, B. Bednarek, L. Lindemann, K.F. Johnson, S. Sampson, J. A. Zakrzewski, Y. Zamora Garcia, H. Beier, Tadeusz Kowalski, M. Nakao, Robert Klanner, A. Vaiciulis, D.G. Roff, H. Salehi, D. Notz, M. Rohde, D. Sideris, T. W. Jones, D. Revel, Michele Arneodo, Ulf Behrens, Federico Cindolo, B.Y. Oh, H. Uijterwaal, U. Schneekloth, D. Acosta, T. Voß, I. Butterworth, I. Suzuki, G. Poelz, F. Zetsche, K. Coböken, D. B. Miller, L.W. Hung, G. L. Bashindzhagyan, W.B. Schmidke, R. J. Teuscher, M. Lancaster, Anselmo Margotti, Enrico Tassi, J. J. Whitmore, R. Waugh, R. Cross, L.W. Wiggers, C. Amelung, Miriam Lucio Martinez, J. Gilmore, S. B. Lee, Y. Iga, A. M. Cooper-Sarkar, S. Dagan, J. Bulmahn, C. A. Heusch, J.T. Wu, A. Ochs, Mariusz Przybycien, M. Corradi, Vincenzo Monaco, L. Suszycki, M. Khakzad, James Crittenden, Andrea Contin, Katsuo Tokushuku, S. Polenz, G. Cases, M. Basile, A. Pellegrino, T. Haas, Giancarlo Susinno, Yu. A. Golubkov, F. Anselmo, M. Inuzuka, C.H. Bokel, Lucia Votano, C. Nath, C.-P. Fagerstroem, R. Yoshida, B.D. Burow, Costas Foudas, L.W. Mo, B. Surrow, Umberto Dosselli, Jongmin Lee, M.C.K. Mattingly, E. Lohrmann, L. S. Durkin, I. Gialas, B. H. Y. Hung, H.J. Grabosch, Luca Stanco, Lev Khein, A. N. Solomin, T. Ishii, B. Musgrave, U. Mallik, J.I. Fleck, J. Zaja̧c, J. M. Pawlak, R. Hamatsu, Janusz Chwastowski, J. Puga, D.G. Stairs, J.D. McFall, T. Monteiro, M. Posocco, O. Deppe, H.E. Blaikley, Y. Eisenberg, L. M. Shcheglova, D.J. Gilkinson, Guillaume Garcia, R. Walczak, S. Kananov, J. P. Fernandez, J. K. Sedgbeer, E. Paul, A. Garfagnini, P.F. Ermolov, K. Nagano, R. Deffner, G. Bruni, K. Muchorowski, E. A. De Wolf, M. Grothe, J. R. Tickner, K. Heinloth, L. Heinz, J. M. Hernandez, J. K. Bienlein, Giuseppe Barbagli, H. Wieber, J. Roldán, M. Adamus, G. Briskin, Leszek Adamczyk, I. A. Korzhavina, G. Marini, R. Wedemeyer, W.N. Cottingham, Wolfram Dietrich Zeuner, A.K. Wróblewski, A. Bamberger, A. Stifutkin, G.P. Heath, Marcella Capua, Giuseppe Iacobucci, D. Westphal, J. Labs, B. Lu, G. Sartorelli, R. Stanek, S.A. Zotkin, N. Tuning, I.H. Park, M.I. Ferrero, M. Przybycien, J. Große-Knetter, U. Karshon, A.A. Savin, D.S. Bailey, D. Mikunas, P. Nylander, K. K. Joo, Luis Hervas, R. G. Feild, J. Ciborowski, D. Boscherini, A.F. Żarnecki, K. Desler, D. Krakauer, I. Bohnet, Tomohiro Abe, G. Castellini, W.N. Murray, Z. Jing, J.S.T. Ng, Vladimir Bashkirov, A. Quadt, P. Cloth, O. Mańczak, P. Markun, D. Kçira, G. F. Hartner, Ben Bylsma, J. Milewski, M. Bukowy, F. Corriveau, G. Grzelak, M. Eckert, N.A. Korotkova, L. Bellagamba, H. Hartmann, T. C. Bacon, M. Dardo, P. Borzemski, W. Liu, S. De Pasquale, A.S. Wilson, Sridhara Dasu, Ian Brock, R. Ayad, O. Yu. Lukina, S Campbell-Robson, Halina Abramowicz, W. Schott, Cd Catterall, A. Polini, Z. Duliński, R.L. Talaga, J.A. Parsons, D. Epperson, J.K. Edmonds, A.I. van Sighem, K. Wick, G. Abbiendi, G. Cara Romeo, M. Riveline, S. Eisenhardt, F. Sciulli, J.N. Lim, G. Howell, R.J. Tapper, A. Meyer, H.G.J.M. Tiecke, E. Strickland, Giovanni Maccarrone, D. Hochman, S. Schlenstedt, P. J. Bussey, E. Rulikowska-Zarȩbska, Joanne Cole, T.P. Shah, Mark Sutton, S. M. Wang, D. H. Saxon, C. Glasman, A. Bornheim, Tachishige Hirose, P. Göttlicher, Roberto Carlin, D. Chapin, J.B. Lane, Gy. Wolf, Roberto Sacchi, T. Matsushita, R. Stroili, Aharon Levy, Laurel E. Sinclair, A. Seiden, J.H. Vossebeld, M. Raso, A. Eskreys, A. T. Doyle, L. Labarga, Wouter Verkerke, B. A. Dolgoshein, Ada Solano, S. Limentani, I. T. Lim, S. Bhadra, B. Löhr, S. Kitamura, A. Kotański, L.A.T. Bauerdick, J.R. Okrasiński, U. Holm, Krzysztof Piotrzkowski, K. Ohrenberg, W. H. Smith, R. Graciami, Mário Costa, F.S. Chlebana, and Zeus (IHEF, IoP, FNWI)

Subjects
COLLISIONS, Nuclear and High Energy Physics, Particle physics, Photon, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Photon energy, 01 natural sciences, 7. Clean energy, CROSS-SECTIONS, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), GLOBAL QCD, 0103 physical sciences, CALORIMETER, 010306 general physics, Nuclear Experiment, COMPTON-SCATTERING, Quantum chromodynamics, Physics, Jet (fluid), ZEUS (particle detector), CONSTRUCTION, 010308 nuclear & particles physics, Compton scattering, ZEUS, HERA, CENTRAL TRACKING DETECTOR, PARTON DISTRIBUTIONS, Pseudorapidity, High Energy Physics::Experiment, HARD SCATTERING
Abstract

Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA.The data were taken with the ZEUS detector, in a $\gamma p$ centre of mass energy range 120--250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon and the jet, $x_\gamma$, shows a strong peak near unity, consistent with LO QCD Monte Carlo predictions. In the transverse energy and pseudorapidity range $5\le \eTg < 10$ GeV, $-0.7 \le \eta^\gamma < 0.8$, $\eTj\ge 5$ GeV, and $-1.5\le \eta^{jet}\le 1.8$, with $\xgO > 0.8,$ the measured cross section is $15.3 \pm 3.8 \pm 1.8 pb$, in good agreement with a recent NLO calculation., Comment: 22 pages including 8 figures

Published
1997

13. Search for excited electrons using the ZEUS detector

Author

J. F. Martin, Fernando Barreiro, Mauro Morandin, Z. Jakubowski, J. Mollen, M. Iori, Guenter Wolf, A. Bernstein, Y. Zamora Garcia, E.N. Kuznetsov, Marcel Vreeswijk, O. Mańczak, G. F. Hartner, Nicolo Cartiglia, S. Yang, R.S. Gilmore, R. Casaccia, J. F. Labs, J. Kochocki, Rosario Nania, F. J. Sciulli, A. Freidhof, B. Lu, L. W. Hung, A. Bargende, Danuta Kisielewska, James Crittenden, A. Prinias, D. Revel, A. A. Voronin, H.F. Sadronzinski, R.J. Tapper, H.J. Grabosch, E. Rulikowska-Zarȩbska, J.A. Zakrzewski, A Furtjes, F. Gasparini, W. Koch, S.S. Wilson, T. Y. Kim, S. Mengel, C. Raine, A. Stopczyński, C. Youngman, S.H. An, J. Mainusch, J. Leslie, Tadeusz Kowalski, T. Watanabe, A. Meyer, Roberto Carlin, B. Gutjahr, A. Dannemann, D. Monaldi, M. Mattioli, G. Poelz, Eduardo Ros, R. J. Cashmore, D. Schramm, C. A. Heusch, Lothar At Bauerdick, Lucia Votano, C. Rethfeldt, W. Schott, Cd Catterall, S. Nagayama, A. Montag, M. Kückes, J. Bulmahn, Luis Labarga, F. W. Bullock, E. Lohrmann, F. Ikraiam, M. Derrick, F. Arzarello, H. Kreutzmann, J. Del Peso, T. Tymieniecka, Mariusz Flasiński, L.E. Sinclair, Marco Schioppa, P. G. Pelfer, S.J.P. Smith, A. Byrne, F.S. Chlebana, K.M. Furutani, K. U. Pösnecker, U. Kötz, B. Hubbard, M.B. Crombie, R. Seidlein, K. Wick, A. Mass, Q. Lin, S. Kartik, Thomas Trefzger, W. Schulz, A. Shapira, Vivian O'Dell, Aharon Levy, T.J. Llewellyn, J. N. Lim, C. O. Kim, J. Ciborowski, R. Ullmann, R. Yoshida, S. Nickel, B.D. Burow, D. B. Miller, T. Kȩdzierski, R. Gläser, V. K. Nadendla, R. J. Nowak, Francois Corriveau, J. M. Pawlak, M. Dardo, J. Gajewski, C. Coldewey, B. Krebs, H.G.J.M. Tiecke, F. Benard, K. Muchorowski, Giuseppe Iacobucci, K. Prytz, D. Lüke, B. Löhr, Giuseppe Levi, I. Ali, R. Wedemeyer, G. Jahnen, Claudia Glasman, P. Joos, P. Giusti, D. Zer-Zion, M. Basile, B. Foster, J.-L. Schneider, W. Vogel, H. Brückmann, R. Stanek, Helen F Heath, Wr Frisken, M. H. Suh, G. Drews, J. A. Parsons, T. Massam, Luisa Cifarelli, L. K. Gladilin, Neville Harnew, J. Biltzinger, J.K. Mayer, W. Hain, P. Luffman, Luca Stanco, P. Göttlicher, A. Kotański, P. Morawitz, I. Fleck, D. Shaw, H. Hultschig, I. H. Park, J. K. Sedgbeer, K. Eskreys, H. Kammerlocher, E. Barberis, Tobias M. Haas, John Hart, S. Kasai, J. F. de Trocóniz, Ben Bylsma, J. Milewski, J. Krüger, U. Mallik, T. Khatri, J.W. Mitchell, T. Poser, T.P. Shah, D. Haun, T. Bienz, G. Bruni, D. H. Saxon, Greg P Heath, L. Zawiejski, Roberto Cirio, P. de Jong, B. Lisowski, R.C.E. Devenish, J.B. Lane, J. Zaja̧c, G. Laurenti, H. Hartmann, Rr Rau, B. Nizioł, A. Contin, L. Köpke, L. Bellagamba, A. Eskreys, M. Rohde, J. Nash, M.A.J. Botje, K. Jeleń, I. Butterworth, Douglas Gingrich, B. Musgrave, S. K. Park, A.H. Walenta, F. Palmonari, Amedeo Staiano, M. St.Laurent, F. Selonke, E. Hilger, Y. Iga, H. Müsch, E. Paul, Ulf Behrens, Federico Cindolo, M. Krzyżanowski, H. Kowalski, Sridhara Dasu, F. Ciralli, A. Cassidy, B.Y. Oh, M. Nakahata, Halina Abramowicz, L. Hagge, Y. Eisenberg, J. Whitmore, T. Ishii, C. Li, K. Heinloth, Giuseppe Barbagli, N. Dyce, R. Meijer Drees, C.J.S. Morgado, C. Voci, S. Bhadra, C. Fordham, Michele Arneodo, N.C. Roocroft, G. Castellini, U. Schneekloth, T. Neumann, T. Barillari, C. Memoz, Silvia Maselli, M. Momayezi, M. Zachara, T. Doeker, S. Kramarczyk, Ta Romanowski, Hiroshi G. Okuno, F. F. Wilson, S. Kitamura, M. Chiarini, G. Sartorelli, R. Timellini, A. Dake, N. H. Brook, V. L. Harris, Jonathan Butterworth, S. Yamada, L. S. Durkin, Ada Solano, P.M. Patel, A. A. Savin, R. Walczak, M. Adamus, G. Marini, A.K. Wróblewski, A. Bamberger, L. Suszycki, S. Limentani, R. R. McNeil, K. Charchuła, W.N. Murray, G. Anzivino, A. Bruni, A. Zichichi, Matthias Kasemann, M. Löwe, M. Nakao, P. Borzemski, D. Notz, Samuel Silverstein, G.A. Blair, M. Brkic, S. H. Yon, M. Lancaster, D. Krakauer, T. W. Jones, Anna Goussiou, D.D. Reeder, G. D'Agostini, B. Diekmann, Stan Bentvelsen, G. L. Bashindzhagyan, N. P. Zotov, W. Kröger, R. J. Teuscher, T. Y. Ling, G. Zech, Amanda Cooper-Sarkar, R. J. Seifert, Giovanni Abbiendi, Robert Klanner, A. Vorvolakos, G. Feild, Stefano Maria Mari, P. Erhard, Jens Hartmann, T.L. Short, Efstathios Stiliaris, S. Böttcher, Y. Nagasawa, L. Lamberti, H. Uijterwaal, P.F. Ermolov, M. de Kamps, P.M. Kooijman, D. K. Hasell, E. Gallo, K. O'Shaughnessy, S. Dagan, H. J. Kim, K. Honscheid, Yu. A. Golubkov, A. Francescato, M. Posocco, Geoffrey Smith, Giovanni Maccarrone, A. Kruse, J. K. Bienlein, S. Schlenstedt, P. J. Bussey, J. Shulman, F. Dal Corso, T. Hasegawa, A. Leich, P. Cloth, P.M. Hallam-Baker, R. Imlay, G. Grzelak, Af Zarnecki, Debades Bandyopadhyay, C. Del Papa, Juan Terron, M. Kasprzak, S. Magill, T. C. Bacon, G. Cases, E. Tscheslog, S. M. Hong, S. De Pasquale, R. L. Talaga, S. Qian, I. Gialas, M. Nuti, J. Schroeder, R. S. Orr, P. B. Straub, B. Behrens, G. Bari, M.I. Ferrero, V.A. Jamieson, B. Bednarek, R. Beuselinck, T. S. Yoon, H. van der Lugt, F. Zetsche, H.-P. Jakob, J. L. Thron, Masashi Hazumi, R. Brugnera, V. A. Kuzmin, D. C. Bailey, M. De Giorgi, D. J. Gilkinson, Gm Levman, P. Filges, W. Metcalf, E. Badura, U. Holm, N. A. McCubbin, Y. Nakamitsu, Katsuo Tokushuku, N. Pavel, Umberto Dosselli, S. W. Nam, David Cussans, Janusz Chwastowski, William S. Lockman, E. A. De Wolf, Krzysztof Piotrzkowski, J.J. Engelen, Kr Long, A.G. Tenner, S. Ritz, D. S. Hanna, Tachishige Hirose, Anselmo Margotti, L.W. Wiggers, G.G. Stairs, T. Tsurugai, M. Kuze, E. McCliment, J. Roldán, R. Hamatsu, J.C. Giddings, A. Seiden, Michele Guida, Jose Repond, M. Przybycień, L. Wai, Meng Wang, R. van Woudenberg, S. Repond, A. T. Doyle, A.M. Khan, W. H. Smith, G. Gloth, R. Schattevoy, Masami Chiba, P.L. Makkar, R. Stroili, Mário Costa, U. Contino, Klaus Kurt Desch, C. Peroni, R. Ayad, M. Roco, G. Cara Romeo, G. Geitz, G. Theisen, U. Karshon, Luis Hervas, D. Boscherini, G. Susinno, Saverio D'Auria, J.S.T. Ng, I. McArthur, P. Bruni, Costas Foudas, L.W. Mo, Dg Stairs, A. Caldwell, F. Frasconi, J. Malos, J.R. Forbes, K.W. McLean, A. Ladage, S. Söldner-Rembold, A. Nigro, A. Dwuraźny, A.F. Whitfield, J.D. Prentice, R. Loveless, M. Geerts, K. Blankenship, C.R. Sampson, H. Dabbous, Derrick, M, Krakauer, D, Magill, S, Musgrave, B, Repond, J, Repond, S, Stanek, R, Talaga, Rl, Thron, J, Arzarello, F, Ayad, R, Bari, G, Basile, M, Bellagamba, L, Boscherini, D, Bruni, A, Bruni, G, Bruni, P, Romeo, Gc, Castellini, G, Chiarini, M, Cifarelli, L, Cindolo, F, Ciralli, F, Contin, A, Lin, Q, Lisowski, B, Maccarrone, G, Margotti, A, Massam, T, Nania, R, Nemoz, C, Palmonari, F, Sartorelli, G, Timellini, R, Garcia, Yz, Zichichi, A, Bargende, A, Crittenden, J, Dabbous, H, Desch, K, Diekmann, B, Doeker, T, Geerts, M, Geitz, G, Hartmann, H, Haun, D, Heinloth, K, Hilger, E, Jakob, Hp, Kramarczyk, S, Kuckes, M, Mass, A, Mengel, S, Mollen, J, Monaldi, D, Musch, H, Paul, E, Schattevoy, R, Schneider, Jl, Schramm, D, Wedemeyer, R, Cassidy, A, Cussans, Dg, Dyce, N, Foster, B, Gilmore, R, Heath, Gp, Heath, Hf, Lancaster, M, Llewellyn, Tj, Malos, J, Morgado, Cj, Tapper, Rj, Wilson, S, Yoshida, R, Rau, Rr, Arneodo, M, Barillari, T, Schioppa, M, Susinno, G, Bernstein, A, Caldwell, A, Gialas, I, Parsons, Ja, Ritz, S, Sciulli, F, Straub, Pb, Wai, L, Yang, S, Chwastowski, J, Dwurazny, A, Eskreys, A, Jakubowski, Z, Niziol, B, Piotrzkowski, K, Zachara, M, Zawiejski, L, Bednarek, B, Borzemski, P, Eskreys, K, Jelen, K, Kisielewska, D, Kowalski, T, Rulikowskazarebska, E, Suszycki, L, Zajac, J, Kedzierski, T, Kotanski, A, Przybycien, M, Bauerdick, Lat, Behrens, U, Bienlein, Jk, Bottcher, S, Coldewey, C, Dannemann, A, Drews, G, Erhard, P, Flasinski, M, Fleck, I, Glaser, R, Gottlicher, P, Gutjahr, B, Haas, T, Hagge, L, Hain, W, Hasell, D, Hultschig, H, Jahnen, G, Joos, P, Kasemann, M, Klanner, R, Koch, W, Kopke, L, Kotz, U, Kowalski, H, Kruger, J, Labs, J, Ladage, A, Lohr, B, Lowe, M, Luke, D, Mainusch, J, Manczak, O, Momayezi, M, Ng, Jst, Nickel, S, Notz, D, Posnecker, Ku, Rohde, M, Roldan, J, Ros, E, Schneekloth, U, Schroeder, J, Schulz, W, Selonke, F, Stiliaris, E, Tscheslog, E, Tsurugai, T, Vogel, W, Wolf, G, Youngman, C, Grabosch, Hj, Leich, A, Meyer, A, Rethfeldt, C, Schlenstedt, S, Barbagli, G, Francescato, A, Nuti, M, Pelfer, P, Anzivino, G, Casaccia, R, Depasquale, S, Qian, S, Votano, L, Bamberger, A, Freidhof, A, Kroger, W, Poser, T, Soldnerrembold, S, Theisen, G, Trefzger, T, Brook, Nh, Bussey, Pj, Doyle, At, Forbes, Jr, Jamieson, Va, Raine, C, Saxon, Dh, Bruckmann, H, Gloth, G, Holm, U, Kammerlocher, H, Krebs, B, Neumann, T, Wick, K, Furtjes, A, Lohrmann, E, Milewski, J, Nakahata, M, Pavel, N, Poelz, G, Schott, W, Terron, J, Zetsche, F, Bacon, Tc, Beuselinck, R, Butterworth, I, Gallo, E, Harris, Vl, Miller, Db, Prinias, A, Sedgbeer, Jk, Vorvolakos, A, Whitfield, A, Bienz, T, Kreutzmann, H, Mallik, U, Mccliment, E, Roco, M, Wang, Mz, Cloth, P, Filges, D, An, Sh, Hong, Sm, Kim, Co, Kim, Ty, Nam, Sw, Park, Sk, Suh, Mh, Yon, Sh, Imlay, R, Kartik, S, Kim, Hj, Mcneil, Rr, Metcalf, W, Nadendla, Vk, Barreiro, F, Cases, G, Hervas, L, Labarga, L, Delpeso, J, Detroconiz, Jf, Ikraiam, F, Mayer, Jk, Smith, Gr, Corriveau, F, Gilkinson, Dj, Hanna, D, Hartmann, J, Hung, Lw, Lim, Jn, Drees, Rm, Mitchell, Jw, Patel, Pm, Sinclair, Le, Stairs, Dg, Stlaurent, M, Ullmann, R, Bashindzhagyan, Gl, Ermolov, Pf, Gladilin, Lk, Golubkov, Ya, Kuzmin, Va, Kuznetsov, En, Savin, Aa, Voronin, Ag, Zotov, Np, Bentvelsen, S, Botje, M, Dake, A, Engelen, J, Dejong, P, Dekamps, M, Kooijman, P, Kruse, A, Vanderlugt, H, Odell, V, Tenner, A, Tiecke, H, Uijterwaal, H, Vreeswijk, M, Wiggers, L, Dewolf, E, Vanwoudenberg, R, Bylsma, B, Durkin, L, Honscheid, K, Li, C, Ling, Ty, Mclean, Kw, Murray, Wn, Park, Ih, Romanowski, Ta, Seidlein, R, Blair, Ga, Byrne, A, Cashmore, Rj, Coopersarkar, Am, Devenish, Rce, Gingrich, Dm, Hallambaker, Pm, Harnew, N, Khatri, T, Long, Kr, Luffman, P, Mcarthur, I, Morawitz, P, Nash, J, Smith, Sjp, Roocroft, Nc, Wilson, Ff, Abbiendi, G, Brugnera, R, Carlin, R, Dalcorso, F, Degiorgi, M, Dosselli, U, Gasparini, F, Limentani, S, Morandin, M, Posocco, M, Stanco, L, Stroili, R, Voci, C, Butterworth, Jm, Bulmahn, J, Feild, G, Oh, By, Whitmore, J, Contino, U, Dagostini, G, Guida, M, Iori, M, Mari, Stefano Maria, Marini, G, Mattioli, M, Nigro, A, Hart, Jc, Mccubbin, Na, Prytz, K, Shah, Tp, Short, Tl, Barberis, E, Cartiglia, N, Heusch, C, Hubbard, B, Leslie, J, Lockman, W, Oshaughnessy, K, Sadrozinski, Hf, Seiden, A, Zerzion, D, Badura, E, Biltzinger, J, Seifert, Rj, Walenta, Ah, Zech, G, Dagan, S, Levy, A, Hasegawa, T, Hazumi, M, Ishii, T, Kasai, S, Kuze, M, Nagasawa, Y, Nakao, M, Okuno, H, Tokushuku, K, Watanabe, T, Yamada, S, Chiba, M, Hamatsu, R, Hirose, T, Kitamura, S, Nagayama, S, Nakamitsu, Y, Cirio, R, Costa, M, Ferrero, Mi, Lamberti, L, Maselli, S, Peroni, C, Solano, A, Staiano, A, Dardo, M, Bailey, Dc, Bandyopadhyay, D, Benard, F, Bhadra, S, Brkic, M, Burow, Bd, Chlebana, F, Crombie, Mb, Hartner, Gf, Levman, Gm, Martin, Jf, Orr, R, Prentice, Jd, Sampson, Cr, Stairs, Gg, Teuscher, Rj, Yoon, T, Bullock, Fw, Catterall, Cd, Giddings, Jc, Jones, Tw, Khan, Am, Lane, Jb, Makkar, Pl, Shaw, D, Shulman, J, Blankenship, K, Kochocki, J, Lu, B, Mo, Lw, Charchula, K, Ciborowski, J, Gajewski, J, Grzelak, G, Kasprzak, M, Krzyzanowski, M, Muchorowski, K, Nowak, Rj, Pawlak, Jm, Stopczynski, A, Tymieniecka, T, Walczak, R, Wroblewski, Ak, Zakrzewski, Ja, Zarnecki, Af, Adamus, M, Abramowicz, H, Eisenberg, Y, Glasman, C, Karshon, U, Montag, A, Revel, D, Shapira, A, Foudas, C, Fordham, C, Loveless, Rj, Goussiou, A, Ali, I, Behrens, B, Dasu, S, Reeder, Dd, Smith, Wh, Silverstein, S, Frisken, Wr, Furutani, Km, Iga, Y, and RI De Pasquale Salvatore/B 9165 2008 Lancaster Mark/C 1693 2008 Doyle Anthony/C 5889 2009 Gladilin Leonid/B 5226 2011 Golubkov Yury/E 1643, 2012

Subjects
Nuclear and High Energy Physics, Particle physics, LUND MONTE-CARLO, LEPTON PRODUCTION, Astrophysics::High Energy Astrophysical Phenomena, Electron, excited electrons, electron proton collider, JET FRAGMENTATION, law.invention, MUONS, Nuclear physics, LIMITS, ZEUS, CENTRAL TRACKING DETECTOR, E+E-PHYSICS, Z0 DECAY, GAMMA-GAMMA%22">E+E-->GAMMA-GAMMA, CALORIMETER, law, Collider, Nuclear Experiment, Physics, Muon, ZEUS (particle detector), Luminosity (scattering theory), Compton scattering, HERA, Excited state, High Energy Physics::Experiment
Abstract

This paper reports a search for excited electrons at the HERA electron-proton collider. In a sample corresponding to an integrated luminosity of 26 nb−, no evidence was found for any resonant state decaying into e−γ, νW− or e−Z0. Limits on the coupling strength of an excited electron have been determined for masses between 45 and 225 GeV. This study also reports the observation of the wide-angle eγ Compton scattering process.

Published
1993

14. Fine structure in the cosmic ray electron spectrum measured by ATIC

Author

Eun-Suk Seo, N. V. Sokolskaya, T. G. Guzik, Evgeny Postnikov, M. Christl, Alexander D. Panov, Jin Chang, M. I. Panasyuk, J. Watts, H. S. Ahn, V. I. Zatsepin, E. N. Kouznetsov, J. P. Wefel, J. Wu, G. L. Bashindzhagyan, Joachim Isbert, James H. Adams, and K. C. Kim

Subjects
Physics, Calorimeter (particle physics), Spectrometer, Astrophysics::High Energy Astrophysical Phenomena, Advanced Thin Ionization Calorimeter, Cosmic ray, Electron, Scintillator, Bismuth germanate, Spectral line, Nuclear physics, chemistry.chemical_compound, chemistry, Nuclear Experiment
Abstract

New analysis to separate electrons from protons in the ATIC experiment has been performed. Five new discriminants were studied by different Monte Carlo programs. New electron spectrum, when compared with the published results [1], show good agreement in the most interesting region of energy (from 90 GeV to 600 GeV). It is argued that there is no disagreement between ATIC’s results and Fermi-LAT ones. Finally, high-resolution electron spectrum is obtained and possible fine structure is found out in it. The ATIC (Advanced Thin Ionization Calorimeter) balloon-borne spectrometer was designed to measure the energy spectra of elements from H to Fe with individual resolution of charges in primary cosmic rays for energy region from 50 GeV to 100 TeV. ATIC has had three successful flights around the South Pole in 2000–2001 (ATIC-1), 2002-2003 (ATIC-2) and 2007-2008 (ATIC-4). ATIC is comprised of a fully active bismuth germanate (BGO) calorimeter, a carbon target with embedded scintillator hodoscopes, and a silicon matrix that is used as the main charge detector. The calorimeter is comprised of 8 layers with 40 BGO crystalls in each for ATIC-1 and ATIC-2 and of 10 layers for ATIC-4. The details of the construction of the apparatus are described in the papers [2–4]. It was shown that it is possible also to measure the spectrum of cosmic ray electrons plus positrons [5] with ATIC (hereinafter we use ’electrons’ for brevity). To separate electrons from the higher background of protons and other nuclei some differences in shower development for incident electrons and for nuclei are used. The spectrum of electrons measured with the ATIC spectrometer by this method was published in the paper [1]. The most notable detail of the electron spectrum reported was an ‘excess’ of electrons between energies of 300–800 GeV. The main purpose of this work is to investigate possible alternate techniques to separate electrons from hadrons and was curried ae-mail: panov@dec1.sinp.msu.ru E, GeV 2 10 3 10 ) 2 G eV -1 st er -1 s -2 (m 3

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