Author: "Elton, Smith" / Topic: physics - Searchworks@Jio Institute Digital Library Search Results

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1. Light dark matter searches with positrons

Author: M. Ungaro, Andrea Bianconi, Michael Wood, A. Italiano, L. Venturelli, Elton Smith, M. Leali, M. Bondì, L. El Fassi, R. De Vita, Enrico Nardi, S. Migliorati, S. Stepanyan, G. Costantini, Paolo Valente, P. L. Cole, Nunzio Randazzo, M. Battaglieri, P. Bisio, Andrea Celentano, M. Spreafico, L. Lanza, V. Mascagna, A. D'Angelo, Luc Darmé, M. De Napoli, Gordan Krnjaic, Elena Santopinto, L. Marsicano, V. Kozhuharov, and Mauro Raggi
Subjects: Dark Photon, dark sector, Physics, Nuclear and High Energy Physics, Particle physics, Dark Photon, Settore FIS/04, Dark matter, FOS: Physical sciences, Electron, High Energy Physics - Experiment, Standard Model, radiation, Hidden sector, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Positron, Physics::Accelerator Physics, Nuclear fusion, Light dark matter, dark sector, performance, Beam (structure)
Abstract: We discuss two complementary strategies to search for light dark matter (LDM) exploiting the positron beam possibly available in the future at Jefferson Laboratory. LDM is a new compelling hypothesis that identifies dark matter with new sub-GeV "hidden sector" states, neutral under standard model interactions and interacting with our world through a new force. Accelerator-based searches at the intensity frontier are uniquely suited to explore it. Thanks to the high intensity and the high energy of the CEBAF (Continuous Electron Beam Accelerator Facility) beam, and relying on a novel LDM production mechanism via positron annihilation on target atomic electrons, the proposed strategies will allow us to explore new regions in the LDM parameters space, thoroughly probing the LDM hypothesis as well as more general hidden sector scenarios., 11 pages, 8 figures. Prepared for submission in EPJA. This work supersedes the corresponding contribution in arXiv:2007.15081. Added aknowledgement to Jefferson Lab
Published: 2021

2. Measurements of the muon flux produced by 10.6 GeV electrons in a beam dump

Author: R. De Vita, N. Randazzo, M. De Napoli, A. Celentano, G. Ottonello, T. Whitlatch, L. Marsicano, Elton Smith, M. Battaglieri, M. Bondì, F. Parodi, and S. Fegan
Subjects: Physics, Nuclear and High Energy Physics, Muon, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Monte Carlo method, Detector, Electron, Scintillator, 01 natural sciences, Dark photon, law.invention, Nuclear physics, law, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Beam dump, 010306 general physics, Instrumentation, Beam (structure)
Abstract: This paper presents the results of an experiment to assess the muon flux produced by the interaction of a 10.6 GeV electron beam with the Hall-A beam dump at Jefferson Lab (JLab). The goal was to benchmark Monte Carlo simulations that are an essential tool for estimating beam-related backgrounds in beam-dump experiments aimed at searching for rare events, such as the Beam Dump eXperiment (BDX) planned at JLab. Beam-produced muons were measured with a CsI(Tl) crystal sandwiched between a set of segmented plastic scintillators placed at two different distances from the dump: 25.7 m and 28.8 m. At each location the muon flux was sampled at different vertical positions with respect to the beam height. Data have been compared with detailed Monte Carlo simulations using FLUKA for the muon production in the dump and propagation to the detector, and GEANT4 to simulate the detector response. The good agreement between data and simulations, within the uncertainties of the soil composition and density, demonstrate the validity of our simulation tools to predict the beam-related muon background in electron beam-dump experiments at ∼ 10 GeV.
Published: 2019

3. The GlueX beamline and detector

Author: T. Whitlatch, N. Wickramaarachchi, N. Cao, Ilya Larin, Michael Dugger, N. K. Walford, V. V. Tarasov, Gerard Visser, W. Phelps, J. Frye, B. Liu, J. Stewart, V. Razmyslovich, S. Schadmand, B. E. Cannon, C.P. Romero, O. Cortes, F. Nerling, S. Adhikari, M. M. Dalton, G. Voulgaris, C. S. Akondi, W. J. Briscoe, J. R. Stevens, W. D. Crahen, G.H. Biallas, H. Marukyan, R.S. Pedroni, C. Gleason, W. McGinley, P. Eugenio, E. Wolin, V. Crede, C. Carlin, L. A. Teigrob, F. Mokaya, T. C. Black, A. Toro, D. G. Meekins, I. A. Semenova, Elton Smith, A. Thiel, Kamal K. Seth, G. J. Lolos, A. M. Schertz, Todd Satogata, G. Kalicy, T. Daniels, N. S. Jarvis, A. Hamdi, I. I. Strakovsky, N. Qin, Mark Richard James Williams, I. Vega, A. Tsaris, Y. Yang, K. Goetzen, T. Erbora, J. Leckey, W. U. Boeglin, R. T. Jones, S. Fegan, D. S. Carman, K. Suresh, V. V. Berdnikov, Barry Ritchie, G. Vasileiadis, T. Carstens, E. Barriga, H. Al Ghoul, K. Moriya, J. Hardin, A. Gerasimov, M. E. McCracken, A. Deur, C. D. Keith, M. J. Staib, Hovanes Egiyan, A. Ali, Vladimir Popov, Jay Benesch, A. Hurley, C. Dickover, Viktor Matveev, Dmitri Romanov, A. Dolgolenko, B. Pratt, Justin I. McIntyre, C. A. Meyer, R. Mendez, A. R. Dzierba, C. Hutton, N. Sandoval, G. M. Huber, L. Guo, Z. Papandreou, Zhiyong Zhang, D. I. Sober, E. Pooser, J. Foote, J. Zarling, M. M. Ito, O. Chernyshov, Blake Leverington, S. Cole, P. Brindza, H. Hakobyan, A. Barnes, Sean A Dobbs, E. G. Anassontzis, T. D. Beattie, D. Werthmüller, X. Shen, Amiran Tomaradze, M. Patsyuk, J. Ritman, M. McCaughan, C. Fanelli, Yujie Qiang, R. A. Miskimen, A. Somov, R. Kliemt, F. Barbosa, A. Austregesilo, R. Dzhygadlo, C. Salgado, B. C.L. Sumner, L. Robison, Joerg Reinhold, Ting Xiao, A. Schick, V. Kakoyan, William Brooks, D. J. Mack, W. I. Levine, N. Gevorgyan, S. Katsaganis, E. Chudakov, Pavlos Ioannou, Lubomir Pentchev, A. Goncalves, A. Yu. Semenov, A. I. Ostrovidov, A. M. Foda, R. Dotel, M. Kamel, R. A. Schumacher, D. G. Ireland, W. B. Li, M. R. Shepherd, Ashot Gasparian, A. Teymurazyan, Krisztian Peters, J. Barlow, B. Zihlmann, Xiang Zhou, J. Pierce, S. Taylor, N. Sparks, L. Gan, S. Somov, L. Ng, A. Ernst, D. Kolybaba, K. Livingston, V. S. Goryachev, Cornelius Schwarz, P. Mattione, Y. Van Haarlem, P. Pauli, I. Tolstukhin, J. Schwiening, M. J. Amaryan, D. Lawrence, J. Brock, H. Ni, C. Stanislav, V. Lyubovitskij, S. Furletov, T. Britton, R. Barsotti, C. Paudel, Christine Kourkoumelis, Sergey Kuleshov, R. E. Mitchell, D. I. Lersch, C. L. Henschel, Q. Zhou, O. Soto, Friedrich Klein, and S.T. Krueger
Subjects: Nuclear and High Energy Physics, GlueX, детектор, Physics - Instrumentation and Detectors, Photon, Physics::Instrumentation and Detectors, фотонный пучок, FOS: Physical sciences, Scintillator, 01 natural sciences, Optics, Hodoscope, 0103 physical sciences, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Physics, GlueX, Spectrometer, Calorimeter (particle physics), 010308 nuclear & particles physics, business.industry, Detector, Instrumentation and Detectors (physics.ins-det), Beamline, High Energy Physics::Experiment, business
Abstract: The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 $\mu$s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation., Comment: Accepted by Nuclear Instruments and Methods A, 78 pages, 54 figures
Published: 2021

4. An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Author: Anthony W. Thomas, M. Battaglieri, R. De Vita, D. Marchand, Latifa Elouadrhiri, S. Habet, Hubert Spiesberger, P. Gueye, David Hamilton, Giovanni Salmè, A. Filippi, Pete Markowitz, D. Perera, G. Kalicy, M. Muhoza, N. Kalantarians, H. Atac, M. Khandaker, J. Xie, F. Sabatié, M. Mazouz, Ashot Gasparian, I.P. Fernando, V. Klimenko, T. A. Forest, D. McNulty, Z. E. Meziani, M. Boer, M. McCaughan, A. Asaturyan, J. P. Chen, V. Kozhuharov, S. Stepanyan, Simonetta Liuti, T. Patel, Alberto Accardi, M. Spata, Andrew Puckett, Andreas Metz, Salina Ali, V. Bellini, L. Barion, V. V. Berdnikov, Alexandre Camsonne, P. E. Reimer, M. Shabestari, P. Bisio, Simon Širca, T. Averett, J. Kim, Nikolaos Sparveris, M. Poelker, M. Spreafico, H. F. Ibrahim, Dipangkar Dutta, V. Bertone, Bogdan Wojtsekhowski, Ross Milner, H. Avakian, C. E. Hyde, P. M. King, Marc Vanderhaeghen, A. Somov, Yulia Furletova, Miha Mihovilovič, V. Tadevosyan, P. Sznajder, S. Migliorati, R. S. Beminiwattha, T. Chetry, M. Guidal, Olfred Hansen, T. Kutz, Z. W. Zhao, Barbara Pasquini, Eric Voutier, L. Lanza, M. J. Amaryan, J. R. M. Annand, Fatiha Benmokhtar, T. Gautam, H. Voskanyan, Richard Trotta, Ian L. Pegg, J. F. Owens, W. J. Briscoe, Jingyi Zhou, P. Valente, M. N. H. Rashad, Gordan Krnjaic, P. Lenisa, Elena Santopinto, Joseph Grames, M. Leali, S. Zhamkochyan, M. Caudron, Kai-Thomas Brinkmann, Elton Smith, L. Marsicano, Andrei Afanasev, Luciano Pappalardo, M. Carmignotto, Donal Day, L. Venturelli, Eugene Pasyuk, M. Ungaro, C. Peng, L. Causse, D. Hasell, G. Costantini, Douglas Higinbotham, N. D’Hose, J. Murphy, P. Chatagnon, R. Dupré, M. Bondì, Alexander Ilyichev, Matteo Rinaldi, P. Stoler, Brian Raue, G. N. Grauvogel, R. Santos Estrada, Kondo Gnanvo, K. Price, Q. Liu, S. Diehl, J. Nazeer, Y. G. Sharabian, X. Zheng, S. Niccolai, P. G. Blunden, J. Arrington, Riad Suleiman, J. Erler, S. Joosten, Andrea Bianconi, H.-S. Ko, P. L. Cole, Nilanga Liyanage, I. Albayrak, K. Joo, Jan C. Bernauer, F.-X. Girod, D. Gaskell, A. Kim, Juliette Mammei, A. Italiano, M. Hattawy, C. Ayerbe Gayoso, I. I. Strakovsky, M. Yurov, N. Randazzo, A. Deur, Wally Melnitchouk, H.-G. Zaunick, Michael Kohl, A. D'Angelo, E. Nardi, M. Paolone, C. Zorn, L. El Fassi, B. T. Kriesten, L. Darmé, M. Rathnayake, A. Shahinyan, Jie Zhang, Alessandro Rizzo, D. Flay, W. Xiong, H. Dutrieux, V. Sergeyeva, S. Zhang, E. R. Kinney, Hervé Moutarde, B. Dongwi, Axel Schmidt, Rolf Ent, S. Zhao, Volker D. Burkert, A. S. Tadepalli, A. S. Biselli, Tanja Horn, G. Niculescu, T. Cao, A. Celentano, P. Nadel-Turonski, Ethan Cline, J. Roche, B. Karky, M. Contalbrigo, H. Szumila-Vance, S. Fucini, O. Rondon-Aramayo, M. De Napoli, V. Mascagna, E. Fuchey, L. Cardman, G. Ciullo, Haiyan Gao, Cynthia Keppel, M. Ehrhart, A. Movsisyan, R. Novotny, A. Hobart, Sergio Scopetta, B. McKinnon, S. A. Wood, H. Mkrtchyan, M. Tiefenback, C. Munoz Camacho, Xinzhan Bai, R. Paremuzyan, B. Sawatzky, D. Sokhan, M. Suresh, Markus Diefenthaler, Z. Ye, Mauro Raggi, M. Kerver, Y. Roblin, A. Mkrtchyan, V. P. Kubarovsky, R. Capobianco, T. J. Hague, Dustin Keller, Sonny Mantry, Vladimir Khachatryan, Peter Schweitzer, Michael Wood, Maxime Defurne, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: cross-section, ratio, Photon, parton distributions, elastic scattering, Parton, polarized beam, Electron, Leptons Accelerators, Structure of Nucleons, 7. Clean energy, 01 natural sciences, Dark photon, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Positron, Economica, electromagnetic form-factors, virtual compton-scattering, generalized, squared 4-momentum transfers, lepton-flavor, violation, electron-proton, parity violation, pair production, Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Elastic scattering, Dark sector, JLab, dark photon, Settore FIS/04, lepton: flavor: violation, nucleon: generalized parton distribution, 3. Good health, High Energy Physics - Phenomenology, Elastic and deep inelastic Scattering, Nucleon, Jefferson Lab, Nuclear and High Energy Physics, nucleon: form factor: electromagnetic, FOS: Physical sciences, Socio-culturale, helium: target, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, 0103 physical sciences, quantum chromodynamics, 010306 general physics, PE2_3, activity report, exchange: two-photon, electroweak interaction, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Ambientale, positron: beam, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], charge: asymmetry, Positron Beams, Physics::Accelerator Physics, proposal, High Energy Physics::Experiment
Abstract: Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab., Comment: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"
Published: 2021

5. The BDX-MINI detector for Light Dark Matter search at JLab

Author: R. De Vita, Elton Smith, G. Ottonello, F. Parodi, T. Whitlatch, P. Bisio, M. Spreafico, Daniel P. Snowden-Ifft, M. Bondì, Michael Wood, L. Marsicano, M. De Napoli, Nunzio Randazzo, M. Battaglieri, Andrea Celentano, and P. L. Cole
Subjects: Physics - Instrumentation and Detectors, Physics and Astronomy (miscellaneous), Physics::Instrumentation and Detectors, FOS: Physical sciences, lcsh:Astrophysics, Electron, Scintillator, law.invention, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Silicon photomultiplier, Optics, law, lcsh:QB460-466, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Beam dump, Nuclear Experiment (nucl-ex), Engineering (miscellaneous), Light dark matter, Nuclear Experiment, Physics, business.industry, Detector, Instrumentation and Detectors (physics.ins-det), Cathode ray, lcsh:QC770-798, Physics::Accelerator Physics, High Energy Physics::Experiment, Neutrino, business
Abstract: This paper describes the design and performance of a compact detector, BDX-MINI, that incorporates all features of a concept that optimized the detection of light dark matter in the MeV-GeV mass range produced by electrons in a beam dump. It represents a reduced version of the future BDX experiment expected to run at JLAB. BDX-MINI was exposed to penetrating particles produced by a 2.176 GeV electron beam incident on the beam dump of Hall A at Jefferson Lab. The detector consists of 30.5 kg of PbWO$$_4$$ 4 crystals with sufficient material following the beam dump to eliminate all known particles except neutrinos. The crystals are read out using silicon photomultipliers. Completely surrounding the detector are a passive layer of tungsten and two active scintillator veto systems, which are also read out using silicon photomultipliers. The design was validated and the performance of the robust detector was shown to be stable during a six month period during which the detector was operated with minimal access.
Published: 2020

6. Measurement of the photon beam asymmetry in γ⃗p→K+Σ0 at Eγ=8.5 GeV

Author: T. D. Beattie, K. Goetzen, W. J. Briscoe, P. Pauli, G. M. Huber, D. I. Sober, M. J. Amaryan, V. Crede, M. M. Dalton, V. S. Goryachev, Christine Kourkoumelis, A. Hurley, R. E. Mitchell, G. Kalicy, N. S. Jarvis, C. A. Meyer, L. Ng, D. Lawrence, A. Ernst, H. Hakobyan, V. Lyubovitskij, G. J. Lolos, I. Larin, C. Salgado, R. Barsotti, S. Adhikari, O. Cortes, Sean A Dobbs, T. Britton, A. Somov, A. Ali, Sergey Kuleshov, C.P. Romero, P. Eugenio, R. A. Schumacher, D. I. Lersch, K. Livingston, M. M. Ito, Barry Ritchie, N. Cao, Ashot Gasparian, A. Hamdi, Krisztian Peters, Michael Dugger, T. C. Black, I. I. Strakovsky, J. Barlow, Joerg Reinhold, S. Fegan, A. Deur, S. Cole, J. Frye, E. Pooser, V. A. Matveev, N. Qin, J. Schwiening, O. Soto, A. M. Schertz, T. Whitlatch, L. Robison, T. Daniels, B. E. Cannon, T. Erbora, H. Ni, Z. Papandreou, Ting Xiao, V. V. Berdnikov, William Brooks, J. R. Stevens, M. McCaughan, Mark Richard James Williams, Lubomir Pentchev, C. Gleason, S. Furletov, Q. Zhou, A. M. Foda, Dmitri Romanov, H. Marukyan, R.S. Pedroni, W. U. Boeglin, W. McGinley, E. Chudakov, N. Wickramaarachchi, A. Thiel, K. K. Seth, C. Fanelli, M. Kamel, W. Phelps, F. Nerling, Elton Smith, B. Liu, G. Vasileiadis, A. Austregesilo, Zhiyong Zhang, M. R. Shepherd, A. Teymurazyan, R. T. Jones, Y. Yang, M. E. McCracken, Xiang Zhou, S. Taylor, L. Gan, S. Somov, L. Guo, J. Zarling, C. Paudel, A. Dolgolenko, V. V. Tarasov, E. Barriga, M. Patsyuk, J. Foote, X. Shen, K. Suresh, Hovanes Egiyan, R. A. Miskimen, R. Dzhygadlo, F. Barbosa, V. Kakoyan, D. J. Mack, A. Goncalves, R. Dotel, B. Zihlmann, A. I. Ostrovidov, H. Li, D. G. Ireland, and W. B. Li
Subjects: Physics, Range (particle radiation), GlueX, Spectrometer, 010308 nuclear & particles physics, Linear polarization, media_common.quotation_subject, Theoretical models, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Photon beam, Nuclear Experiment, 010306 general physics, Beam (structure), media_common
Abstract: We report measurements of the photon beam asymmetry Σ for the reaction γp→K+Σ0 (1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2–8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Σ was measured as a function of the Mandelstam variable t , and a single value of Σ was extracted for events produced in the u channel. These are the first exclusive measurements of the photon beam asymmetry Σ for the reaction in this energy range. For the t channel, the measured beam asymmetry is close to unity over the t range studied, − t = ( 0.1 – 1.4 ) ( GeV / c ) 2 , with an average value of Σ = 1.00 ± 0.05 . This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K ∗ (892) Regge trajectory. A value of Σ = 0.41 ± 0.09 is obtained for the u channel integrated up to − u = 2.0 ( GeV / c ) 2 .
Published: 2020

7. Beam asymmetry Σ for the photoproduction of η and η′ mesons at Eγ=8.8GeV

Author: A. Hurley, L. Gan, C. A. Meyer, J. Frye, C. Paudel, V. V. Tarasov, A. Dolgolenko, H. Hakobyan, C. Salgado, A. M. Schertz, E. Barriga, T. Daniels, C. Fanelli, R. T. Jones, W. Phelps, F. Nerling, M. E. McCracken, Krisztian Peters, Michael Dugger, V. Kakoyan, M. J. Staib, B. E. Cannon, T. Erbora, E. Pooser, I. A. Semenova, Z. Zhang, V. A. Matveev, A. Barnes, Dmitri Romanov, Sean A Dobbs, V. V. Berdnikov, A. Hamdi, J. Barlow, I. I. Strakovsky, Mark Richard James Williams, K. Suresh, T. Whitlatch, A. Somov, T. C. Black, D. Lawrence, A. Thiel, M. M. Dalton, H. Marukyan, Hovanes Egiyan, L. Ng, A. Ernst, M. McCaughan, R.S. Pedroni, W. McGinley, G. M. Huber, D. I. Sober, L. Robison, K. Livingston, V. Lyubovitskij, A. Deur, Ting Xiao, Q. Zhou, R. A. Miskimen, William Brooks, X. Zhou, P. Eugenio, G. Zhao, N. Wickramaarachchi, O. Cortes, N. Qin, L. Guo, E. Chudakov, R. Barsotti, Lubomir Pentchev, N. Cao, O. Soto, K. K. Seth, R. Dzhygadlo, F. Barbosa, B. Zihlmann, S. Fegan, M. Kamel, A. M. Foda, D. J. Mack, R. A. Schumacher, N. Gevorgyan, T. Britton, A. I. Ostrovidov, B. Liu, V. Crede, C.P. Romero, G. J. Lolos, I. Larin, G. Vasileiadis, H. Li, Ashot Gasparian, Sergey Kuleshov, D. I. Lersch, D. G. Ireland, A. Goncalves, Z. Papandreou, V. S. Goryachev, M. J. Amaryan, P. Mattione, S. Adhikari, M. Patsyuk, W. B. Li, A. Yu. Semenov, R. Dotel, Elton Smith, J. Schwiening, Barry Ritchie, J. R. Stevens, S. Somov, M. Boer, J. Foote, J. Zarling, M. R. Shepherd, A. Teymurazyan, C. Gleason, G. Kalicy, N. S. Jarvis, X. Shen, A. Austregesilo, S. Cole, Christine Kourkoumelis, Joerg Reinhold, A. Ali, R. E. Mitchell, W. U. Boeglin, Y. Yang, M. M. Ito, P. Pauli, S. Furletov, W. J. Briscoe, T. D. Beattie, and K. Goetzen
Subjects: Physics, GlueX, Meson, 010308 nuclear & particles physics, Linear polarization, media_common.quotation_subject, Momentum transfer, Parity (physics), 01 natural sciences, 7. Clean energy, Asymmetry, 0103 physical sciences, Quasiparticle, Atomic physics, Photon beam, 010306 general physics, media_common
Abstract: We report on the measurement of the beam asymmetry Σ for the reactions → γ p → p η and → γ p → p η ′ from the GlueX experiment using an 8.2–8.8-GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Laboratory. These measurements are made as a function of momentum transfer − t with significantly higher statistical precision than our earlier η measurements and are the first measurements of η ′ in this energy range. We compare the results to theoretical predictions based on t -channel quasiparticle exchange. We also compare the ratio of Σ η to Σ η ′ to these models as this ratio is predicted to be sensitive to the amount of s ¯ s exchange in the production. We find that photoproduction of both η and η ′ is dominated by natural parity exchange with little dependence on − t .
Published: 2019

8. Large-size CsI(Tl) crystal read-out by SiPM for low-energy charged-particles detection

Author: Elton Smith, N. Randazzo, M. Bondì, L. Marsicano, A. Celentano, M. Carpinelli, Valeria Sipala, M. Battaglieri, R. De Vita, M. De Napoli, Bondí, M, Battaglieri, M, Carpinelli, M, Celentano, A, De Napoli, M, De Vita, R, Marsicano, L, Randazzo, N, Sipala, V, and Smith, E
Subjects: Nuclear and High Energy Physics, Photon, Proton, APDS, Physics::Instrumentation and Detectors, Physics::Medical Physics, Silicon photomultiplier, 01 natural sciences, law.invention, CsI(Tl), Crystal, Nuclear physics, Optics, law, Beam-dump experiment, 0103 physical sciences, Irradiation, Nuclear Experiment, 010306 general physics, Instrumentation, Physics, Light dark matter, 010308 nuclear & particles physics, business.industry, Detector, Low-energy charged-particle detection, Charged particle, Physics::Accelerator Physics, business
Abstract: Silicon photomultipliers are a novel technology for the detection of photons in near ultraviolet, visible, and near-infrared spectral ranges. Their application is rapidly growing and extending to many fields in physics, replacing traditional PMTs and APDs. In this study a large-size CsI(Tl) crystal coupled to small-area SiPM ( 3 × 3 mm 2 ) was used to detect α -particles and low energy protons. In particular, the detector was irradiated with proton beams accelerated by the Tandem Van-der-Graff of the INFN-Laboratori Nazionali del Sud (LNS), at incident energies between 2.5 MeV and 24 MeV. The detector performance was studied in terms of light yield, linearity and energy resolution. In addition, we investigated the dependence of the detector response on the impact point of the particles.
Published: 2017

9. The BDX detector prototype for dark matter searches in a Beam Dump eXperiment at JLAB

Author: R. De Vita, Valeria Sipala, A. Italiano, M. Bondì, N. Randazzo, L. Marsicano, M. Battaglieri, Elton Smith, A. Celentano, and M. De Napoli
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Physics::Medical Physics, Dark matter, Detector, Cosmic ray, Linear particle accelerator, law.invention, Nuclear physics, law, Physics::Accelerator Physics, Beam dump, Nuclear Experiment, Instrumentation, Light dark matter, Mathematical Physics
Abstract: The Beam Dump eXperiment (BDX) is an electron-beam thick-target experiment aimed to investigate the existence of light dark matter particles in the MeV-GeV mass range at Jefferson Lab. A small-scale prototype (BDX-Proto) of the BDX detector has been constructed in order to validate the proposed design and to demonstrate with real measurements the capability to efficiently reject the cosmogenic backgrounds. In this paper we report the peformance of BDX-Proto extracted from a long campaign of cosmic ray measurements performed at INFN, Sez. Catania and INFN, LNS.
Published: 2020

10. Light yield of Kuraray SCSF-78MJ scintillating fibers for the Gluex barrel calorimeter

Author: T. D. Beattie, L. A. Teigrob, G. J. Lolos, A.P. Fischer, Elton Smith, I. A. Semenova, Z. Papandreou, E.L. Plummer, L.M. Sichello, S.T. Krueger, and A. Yu. Semenov
Subjects: Physics, Nuclear and High Energy Physics, Photomultiplier, GlueX, Yield (engineering), Calorimeter (particle physics), business.industry, Barrel (horology), Photodetector, Photoelectric effect, Optics, Optoelectronics, business, Instrumentation
Abstract: Over three quarters of a million 1-mm-diameter 4-m-long Kuraray double-clad SCSF-78MJ (blue-green) scintillating fibers have been used in the construction of the GlueX electromagnetic barrel calorimeter for the Hall D experimental program at Jefferson Lab. The quality of a random sample of 4750 of these fibers was evaluated by exciting the fibers at their mid point using a 90Sr source in order to determine the light yield using a calibrated vacuum photomultiplier as the photosensor. A novel methodology was developed to extract the number of photoelectrons detected for measurements where individual photoelectron peaks are not discernible. The average number of photoelectrons from this sample of fibers was 9.17±0.6 at a source distance of 200 cm from the PMT.
Published: 2014

11. Measurement of the beam asymmetry Σ for π0 and η photoproduction on the proton at Eγ=9 GeV

Author: E. Chudakov, J. Nys, V. Kakoyan, D. Lawrence, V. Lyubovitskij, F. Nerling, V. E. Tarasov, P. Eugenio, Z. Zhang, R. Dzhygadlo, H. Al Ghoul, F. Barbosa, N. K. Walford, V. Crede, Sean A Dobbs, J. Hardin, Dmitri Romanov, J. Schwiening, A. Barnes, S. Somov, A. Somov, B. Zihlmann, I. Vega, M. Lara, Kamal K. Seth, G. Nigmatkulov, Mark Richard James Williams, M. M. Dalton, Sergey Kuleshov, D. W. Bennett, C. Salgado, A. Yu. Semenov, L. Gan, L. Robison, V. A. Matveev, D. J. Mack, Ting Xiao, William Brooks, T. D. Beattie, N. Gevorgyan, M. R. Shepherd, A. Teymurazyan, Lubomir Pentchev, C. Kourkoumeli, A. M. Foda, S. Furletov, A. Subedi, Z. Papandreou, J.R. Stevens, W. J. Briscoe, R. A. Schumacher, Friedrich Klein, S. Taylor, I. A. Semenova, F. Mokaya, K. Goetzen, N. S. Jarvis, Ashot Gasparian, T. Whitlatch, C. Fanelli, G. Vasileiadis, Hovanes Egiyan, M. Kamel, Joerg Reinhold, A. Toro, D. I. Sober, Michael Dugger, J. Frye, Vincent Mathieu, D. Werthmüller, Justin I. McIntyre, Igor Strakovsky, M. Patsyuk, A. Tsaris, I. Kuznetsov, W. I. Levine, J. Zarling, A. Deur, R. E. Mitchell, R. T. Jones, A. Gerasimov, H. Hakobyan, M. E. McCracken, A. Dolgolenko, M. J. Staib, V. V. Berdnikov, N. Ochoa, L. Guo, B. Pratt, M. M. Ito, O. Chernyshov, R. Mendez, K. Livingston, V. S. Goryachev, K. Moriya, Krisztian Peters, Amiran Tomaradze, Michael R. Pennington, A. Henderson, Cornelius Schwarz, E. Pooser, G. M. Huber, P. Mattione, R. Kliemt, N. Sparks, W. U. Boeglin, B. E. Cannon, A. I. Ostrovidov, D. G. Ireland, A. Austregesilo, R.S. Pedroni, W. McGinley, G. J. Lolos, E. G. Anassontzis, C. A. Meyer, Barry Ritchie, Elton Smith, O. Soto, Ilya Larin, M. McCaughan, T. C. Black, Yujie Qiang, R. Miskimen, I. Tolstukhin, and E. Wolin
Subjects: Physics, Particle physics, GlueX, Proton, 010308 nuclear & particles physics, Linear polarization, media_common.quotation_subject, Momentum transfer, 01 natural sciences, 7. Clean energy, Asymmetry, Nuclear physics, 0103 physical sciences, Quasiparticle, Nuclear Experiment, 010306 general physics, Liquid hydrogen, Beam (structure), media_common
Abstract: We report measurements of the photon beam asymmetry Σ for the reactions γ - p→pπ0 and γ - p→pη from the GlueX experiment using a 9 GeV linearly polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous π0 measurements and are the first η measurements in this energy regime. The results are compared with theoretical predictions based on t-channel, quasiparticle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.
Published: 2017

12. Relative gain monitoring of the GlueX calorimeters

Author: E. G. Anassontzis, G. Vasileiadis, J. Frye, Pavlos Ioannou, G. J. Lolos, Elton Smith, S.T. Krueger, M. Shepherd, T. Bogart, D. Lawrence, John P. Leckey, G. Voulgaris, Z. Papandreou, A. Yu. Semenov, Christine Kourkoumelis, T. D. Beattie, and E. Kappos
Subjects: Physics, Nuclear and High Energy Physics, Optical fiber, GlueX, business.industry, Controller (computing), Detector, Electrical engineering, Barrel (horology), Photodetector, Modular design, law.invention, Power (physics), law, business, Instrumentation
Abstract: The relative gain of the photodetectors for the GlueX Barrel and Forward calorimeters will be monitored using modular LED driver systems. The BCAL system consists of a global controller that feeds power, bias voltage and trigger signals to 96 local controllers situated at the ends of the 48 BCAL modules, which drive 40 LEDs associated with the 40 light guides at the end of each module. The FCAL system consists also of a global controller, a local controller for each acrylic quadrant covering the face of the FCAL, and ten 4-LED pulser boards per local controller connected in a star configuration along the edges of the acrylic panes. The respective systems are currently being installed on the detectors and their tested performance is presented herein.
Published: 2014

13. A measurement of the energy and timing resolution of the GlueX Forward Calorimeter using an electron beam

Author: K. Bauer, M. R. Shepherd, J. Frye, P.T. Smith, S.J. Henderson, D. Lawrence, J. Gonzalez, J. Leckey, Elton Smith, D. Bennett, A. Somov, K. Moriya, Hovanes Egiyan, and R. E. Mitchell
Subjects: Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, GlueX, Calorimeter (particle physics), Physics::Instrumentation and Detectors, business.industry, Detector, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Particle detector, Linear particle accelerator, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Nuclear magnetic resonance, Bunches, Optics, Measuring instrument, Cathode ray, Physics::Accelerator Physics, Nuclear Experiment (nucl-ex), business, Nuclear Experiment, Instrumentation
Abstract: The performance of the GlueX Forward Calorimeter was studied using a small version of the detector and a variable energy electron beam derived from the Hall B tagger at Jefferson Lab. For electron energies from 110 MeV to 260 MeV, which are near the lower-limits of the design sensitivity, the fractional energy resolution was measured to range from 20% to 14%, which meets the design goals. The use of custom 250 MHz flash ADCs for readout allowed precise measurements of signal arrival times. The detector achieved timing resolutions of 0.38 ns for a single 100 mV pulse, which will allow timing discrimination of photon beam bunches and out-of-time background during the operation of the GlueX detector., Comment: 8 pages, 11 figures, submitted to NIMA
Published: 2013

14. Radiation hardness tests of SiPMs for the JLab Hall D Barrel calorimeter

Author: F. Barbosa, Carl Zorn, Yi Qiang, and Elton Smith
Subjects: Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Radiation, Neutron radiation, Particle detector, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Neutron flux, Neutron source, Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, Instrumentation, Radiation hardening, Dark current
Abstract: We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am-Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase linearly as a function of the 1 MeV equivalent neutron fluence and a temperature dependent self-annealing effect is observed., arXiv admin note: substantial text overlap with arXiv:physics/0211118
Published: 2013

15. Silicon photomultiplier characterization for the GlueX barrel calorimeter

Author: J. E. McKisson, Yujie Qiang, Carl Zorn, Elton Smith, John McKisson, and F. Barbosa
Subjects: Physics, Nuclear and High Energy Physics, GlueX, Physics::Instrumentation and Detectors, business.industry, Detector, Photodetector, Photodetection, Linear particle accelerator, Calorimeter, Silicon photomultiplier, Measuring instrument, Optoelectronics, High Energy Physics::Experiment, business, Instrumentation
Abstract: GlueX is a new detector being constructed at Jefferson Laboratory to study gluonic excitations and confinement via the detection of exotic meson states. The hermetic detector includes a barrel calorimeter where the photodetectors must operate in a high magnetic field exceeding 0.5 T. After extensive tests with a variety of sensors, the chosen photodetector will be a custom silicon photomultiplier (SiPM) array manufactured by Hamamatsu Corporation. This paper will focus on the characterization of the first 80 production samples of these SiPMs, including dark rate, photodetection efficiency (PDE), crosstalk, response uniformity and radiation tolerance.
Published: 2012

16. Photoproduction of the f(1)(1285) meson

Author: Nicholas Zachariou, E. Voutier, P. Lenisa, K. Livingston, V. Mokeev, Jie Zhang, I. Zonta, R. A. Badui, I. I. Strakovsky, F. X. Girod, N. Dashyan, A. Filippi, N. Compton, L. Colaneri, B. S. Ishkhanov, R. De Vita, M. Khandaker, C. Djalali, K. Park, A. Deur, V. Sytnik, L. Zana, G. Rosner, A. Celentano, I. Stankovic, R. W. Gothe, A. Ni, K. Hicks, S. Chandavar, W. Phelps, M. Battaglieri, N. Markov, W. Kim, S. Pisano, Friedrich Klein, Gerard Gilfoyle, Brian Raue, M. Ripani, M. Contalbrigo, S. Anefalos Pereira, Y. Ghandilyan, P. Roy, D. Sokhan, H. Y. Lu, P. L. Cole, J. W. Price, P. Nadel-Turonski, B. McKinnon, Dustin Keller, P. Mattione, M. Taiuti, Iu. Skorodumina, M. J. Amaryan, V. Crede, G. Khachatryan, A. I. Ostrovidov, S. Strauch, M. Ungaro, Michael Dugger, M. Mirazita, Z. Akbar, D. P. Watts, G. Ciullo, Eugene Pasyuk, J. A. Fleming, H. Hakobyan, D. G. Ireland, S. Joosten, H. Jiang, Y. Prok, D. S. Carman, L. Guo, N. Gevorgyan, K. L. Giovanetti, V. Batourine, G. D. Smith, M. Holtrop, A. Rizzo, Volker D. Burkert, A. S. Biselli, H. S. Jo, R. A. Schumacher, R. Dupre, A. Kim, K. A. Griffioen, Michael Wood, D. Weygand, K. Hafidi, C. Hanretty, N. Harrison, M. Osipenko, Andrew Puckett, L. Lanza, E. De Sanctis, N. K. Walford, I. Bedlinskiy, Taya Chetry, K. P. Adhikari, I. J. D. MacGregor, S. Stepanyan, E. Munevar, Nikolaos Sparveris, D. I. Sober, T. Cao, A. D'Angelo, E. Fanchini, L. El Fassi, Elton Smith, Ryan Dickson, L. A. Net, V. P. Kubarovsky, Y. G. Sharabian, Sergey Kuleshov, P. Eugenio, G. Charles, O. Pogorelko, S. M. Hughes, H. Voskanyan, W. J. Briscoe, Kei Moriya, C. A. Meyer, G. V. Fedotov, G. Murdoch, C. Salgado, J. Ball, M. Hattawy, O. Cortes, E. L. Isupov, S. Boiarinov, E. Seder, A. El Alaoui, Y. Ilieva, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: M008W, Dalitz plot, Analytical chemistry, 01 natural sciences, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment (hep-ex), CHANNEL, PSEUDOSCALAR RESONANCES, meson: exchange, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Monte Carlo, QC, Physics, F(1) 1285, radiative decay, AXIAL-VECTOR, amplitude analysis, K K, Pseudoscalar, Full width at half maximum, ETA-PI+PI-SYSTEM, CENTRAL PP INTERACTIONS, 450 GEV/C, PSEUDOSCALAR, RESONANCES, CLAS, SPIN, COLLISIONS, differential cross section, M008M, branching ratio, f1(1285): photoproduction, missing-mass, Jefferson Lab, Scattering cross-section, Meson, M008.13, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], eta(1295), Nuclear physics, p: target, 0103 physical sciences, Pi, 010306 general physics, numerical calculations, Pseudovector, M008.1, 010308 nuclear & particles physics, Branching fraction, M008.5, M008.4, M008.3, High Energy Physics::Experiment, experimental results
Abstract: The $f_1(1285)$ meson with mass $1281.0 \pm 0.8$ MeV/$c^2$ and width $18.4 \pm 1.4$ MeV (FWHM) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the $\eta\pi^{+}\pi^{-}$, $K^+\bar{K}^0\pi^-$, and $K^-K^0\pi^+$ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the $\eta\pi^{+}\pi^{-}$ final-state Dalitz distribution are consistent with the axial-vector $J^P=1^+$ $f_1(1285)$ identity, rather than the pseudoscalar $0^-$ $\eta(1295)$. The production mechanism is more consistent with $s$-channel decay of a high-mass $N^*$ state, and not with $t$-channel meson exchange. Decays to $\eta\pi\pi$ go dominantly via the intermediate $a_0^\pm(980)\pi^\mp$ states, with the branching ratio $\Gamma(a_0\pi \text{ (no} \bar{K} K\text{)}) / \Gamma(\eta\pi\pi \text{(all)}) = 0.74\pm0.09$. The branching ratios $\Gamma(K \bar{K} \pi)/\Gamma(\eta\pi\pi) = 0.216\pm0.033$ and $\Gamma(\gamma\rho^0)/\Gamma(\eta\pi\pi) = 0.047\pm0.018$ were also obtained. The first is in agreement with previous data for the $f_1(1285)$, while the latter is lower than the world average., Comment: 26 pages, 16 figures, Reference added, submitted to Physical Review C
Published: 2016

17. Evidence for the onset of color transparency in ρ0 electroproduction off nuclei

Author: G. Niculescu, S. Tkachenko, R. Dupre, M. Battaglieri, L. Guo, P. Khetarpal, R. De Vita, Paolo Rossi, C. Djalali, G. Ricco, Martin K. Mayer, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, F. X. Girod, V. Mokeev, Barry Ritchie, P. E. Reimer, B. Vernarsky, J. W. Price, V. Kuznetsov, M. S. Saini, E. Voutier, S. Procureur, F. Sabatié, A. Kim, B. Zhao, I. Niculescu, D. G. Ireland, Friedrich Klein, Brian Raue, V. Crede, W. Tang, M. Ripani, K. A. Griffioen, Michael Vineyard, E. De Sanctis, M. Aghasyan, D. I. Sober, J. T. Goetz, W. Gohn, T. Mineeva, D. Schott, P. Nadel-Turonski, M. Osipenko, Y. Mao, V. P. Kubarovsky, S. Niccolai, C. E. Hyde, S. S. Jawalkar, J. Arrington, P. Stoler, Latifa Elouadrhiri, C. A. Meyer, B. Dey, I. J. D. MacGregor, E. Munevar, B. S. Ishkhanov, S. E. Kuhn, C. Hanretty, K. Hicks, G. V. Fedotov, H. Avakian, E. L. Isupov, K. P. Adhikari, A. Celentano, R. W. Gothe, A. Deur, D. P. Weygand, Elton Smith, George Davey Smith, D. J. Tedeschi, H. Voskanyan, R. A. Schumacher, P. Eugenio, M. Taiuti, M. Anghinolfi, W. J. Briscoe, E. Pasyuk, W. K. Brooks, I. Bedlinskiy, H. Seraydaryan, Lorenzo Zana, S. Park, Y. G. Sharabian, A. D'Angelo, H. Hakobyan, S. Bültmann, X. Zheng, A. I. Ostrovidov, K. Park, M. Contalbrigo, R. J. Holt, C. E. Taylor, S. Stepanyan, C. Salgado, Avraham Klein, L. El Fassi, A. Ni, E. Golovatch, M. Ungaro, J. McAndrew, Z. W. Zhao, Michael Wood, Volker D. Burkert, K. Hafidi, A. S. Biselli, B. McKinnon, D. Branford, M. Mirazita, E. Phelps, J. M. Laget, S. S. Stepanyan, N. Gevorgyan, V. Batourine, N. Markov, D. Keller, Sergey Kuleshov, M. Khandaker, Hovanes Egiyan, M. J. Amaryan, R. Paremuzyan, H. Moutarde, K. L. Giovanetti, Larry Weinstein, Gerard Gilfoyle, D. Doughty, D. Heddle, D. Sokhan, D. Adikaram, M. Guidal, B. Mustapha, M. Holtrop, A. Daniel, Luciano Pappalardo, G. Rosner, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. Rimal, B. Moreno, R. Dickson, P. L. Cole, D. Protopopescu, S. Pozdniakov, M. Garçon, S. Chandavar, S. Strauch, D. P. Watts, M. Y. Gabrielyan, D. S. Carman, N. Dashyan, H. Baghdasaryan, S. Fegan, C. Bookwalter, and W. Kim
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, Virtual particle, Electron, 01 natural sciences, Coherence length, Nuclear physics, Color model, Deuterium, Nuclear transparency, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: We have measured the nuclear transparency of the incoherent diffractive A(e,e′ρ0) process in 12C and 56Fe targets relative to 2H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced ρ0ʼs on a nucleus relative to deuterium, which is sensitive to ρA interaction, was studied as function of the coherence length (lc), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q2). While the transparency for both 12C and 56Fe showed no lc dependence, a significant Q2 dependence was measured, which is consistent with calculations that included the color transparency effects.
Published: 2012

18. PRODUCTION AND SEARCHES FOR CASCADE BARYONS WITH CLAS

Author: Elton Smith
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, General Physics and Astronomy, Strangeness, Pentaquark, Nuclear physics, Baryon, Deuterium, Cascade, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Excited state, Invariant mass, Ground state
Abstract: We present the results of photoproduction cross sections of the ground state cascade Ξ- and the first excited state Ξ*-(1530) measured with the CLAS detector. The photoproduction of the cascade resonances has been investigated in the reactions γp → K+K+(X) and γp → K+K+π-(X). The differential and total cross sections of the Ξ- were determined for photon beam energies from 2.75 to 4.75 GeV and are consistent with a production mechanism of Y* → K+Ξ- through a t-channel process. The cross-section of the Ξ*-(1530) has been determined for photon beam energies from 3.35 to 4.75 GeV. The reaction γp → K+K+π-(Ξ0) has also been investigated in the search for excited cascade resonances decaying to π-Ξ0. No significant signal of excited cascade states other than the well-known Ξ*-(1530) is observed. We also present the latest results of a search for the Φ--(1862) exotic pentaquark state in a photoproduction experiment on a deuterium target. A high-statistics sample of π-Ξ- events have been collected and analyzed. A preliminary invariant mass spectrum of the π-Ξ- system is presented, which is used to set upper limits on the photoproduction of the Φ-- pentaquark state.
Published: 2010

19. The extraction of ϕ–N total cross section from d(γ,pK+K−)n

Author: K. Livingston, P. Eugenio, R. Dickson, M. Taiuti, D. Doughty, S. Park, D. Heddle, M. Battaglieri, R. A. Schumacher, S. Stepanyan, Avraham Klein, Michael Vineyard, S. Fegan, K. A. Griffioen, P. Collins, Y. Ilieva, H. Hakobyan, C. E. Hyde, C. Bookwalter, G. E. Dodge, H. Y. Lu, D. G. Ireland, W. Xu, V. Crede, Marco Ripani, F. Sabatié, R. G. Fersch, I. Niculescu, D. J. Tedeschi, M. J. Amaryan, D. Schott, P. L. Cole, Elton Smith, E. L. Isupov, M. E. McCracken, N. Dashyan, I. Bedlinskiy, Gerard Gilfoyle, V. P. Kubarovsky, Michael L. Williams, Tsutomu Mibe, N. Hassall, M. Bellis, S. L. Careccia, D. Sokhan, O. Pogorelko, C. Djalali, Z. W. Zhao, V. Kuznetsov, W. Gohn, A. D'Angelo, H. Baghdasaryan, M. Anghinolfi, Paolo Rossi, K. Hicks, D. Protopopescu, F. X. Girod, Sergey Kuleshov, K. L. Giovanetti, B. McKinnon, I. I. Strakovsky, Lorenzo Zana, S. Pozdniakov, Larry Weinstein, H. Seraydaryan, C. Hanretty, E. Wolin, Friedrich Klein, S. Niccolai, G. Rosner, W. J. Briscoe, Giovanni Ricco, R. Nasseripour, A. Fradi, E. Pasyuk, D. Keller, D. Branford, Brian Raue, J. W. Price, W. Chen, Y. G. Sharabian, J. P. Ball, J. R. Johnstone, L. Guo, C. Salgado, J. M. Laget, A. Deur, Xin Qian, D. S. Carman, Haiyan Gao, M. Ungaro, M. Guidal, M. Khandaker, V. Batourine, S. Tkachenko, S. Pisano, W. K. Brooks, S. Procureur, Martin K. Mayer, K. Joo, B. Zhao, M. S. Saini, A. I. Ostrovidov, K. Park, J. T. Goetz, M. Mirazita, M. Holtrop, A. Daniel, B. Morrison, K. Kramer, Michael Wood, K. Hafidi, Volker D. Burkert, A. S. Biselli, Kei Moriya, C. A. Meyer, J. Zhang, P. Nadel-Turonski, S. S. Jawalkar, E. Golovatch, R. Dupre, G. V. Fedotov, S. Dhamija, R. W. Gothe, S. Strauch, D. P. Watts, K. P. Adhikari, M. Y. Gabrielyan, D. P. Weygand, Barry Ritchie, B. Dey, M. Osipenko, D. Martinez, V. Mokeev, W. Kim, G. Niculescu, P. Khetarpal, C. S. Nepali, R. De Vita, T. Mineeva, S. Anefalos Pereira, E. De Sanctis, D. I. Sober, E. Munevar, B. S. Ishkhanov, and M. R. Niroula
Subjects: Baryon, Nuclear reaction, Physics, Nuclear and High Energy Physics, Cross section (physics), Meson, Deuterium, Proton, Hadron, Analytical chemistry, Atomic physics, Nucleon
Abstract: We report on the first measurement of the differential cross section of ϕ-meson photoproduction for the d ( γ , p K + K − ) n exclusive reaction channel. The experiment was performed using a tagged-photon beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the d ( γ , p K + K − ) n channel and those from a previous publication on coherent ϕ production on the deuteron has been carried out to extract the ϕ − N total cross section, σ ϕ N . The extracted ϕ − N total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for ϕ photoproduction on the proton.
Published: 2009

20. Moments of the spin structure functions g1p and g1d for 0.05<Q2<3.0 GeV2

Author: R. A. Schumacher, G. V. O'Rielly, C. D. Keith, Cynthia Marie Hadjidakis, Z. W. Zhao, Chaden Djalali, D. G. Jenkins, Michael Dugger, S. Tkachenko, H. O. Funsten, A. I. Ostrovidov, A. C S Lima, S. Bültmann, L. Morand, M. R. Niroula, T. A. Forest, D. G. Ireland, G. Asryan, Volker D. Burkert, A. S. Biselli, J. Pierce, Elton Smith, M. J. Amaryan, M. MacCormick, O. P. Dzyubak, R. A. Niyazov, I. Hleiqawi, S. L. Careccia, Larry Weinstein, Avraham Klein, E. Golovatch, H. G. Juengst, K. Moriya, Daniel S. Carman, J. Kuhn, Philip L. Cole, S. McAleer, H. Hakobyan, S. Anefalos Pereira, P. D. Rubin, L. Blaszczyk, P. Corvisiero, Y. G. Sharabian, A. Fradi, L. Cheng, G. Audit, A.V. Stavinsky, C. E. Hyde-Wright, F. Sabatié, Nikolay Shvedunov, D. Heddle, P. Stoler, Friedrich Klein, J. P. Cummings, R. De Vita, N. Markov, V. Sapunenko, C. Salgado, Dinko Pocanic, L. Elouadrhiri, N. Kalantarians, S. Stepanyan, K. S. Egiyan, R. C. Minehart, C. A. Meyer, J. Ball, M. Taiuti, S. E. Kuhn, I. I. Strakovsky, M. Bektasoglu, M. Kossov, K. Mikhailov, K.H. Hicks, R. J. Feuerbach, G. V. Fedotov, M. Nozar, A. Deur, I. Popa, V. Crede, J. W. Price, Shifeng Chen, M. Anghinolfi, Laird Kramer, D. P. Watts, H. Egiyan, G. Gavalian, John A. Mueller, L. Casey, B. L. Berman, P. Mattione, B. B. Niczyporuk, G. Rosner, N. Benmouna, N. Pivnyuk, Kwangsoo Kim, J. T. Goetz, M. Mirazita, G. Riccardi, J. R. Calarco, R. A. Miskimen, B. A. Raue, B. McKinnon, W. J. Briscoe, L. M. Qin, R. G. Fersh, P. Eugenio, J. Langheinrich, C. Butuceanu, C. Hanretty, S. S. Stepanyan, E. Pasyuk, S. A. Philips, M. Ripani, G. Ricco, S. A. Morrow, C. Paterson, Y. Ilieva, Michael Vineyard, Victor Mokeev, M. Klusman, B. M. Preedom, D. Branford, P. Collins, B. Moreno, J. R. Johnstone, Lorenzo Zana, J. P. Santoro, Tsutomu Mibe, Gerald Feldman, J. M. Laget, L. Todor, D. Protopopescu, K. L. Giovanetti, S. V. Kuleshov, C. Marchand, S. Pozdniakov, M. Garçon, M. L. Seely, Ji Li, D. J. Tedeschi, G. E. Dodge, H. Y. Lu, J. Lachniet, I. Bedlinskiy, Marco A. Huertas, A. Tkabladze, M. D. Mestayer, E. L. Isupov, P. V. Degtyarenko, D. Rowntree, K. Livingston, Michael L. Williams, M. Holtrop, R. Suleiman, V. Kuznetsov, D. S. Dale, J. Zhang, S. Boiarinov, D. I. Sober, Gerard Gilfoyle, F. X. Girod, G. S. Mutchler, N. A. Baltzell, I. Niculescu, D. Sokhan, J. Salamanca, K. A. Griffioen, D. Lawrence, M. Guillo, N. Guler, R. De Masi, L. El Fassi, J. W C McNabb, Sylvain Bouchigny, H. Denizli, M. Guidal, M. Battaglieri, J. Hardie, S. Strauch, J. D. Kellie, Z. Krahn, R. Nasseripour, S. Barrow, P. Rossi, R. Dickson, N. Baillie, D. Doughty, V. Gyurjyan, R. Bradford, K. Lukashin, B. E. Stokes, G. S. Adams, H. Bagdasaryan, P. Nadel-Turonski, A. V. Skabelin, K. Joo, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, L. Guo, M. Ungaro, D. P. Weygand, E. Wolin, N. Hassall, M. Bellis, D. G. Crabb, J. Yun, D. Cords, P. Bosted, A. Yegneswaran, N. Dashyan, Y. Prok, Barry Ritchie, E. De Sanctis, H. S. Jo, S. Niccolai, R. Fatemi, A. V. Vlassov, P. Coltharp, R. W. Gothe, M. M. Ito, K. Y. Kim, M. Osipenko, K. Beard, L. C. Smith, E. Munevar, Kalvir S. Dhuga, B. S. Ishkhanov, O. Pogorelko, M. Khandaker, B. Zhao, F. W. Hersman, W. Kim, G. Niculescu, N. Gevorgyan, L. C. Dennis, B. E. Bonner, H. Avakian, D. Sharov, S. A. Dytman, W. K. Brooks, K. Park, V. P. Kubarovsky, J. Shaw, Michael Wood, K. Hafidi, and V. S. Serov
Subjects: Physics, Nuclear and High Energy Physics, Chiral perturbation theory, Heavy baryon chiral perturbation theory, Proton, 010308 nuclear & particles physics, Nuclear Theory, Hadron, 01 natural sciences, Baryon, Nuclear physics, Polarizability, 0103 physical sciences, Sum rule in quantum mechanics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The spin structure functions g 1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 Q 2 5 GeV 2 and W 3 GeV . The first moments of g 1 for the proton and deuteron are presented – both have a negative slope at low Q 2 , as predicted by the extended Gerasimov–Drell–Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ 0 p is also reported. This quantity shows strong Q 2 dependence at low Q 2 . Our analysis of the Q 2 evolution of the first moment of g 1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ 0 p data and Chiral Perturbation calculations for γ 0 p , even at the lowest Q 2 .
Published: 2009

21. Exclusive ρ0 electroproduction on the proton at CLAS

Author: J. Langheinrich, S. S. Stepanyan, E. Pasyuk, S. A. Philips, N. Dashyan, V. Sapunenko, G. Ricco, Alexei V. Klimenko, N. A. Baltzell, C. Salgado, Dinko Pocanic, Barry Ritchie, H. Denizli, A. V. Skabelin, K. A. Griffioen, B. Zhao, V. Gyurjyan, A. I. Ostrovidov, R. Fatemi, K. Park, S. E. Kuhn, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, H. G. Juengst, B. E. Stokes, G. S. Adams, G. V. Fedotov, V. P. Kubarovsky, J. Zhang, P. Eugenio, K. P. Adhikari, A. V. Vlassov, D. P. Weygand, G. E. Dodge, H. Y. Lu, M. J. Amaryan, G. V. O'Rielly, S. Niccolai, Z. W. Zhao, V. Mokeev, Y. Ilieva, Ji Li, D. G. Jenkins, C. Tur, Gerard Gilfoyle, Elton Smith, H. Hakobyan, A.V. Stavinsky, J. D. Kellie, M. Guidal, M. MacCormick, I. Hleiqawi, S. L. Careccia, R. De Vita, Friedrich Klein, Brian Raue, P. V. Degtyarenko, M. D. Mestayer, J. P. Didelez, R. Nasseripour, L. Todor, F. W. Hersman, P. Coltharp, E. L. Isupov, J. P. Cummings, W. Gohn, S. A. Morrow, S. McAleer, M. Anghinolfi, P. Nadel-Turonski, D. Sokhan, D. Protopopescu, D. J. Tedeschi, M. Holtrop, Michael L. Williams, P. Collins, K. L. Giovanetti, I. Niculescu, F. X. Girod, L. Blaszczyk, B. Carnahan, James Mueller, D. Lawrence, R. G. Fersch, R. A. Miskimen, B. McKinnon, S. Pozdniakov, M. Garçon, J. J. Melone, M. M. Ito, S. Boiarinov, Larry Weinstein, L. Zana, P. D. Rubin, R. De Masi, D. Keller, I. Bedlinskiy, B. M. Preedom, S. Anefalos Pereira, D. Schott, Y. G. Sharabian, R. A. Schumacher, P. L. Cole, M. Yurov, M. Taiuti, S. Mehrabyan, D. Branford, L. C. Smith, E. Munevar, G. S. Mutchler, B. S. Ishkhanov, Michael Wood, K. Hafidi, L. Graham, M. Kossov, M. E. McCracken, C. I O Gordon, J. M. Laget, V. Kuznetsov, J. Kuhn, E. Hourany, M. Khandaker, V. S. Serov, L. C. Dennis, B. E. Bonner, J. W. Price, Tsutomu Mibe, S. Bültmann, G. Audit, Shifeng Chen, C. Bookwalter, N. Gevorgyan, M. Osipenko, C. E. Hyde-Wright, J. P. Santoro, H. S. Jo, H. Avakian, L. Morand, I. Popa, D. Sharov, T. A. Forest, G. Riccardi, M. R. Niroula, E. De Sanctis, O. Pogorelko, S. Stepanyan, P. Mattione, C. Butuceanu, M. S. Saini, D. Doughty, J. Pierce, M. Ripani, B. L. Berman, Avraham Klein, L. M. Qin, M. Aghasyan, E. Wolin, Sergey Kuleshov, W. J. Briscoe, D. Heddle, J. T. Goetz, D. I. Sober, Kalvir S. Dhuga, M. Bektasoglu, S. A. Dytman, S. Dhamija, M. Nozar, E. Polli, M. Mirazita, C. Paterson, J. P. Ball, R. W. Gothe, Y. Prok, B. Moreno, W. Kim, J. Hardie, Hall Crannell, D. S. Carman, K. Livingston, G. Rosner, C. Marchand, G. Niculescu, D. S. Dale, N. Baillie, S. Park, Sylvain Bouchigny, J. Lachniet, A. Tkabladze, D. G. Crabb, R. Dickson, Michael Vineyard, D. G. Ireland, V. Crede, J. R. Calarco, P. Khetarpal, N. Guler, J. Salamanca, L. El Fassi, J. W C McNabb, S. Barrow, P. Rossi, L. Casey, H. Bagdasaryan, Volker D. Burkert, A. S. Biselli, B. B. Niczyporuk, N. Pivnyuk, P. Stoler, C. Hanretty, Laird Kramer, J. R. Johnstone, L. Guo, M. Ungaro, A. Fradi, K. Joo, D. Cords, N. Markov, A. Yegneswaran, K. Hicks, M. Battaglieri, R. Bradford, K. S. Egiyan, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, N. Hassall, M. Bellis, K. Mikhailov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, S. Strauch, D. P. Watts, H. Egiyan, I. I. Strakovsky, A. Deur, W. K. Brooks, R. J. Feuerbach, Cynthia Marie Hadjidakis, M. Guillo, Chaden Djalali, Michael Dugger, L. Cheng, F. Sabatié, Nikolay Shvedunov, N. Kalantarians, G. Gavalian, S. Tkachenko, and N. Benmouna
Subjects: Quark, Physics, REPRESENTATION, Nuclear and High Energy Physics, Particle physics, Valence (chemistry), Proton, Hadron, Parton, VECTOR-MESON ELECTROPRODUCTION, Approx, PHOTONS, QCD, EVOLUTION, High Energy Physics - Experiment, Regge theory, Nuclear physics, Scattering amplitude, GENERALIZED PARTON DISTRIBUTIONS, VIRTUAL COMPTON-SCATTERING, VECTOR-MESON ELECTROPRODUCTION, LARGE MOMENTUM-TRANSFER, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, PHOTONS, QCD, REPRESENTATION, EVOLUTION, LARGE MOMENTUM-TRANSFER, GENERALIZED PARTON DISTRIBUTIONS, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, Nuclear Experiment, VIRTUAL COMPTON-SCATTERING
Abstract: The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present., Comment: 29 pages, 29 figures
Published: 2008

22. Performance of the prototype module of the GlueX electromagnetic barrel calorimeter

Author: E. Wolin, Andrei Semenov, D. Lawrence, Christina Kourkoumeli, J. P. Santoro, Franz Klein, Eric L. Scott, G. M. Huber, D. I. Sober, Daniel S. Carman, Zisis Papandreou, G.J. Lolos, Simon Taylor, Elton Smith, Blake Leverington, Rafael Hakobyan, Kathryn Janzen, and M. Shepherd
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), GlueX, Calorimeter (particle physics), Physics::Instrumentation and Detectors, business.industry, Barrel (horology), Photoelectric effect, Optics, Perpendicular, Photon beam, Nuclear Experiment, business, Instrumentation, Energy (signal processing)
Abstract: A photon beam test of the 4 m long prototype lead/scintillating-fibre module for the GlueX electromagnetic barrel calorimeter was carried out in Hall B at the Thomas Jefferson National Accelerator Facility with the objective of measuring the energy and timing resolutions of the module as well as the number of photoelectrons generated. Data were collected over an energy range of 150–650 MeV at multiple positions and angles along the module. Details of the analysis at the centre of and perpendicular to the module are shown herein; the results are σ E / E = 5.4 % / E ( GeV ) ⊕ 2.3 % , σ Δ T / 2 = 70 / E ps, and 660 photoelectrons for 1 GeV at each end of the module.
Published: 2008

23. Performance of the radphi detector and trigger in a high rate tagged photon beam

Author: M. Kornicer, D. R. Rust, D. Krop, R. Lindenbusch, C Steffen, E. Walker, B.E. Evans, G. S. Adams, J. J. Kolata, D.I. Sober, L.J. Kaufman, C. Campbell, R.R. Mammei, Larry Lamm, D. J. Steiner, Eric L. Scott, J. H. D. Clark, J. Napolitano, E. Collins, Dinko Pocanic, P.T. Smith, J. Gunter, Emil Frlez, H. Crannell, A. R. Dzierba, L. McGlinchey, Elton Smith, D. S. Armstrong, P. D. Rubin, Grigory Rogachev, S. Teige, T. Bogue, R. T. Jones, and Robert Gardner
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Resolution (electron density), Detector, Physics::Optics, Flux, Calorimeter, Nuclear physics, Radiative transfer, High Energy Physics::Experiment, Photon beam, Nuclear Experiment, Instrumentation
Abstract: We describe the design and operation of a detector system for measuring all-photon decays of mesons photoproduced in a tagged photon beam with energies between 4.3 and 5.4 GeV and a flux of 5×107 tagged photons per second. Photons from meson decays were detected with a lead-glass calorimeter with an energy resolution of 11% at 1 GeV. Various veto and trigger components were also present. Final states with as many as six photons were successfully detected and reconstructed.
Published: 2007

24. Measurements ofep→e′π+nat1.6<W<2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS

Author: B. S. Ishkhanov, I. Zonta, J. Bono, P. Nadel-Turonski, X. Wei, E. De Sanctis, P. Eugenio, M. Taiuti, K. A. Griffioen, B. Garillon, Z. W. Zhao, C. E. Hyde, A. Filippi, D. Protopopescu, A. Kim, M. Garçon, S. Niccolai, A. Trivedi, Andrew Puckett, J. T. Goetz, F. X. Girod, Michael Paolone, I. I. Strakovsky, V. Crede, L. Guo, R. A. Schumacher, Sergey Kuleshov, M. Khandaker, Alessandro Rizzo, S. Chandavar, W. Tang, G. Charles, A. Deur, M. Osipenko, Latifa Elouadrhiri, Gerard Gilfoyle, Nikolaos Sparveris, M. Battaglieri, W. K. Brooks, A. Simonyan, R. De Vita, R. A. Montgomery, D. Martinez, B. Guegan, H. Hakobyan, C. Hanretty, C. E. Taylor, K. Livingston, N. Dashyan, G. V. Fedotov, S. Strauch, V. Sytnik, E. Golovatch, R. Dupre, Avraham Klein, H. S. Jo, Jie Zhang, S. Anefalos Pereira, V. Mokeev, P. Lenisa, V. P. Kubarovsky, H. S. Joo, H. Y. Lu, W. Phelps, Eugene Pasyuk, Inna Aznauryan, O. Pogorelko, S. M. Hughes, K. P. Adhikari, I. Bedlinskiy, C. Salgado, P. Roy, S. E. Kuhn, P. Peng, Hovanes Egiyan, C. Munoz Camacho, W. Kim, J. A. Fleming, M. Guidal, G. Niculescu, Yordanka Ilieva, H. Avakian, C. Djalali, K. Park, M. Ripani, I. Niculescu, B. McKinnon, P. Rossi, M. J. Amaryan, S. Joosten, G. D. Smith, M. Holtrop, Friedrich Klein, A. El Alaoui, M. Hattawy, Brian Raue, L. Zana, G. Rosner, H. Voskanyan, Nicholas Zachariou, Elton Smith, D. G. Jenkins, W. J. Briscoe, E. Seder, F. Sabatié, P. Stoler, D. P. Watts, S. Procureur, H. Moutarde, Dustin Keller, M. Ungaro, Michael Wood, K. Hicks, Y. G. Sharabian, K. Joo, O. Cortes, E. L. Isupov, Ye Tian, J. W. Price, K. L. Giovanetti, S. Fegan, Iu. Skorodumina, Larry Weinstein, D. Doughty, Y. Prok, D. S. Carman, E. Voutier, M. Contalbrigo, R. A. Badui, A. Celentano, R. W. Gothe, N. K. Walford, J. J. Phillips, I. J. D. MacGregor, A. D'Angelo, L. El Fassi, R. G. Fersch, Diane Schott, P. L. Cole, A. I. Ostrovidov, N. Gevorgyan, D. G. Ireland, H. Jiang, Volker D. Burkert, A. S. Biselli, L. Colaneri, N. Markov, and S. Pisano
Subjects: Physics, Quark, Nuclear and High Energy Physics, Particle physics, Amplitude, Isospin, Quark model, Isobar, Resonance, Invariant mass, Nucleon
Abstract: Differential cross sections of the exclusive process $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}n$ were measured with good precision in the range of the photon virtuality ${Q}^{2}=1.8--4.5$ ${\mathrm{GeV}}^{2}$ and the invariant mass range of the ${\ensuremath{\pi}}^{+}n$ final state $W=1.6--2.0$ GeV using the Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the $n{\ensuremath{\pi}}^{+}$ center-of-mass system. More than 37 000 cross-section points were measured. The contributions of the isospin $I=\frac{1}{2}$ resonances $N(1675){\frac{5}{2}}^{\ensuremath{-}},N(1680){\frac{5}{2}}^{+}$, and $N(1710){\frac{1}{2}}^{+}$ were extracted at different values of ${Q}^{2}$ using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-$t$ dispersion relations, were employed in the analysis. We observe significant strength of the $N(1675){\frac{5}{2}}^{\ensuremath{-}}$ in the ${A}_{1/2}$ amplitude, which is in strong disagreement with quark models that predict both transverse amplitudes to be strongly suppressed. For the $N(1680){\frac{5}{2}}^{+}$ we observe a slow changeover from the dominance of the ${A}_{3/2}$ amplitude at the real photon point $({Q}^{2}=0)$ to a ${Q}^{2}$ where ${A}_{1/2}$ begins to dominate. The scalar amplitude ${S}_{1/2}$ drops rapidly with ${Q}^{2}$ consistent with quark model prediction. For the $N(1710){\frac{1}{2}}^{+}$ resonance our analysis shows significant strength for the ${A}_{1/2}$ amplitude at ${Q}^{2}l2.5$ ${\mathrm{GeV}}^{2}$.
Published: 2015

25. Time-of-flight resolution of scintillating counters with Burle 85001 microchannel plate photomultipliers in comparison with Hamamatsu R2083

Author: Vladimir Popov, S.S. Stepanyan, W. Kim, Elton Smith, Volker D. Burkert, Carl Zorn, K.H. Park, V. Baturin, Dong-Chul Son, and S. Majewsky
Subjects: Physics, Nuclear and High Energy Physics, Photomultiplier, Spectrometer, business.industry, Resolution (electron density), Cosmic ray, Particle accelerator, Particle identification, law.invention, Nuclear physics, Time of flight, Optics, law, Microchannel plate detector, business, Instrumentation
Abstract: Improvements in the time resolution of the CEBAF Large Acceptance Spectrometer (CLAS) below ≈50ps will be required for experiments using the planned upgraded accelerator facility at Jefferson Lab. The improved time resolution will allow particle identification using time-of-flight techniques to be used effectively up to the proposed operating energy of 12GeV. The challenge of achieving this time resolution over a relatively large area is compounded because the photomultipliers (PM) in the CLAS “time-zero” scintillating counters must operate in very high magnetic fields. Therefore, we have studied the resolution of “time-zero” prototypes with microchannel plate PMs 85001-501 from Burle. For reference and comparison, measurements were also made using the standard PMs R2083 from Hamamatsu using two timing methods. The cosmic ray method, which utilizes three identical scintillating counters (Bicron BC-408, 2×3×50cm3) with PMs at the ends, yields σR2083=59.1±0.7ps. The location method of particles from a radiative source with known coordinates has been used to compare timing resolutions of R2083 and 85001-501. This method yields σR2083=59.5±0.7ps and it also provides an estimate of the number of primary photoelectrons. For the microchannel plate PM from Burle the method yields σ85001=130±4ps due to lower number of primary photoelectrons.
Published: 2006

26. JLab: probing hadronic physics with electrons and photons

Author: Elton Smith
Subjects: Quantum chromodynamics, Physics, Photon, Proton, Physics::Instrumentation and Detectors, Nuclear Theory, Hadron, FOS: Physical sciences, General Physics and Astronomy, Electron, Strangeness, Nuclear physics, Recoil, Nuclear Experiment (nucl-ex), Nuclear Experiment, Nucleon
Abstract: Precision measurements of the structure of nucleons and nuclei in the regime of strong interaction QCD are now possible with the availability of high current polarized electron beams, polarized targets, and recoil polarimeters, in conjunction with modern spectrometers and detector instrumentation. The physics at JLab will be highlighted using two recent measurements of general interest. The ratio of the proton electric to magnetic form factors indicates the importance of the role of angular momentum in the structure of the nucleon. The existence of 5-quark configurations in the ground state wavefunctions of hadrons is confirmed by a narrow peak attributed to an exotic baryon with strangeness S=+1. These and other examples will be used to illustrate the capabilities and focus of the experimental program at JLab., Comment: V Latinamerican Symposium on Nuclear Physics, Santos, Brazil (Sept 1-5, 2003) 4 pages, 4 figures
Published: 2004

27. Physics prospects with the JLab 12-GeV upgrade

Author: Elton Smith
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Nuclear physics, Upgrade, Primary (astronomy), High Energy Physics::Experiment, Color confinement, Nuclear Experiment, Beam energy
Abstract: Increasing the beam energy of the CEBAF accelerator to 12 GeV will greatly expand the physics opportunities to explore the nature of strongly interacting matter. The primary thrusts of the experimental program will include the study of quark confinement and the direct exploration of the quark-gluon structure of hadrons and nuclei in the valence-quark region.
Published: 2003

28. Meson Spectroscopy at GlueX

Author: Carlos Salgado and Elton Smith
Subjects: Physics, Quantum chromodynamics, Quark, Particle physics, GlueX, Photon, Meson, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, Hadron, Bremsstrahlung, Magnetic detector, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The goal of the GlueX experiment \cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.
Published: 2014

29. The light meson spectroscopy program

Author: Elton Smith
Subjects: Quark, Physics, Particle physics, Meson, High Energy Physics::Lattice, QC1-999, Nuclear Theory, High Energy Physics::Phenomenology, law.invention, Nuclear physics, law, High Energy Physics::Experiment, Spectroscopy, Collider
Abstract: Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.
Published: 2014

30. Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp→ϕp

Author: D. P. Watts, A. V. Vlassov, E. Munevar, A. El Alaoui, Y. Ilieva, D. I. Glazier, R. Paremuzyan, B. S. Ishkhanov, A. Celentano, Nicholas Zachariou, R. W. Gothe, R. De Vita, Gerard Gilfoyle, D. Sokhan, K. Hafidi, H. Y. Lu, D. Rimal, A. Kim, W. Kim, S. Anefalos Pereira, H. S. Jo, B. McKinnon, G. Niculescu, C. Munoz Camacho, M. Mirazita, C. E. Hyde, M. Contalbrigo, N. Gevorgyan, S. Chandavar, A. Simonyan, F. Sabatié, N. A. Baltzell, E. De Sanctis, D. Protopopescu, M. Ungaro, J. P. Ball, D. S. Carman, D. Schott, R. A. Schumacher, M. Aghasyan, D. Keller, S. Pozdniakov, M. Garçon, J. W. Price, O. Cortes, J. J. Phillips, Michael L. Williams, D. I. Sober, B. Vernarsky, L. Colaneri, I. J. D. MacGregor, A. D'Angelo, I. Bedlinskiy, L. Zana, I. Zonta, R. Dupre, S. Boiarinov, P. Lenisa, V. P. Kubarovsky, K. A. Griffioen, N. Markov, M. Khandaker, I. I. Strakovsky, S. Pisano, V. Mokeev, K. Livingston, K. Joo, A. Deur, O. Pogorelko, Y. Ghandilyan, V. Sytnik, Avraham Klein, K. Park, N. Dashyan, M. J. Amaryan, L. El Fassi, D. G. Ireland, V. Crede, W. K. Brooks, Volker D. Burkert, A. S. Biselli, J. T. Goetz, T. Mineeva, C. Hanretty, H. Moutarde, D. Ho, Friedrich Klein, M. Bellis, I. Niculescu, R. A. Montgomery, K. L. Giovanetti, W. Tang, N. K. Walford, S. Niccolai, H. Voskanyan, M. Ripani, E. Voutier, M. Osipenko, M. Taiuti, D. Doughty, J. Zhang, Alessandro Rizzo, W. J. Briscoe, E. Pasyuk, P. Peng, Michael Dugger, P. Rossi, S. Procureur, M. Battaglieri, P. L. Cole, S. Fegan, M. E. McCracken, E. Seder, S. Strauch, Latifa Elouadrhiri, Kei Moriya, C. A. Meyer, G. V. Fedotov, K. P. Adhikari, Andrew Puckett, Martin K. Mayer, Barry Ritchie, M. S. Saini, S. E. Kuhn, M. Hattawy, S. Tkachenko, J. A. Fleming, Elton Smith, P. Roy, Y. G. Sharabian, N. Harrison, D. Adikaram, M. Guidal, C. Djalali, P. Stoler, M. Holtrop, B. Dey, I. Senderovich, K. Hicks, Luciano Pappalardo, Sergey Kuleshov, S. S. Stepanyan, J. Bono, P. Nadel-Turonski, F. X. Girod, S. Koirala, Z. W. Zhao, and D. G. Jenkins
Subjects: Physics, Nuclear and High Energy Physics, Scattering, Detector, Bremsstrahlung, Vector meson dominance, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Momentum, Matrix (mathematics), Vector meson, Atomic physics, Nuclear Experiment, Event (particle physics)
Abstract: High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γ p → ϕ p have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ( s ) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- ( ϕ → K + K − ) and neutral- ( ϕ → K S 0 K L 0 ) K K ¯ decay modes of the ϕ . Further, for the charged mode, we differentiate between the cases where the final K − track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed ϕ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide s bins for the charged- and the neutral-modes, respectively. Possible effects from K + Λ * channels with p K K ¯ final states are discussed. These present results constitute the most precise and extensive ϕ photoproduction measurements to date and in conjunction with the ω photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.
Published: 2014

31. The CLAS start counter

Author: Elton Smith, S. Ahmad, J. Distelbrink, Susan Taylor, G. S. Mutchler, and Thomas E. Smith
Subjects: Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Particle accelerator, Time resolution, Scintillator, law.invention, Nuclear physics, Time of flight, law, Scintillation counter, Physics::Accelerator Physics, Photon beams, Start time, Photon beam, Instrumentation
Abstract: The design, construction, and performance of a hexagonal-nose-cone-shaped plastic scintillation counter system is described. This “Start Counter” is used as part of the trigger and to measure event start times for photon beam running with CLAS in Hall B at the Thomas Jefferson National Accelerator Facility. The Start Counter is constructed of three 3-mm thick coupled-paddle scintillators and achieves a software-corrected time resolution of 260 ps. Each coupled-paddle scintillator operated without appreciable sagging up to ∼1.2 MHz rate.
Published: 2001

32. Theep→e′pηReaction at and above theS11(1535)Baryon Resonance

Author: M. J. Amaryan, M. Taiuti, S. K. Matthews, J. Ficenec, Gyurjyan, W. Kim, A. Longhi, R. A. Schumacher, B. E. Bonner, L. Elouadrhiri, A. P. Freyberger, R. Magahiz, Robert E. Welsh, S. Dytman, S. Whisnant, B. M. Preedom, Federico Ronchetti, R. J. Feuerbach, K. L. Giovanetti, B. Asavapibhop, Michael Dugger, Shalev Gilad, De Sanctis E, A. V. Vlassov, G. Ricco, J. R. Kane, H. Avakian, Philip L. Cole, J. P. Cummings, G. S. Adams, Larry Weinstein, R. A. Miskimen, K. Joo, J. Shaw, R. W. Major, Moshe Gai, M. Kossov, W. J. Briscoe, D. Rowntree, D. Doughty, K. Beard, W. K. Brooks, Friedrich Klein, R. S. Hicks, Brian Raue, Kevin Fissum, Kalvir S. Dhuga, Barry Ritchie, A. Coleman, K. A. Griffioen, M. M. Ito, G. Riccardi, L. M. Qin, J. J. Manak, M. Mirazita, J. M. Laget, C. E. Hyde-Wright, J. W C McNabb, M. S. Ohandjanyan, D. Heddle, C. Salgado, H. R. Weller, Roy Thompson, Curtis Smith, D. P. Weygand, Herbert O. Funsten, S. A. Philips, Patrick Girard, Y. Kuang, H. Egiyan, M. Witkowski, Bernhard Mecking, Mestayer, A. J. Sarty, Jing Zhao, S. Stepanyan, De Vita R, D. G. Jenkins, C. Djalali, Z. L. Zhou, M. Lucas, Airton Deppman, D. I. Sober, A. Shafi, D. Hancock, Avraham Klein, Leskin Ga, M. Battaglieri, S. McAleer, William Bertozzi, E. Polli, E. Anciant, L. Farhi, G. E. Dodge, Daniel S. Carman, V. B. Gavrilov, O. Pogorelko, A. K. Opper, G. Audit, J. W. Price, M. Khandaker, E. Wolin, P. V. Degtyarenko, Y. Patois, Gerard Gilfoyle, Dinko Pocanic, L.C. Dennis, K. Loukachine, N. Pivnyuk, M. Bektasoglu, S. E. Kuhn, S. M. Shuvalov, D. Lawrence, M. Eckhause, J. Napolitano, M. Ripani, M. Guillo, Jochen Heisenberg, Y. V. Efremenko, Volker D. Burkert, M. Sanzone, J. Connelly, Donal Day, M. Sargsyan, G. A. Peterson, M. Guidal, A. V. Skabelin, J. Yun, D. Cords, A. Yegneswaran, A. S. Biselli, Elton Smith, S. Barrow, M. Holtrop, Thomas E. Smith, G. S. Mutchler, M. Anghinolfi, Hall Crannell, D. G. Crabb, James Mueller, S. Taylor, P. D. Rubin, G. Capitani, F. Roudot, D. J. Tedeschi, Y. G. Sharabian, M. Spraker, Sapunenko, R. C. Minehart, M. Klusman, Nicola Bianchi, S. Boiarinov, C. A. Meyer, J. S. McCarthy, B. Carnahan, Thierry Auger, A. R. Reolon, Michael Vineyard, C. Marchand, P. Rossi, P. Dragovitsch, F. W. Hersman, R. A. Demirchyan, T. Y. Tung, J. Hardie, K. Y. Kim, Muccifora, R. A. Niyazov, John T. O'Brien, P. Corvisiero, K. S. Egiyan, Calarco, P. Stoler, and K. Hicks
Subjects: Baryon, Physics, Nuclear physics, Particle physics, Photon, Amplitude, Angular distribution, Meson, Momentum transfer, General Physics and Astronomy, Resonance, Invariant (physics), Nuclear Experiment
Abstract: New cross sections for the reaction e p-->e p eta are reported for total center of mass energy W = 1.5--1.86 GeV and invariant momentum transfer Q2 = 0.25--1.5 (GeV/c)(2). This large kinematic range allows extraction of important new information about response functions, photocouplings, and eta N coupling strengths of baryon resonances. Newly observed structure at W approximately 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.
Published: 2001

33. Recent results from Jefferson Lab

Author: Elton Smith
Subjects: Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Hadron, Strong interaction, Nuclear structure, Elementary particle, Electron, Nuclear physics, Recoil, Nuclear Experiment, Nucleon
Abstract: Precision measurements of the structure of nucleons and nuclei in the regime of strong interaction QCD are now possible with the availability of high current polarized electron beams, polarized targets, and recoil polarimeters, in conjunction with modern spectrometers and detector instrumentation. The authors present some recent results from the Jefferson Lab on the charge and current distributions of nucleons and nuclei. They also review measurements which relate physics at small distances to the regime where strong interaction QCD is the relevant theory.
Published: 2001

34. The bremsstrahlung tagged photon beam in Hall B at JLab

Author: W. R. Dodge, Hall Crannell, B. L. Berman, M. Khandaker, M. Klusman, D. I. Sober, Barry Ritchie, E. Anciant, D. Lawrence, C. Salgado, Elton Smith, Philip L. Cole, Michael Dugger, Thierry Auger, S. A. Philips, J.M. Lambert, A. Longhi, Jim Napolitano, A. J. Sarty, J. Connelly, C. Marchand, L. Y. Murphy, S. K. Matthews, G. Audit, John T. O'Brien, and W. J. Briscoe
Subjects: Physics, Nuclear and High Energy Physics, Photon, Physics::Instrumentation and Detectors, Bremsstrahlung, Scintillator, Photon energy, Nuclear physics, Beamline, Hodoscope, Dipole magnet, Physics::Accelerator Physics, Instrumentation, Beam (structure)
Abstract: We describe the design and commissioning of the photon tagging beamline installed in experimental Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This system can tag photon energies over a range from 20% to 95% of the incident electron energy, and is capable of operation with beam energies up to 6.1 GeV. A single dipole magnet is combined with a hodoscope containing two planar arrays of plastic scintillators to detect energy-degraded electrons from a thin bremsstrahlung radiator. The first layer of 384 partially overlapping small scintillators provides photon energy resolution, while the second layer of 61 larger scintillators provides the timing resolution necessary to form a coincidence with the corresponding nuclear interaction triggered by the tagged photon. The definitions of overlap channels in the first counter plane and of geometric correlation between the two planes are determined using digitized time information from the individual counters. Auxiliary beamline devices are briefly described, and performance results to date under real operating conditions are presented. The entire photon-tagging system has met or exceeded its design goals.
Published: 2000

35. The time-of-flight system for CLAS

Author: Elton Smith, K. Loukachine, A. D. Hancock, C. Marchand, J. Distelbrink, L. C. Smith, W. Kim, T.Y. Tung, J. Ficenec, K. MacArthur, G. S. Mutchler, Andrew G. Weisenberger, D. Schutt, Bernhard Mecking, L. Elouadrhiri, Robert E. Welsh, D. A. Jenkins, T. Carstens, F. W. Hersman, M. Guidal, M. Holtrop, Susan Taylor, H. Egiyan, T. P. Smith, and M. Eckhause
Subjects: Physics, Nuclear and High Energy Physics, Spectrometer, Cosmic ray, Particle accelerator, Particle identification, Particle detector, Linear particle accelerator, law.invention, Nuclear physics, Time of flight, law, Scintillation counter, Instrumentation
Abstract: The time-of-flight system for the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility is described. The system, covering an area of 206-square-meters, is composed of scintillation counters 5.08 cm thick, 15 and 22 cm wide, and lengths which vary from 32 cm at the most forward angle to 450 cm at larger angles. All of the components of the system have been designed to optimize the time resolution. Event timing, achieved by leading-edge discrimination with time-walk correction, has been measured with cosmic rays, a laser pulser, and known particle interactions. The intrinsic time resolution varies from about 80 ps for the short counters to 160 ps for the longer counters. Reconstruction of interacting particles during the first period of operation yields an average time resolution for electrons of 163 ps.
Published: 1999

36. Demonstration of a novel technique to measure two-photon exchange effects in elastice±pscattering

Author: R. P. Bennett, P. Eugenio, J. Bono, N. A. Baltzell, K. A. Griffioen, Andrew Puckett, S. Strauch, Martin K. Mayer, H. Y. Lu, M. MacCormick, A. Deur, R. Paremuzyan, M. Battaglieri, M. S. Saini, I. Zonta, H. Egiyan, Gerard Gilfoyle, R. De Vita, D. Sokhan, I. Niculescu, J. T. Goetz, B. McKinnon, P. Collins, S. Tkachenko, E. Seder, M. Mirazita, E. Phelps, S. Anefalos Pereira, L. Guo, Z. W. Zhao, G. Rosner, R. Nasseripour, N. Gevorgyan, S. Chandavar, W. Gohn, D. Ho, V. Batourine, Kei Moriya, C. E. Taylor, William Brooks, S. E. Kuhn, O. Cortes, V. P. Kubarovsky, G. V. Fedotov, E. L. Isupov, Ye Tian, J. A. Fleming, S. Park, J. Zhang, Andrei Afanasev, E. De Sanctis, E. Golovatch, O. Pogorelko, S. Boiarinov, A. Celentano, R. Dupre, R. W. Gothe, P. Rossi, M. Aghasyan, R. A. Schumacher, C. Munoz Camacho, K. P. Adhikari, Lorenzo Zana, H. Avakian, J. Lachniet, D. I. Sober, H. Hakobyan, C. Hanretty, S. Procureur, N. Harrison, Maryam Moteabbed, E. Munevar, B. S. Ishkhanov, V. Crede, C. Salgado, N. K. Walford, M. Ungaro, H. Voskanyan, R. A. Montgomery, Chaden Djalali, Elton Smith, M. R. Niroula, H. Seraydaryan, Y. G. Sharabian, A. Kubarovsky, S. Lewis, F. Sabatié, S. Stepanyan, G. Niculescu, W. J. Briscoe, I. Bedlinskiy, H. S. Jo, K. Joo, T. Mineeva, J. J. Phillips, George Davey Smith, Dustin Keller, S. Fegan, S. Pisano, I. J. D. MacGregor, S. Koirala, A. Kim, W. Tang, Michael Wood, M. Contalbrigo, A. D'Angelo, M. Osipenko, K. Hafidi, Victor Mokeev, K. Hicks, D. Martinez, F. X. Girod, N. Dashyan, L. El Fassi, J. W. Price, D. Protopopescu, P. Nadel-Turonski, S. Pozdniakov, E. Voutier, Diane Schott, A. I. Ostrovidov, K. Park, D. G. Ireland, N. Guler, Volker D. Burkert, A. S. Biselli, Y. Ilieva, Nicholas Zachariou, J. P. Ball, D. Rimal, R. G. Fersch, D. S. Carman, P. L. Cole, D. Doughty, S. Niccolai, D. Heddle, M. J. Amaryan, H. Moutarde, K. L. Giovanetti, Sergey Kuleshov, D. Adikaram, Larry Weinstein, M. Guidal, M. Holtrop, Luciano Pappalardo, M. Khandaker, C. E. Hyde, Friedrich Klein, J. Arrington, Brian Raue, and M. Ripani
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, Photon, Proton, 010308 nuclear & particles physics, Scattering, Electron, 01 natural sciences, Nuclear physics, Positron, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Electron scattering, Beam (structure)
Abstract: Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections. Purpose: The TPE contributions depend on the sign of the lepton charge in e(+/-)p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e(+/-)p comparisons, which has the potential to make precise measurements over a broad range in Q(2) and scattering angles. Methods: We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton. Results: The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q(2) and scattering angle. Nonetheless, this measurement yields a data sample for e(+/-)p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable to study the difference between the incoming electron and positron beams. This systematic effect leads to the largest uncertainty in the final ratio of positron to electron scattering: R = 1.027 +/- 0.005 +/- 0.05 for = 0.206 GeV2 and 0.830
Published: 2013

37. Measuring the charged pion polarizability in the γγ → π^{+} π^{-} reaction

Author: Rory Miskimen, Alexander Muskarenkov, David J. Lawrence, and Elton Smith
Subjects: Quantum chromodynamics, Physics, Particle physics, GlueX, Linear polarization, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Measure (mathematics), Nuclear physics, Pion, Polarizability, High Energy Physics::Experiment, Production (computer science), Beta (velocity)
Abstract: Development has begun of a new experiment to measure the charged pion polarizability $$\alpha_{\pi}-\beta_{\pi}$$. The charged pion polarizability ranks among the most important tests of low-energy QCD presently unresolved by experiment. Analogous to precision measurements of $$\pi^{\circ}\rightarrow\gamma\gamma$$ that test the intrinsic odd-parity (anomalous) sector of QCD, the pion polarizability tests the intrinsic even-parity sector of QCD. The measurement will be performed using the $$\gamma\gamma\rightarrow\pi^{+{}}\pi^{-{}}$$ cross section accessed via the Primakoff mechanism on nuclear targets using the GlueX detector in Hall D at Jefferson Lab. The linearly polarized photon source in Hall-D will be utilized to separate the Primakoff cross-section from coherent $$\rho^{\circ}$$ production.
Published: 2013

38. Measurement of theΣπphotoproduction line shapes near theΛ(1405)

Author: P. Eugenio, B. S. Ishkhanov, R. A. Schumacher, P. Collins, C. E. Taylor, F. X. Girod, C. E. Hyde, H. Hakobyan, W. Tang, M. D. Mestayer, E. Golovatch, P. Khetarpal, N. A. Baltzell, K. A. Griffioen, J. P. Ball, D. S. Carman, C. Hanretty, M. Osipenko, E. L. Isupov, D. Adikaram, M. Guidal, Barry Ritchie, R. Paremuzyan, S. Taylor, Diane Schott, Ye Tian, Michael L. Williams, P. L. Cole, A. I. Ostrovidov, K. Park, M. Holtrop, S. Stepanyan, E. Munevar, Gerard Gilfoyle, D. Protopopescu, J. W. Price, S. Pozdniakov, Avraham Klein, D. G. Ireland, Z. W. Zhao, G. Charles, M. E. McCracken, S. Tkachenko, D. Ho, B. Vernarsky, Volker D. Burkert, A. S. Biselli, I. Bedlinskiy, A. Kim, R. Dupre, N. K. Walford, M. Battaglieri, S. Strauch, S. S. Stepanyan, S. Koirala, H. Voskanyan, D. P. Watts, L. L. Pappalardo, I. Zonta, A. Celentano, R. W. Gothe, W. J. Briscoe, E. Pasyuk, N. Harrison, George Davey Smith, N. D. Kvaltine, A. Kubarovsky, K. Livingston, V. Mokeev, J. Bono, P. Nadel-Turonski, H. Y. Lu, S. Park, Jie Zhang, A. D'Angelo, W. Gohn, S. Niccolai, Sergey Kuleshov, Friedrich Klein, R. Fersch, E. Seder, S. Chandavar, T. Mineeva, Hovanes Egiyan, P. Rossi, C. Munoz Camacho, I. Niculescu, L. El Fassi, S. Fegan, N. Pivnyuk, R. Nasseripour, P. Stoler, I. I. Strakovsky, V. P. Kubarovsky, Kei Moriya, B. Dey, C. A. Meyer, F. Sabatié, O. Pogorelko, K. Hicks, W. Kim, G. V. Fedotov, V. Crede, C. Djalali, B. McKinnon, Y. Ilieva, G. Niculescu, S. Procureur, Nicholas Zachariou, A. Deur, R. A. Montgomery, G. Rosner, M. Taiuti, Dustin Keller, E. Voutier, N. Markov, D. Rimal, K. P. Adhikari, D. P. Weygand, S. Pisano, C. S. Nepali, K. Hafidi, M. Mirazita, N. Dashyan, E. Phelps, N. Gevorgyan, V. Batourine, M. Bellis, J. J. Phillips, I. J. D. MacGregor, Elton Smith, M. Ripani, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, M. S. Saini, M. Khandaker, D. Doughty, J. A. Fleming, D. Heddle, B. Torayev, A. V. Vlassov, K. L. Giovanetti, R. De Vita, S. Anefalos Pereira, E. De Sanctis, M. Aghasyan, D. I. Sober, M. Ungaro, S. Boiarinov, J. T. Goetz, Lorenzo Zana, H. S. Jo, and C. Salgado
Subjects: Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Quark model, Sigma, Lambda, 01 natural sciences, Baryon, Amplitude, Isospin, 0103 physical sciences, Invariant mass, Production (computer science), Atomic physics, 010306 general physics
Abstract: The reaction {gamma} + p -> K{sup +} + {Sigma} + {p}i was used to determine the invariant mass distributions or "line shapes" of the {Sigma}{sup +} {pi}{sup -}, {Sigma}{sup -} {pi}{sup +} and {Sigma}{sup 0} {pi}{sup 0} final states, from threshold at 1328 MeV/c^2 through the mass range of the {Lambda}(1405) and the {Lambda}(1520). The measurements were made with the CLAS system at Jefferson Lab using tagged real photons, for center-of-mass energies 1.95 < W < 2.85 GeV. The three mass distributions differ strongly in the vicinity of the I=0 {Lambda}(1405), indicating the presence of substantial I=1 strength in the reaction. Background contributions to the data from the {Sigma}{sup 0}(1385) and from K* {Sigma} production were studied and shown to have negligible influence. To separate the isospin amplitudes, Breit-Wigner model fits were made that included channel-coupling distortions due to the Nkbar threshold. A best fit to all the data was obtained after including a phenomenological I=1, J{sup P} = 1/2{sup -} amplitude with a centroid at 1394\pm20 MeV/c^2 and a second I=1 amplitude at 1413\pm10 MeV/c^2. The centroid of the I=0 {Lambda}(1405) strength was found at the {Sigma} {pi} threshold, with the observed shape determined largely by channel-coupling, leadingmore » to an apparent overall peak near 1405 MeV/c^2.« less
Published: 2013

39. Neutron radiation hardness tests of SiPMs

Author: F. Barbosa, Yi Qiang, Carl Zorn, and Elton Smith
Subjects: Physics, GlueX, Calorimeter (particle physics), Spectrometer, Physics::Instrumentation and Detectors, business.industry, Detector, Photodetector, Neutron radiation, Indentation hardness, Nuclear physics, Silicon photomultiplier, Optics, High Energy Physics::Experiment, Nuclear Experiment, business
Abstract: Hall D at Jefferson Laboratory is building its new GlueX spectrometer to study QCD gluonic excitations. The hermetic detector includes a scintillating fiber-lead barrel calorimeter where the photodetectors must operate in a high magnetic field. The silicon photomultiplier (SiPM) array manufactured by Hamamatsu Corporation was chosen for the photodetector of the BCAL. We report on the measurement of neutron radiation hardness of SiPMs at Jefferson Lab.
Published: 2013

40. Comment on 'Observation of a narrow structure in1H(γ,KS0)Xvia interference withϕ-meson production'

Author: A. Celentano, B. McKinnon, M. Ungaro, B. Zhao, G. Ricco, D. Doughty, A. I. Ostrovidov, K. Park, A. El Alaoui, P. Stoler, Nicholas Zachariou, D. Heddle, B. Dey, Volker D. Burkert, Sergey Kuleshov, R. De Vita, K. Hicks, M. Mirazita, F. X. Girod, R. A. Schumacher, M. Guidal, S. Anefalos Pereira, Michael Dugger, J. T. Goetz, S. Park, R. Dickson, S. Niccolai, S. S. Stepanyan, E. Seder, A. Ni, M. Holtrop, Elton Smith, J. W. Price, M. Bellis, L. Guo, E. De Sanctis, M. Anghinolfi, H. Y. Lu, D. G. Ireland, V. Crede, D. I. Sober, Y. G. Sharabian, N. A. Baltzell, Gerard Gilfoyle, I. Niculescu, P. L. Cole, R. Dupre, D. Schott, Paolo Rossi, M. Battaglieri, M. E. McCracken, P. Eugenio, J. P. Ball, I. Bedlinskiy, D. S. Carman, Michael Wood, K. Hafidi, S. Pozdniakov, M. Garçon, B. Morrison, K. L. Giovanetti, M. Ripani, B. S. Ishkhanov, Barry Ritchie, L. El Fassi, P. Khetarpal, Latifa Elouadrhiri, Kei Moriya, C. A. Meyer, B. Vernarsky, G. V. Fedotov, V. P. Kubarovsky, D. P. Weygand, O. Pogorelko, A. S. Biselli, P. Bosted, C. Bookwalter, N. Markov, S. Pisano, A. Kim, E. Golovatch, W. Tang, Michael Vineyard, M. Osipenko, H. Hakobyan, I. J. D. MacGregor, H. S. Jo, W. Kim, G. Niculescu, H. Egiyan, M. Y. Gabrielyan, M. D. Mestayer, V. Mokeev, E. L. Isupov, S. Chandavar, and S. Boiarinov
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Meson production, Meson, Structure (category theory), Mass spectrum, Interference (wave propagation), Pentaquark, Interpretation (model theory)
Abstract: In Ref. [1], the authors claim to observe a narrow structure in the mass spectrum constructed from the (pK_L) system using data from the CLAS detector. The interpretation of this narrow structure given in Ref. [1] is as follows: “It may be due to the photoproduction of the Theta+ pentaquark or some unknown Sigma∗ resonance.” The authors go on to say that “it is unlikely for the observed structure to be due to a Sigma∗ resonance.” This analysis was reviewed by the CLAS Collaboration, following the established procedures for all CLAS papers, and did not receive approval. The purpose of this Comment is to explain the reasons why that analysis was not approved for publication.
Published: 2012

41. Comparison of forward and backwardpppair knockout in3He(e,e′pp)n

Author: V. Crede, S. Strauch, M. Contalbrigo, M. Paolone, H. Egiyan, M. J. Amaryan, S. Niccolai, M. Taiuti, N. Dashyan, D. G. Jenkins, N. A. Saylor, S. Procureur, S. V. Kuleshov, Michael Wood, D. Sokan, B. S. Ishkhanov, K. Hafidi, W. Tang, M. Y. Gabrielyan, K. L. Giovanetti, B. McKinnon, H. S. Jo, K. A. Griffioen, M. Osipenko, Larry Weinstein, A. D'Angelo, A. Celentano, R. W. Gothe, E. Voutier, E. De Sanctis, D. Doughty, P. Khetarpal, G. Charles, S. Pisano, F. X. Girod, H. Baghdasaryan, J. Ball, A. El Alaoui, S. Chandavar, M. Aghasyan, L. El Fassi, V. Mokeev, Lorenzo Zana, M. Mirazita, J. M. Laget, S. Park, H. Moutarde, S. S. Stepanyan, K. Park, V. P. Kubarovsky, W. Gohn, D. Rimal, P. Rossi, D. I. Sober, D. G. Ireland, S. Tkachenko, H. Voskanyan, R. Dupre, N. Gevorgyan, K. Joo, M. Battaglieri, R. A. Schumacher, Volker D. Burkert, A. S. Biselli, Latifa Elouadrhiri, A. Kim, B. Zhao, W. Kim, A. Kubarovsky, G. Rosner, G. V. Fedotov, G. Niculescu, P. L. Cole, W. K. Brooks, R. Paremuzyan, W. J. Briscoe, M. Guidal, S. Pozdniakov, K. P. Adhikari, D. S. Carman, M. Khandaker, S. Stepanyan, E. Munevar, Gerard Gilfoyle, R. De Vita, G. E. Dodge, H. Y. Lu, N. D. Kvaltine, A. Daniel, I. Niculescu, Luciano Pappalardo, I. J. D. MacGregor, D. Schott, K. Hicks, C. E. Hyde, G. Ricco, Brian Raue, B. Guegan, M. Ripani, Chaden Djalali, S. E. Kuhn, Elton Smith, M. Anghinolfi, H. Seraydaryan, and M. S. Saini
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Momentum (technical analysis), Proton, 010308 nuclear & particles physics, Nuclear Theory, Momentum transfer, EMC effect, Few-body systems, 01 natural sciences, Nuclear physics, 0103 physical sciences, Nuclear force, Neutron, Nuclear Experiment, 010306 general physics, Wave function
Abstract: Measuring nucleon-nucleon Short Range Correlations (SRC) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wavefunction, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the 3He(e,e'pp)n reaction, looking at events with high momentum protons (pp > 0.35 GeV/c) and a low momentum neutron (pn < 0.2 GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, →q). Thus, the measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state pp relative momentum distribution, indicating that this is the preferred configuration for measuring SRC.
Published: 2012

42. Measurement of the generalized form factors near threshold viaγ*p→nπ+at highQ2

Author: R. Paremuzyan, Gerard Gilfoyle, R. A. Schumacher, George Davey Smith, A. D'Angelo, R. Nasseripour, L. El Fassi, I. I. Strakovsky, A. Fradi, C. Bookwalter, K. A. Griffioen, L. Graham, W. Kim, Martin K. Mayer, C. E. Hyde, M. Contalbrigo, A. Deur, N. Kalantarians, D. Sokhan, V. P. Kubarovsky, H. Hakobyan, C. Hanretty, P. Eugenio, M. Taiuti, G. Niculescu, P. L. Cole, M. S. Saini, S. Pozdniakov, W. K. Brooks, E. Munevar, B. S. Ishkhanov, B. McKinnon, O. Pogorelko, N. Markov, S. Pisano, K. Livingston, D. Doughty, E. De Sanctis, J. P. Ball, I. Bedlinskiy, Y. Prok, J. T. Goetz, S. S. Stepanyan, S. Park, S. Stepanyan, D. Heddle, D. I. Sober, D. Branford, M. Mirazita, R. Dupre, M. Battaglieri, D. S. Carman, Avraham Klein, A. I. Ostrovidov, K. Park, A. Kubarovsky, P. Rossi, W. Tang, Z. W. Zhao, P. Stoler, D. G. Ireland, E. Phelps, N. Gevorgyan, W. Gohn, V. Batourine, H. S. Jo, W. J. Briscoe, C. E. Taylor, N. D. Kvaltine, S. Chandavar, V. Crede, F. Sabatié, H. Y. Lu, A. V. Vlassov, D. G. Jenkins, Volker D. Burkert, A. S. Biselli, M. Osipenko, C. Salgado, S. E. Kuhn, E. Golovatch, N. Dashyan, G. Ricco, Y. Ilieva, B. Zhao, A. Kim, C. A. Meyer, G. V. Fedotov, Sergey Kuleshov, F. X. Girod, T. Mineeva, K. Hicks, A. El Alaoui, R. De Vita, H. Baghdasaryan, D. Adikaram, M. Guidal, P. Khetarpal, I. Niculescu, M. Ripani, S. Strauch, Nicholas Zachariou, S. Niccolai, D. P. Watts, M. Holtrop, I. J. D. MacGregor, S. Anefalos Pereira, Friedrich Klein, A. Daniel, D. Schott, Michael Wood, K. Hafidi, J. W. Price, Elton Smith, Luciano Pappalardo, M. Khandaker, D. Rimal, A. Celentano, R. W. Gothe, M. Paolone, M. Y. Gabrielyan, B. Vernarsky, M. D. Mestayer, E. L. Isupov, S. Tkachenko, K. P. Adhikari, G. Charles, D. P. Weygand, Ye Tian, G. Rosner, S. Procureur, R. P. Bennett, L. Guo, S. Boiarinov, M. Anghinolfi, H. Moutarde, K. L. Giovanetti, H. Seraydaryan, Y. G. Sharabian, Barry Ritchie, C. Djalali, E. Voutier, P. Nadel-Turonski, M. Ungaro, K. Joo, Victor Mokeev, and A. Trivedi
Subjects: Physics, Nuclear and High Energy Physics, Proton, Spectrometer, 010308 nuclear & particles physics, Momentum transfer, Form factor (quantum field theory), 01 natural sciences, Transverse plane, Light cone, 0103 physical sciences, Cathode ray, Atomic physics, Nuclear Experiment, 010306 general physics, Multipole expansion
Abstract: We report the first extraction of the pion-nucleon multipoles near the production threshold for the nπ+ channel at relatively high momentum transfer (Q2 up to 4.2 GeV2). The dominance of the s-wave transverse multipole (E0+), expected in this region, allowed us to access the generalized form factor G1 within the light-cone sum-rule (LCSR) framework as well as the axial form factor GA. The data analyzed in this work were collected by the nearly 4π CEBAF Large Acceptance Spectrometer (CLAS) using a 5.754-GeV electron beam on a proton target. The differential cross section and the π-N multipole E0+/GD were measured using two different methods, the LCSR and a direct multipole fit. The results from the two methods are found to be consistent and almost Q2 independent.
Published: 2012

43. Branching ratio of the electromagnetic decay of the Σ+(1385)

Author: S. S. Stepanyan, V. Mokeev, R. Nasseripour, A. El Alaoui, Y. Ilieva, A. V. Vlassov, M. Paolone, N. Dashyan, Nicholas Zachariou, A. Kubarovsky, R. Dupre, M. Battaglieri, R. De Vita, V. Crede, D. Keller, P. Eugenio, Latifa Elouadrhiri, S. Tkachenko, L. Guo, D. Rimal, G. Ricco, C. A. Meyer, M. Taiuti, S. Strauch, M. Ripani, G. V. Fedotov, P. L. Cole, P. Nadel-Turonski, D. Adikaram, M. Guidal, B. McKinnon, S. Anefalos Pereira, H. Baghdasaryan, D. P. Watts, R. A. Schumacher, M. Khandaker, Michael Wood, K. P. Adhikari, C. E. Taylor, K. Hafidi, Elton Smith, K. Joo, E. Golovatch, G. D. Smith, M. Holtrop, S. Niccolai, N. Markov, A. D'Angelo, Friedrich Klein, E. De Sanctis, C. Djalali, Brian Raue, T. Mineeva, D. Protopopescu, Barry Ritchie, A. Daniel, Luciano Pappalardo, S. Pisano, S. Pozdniakov, W. Tang, D. I. Sober, L. Graham, F. Sabatié, P. Khetarpal, C. Bookwalter, M. J. Amaryan, M. Anghinolfi, M. Osipenko, A. Celentano, R. W. Gothe, Z. W. Zhao, S. Procureur, D. Branford, L. El Fassi, Michael Vineyard, H. Seraydaryan, H. Hakobyan, V. P. Kubarovsky, M. Y. Gabrielyan, O. Pogorelko, H. Moutarde, Lorenzo Zana, A. I. Ostrovidov, K. Park, M. Mirazita, E. Voutier, Y. G. Sharabian, S. Stepanyan, K. L. Giovanetti, J. P. Ball, B. Vernarsky, N. Gevorgyan, W. Gohn, S. Park, Y. Prok, D. S. Carman, M. Contalbrigo, P. Stoler, H. S. Jo, N. Guler, D. G. Ireland, D. Doughty, Sergey Kuleshov, E. Munevar, Martin K. Mayer, G. Rosner, P. Rossi, H. Voskanyan, I. Bedlinskiy, B. S. Ishkhanov, K. Hicks, H. Y. Lu, K. A. Griffioen, Volker D. Burkert, A. S. Biselli, C. Salgado, W. J. Briscoe, M. S. Saini, E. Pasyuk, S. Chandavar, Y. Mao, W. Kim, I. Niculescu, E. L. Isupov, B. Zhao, G. Niculescu, D. Schott, S. Boiarinov, R. Paremuzyan, William Brooks, Gerard Gilfoyle, I. J. D. MacGregor, D. Sokhan, A. Kim, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), CLAS, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, Particle physics, STRANGENESS, TRANSITIONS, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, QUARK-MODEL, RADIATIVE DECAYS, HYPERFINE INTERACTIONS, BARYONS, HYPERONS, 0103 physical sciences, Fitting algorithm, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Photon beam, Nuclear Experiment, 010306 general physics, Physics, Partial width, 010308 nuclear & particles physics, Branching fraction, Hyperon, Symmetry test, Photon beams, High Energy Physics::Experiment, Energy (signal processing)
Abstract: The CLAS detector was used to obtain the first ever measurement of the electromagnetic decay of the ${\ensuremath{\Sigma}}^{*+}(1385)$ from the reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\Sigma}}^{*+}(1385)$. A real photon beam with a maximum energy of 3.8 GeV was incident on a liquid-hydrogen target, resulting in the photoproduction of the kaon and ${\ensuremath{\Sigma}}^{*}$ hyperon. Kinematic fitting was used to separate the reaction channel from the background processes. The fitting algorithm exploited a new method to kinematically fit neutrons in the CLAS detector, leading to the measured decay widths ratio ${\ensuremath{\Sigma}}^{+}(1385)\ensuremath{\rightarrow}{\ensuremath{\Sigma}}^{+}\ensuremath{\gamma}/{\ensuremath{\Sigma}}^{+}(1385)\ensuremath{\rightarrow}{\ensuremath{\Sigma}}^{+}{\ensuremath{\pi}}^{0}=11.95\ifmmode\pm\else\textpm\fi{}2.21(\mathrm{stat}{)}_{\ensuremath{-}1.21}^{+0.53}(\mathrm{sys})%$ and a deduced partial width of $250.0\ifmmode\pm\else\textpm\fi{}56.9(\mathrm{stat}{)}_{\ensuremath{-}41.2}^{+34.3}(\mathrm{sys})\text{ }\text{ }\mathrm{keV}$. A U-spin symmetry test using the SU(3) flavor-multiplet representation yields predictions for the ${\ensuremath{\Sigma}}^{*+}(1385)\ensuremath{\rightarrow}{\ensuremath{\Sigma}}^{+}\ensuremath{\gamma}$ and ${\ensuremath{\Sigma}}^{*0}(1385)\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma}$ partial widths that agree with the experimental measurements.
Published: 2012

44. Electromagnetic decay of theΣ0(1385)toΛγ

Author: P. Nadel-Turonski, L. Casey, R. Dupre, R. Dickson, M. Battaglieri, J. P. Ball, D. S. Carman, E. De Sanctis, Y. G. Sharabian, V. Kuznetsov, M. Aghasyan, D. I. Sober, P. Eugenio, R. De Vita, A. M. Micherdzinska, S. Anefalos Pereira, G. Gavalian, M. Taiuti, E. Voutier, E. L. Isupov, D. Keller, H. Y. Lu, M. Ripani, S. Niccolai, M. Amarian, Kei Moriya, C. A. Meyer, G. V. Fedotov, M. Khandaker, B. Guegan, S. Fegan, I. Niculescu, D. Protopopescu, H. Hakobyan, Z. W. Zhao, George Davey Smith, K. P. Adhikari, D. G. Jenkins, S. Pozdniakov, A. D'Angelo, D. Doughty, M. S. Saini, D. Schott, R. P. Bennett, B. Morrison, R. A. Schumacher, R. Paremuzyan, L. El Fassi, S. Strauch, Michael Vineyard, Barry Ritchie, L. Graham, F. X. Girod, F. Sabatié, N. Dashyan, P. Konczykowski, D. P. Watts, C. Djalali, S. Procureur, I. Bedlinskiy, Elton Smith, N. Markov, Lorenzo Zana, P. L. Cole, A. Ni, A. El Alaoui, Y. Ilieva, S. Pisano, Sergey Kuleshov, T. A. Forest, Friedrich Klein, H. Seraydaryan, H. S. Jo, Brian Raue, A. Kim, Avraham Klein, Nicholas Zachariou, C. Salgado, H. Baghdasaryan, S. L. Careccia, M. Y. Gabrielyan, E. Seder, J. W. Price, S. Park, P. Khetarpal, K. L. Giovanetti, B. McKinnon, P. Rossi, Larry Weinstein, D. Adikaram, M. Guidal, D. Branford, V. Crede, M. Mirazita, M. Holtrop, B. Moreno, A. Daniel, N. Gevorgyan, C. Hanretty, G. Rosner, V. Batourine, Luciano Pappalardo, A. I. Ostrovidov, K. Park, D. G. Ireland, S. S. Stepanyan, Volker D. Burkert, A. S. Biselli, Victor Mokeev, Hovanes Egiyan, H. Moutarde, B. Vernarsky, K. Joo, E. Munevar, I. I. Strakovsky, A. Deur, W. K. Brooks, C. E. Taylor, E. Golovatch, W. Gohn, W. Kim, G. Niculescu, W. Tang, M. Osipenko, B. Zhao, S. S. Jawalkar, I. J. D. MacGregor, M. Contalbrigo, V. P. Kubarovsky, O. Pogorelko, R. W. Gothe, J. McAndrew, Michael Wood, K. Hafidi, W. J. Briscoe, E. Pasyuk, P. Stoler, B. Dey, and K. Hicks
Subjects: Physics, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Hadron, Elementary particle, Lambda, Lambda baryon, 01 natural sciences, Sigma baryon, Nuclear physics, Particle decay, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Nucleon
Abstract: The electromagnetic decay $\Sigma^0(1385) \to \Lambda \gamma$ was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV was incident on a proton target, producing an exclusive final state of $K^+\Sigma^{*0}$. We report the decay widths ratio $\Sigma^0(1385) \to \Lambda\gamma$/ $\Sigma^0(1385) \to \Lambda\pi^0$ = $1.42 \pm 0.12(\text{stat})_{-0.07}^{+0.11}(\text{sys})$%. This ratio is larger than most theoretical predictions by factors ranging from 1.5-3, but is consistent with the only other experimental measurement. From the reported ratio we calculate the partial width and electromagnetic transition magnetic moment for $\Sigma^0(1385) \to \Lambda\gamma$.
Published: 2011

45. Near-threshold photoproduction of ϕ mesons from deuterium

Author: V. Mokeev, E. Seder, S. Fegan, A. El Alaoui, Y. Ilieva, D. G. Ireland, Z. W. Zhao, V. Crede, M. E. McCracken, Kei Moriya, C. A. Meyer, Barry Ritchie, Tsutomu Mibe, Friedrich Klein, K. P. Adhikari, D. P. Weygand, F. Sabatié, Nicholas Zachariou, S. Pisano, C. Bookwalter, W. Kim, E. De Sanctis, R. A. Schumacher, A. Kim, R. Paremuzyan, George Davey Smith, F. X. Girod, K. A. Griffioen, S. Dhamija, P. Eugenio, B. Moreno, L. Graham, Xin Qian, D. I. Sober, M. Taiuti, S. Strauch, J. Zhang, R. W. Gothe, G. Rosner, K. Livingston, A. D'Angelo, S. Stepanyan, Avraham Klein, A. Ni, M. Ripani, H. Egiyan, S. Tkachenko, N. Dashyan, Gerard Gilfoyle, J. W. Price, I. Niculescu, P. Collins, G. Ricco, S. Park, C. E. Taylor, N. Hassall, M. Bellis, D. Sokhan, M. Osipenko, Michael Vineyard, Sergey Kuleshov, D. Schott, P. Rossi, R. De Vita, D. Martinez, B. McKinnon, A. I. Ostrovidov, K. Park, T. Mineeva, D. Protopopescu, C. Hanretty, Lorenzo Zana, S. Pozdniakov, P. L. Cole, S. Anefalos Pereira, E. Munevar, S. S. Stepanyan, H. S. Jo, M. Y. Gabrielyan, Wei-Jiang Xu, Volker D. Burkert, L. Guo, M. Ungaro, B. Zhao, C. Salgado, A. S. Biselli, M. R. Niroula, D. Branford, M. Guidal, S. S. Jawalkar, J. P. Ball, D. S. Carman, P. Khetarpal, M. Mirazita, M. Holtrop, Haiyan Gao, A. Daniel, J. M. Laget, K. Kramer, K. Joo, N. Gevorgyan, R. Dupre, M. Battaglieri, H. Moutarde, V. Batourine, B. Vernarsky, K. Mikhailov, P. Stoler, B. Dey, K. Hicks, P. Konczykowski, S. Procureur, Yujie Qiang, Martin K. Mayer, M. S. Saini, J. T. Goetz, Elton Smith, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, I. I. Strakovsky, A. Deur, W. K. Brooks, P. Nadel-Turonski, E. Voutier, W. Gohn, C. Djalali, B. Morrison, J. McAndrew, Michael Wood, K. Hafidi, D. Doughty, D. Keller, W. J. Briscoe, W. Chen, M. Khandaker, M. J. Amaryan, V. P. Kubarovsky, O. Pogorelko, S. L. Careccia, K. L. Giovanetti, Larry Weinstein, V. Kuznetsov, S. Niccolai, H. Hakobyan, D. J. Tedeschi, I. Bedlinskiy, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), CLAS, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology. Department of Physics, and Xu, W.
Subjects: Nuclear and High Energy Physics, Photon, Proton, Meson, Hadron, Nuclear Theory, FOS: Physical sciences, Photon energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], phi meson photoproduction, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Near threshold, 0103 physical sciences, Deuteron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Quasi free, Physics, 010308 nuclear & particles physics, Momentum transfer, NUCLEAR-BOUND QUARKONIUM, Deuterium, High Energy Physics::Experiment, Nucleon
Abstract: We report the first, kinematically-complete measurement of the differential cross section of ϕ-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K[superscript +] and K[superscript −] near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσ/dt for the initial photon energy range of 1.65–1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on ϕ-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region., United States. Dept. of Energy, National Science Foundation (U.S.)
Published: 2011

46. Limits on neutrino oscillations fromν¯eappearance

Author: Elton Smith, W. Metcalf, J. W. Mitchell, S. J. Freedman, K. T. Lesko, T. A. Romanowski, G. T. Garvey, R. D. McKeown, J. B. Donahue, J. Napolitano, J. E. Nelson, M. Timko, A. R. Fazely, L. S. Durkin, T. Y. Ling, V. D. Sandberg, W. C. Choi, B. K. Fujikawa, R. L. Imlay, and R. W. Harper
Subjects: Scattering cross-section, Physics, Particle physics, Muon, Meson, Computer Science::Information Retrieval, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Neutrino oscillation, Mathematical physics
Abstract: A 20-ton neutrino detector located near the Los Alamos Meson Physics Facility beam stop is used to search for [bar [nu]][sub [ital e]] generated via neutrino oscillations from any of the three neutrino types, [nu][sub [mu]], [bar [nu]][sub [mu]], and [nu][sub [ital e]], which radiate from the beam stop. The analysis of three years of data provides limits on the oscillation modes [bar [nu]][sub [mu]][r arrow][bar [nu]][sub [ital e]], [nu][sub [ital e]][r arrow][bar [nu]][sub [ital e]], and [nu][sub [mu]][r arrow][bar [nu]][sub [ital e]], and the lepton-number-violating decay process [mu][sup +][r arrow][ital e][sup +]+[bar [nu]][sub [ital e]]+[nu][sub [mu]]. The 90%-confidence-level limits for [bar [nu]][sub [mu]][r arrow][bar [nu]][sub [ital e]] oscillations are [delta][ital m][sup 2][le]0.14 eV[sup 2] for maximal mixing, and sin[sup 2]2[theta][le]0.024 for large [delta][ital m][sup 2].
Published: 1993

47. Differential cross sections and recoil polarizations for the reactionγp→K+Σ0

Author: L. Guo, M. Ungaro, H. Hakobyan, S. Dhamija, Michael Dugger, S. S. Stepanyan, R. De Vita, K. Livingston, D. J. Tedeschi, R. Dickson, R. W. Gothe, M. Holtrop, A. Daniel, S. Anefalos Pereira, K. Joo, E. Seder, W. Gohn, Sergey Kuleshov, I. Bedlinskiy, I. Niculescu, A. Yegneswaran, George Davey Smith, N. Guler, A. Fradi, D. Schott, Kei Moriya, C. A. Meyer, I. I. Strakovsky, V. Kuznetsov, Elton Smith, A. D'Angelo, B. L. Berman, A. Deur, C. Hanretty, A. Ni, D. Protopopescu, K. L. Giovanetti, W. K. Brooks, Larry Weinstein, B. Zhao, B. McKinnon, M. Anghinolfi, S. Pozdniakov, K. P. Adhikari, W. Tang, H. Moutarde, D. Keller, M. Ripani, C. E. Taylor, K. A. Griffioen, N. Hassall, E. De Sanctis, J. P. Ball, H. Seraydaryan, D. Branford, S. Park, L. El Fassi, M. Aghasyan, B. Vernarsky, M. Mirazita, D. S. Carman, M. Osipenko, S. Niccolai, D. I. Sober, Y. G. Sharabian, R. A. Schumacher, A. El Alaoui, Y. Ilieva, S. S. Jawalkar, Friedrich Klein, A. Kim, D. P. Watts, P. Rossi, E. Voutier, V. Batourine, Barry Ritchie, L. Graham, E. Munevar, Brian Raue, G. Rosner, R. Nasseripour, Michael L. Williams, M. Khandaker, R. Paremuzyan, Z. W. Zhao, P. Nadel-Turonski, J. McAndrew, D. G. Ireland, S. Fegan, J. Zhang, D. Martinez, R. Dupre, P. Konczykowski, S. Procureur, B. Moreno, V. Crede, Michael Wood, K. Hafidi, M. R. Niroula, Avraham Klein, I. J. D. MacGregor, Gerard Gilfoyle, D. Doughty, M. E. McCracken, G. Ricco, D. Sokhan, S. Strauch, W. Kim, G. Niculescu, M. Battaglieri, M. Y. Gabrielyan, V. P. Kubarovsky, O. Pogorelko, P. Khetarpal, F. X. Girod, C. S. Nepali, W. J. Briscoe, E. Pasyuk, H. S. Jo, V. Mokeev, C. Salgado, M. Bellis, M. F. Vineyard, J. W. Price, A. I. Ostrovidov, K. Park, Volker D. Burkert, A. S. Biselli, J. Salamanca, B. Morrison, C. Djalali, K. Mikhailov, B. Dey, K. Hicks, S. Tkachenko, and P. Eugenio
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Sigma, 01 natural sciences, Sigma baryon, Nuclear physics, Baryon, Recoil, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract: High-statistics measurements of differential cross sections and recoil polarizations for the reaction. gamma p -> K(+)Sigma(0) have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (root s) from 1.69 to 2.84 GeV, with an extensive coverage in the K+ production angle. Independent measurements were made using the K(+) p pi(-)(gamma) and K(+) p(pi(-),gamma) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better statistical precision and a 300-MeV increase in root s coverage. Above root s approximate to 2.5 GeV, t- and u-channel Regge scaling behavior can be seen at forward and backward angles, respectively. Our recoil polarization (P(Sigma)) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles, we find that P(Sigma) is of the same order of magnitude but opposite sign as P(A,) in agreement with the static SU(6) quark model prediction of P(Sigma) approximate to P(A). This expectation is violated in some mid-and backward-angle kinematic regimes, where P(Sigma) and P(Sigma) are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial-wave analyses being performed to search for missing baryon resonances.
Published: 2010

48. The GlueX Central Drift Chamber: Design and Performance

Author: C. A. Meyer, Elton Smith, G.R. Wilkin, Gerard Visser, F. Barbosa, V. Razmyslovich, B. Zihlmann, D. Lawrence, B. Dey, T. Whitlatch, and Y. Van Haarlem
Subjects: Physics, Nuclear and High Energy Physics, GlueX, Physics - Instrumentation and Detectors, business.industry, Physics::Instrumentation and Detectors, Detector, Monte Carlo method, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Particle identification, Particle detector, Nuclear physics, Measuring instrument, Electronics, Aerospace engineering, Nuclear Experiment (nucl-ex), business, Instrumentation, Image resolution, Nuclear Experiment
Abstract: Tests and studies concerning the design and performance of the GlueX Central Drift Chamber (CDC) are presented. A full-scale prototype was built to test and steer the mechanical and electronic design. Small scale prototypes were constructed to test for sagging and to do timing and resolution studies of the detector. These studies were used to choose the gas mixture and to program a Monte Carlo simulation that can predict the detector response in an external magnetic field. Particle identification and charge division possibilities were also investigated., 16 pages, 29 figures
Published: 2010

49. Study of the two pion final state photoproduction on deuterium

Author: Lewis Graham, Kijun Park, Ralf Gothe, Elton Smith, Volker Crede, Paul Eugenio, and A. Ostrovidov
Subjects: Quantum chromodynamics, Quark, Physics, Particle physics, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Strong interaction, Elementary particle, Fundamental interaction, Gluon, Nuclear physics, Baryon, High Energy Physics::Experiment, Nuclear Experiment
Abstract: Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD). However, solutions of this theory in the non‐perturbative domain of the interaction are extremely difficult to achieve. In inelastic electron scattering, very little is known about exclusive hadron production purely contributed to a lack of knowledge. The γN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be tested through the amplitudes of the N and Δ resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through pion photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of Δ and the meso...
Published: 2010

50. Partial wave analysis of the reactionγp→pωand the search for nucleon resonances

Author: Martin K. Mayer, S. Dhamija, R. W. Gothe, M. S. Saini, D. Keller, V. Mokeev, J. Zhang, Michael Vineyard, B. Zhao, M. Guidal, G. E. Dodge, H. Y. Lu, B. L. Berman, S. S. Jawalkar, M. Mirazita, S. Tkachenko, S. Park, M. Khandaker, K. A. Griffioen, M. Holtrop, Elton Smith, A. Daniel, P. Eugenio, M. Taiuti, V. Kuznetsov, K. Livingston, C. Hanretty, M. Anghinolfi, I. Niculescu, R. A. Niyazov, H. Seraydaryan, D. Applegate, J. Salamanca, Y. G. Sharabian, Friedrich Klein, V. Crede, S. L. Careccia, P. L. Cole, J. R. Johnstone, Paolo Rossi, M. Osipenko, B. Morrison, R. Dickson, P. Stoler, E. Munevar, B. S. Ishkhanov, S. S. Stepanyan, A. D'Angelo, P. Collins, Barry Ritchie, B. Dey, S. Procureur, P. Nadel-Turonski, D. Schott, K. L. Giovanetti, L. Guo, M. Ungaro, F. X. Girod, E. L. Isupov, Michael L. Williams, Mark W. Paris, K. Hicks, Marco Ripani, F. Sabatié, Latifa Elouadrhiri, W. Kim, D. Doughty, J. P. Ball, Kei Moriya, C. A. Meyer, G. Niculescu, S. Niccolai, G. V. Fedotov, M. R. Niroula, Y. Perrin, Michael Dugger, M. Bellis, Giovanni Ricco, N. Guler, P. Khetarpal, K. P. Adhikari, S. Strauch, D. S. Carman, D. P. Weygand, J. W. Price, C. S. Nepali, K. Joo, D. P. Watts, H. Hakobyan, N. Hassall, M. E. McCracken, Sergey Kuleshov, C. Djalali, D. J. Tedeschi, H. S. Jo, R. A. Schumacher, M. Y. Gabrielyan, R. Dupre, M. Battaglieri, I. Bedlinskiy, E. Voutier, C. Salgado, D. Protopopescu, S. Pozdniakov, M. Garçon, G. Rosner, W. J. Briscoe, E. Pasyuk, Avraham Klein, Y. Ilieva, V. P. Kubarovsky, R. De Vita, O. Pogorelko, A. El Alaoui, B. Moreno, J. McAndrew, Michael Wood, K. Hafidi, S. Anefalos Pereira, E. De Sanctis, H. Baghdasaryan, D. I. Sober, S. Fegan, A. Fradi, S. Pisano, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, Z. Krahn, B. McKinnon, Gerard Gilfoyle, D. Sokhan, E. Golovatch, W. Gohn, I. I. Strakovsky, A. Deur, and W. K. Brooks
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Omega baryon, 01 natural sciences, Omega, Baryon, Pion, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon
Abstract: An event-based partial wave analysis (PWA) of the reaction {gamma}p{yields}p{omega} has been performed on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis benefits from access to the world's first high-precision spin-density matrix element measurements, available to the event-based PWA through the decay distribution of {omega}{yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0}. The data confirm the dominance of the t-channel {pi}{sup 0} exchange amplitude in the forward direction. The dominant resonance contributions are consistent with the previously identified states F{sub 15}(1680) and D{sub 13}(1700) near threshold, as well as the G{sub 17}(2190) at higher energies. Suggestive evidence for the presence of a J{sup P}=5/2{sup +} state around 2 GeV, a ''missing'' state, has also been found. Evidence for other states is inconclusive.
Published: 2009

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