Author: "M. E. McCracken" - Searchworks@Jio Institute Digital Library Search Results

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1. Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield

Author: B. A. Woodcock, M. P. D. Garratt, G. D. Powney, R. F. Shaw, J. L. Osborne, J. Soroka, S. A. M. Lindström, D. Stanley, P. Ouvrard, M. E. Edwards, F. Jauker, M. E. McCracken, Y. Zou, S. G. Potts, M. Rundlöf, J. A. Noriega, A. Greenop, H. G. Smith, R. Bommarco, W. van der Werf, J. C. Stout, I. Steffan-Dewenter, L. Morandin, J. M. Bullock, and R. F. Pywell
Subjects: Science
Abstract: Pollinator communities could have nuanced effects on crop yield depending on their species and functional trait compositions. Here, the authors use a meta-analysis to show that, in addition to pollinator abundance, functional trait divergence also positively impacts yield of oilseed rape crops.
Published: 2019
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2. Photoproduction of the f2(1270) Meson Using the CLAS Detector

Author: V. Mokeev, P. Eugenio, Vincent Mathieu, D. Heddle, R. A. Schumacher, M. Battaglieri, K. A. Griffioen, R. Paremuzyan, Laura Clark, L. Marsicano, L. Lanza, M. J. Amaryan, M Carver, G. Angelini, D. P. Watts, Gerard Gilfoyle, M. Osipenko, N. Gevorgyan, P. Lenisa, M. Contalbrigo, H. Egiyan, K. Livingston, R. Tyson, D. Sokhan, S. Stepanyan, I. J. D. MacGregor, F. X. Girod, S. Adhikari, Dustin Keller, F. Sabatié, B. McKinnon, G. Niculescu, G. Rosner, B. A. Clary, D. G. Ireland, V. Crede, D. Bulumulla, William Brooks, E. Munevar, Jie Zhang, T. B. Hayward, K. Hafidi, A. Filippi, W. Phelps, Z. E. Meziani, B. Yale, Aditya R. Khanal, L. Venturelli, M. Ehrhart, M. Khandaker, E. L. Isupov, Friedrich Klein, Alessandro Rizzo, A. Kim, Michael Paolone, S. Boiarinov, Andrea Bianconi, G. Ciullo, A. Pilloni, C. W. Kim, A. Celentano, R. W. Gothe, Y. Prok, C. E. Hyde, I. Bedlinskiy, A. El Alaoui, N. A. Baltzell, F. Bossu, T. Chetry, D. S. Carman, Nicholas Zachariou, H. S. Jo, U. Shrestha, J. C. Carvajal, H. Voskanyan, Z. W. Zhao, Fatiha Benmokhtar, Nikos Sparveris, X. Wei, W. J. Briscoe, O. Soto, V. Mascagna, Maxime Defurne, M. Holtrop, S. Joosten, S. Niccolai, D. Protopopescu, E. Voutier, Luciano Pappalardo, A. Movsisyan, R. De Vita, H. Hakobyan, O. Pogorelko, S. Strauch, J. Ritman, J. Rowley, A. I. Ostrovidov, P. Chatagnon, K. Wei, S. Diehl, C. Salgado, S. Fegan, H. Atac, Volker D. Burkert, C. Munoz Camacho, Eugene Pasyuk, A. S. Biselli, G. Gavalian, V. P. Kubarovsky, Krishna Neupane, M. Ripani, M. Hattawy, K. Hicks, N. Dashyan, Michael Dugger, Yordanka Ilieva, L. Barion, Barry Ritchie, R. Dupre, D. Marchand, M. Ungaro, G. V. Fedotov, Q. Huang, K. P. Adhikari, K. Joo, D. G. Jenkins, M. Leali, Axel Schmidt, I. I. Strakovsky, P. Nadel-Turonski, A. Deur, Mark W. Bondi, M. E. McCracken, N. Tyler, C. Djalali, A. D'Angelo, L. El Fassi, A. Kripko, Y. G. Sharabian, and P. L. Cole
Subjects: Quark, Physics, Spectrometer, Meson, High Energy Physics::Lattice, Nuclear Theory, Quark model, Detector, General Physics and Astronomy, Quantum number, 01 natural sciences, 7. Clean energy, Resonance (particle physics), Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract: The quark structure of the f2(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq¯) resonance with quantum numbers JPC=2++. Recently, it was proposed that the f2(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π+π-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π0π0p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f2(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.
Published: 2021

3. Measurement of beam asymmetry for π−Δ++ photoproduction on the proton at Eγ=8.5GeV

Author: E. S. Smith, T. Erbora, Ilya Larin, V. V. Tarasov, J. Schwiening, K. Luckas, B. E. Cannon, A. Austregesilo, C. Fanelli, A. Hurley, H. Marukyan, J. Fitches, R.S. Pedroni, W. McGinley, C. A. Meyer, L. Guo, J. Reinhold, A. Ali, T. D. Beattie, S. Furletov, M. M. Dalton, A. Smith, Z. Zhao, M. M. Ito, G. Rodriguez, F. Barbosa, D. Romanov, W. J. Briscoe, V. A. Matveev, A. M. Schertz, D. G. Ireland, V. Crede, T. Daniels, L. Gan, H. Egiyan, B. C.L. Sumner, A. LaDuke, G. J. Lolos, C. S. Akondi, V. Lyubovitskij, S. Somov, S. Fegan, R. Barsotti, S. Adhikari, M. R. Shepherd, A. Gasparian, E. Pooser, T. Whitlatch, N. Wickramaarachchi, Xiang Zhou, T. Britton, Sergey Kuleshov, B. Liu, M. Khatchatryan, H. Hakobyan, A. I. Ostrovidov, D. I. Lersch, K. Suresh, H. Li, P. Eugenio, W. B. Li, J. Barlow, Stephen Taylor, W. Phelps, J. Ritman, J. R. Stevens, M. McCaughan, Haiyan Gao, Mark Richard James Williams, Michael Dugger, Q. Zhou, Barry Ritchie, G. M. Huber, D. I. Sober, C. Gleason, K. Livingston, A. Thiel, A. Hamdi, I. I. Strakovsky, A. Schick, E. Barriga, V. S. Goryachev, A. Deur, Carlos A. Salgado, P. Pauli, V. Neelamana, Z. Baldwin, Z. Papandreou, O. Soto, R. Dzhygadlo, S. Schadmand, I. Jaegle, V. Khachatryan, J. Zarling, R. Dotel, Krisztian Peters, K. Goetzen, M. J. Amaryan, A. Asaturyan, F. Nerling, R. A. Schumacher, X. Shen, Christine Kourkoumelis, R. E. Mitchell, R. A. Miskimen, B. Zihlmann, L. Ng, A. Ernst, Zhiyong Zhang, V. V. Berdnikov, G. Vasileiadis, W.U. Boeglin, V. Kakoyan, D. J. Mack, D. Lawrence, Sean A Dobbs, A. Somov, William Brooks, Lubomir Pentchev, C. Paudel, A. M. Foda, G. Kalicy, N. S. Jarvis, A. Dolgolenko, S. Cole, O. Cortes, C.P. Romero, T. C. Black, R. T. Jones, M. E. McCracken, J. Zhou, K. Mizutani, M. Kamel, A. Teymurazyan, Y. Yang, and E. Chudakov
Subjects: Physics, Range (particle radiation), GlueX, Proton, Meson, 010308 nuclear & particles physics, media_common.quotation_subject, Momentum transfer, 01 natural sciences, Asymmetry, Pseudoscalar, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract: We report a measurement of the π − photoproduction beam asymmetry for the reaction → γ p → π − Δ + + using data from the GlueX experiment in the photon beam energy range 8.2–8.8 GeV. The asymmetry Σ is measured as a function of four-momentum transfer t to the Δ + + and compared to phenomenological models. We find that Σ varies as a function of t : negative at smaller values and positive at higher values of | t | . The reaction can be described theoretically by t -channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy.
Published: 2021

4. 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

5. Photoproduction of η mesons off the proton for 1.2<Eγ<4.7GeV using CLAS at Jefferson Laboratory

Author: I. Illari, R. A. Schumacher, U. Shrestha, M. Leali, S. Adhikari, B. McKinnon, C. A. Meyer, E. Munevar, P. Chatagnon, B. S. Ishkhanov, Aditya R. Khanal, G. V. Fedotov, P. Lenisa, J. Ritman, S. Stepanyan, N. Dashyan, D. P. Watts, Andrea Bianconi, M. Ungaro, K. P. Adhikari, A. El Alaoui, I. I. Strakovsky, G. Rosner, T. Chetry, A. Deur, C. W. Kim, Laura Clark, W. Phelps, M. Battaglieri, Nicholas Zachariou, J. C. Carvajal, Alexander Schmidt, M. J. Amaryan, William Brooks, Yordanka Ilieva, T. B. Hayward, V. Mascagna, B. A. Clary, E. L. Isupov, Y. G. Sharabian, H. Voskanyan, Friedrich Klein, W. J. Briscoe, P. Eugenio, S. Boiarinov, Brian Raue, G. Angelini, L. Barion, K. Joo, M. Guidal, Michael Paolone, Z. W. Zhao, F. X. Girod, F. Bossu, R. Cruz-Torres, E. Golovatch, M. Holtrop, R. Dupre, S. Strauch, Hovanes Egiyan, Maxime Defurne, K. A. Griffioen, Dustin Keller, C. Munoz Camacho, H. Hakobyan, Y. Prok, H. S. Jo, M. Hattawy, Michael Wood, K. Hafidi, D. G. Ireland, Luciano Pappalardo, V. Crede, A. Kim, D. I. Glazier, G. Ciullo, D. S. Carman, F. Sabatié, T. Hu, R. Paremuzyan, R. De Vita, D. Marchand, D. Protopopescu, Eugene Pasyuk, X. Wei, L. Venturelli, S. Diehl, Fatiha Benmokhtar, O. Soto, C. Salgado, E. Voutier, L. Lanza, Nicholas M. Harrison, Gerard Gilfoyle, A. Filippi, A. Movsisyan, J. W. Price, D. Sokhan, V. P. Kubarovsky, I. Bedlinskiy, M. Khandaker, M. Khachatryan, Nikolaos Sparveris, Z. E. Meziani, K. Wei, S. Niccolai, K. Livingston, N. Markov, Iu. Skorodumina, N. Tyler, C. Djalali, J. A. Tan, V. I. Mokeev, D. Heddle, Jie Zhang, G. Gavalian, D. G. Jenkins, R. Fersch, M. Ehrhart, M. Ripani, O. Pogorelko, P. L. Cole, J. Rowley, Tim O'Connell, A. I. Ostrovidov, Michael Dugger, T. Mineeva, P. Nadel-Turonski, H. Atac, A. S. Biselli, A. D'Angelo, L. Guo, Sylvester Joosten, Alessandro Rizzo, G. Asryan, L. El Fassi, C. Ayerbe Gayoso, M. E. McCracken, A. Hobart, C. Hanretty, W. Kim, G. Niculescu, P. Stoler, M. Osipenko, I. J. D. MacGregor, K. Hicks, M. Contalbrigo, J. Poudel, Z. Akbar, A. Celentano, and R. W. Gothe
Subjects: Physics, Particle physics, Range (particle radiation), Photon, Proton, Meson, 010308 nuclear & particles physics, Sigma, Photon energy, 01 natural sciences, 7. Clean energy, Resonance (particle physics), 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Photoproduction cross sections are reported for the reaction $\gamma p\to p\eta$ using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The $\eta$ mesons are detected in their dominant charged decay mode, $\eta\to \pi^+\pi^-\pi^0$, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new $\eta$ photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are compared with the experimental results from several other experiments, and with predictions of $\eta$ MAID\,2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections $d\sigma/dt$ are presented for incident photon energies $E_\gamma > 2.9$ GeV ($W > 2.5$ GeV), and compared with predictions which are based on Regge trajectories exchange in the $t$-channel (Regge models). The data confirm the expected dominance of $\rho$, $\omega$ vector-meson exchange in an analysis by the Joint Physics Analysis Center.
Published: 2020

6. First measurement of direct photoproduction of the a2(1320)0 meson on the proton

Author: J. Rowley, A. I. Ostrovidov, Volker D. Burkert, A. S. Biselli, W. Phelps, K. A. Griffioen, V. Mascagna, N. Markov, M. E. McCracken, A. Hobart, Carlos A. Salgado, A. Filippi, A. Pilloni, Frank Klein, Dustin Keller, P. Eugenio, L. Marsicano, Sylvester Joosten, Maxime Defurne, M. Khandaker, M. Khachatryan, M. Osipenko, Pawel Nadel-Turonski, Michael Paolone, Alexander Schmidt, D. I. Glazier, D. Bulumulla, E. Munevar, B. S. Ishkhanov, Aditya R. Khanal, Nikolaos Sparveris, M. Ungaro, K. Hafidi, F. Bossu, M. Guidal, G. Niculescu, L. Lanza, D. G. Jenkins, I. J. D. MacGregor, R. De Vita, M. Leali, Laura Clark, M. J. Amaryan, Andrea Bianconi, C. W. Kim, W. Kim, W. Gohn, F. X. Girod, N. Tyler, C. Djalali, J. A. Tan, P. Chatagnon, G. V. Fedotov, H. Voskanyan, A. D'Angelo, T. Chetry, I. Bedlinskiy, L. Elouadrhiri, M. Holtrop, F. Hauenstein, W. J. Briscoe, E. Pasyuk, S. Strauch, K. Joo, H. Atac, D. P. Watts, H. Egiyan, G. Angelini, L. El Fassi, I. I. Strakovsky, R. Dupre, M. Battaglieri, F. Sabatié, Luciano Pappalardo, D. Heddle, A. Deur, M. Ripani, G. Gavalian, V. Mokeev, D. Marchand, V. Lucherini, V. P. Kubarovsky, Michael Dugger, Fatiha Benmokhtar, Krishna Neupane, R. G. Fersch, O. Pogorelko, O. Soto, S. Niccolai, Vincent Mathieu, P. L. Cole, Z. W. Zhao, Alessandro Rizzo, E. Golovatch, P. Lenisa, K. Hicks, M. Ehrhart, S. Adhikari, T. B. Hayward, J. Zhang, M. Hattawy, J. W. Price, N. Dashyan, Yordanka Ilieva, L. Barion, G. Rosner, William Brooks, G. Ciullo, Y. Prok, L. Venturelli, D. S. Carman, R. A. Schumacher, A. El Alaoui, X. Wei, Nicholas Zachariou, J. C. Carvajal, S. Stepanyan, E. Voutier, A. Movsisyan, Adam P. Szczepaniak, D. Sokan, Z. E. Meziani, K. Livingston, K. P. Adhikari, H. Hakobyan, H. S. Jo, A. Kim, J. Ritman, S. Diehl, D. G. Ireland, V. Crede, O. Cortes, E. L. Isupov, R. Paremuzyan, S. Boiarinov, R. Cruz-Torres, Nicholas M. Harrison, U. Shrestha, M. Contalbrigo, C. Munoz Camacho, M. H. Wood, B. McKinnon, A. Celentano, R. W. Gothe, M. Mirazita, and N. Gevorgyan
Subjects: Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Sigma, Photon energy, 01 natural sciences, Nuclear physics, Amplitude, 0103 physical sciences, Invariant mass, Nuclear Experiment, 010306 general physics, Phenomenology (particle physics)
Abstract: We present the first measurement of the exclusive reaction $\gamma p \rightarrow a_2(1320)^0 \, p$ in the photon energy range $3.5$-$5.5$ GeV and four-momentum transfer squared $0.2
Published: 2020

7. 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

8. 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

9. Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

Author: P. Lenisa, W. Kim, R. Dupre, M. Battaglieri, G. Niculescu, G. Rosner, K. Livingston, M. Hattawy, Friedrich Klein, Y. Ghandilyan, A. Filippi, X. Wei, Brian Raue, M. Khandaker, M. J. Amaryan, V. I. Mokeev, D. Heddle, K. L. Giovanetti, Larry Weinstein, G. Hollis, R. A. Schumacher, Jie Zhang, K. A. Griffioen, Dustin Keller, C. Hanretty, N. Guler, G. Khachatryan, A. Celentano, R. W. Gothe, D. P. Watts, P. Nadel-Turonski, Michael Wood, Taya Chetry, W. J. Briscoe, H. Egiyan, M. Ungaro, Laura Clark, L. Lanza, S. Bültmann, M. E. McCracken, Sergey Kuleshov, K. P. Adhikari, T. A. Forest, C. Carlin, H. Avakian, F. X. Girod, S. Pisano, B. S. Ishkhanov, Sylvester Joosten, P. Eugenio, F. Cao, P. Bosted, P. Rossi, S. Strauch, D. Adikaram, E. De Sanctis, M. Guidal, M. Taiuti, J. Brock, C. Munoz Camacho, K. Joo, H. Hakobyan, D. Protopopescu, G. D. Smith, M. Holtrop, W. Phelps, V. Crede, C. Salgado, D. I. Sober, M. Garçon, J. Pierce, E. Voutier, S. Adhikari, B. McKinnon, Avraham Klein, R. A. Montgomery, C. Djalali, H. Voskanyan, Maxime Defurne, I. Bedlinskiy, L. Colaneri, O. Cortes, M. Mirazita, E. Phelps, H. Y. Lu, E. L. Isupov, E. Pasyuk, V. Batourine, R. De Vita, A. El Alaoui, S. Boiarinov, Nicholas Zachariou, A. D'Angelo, R. Paremuzyan, S. Anefalos Pereira, Nicholas M. Harrison, Gerard Gilfoyle, A. Kim, D. Sokhan, N. Markov, N. A. Baltzell, L. El Fassi, J. W. Price, I. Niculescu, V. P. Kubarovsky, Z. W. Zhao, K. Hicks, D. Riser, C. D. Keith, A. I. Ostrovidov, L. Guo, Alessandro Rizzo, O. Pogorelko, S. M. Hughes, K. Park, G. Ddoge, D. G. Ireland, I. Stankovic, T. Mineeva, H. Jiang, R. G. Fersch, Volker D. Burkert, A. S. Biselli, William Brooks, P. L. Cole, S. Koirala, A. Fradi, M. Osipenko, M. Contalbrigo, D. G. Jenkins, Iu. Skorodumina, Z. Akbar, G. Charles, A. Simonyan, F. Sabatié, N. K. Walford, S. S. Jawalkar, I. J. D. MacGregor, W. Gohn, E. Golovatch, A. Deur, L. A. Net, Latifa Elouadrhiri, C. A. Meyer, Y. G. Sharabian, G. V. Fedotov, N. Dashyan, S. E. Kuhn, Yordanka Ilieva, J. A. Fleming, Martin K. Mayer, M. Khachatryan, S. Fegan, C. Gleason, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, S. Niccolai, A. Movsisyan, M. Ripani, E. Seder, 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), CLAS, and 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)
Subjects: Single spin asymmetries, Hadron, fragmentation function, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, transverse momentum: momentum spectrum, Collins, hadron: production, Nuclear Experiment, Spin-½, Physics, deep inelastic scattering: semi-inclusive reaction, suppression, Collins fragmentation, hadron: energy, lcsh:QC1-999, Double spin asymmetries, Semi-inclusive deep-inelastic scattering, Transverse momentum distributions, High Energy Physics - Phenomenology, transverse, electron: scattering, cryogenics, spin: asymmetry, Jefferson Lab, Nuclear and High Energy Physics, pi: momentum, Quark, Socio-culturale, quark gluon: correlation, lepton: scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], quark, pi: electroproduction, Nuclear physics, Pion, target: spin, deep inelastic scattering, CLAS, 0103 physical sciences, 010306 general physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deep inelastic scattering, Gluon, Automatic Keywords, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, higher-dimensional, lcsh:Physics, experimental results, Lepton
Abstract: We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic $^{14}$NH$_3$ target, and extracted double and single target spin asymmetries for $ep\rightarrow e^\prime\pi^0X$ in multidimensional bins in four-momentum transfer ($1.0, Comment: 18 preprint pages, 3 figures
Published: 2018

10. Photoproduction of K+K− meson pairs on the proton

Author: G. Ricco, R. A. Schumacher, K. Mikhailov, L. Bibrzycki, P. Stoler, A. D'Angelo, K. Hicks, H. Hakobyan, Ashot Gasparian, L. Gan, V. Mokeev, A.V. Stavinsky, K. Livingston, D. S. Dale, S. Anefalos Pereira, A. V. Vlassov, D. J. Tedeschi, V. V. Mochalov, K. A. Griffioen, S. Fegan, E. Clinton, Michael Wood, N. Hassall, M. Bellis, K. Hafidi, Michael Vineyard, R. De Vita, S. Stepanyan, C. Bookwalter, P. Nadel-Turonski, M. Kossov, Avraham Klein, T. Mineeva, V. Drozdov, S. Strauch, V. Kuznetsov, Friedrich Klein, D. P. Watts, E. L. Isupov, E. Munevar, H. Egiyan, I. Nakagawa, I. Bedlinskiy, Brian Raue, W. J. Briscoe, Michael L. Williams, A. Kubarovsky, W. Gohn, E. Wolin, Lorenzo Zana, M. Y. Gabrielyan, C. E. Hyde, O. Glamazdin, M. R. Niroula, Z. W. Zhao, S. Niccolai, Y. Prok, D. S. Carman, M. Battaglieri, Barry Ritchie, N. Pivnyuk, I. I. Strakovsky, D. Protopopescu, C. Salgado, E. De Sanctis, M. Garçon, S. Pozdniakov, A. Deur, G. E. Dodge, Martin K. Mayer, G. Rosner, H. Y. Lu, Kei Moriya, C. A. Meyer, M. Osipenko, N. Dashyan, D. I. Sober, F. X. Girod, E. Pasyuk, G. V. Fedotov, S. Tkachenko, Adam P. Szczepaniak, M. S. Saini, I. Niculescu, P. Eugenio, H. Baghdasaryan, K. P. Adhikari, D. P. Weygand, E. Golovatch, M. Taiuti, J. T. Goetz, D. Schott, J. W. Price, C. Djalali, F. Sabatié, V. P. Kubarovsky, O. Pogorelko, W. Kim, P. Collins, M. Anghinolfi, Leonard Lesniak, H. Seraydaryan, J. Zhang, P. Khetarpal, Y. G. Sharabian, C. S. Nepali, M. Ripani, V. Crede, C. Hanretty, J. R. Johnstone, L. Guo, M. Ungaro, S. Park, P. Rossi, K. Joo, M. Guidal, M. Holtrop, A. Daniel, A. I. Ostrovidov, K. Park, Sergey Kuleshov, D. G. Ireland, S. S. Stepanyan, Mark W. Paris, B. Zhao, Volker D. Burkert, A. S. Biselli, S. Dhamija, R. W. Gothe, A. Fradi, M. J. Amaryan, J. Goett, B. McKinnon, D. Branford, S. Pisano, M. Mirazita, S. L. Careccia, J. M. Laget, K. L. Giovanetti, Larry Weinstein, D. Keller, Gerard Gilfoyle, M. Khandaker, M. E. McCracken, Y. Ilieva, D. Sokhan, D. Doughty, A. Teymurazyan, and P. L. Cole
Subjects: Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Particle decay, Pion, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The exclusive reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ was studied in the photon energy range 3.0--3.8 GeV and the momentum transfer range $0.4l\ensuremath{-}tl1.0\text{ }\text{ }{\mathrm{GeV}}^{2}$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range, the integrated luminosity was about $20\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. The reaction was isolated by detecting the ${\ensuremath{\pi}}^{+}$ and proton in CLAS, and reconstructing the ${\ensuremath{\pi}}^{\ensuremath{-}}$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves, in the ${M}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}$ mass range 0.4--1.4 GeV, were derived performing a partial wave expansion of the extracted moments. Beside the dominant contribution of the $\ensuremath{\rho}(770)$ meson in the $P$-wave, evidence for the ${f}_{0}(980)$ and the ${f}_{2}(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\ensuremath{\sigma}/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the ${f}_{0}(980)$ has been measured in a photoproduction experiment.
Published: 2018

11. Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

Author: William Brooks, George Davey Smith, R. A. Schumacher, A. El Alaoui, S. Stepanyan, J. Pierce, H. Y. Lu, P. Eugenio, G. Gavalian, I. Denisenko, N. Dashyan, Taya Chetry, M. Taiuti, A. Filippi, A. Fradi, D. P. Watts, K. A. Griffioen, Friedrich Klein, V. Crede, M. Khandaker, D. G. Meekins, Brian Raue, A. D'Angelo, A. V. Sarantsev, Yordanka Ilieva, Nicholas Zachariou, E. Pasyuk, V. Mokeev, V. Batourine, R. Paremuzyan, R. De Vita, N. Markov, L. Lanza, G. Rosner, E. Golovatch, K. Hicks, W. Kim, Sergey Kuleshov, M. Ripani, R. A. Montgomery, F. Sabatié, S. Niccolai, Carlos A. Salgado, C. D. Keith, Pawel Nadel-Turonski, D. G. Jenkins, Eberhard Klempt, B. A. Clary, J. Brock, Alessandro Rizzo, R. Dupre, M. Battaglieri, J. Zhang, C. Djalali, J. A. Tan, L. El Fassi, J. W. Price, S. Anefalos Pereira, K. Livingston, C. Hanretty, C. Carlin, M. Guidal, L. Guo, M. Ungaro, Gerard Gilfoyle, A. I. Ostrovidov, A. V. Anisovich, K. Park, G. Charles, G. Niculescu, V. A. Nikonov, G. Ciullo, J. P. Ball, B. Torayev, Y. Prok, F. X. Girod, M. E. McCracken, D. S. Carman, D. G. Ireland, M. Holtrop, K. Joo, I. Bedlinskiy, V. P. Kubarovsky, D. Riser, M. Osipenko, Andreas Klein, Nikos Sparveris, X. Wei, T. Mineeva, D. Sokhan, O. Pogorelko, S. Procureur, W. Gohn, A. Kim, Z. E. Meziani, W. Phelps, Volker D. Burkert, M. Bashkanov, A. S. Biselli, B. S. Ishkhanov, L. Elouadrhiri, K. L. Giovanetti, I. Balossino, S. Strauch, Michael Dugger, D. I. Sober, E. Voutier, I. I. Strakovsky, A. Movsisyan, B. McKinnon, Dustin Keller, S. Park, A. Deur, K. Hafidi, Iu. Skorodumina, Sylvester Joosten, S. Fegan, G. Khachatryan, P. L. Cole, Z. W. Zhao, E. Phelps, N. Gevorgyan, D. Protopopescu, W. J. Briscoe, C. Munoz Camacho, M. H. Wood, A. Celentano, R. W. Gothe, M. Contalbrigo, Z. Akbar, N. K. Walford, I. J. D. MacGregor, S. Adhikari, M. Hattawy, Martin K. Mayer, Y. G. Sharabian, C. Gleason, Barry Ritchie, P. Roy, C. A. Meyer, G. V. Fedotov, E. L. Isupov, S. Boiarinov, K. P. Adhikari, H. Hakobyan, and P. Lenisa
Subjects: Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, media_common.quotation_subject, Nuclear Theory, Bremsstrahlung, Observable, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Asymmetry, Baryon, Nuclear physics, 13. Climate action, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract: The photoproduction of ω mesons off the proton has been studied in the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω→π+π-π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.
Published: 2018

12. Measurement of Unpolarized and Polarized Cross Sections for Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory with CLAS

Author: F. Cao, W. Phelps, M. Guidal, E. Pasyuk, N. Dashyan, P. Lenisa, Andrea Celentano, M. Holtrop, S. Procureur, W. Gohn, S. E. Kuhn, G. Charles, M. J. Amaryan, H. S. Jo, H. Y. Lu, H. Voskanyan, B. McKinnon, Iu. Skorodumina, Friedrich Klein, Z. W. Zhao, A. I. Ostrovidov, R. A. Montgomery, Y. Prok, F. Sabatié, David M. Keller, Maxime Defurne, B. Guegan, K. A. Griffioen, H. Hakobyan, P. Stoler, A. Kim, M. Mirazita, A. El Alaoui, A. Filippi, N. Markov, A. Fradi, Latifa Elouadrhiri, X. Wei, G. Rosner, Taya Chetry, C. A. Meyer, I. Balossino, N. Gevorgyan, S. Johnston, K. L. Giovanetti, E. L. Isupov, G. V. Fedotov, K. Hicks, Y. Ghandilyan, Nicholas Zachariou, P. Eugenio, G. Niculescu, V. Batourine, D. G. Ireland, Sergey Kuleshov, M. Ripani, A. Deur, L. Guo, T. Mineeva, K. P. Adhikari, J. A. Tan, M. L. Kabir, S. Niccolai, Volker D. Burkert, W. K. Brooks, D. P. Watts, B. S. Ishkhanov, S. Adhikari, A. S. Biselli, D. Heddle, M. Battaglieri, C. Gleason, M. Khachatryan, D. G. Jenkins, M. Ungaro, R. De Vita, G. Khachatryan, E. Golovatch, R. Dupre, K. Park, Y. Ilieva, Nikolaos Sparveris, L. Lanza, R. W. Gothe, W. Kim, I. Bedlinskiy, K. Livingston, C. Munoz Camacho, M. Hattawy, R. A. Schumacher, M. Osipenko, P. Rossi, W. J. Briscoe, A. D'Angelo, R. G. Fersch, V. P. Kubarovsky, P. Nadel-Turonski, D. Riser, M. Khandaker, S. Stepanyan, R. Paremuzyan, K. Hafidi, S. Bültmann, T. A. Forest, P. L. Cole, Sylvester Joosten, O. Pogorelko, S. Diehl, S. Anefalos Pereira, Avraham Klein, Nicholas M. Harrison, Gerard Gilfoyle, J. W. Price, I. J. D. MacGregor, M. Contalbrigo, Martin Wood, C. Hanretty, L. Barion, C. Salgado, M. Taiuti, J. Zhang, D. Protopopescu, Victor Mokeev, Z. Akbar, M. Garçon, E. Voutier, Y. G. Sharabian, G. Ciullo, J. P. Ball, D. S. Carman, A. Rizzo, A. Movsisyan, L. El Fassi, Zein-Eddine Meziani, M. E. McCracken, F. X. Girod, O. Cortes, S. Boiarinov, Chaden Djalali, G. D. Smith, S. Strauch, G. Gavalian, B. A. Clary, N. Hirlinger Saylor, Michael Paolone, N. A. Baltzell, K. Joo, H. Egiyan, 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and 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)
Subjects: electron p: deep inelastic scattering, interference: Bethe-Heitler, Nuclear and High Energy Physics, generalized parton distribution, Proton, accelerator, electron: polarized beam, Hadronic Physics and QCD, FOS: Physical sciences, Socio-culturale, parton: distribution function, Parton, Newport News CEBAF Linac, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], momentum transfer dependence, 01 natural sciences, beam: energy, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, x-dependence, Nuclear physics, Cross section (physics), High Energy Physics - Experiment (hep-ex), spectrometer: acceptance, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Quantum chromodynamics, Physics, Spectrometer, 010308 nuclear & particles physics, Compton scattering, cross section: difference, HERA, magnetic spectrometer, photon: electroproduction, High Energy Physics - Phenomenology, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nucleon, channel cross section: measured, experimental results
Abstract: This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data., 27 pages, 24 figures, Accepted for publication in PRC
Published: 2018

13. Double $K_S^0$ Photoproduction off the Proton at CLAS

Author: W. Gohn, Pawel Nadel-Turonski, R. Paremuzyan, R. A. Schumacher, N. Markov, P. Eugenio, Nicholas M. Harrison, D. G. Jenkins, Gerard Gilfoyle, D. Sokhan, E. Golovatch, R. Dupre, I. Bedlinskiy, M. L. Kabir, L. Lanza, C. Munoz Camacho, M. Battaglieri, M. Bashkanov, B. McKinnon, X. Wei, C. A. Meyer, F. X. Girod, Y. Ilieva, G. V. Fedotov, H. Egiyan, L. Guo, A. D'Angelo, C. Hanretty, S. Niccolai, I. I. Strakovsky, P. Lenisa, K. P. Adhikari, Chaden Djalali, Avraham Klein, A. Simonyan, A. Deur, Laura Clark, E. De Sanctis, Iu. Skorodumina, G. Khachatryan, W. Kim, K. Park, W. Phelps, Sylvester Joosten, A. Fradi, K. Joo, W. J. Briscoe, G. Charles, M. Osipenko, Barry Ritchie, W. K. Brooks, S. Adhikari, Friedrich Klein, Brian Raue, J. Zhang, D. Protopopescu, E. Voutier, Y. G. Sharabian, S. Chandavar, S. Strauch, Y. Prok, T. Mineeva, G. Ciullo, J. P. Ball, D. S. Carman, Maxime Defurne, V. Crede, A. Rizzo, G. Rosner, G. Gavalian, F. Sabatié, D. I. Glazier, K. A. Griffioen, M. C. Kunkel, S. Johnston, David M. Keller, V. P. Kubarovsky, Y. Ghandilyan, Carlos A. Salgado, M. Khachatryan, R. De Vita, K. Livingston, M. Hattawy, K. Hicks, A. Movsisyan, E. L. Isupov, D. Riser, H. Hakobyan, Nikolaos Sparveris, Michael Paolone, M. Khandaker, A. I. Ostrovidov, D. G. Ireland, S. Stepanyan, Volker D. Burkert, A. S. Biselli, Andrea Celentano, A. El Alaoui, Nicholas Zachariou, M. Ripani, F. Cao, M. Guidal, G. Niculescu, E. Pasyuk, N. Dashyan, M. Holtrop, D. P. Weygand, I. Balossino, Taya Chetry, George Davey Smith, J. W. Price, M. Ungaro, L. El Fassi, M. Contalbrigo, Z. Akbar, O. Pogorelko, I. J. D. MacGregor, P. L. Cole, Z. W. Zhao, M. E. McCracken, Victor Mokeev, R. W. Gothe, L. Barion, A. Filippi, D. Heddle, K. Hafidi, J. T. Goetz, 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), 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), CLAS, 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), 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 ), and 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 )
Subjects: Nuclear and High Energy Physics, Meson, Proton, Dalitz plot, FOS: Physical sciences, Socio-culturale, Photon energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], time-of-flight, 01 natural sciences, Resonance (particle physics), Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, mass spectrum, p: target, background: low, CLAS, 0103 physical sciences, mixing, Invariant mass, Nuclear Experiment (nucl-ex), [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Glueball, background, meson resonance, photon: energy, momentum transfer: measured, Automatic Keywords, glueball, meson: photoproduction, Mass spectrum, baryon: hadron spectroscopy, High Energy Physics::Experiment, missing-mass, photoproduction, experimental results
Abstract: The $f_0$(1500) meson resonance is one of several contenders to have significant mixing with the lightest glueball. This resonance is well established from several previous experiments. Here we present the first photoproduction data for the $f_0$(1500) via decay into the $K_S^0 K_S^0$ channel using the CLAS detector. The reaction $��p$ -> $f_0 p$ -> $K_S^0 K_S^0 p$, where J = 0, 2, was measured with photon energies from 2.7 to 5.1 GeV. A clear peak is seen at 1500 MeV in the background subtracted invariant mass spectra of the two kaons. This is enhanced if the measured 4-momentum transfer to the proton target is restricted to be less than 1.0 GeV2. By comparing data with simulations, it can be concluded that the peak at 1500 MeV is produced primarily at low t, which is consistent with a t-channel production mechanism., 12 pages, 12 figures
Published: 2018

14. First Exclusive Measurement of Deeply Virtual Compton Scattering off He4 : Toward the 3D Tomography of Nuclei

Author: M. J. Amaryan, Laura Clark, C. Gleason, P. Lenisa, W. Phelps, H. Moutarde, X. Wei, K. A. Griffioen, B. S. Ishkhanov, K. L. Giovanetti, Taya Chetry, M. Hattawy, Hovanes Egiyan, Larry Weinstein, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, P. Eugenio, E. Golovatch, S. Strauch, J. W. Price, Friedrich Klein, L. Guo, Alessandro Rizzo, C. Munoz Camacho, D. G. Ireland, E. Voutier, Latifa Elouadrhiri, R. De Vita, V. Crede, M. Taiuti, C. Djalali, Michael Paolone, A. Movsisyan, O. Cortes, E. L. Isupov, S. Niccolai, Z. W. Zhao, C. A. Meyer, H. Y. Lu, L. Lanza, Whitney Armstrong, A. I. Ostrovidov, K. Park, G. V. Fedotov, D. P. Watts, G. Rosner, R. A. Montgomery, A. Celentano, Martin K. Mayer, R. W. Gothe, K. Livingston, A. Deur, H. Jiang, Volker D. Burkert, A. S. Biselli, D. G. Jenkins, R. Paremuzyan, Sergey Kuleshov, M. Khachatryan, A. Simonyan, Y. Ghandilyan, V. I. Mokeev, D. Heddle, H. Hakobyan, M. H. Wood, R. Dupre, S. Boiarinov, L. Colaneri, Iu. Skorodumina, S. Adhikari, S. Anefalos Pereira, S. Fegan, Jie Zhang, I. Niculescu, F. Cao, E. Pasyuk, Nikolaos Sparveris, N. Markov, K. Hicks, D. Adikaram, B. Torayev, M. Guidal, G. Charles, F. X. Girod, Z. E. Meziani, Nicholas M. Harrison, Gerard Gilfoyle, I. Bedlinskiy, N. A. Baltzell, C. Hanretty, W. Kim, P. Nadel-Turonski, William Brooks, A. Filippi, G. D. Smith, M. Holtrop, Lorenzo Zana, G. Khachatryan, M. Battaglieri, G. Niculescu, E. Seder, R. G. Fersch, F. Sabatié, W. Gohn, P. Rossi, V. P. Kubarovsky, D. Sokhan, P. L. Cole, M. Khandaker, O. Pogorelko, D. Protopopescu, B. G. Ritchie, M. Bashkanov, R. A. Schumacher, M. Ungaro, S. M. Hughes, M. Garçon, N. Dashyan, A. D'Angelo, E. De Sanctis, Sylvester Joosten, B. McKinnon, M. E. McCracken, L. A. Net, L. El Fassi, C. Salgado, M. Osipenko, Dustin Keller, A. El Alaoui, N. K. Walford, Y. Perrin, T. Mineeva, Nicholas Zachariou, S. Bültmann, M. Mirazita, E. Phelps, K. P. Adhikari, T. A. Forest, K. Hafidi, N. Gevorgyan, I. J. D. MacGregor, V. Batourine, H. Avakian, S. Stepanyan, Y. G. Sharabian, S. Pisano, K. Joo, Simonetta Liuti, Avraham Klein, M. Contalbrigo, H. Voskanyan, A. Kim, W. J. Briscoe, A. Fradi, S. E. Kuhn, J. A. Fleming, Z. Akbar, and M. Ripani
Subjects: Physics, Particle physics, Time projection chamber, Photon, Proton, Meson, 010308 nuclear & particles physics, Compton scattering, General Physics and Astronomy, Electron, HERA, 01 natural sciences, 7. Clean energy, Nuclear physics, Recoil, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics
Abstract: We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized $^{4}\mathrm{He}$ gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling $^{4}\mathrm{He}$ nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only $^{4}\mathrm{He}$ Compton form factor, ${\mathcal{H}}_{A}$. This first measurement of coherent deeply virtual Compton scattering on the $^{4}\mathrm{He}$ nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.
Published: 2017

15. 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

16. Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2 . II. ep→eπ0p

Author: G. Murdoch, I. Zonta, D. Heddle, G. Hollis, R. A. Schumacher, S. Koirala, F. Sabatié, E. Golovatch, K. A. Griffioen, G. Charles, S. Niccolai, E. De Sanctis, I. Balossino, C. Djalali, Alessandro Rizzo, Frank Klein, G. V. Fedotov, B. Torayev, Dustin Keller, Taya Chetry, D. P. Watts, H. Egiyan, G. Ciullo, J. P. Ball, Y. Prok, T. Mineeva, D. S. Carman, T. A. Forest, D. G. Jenkins, C. Hanretty, G. Rosner, P. Lenisa, S. Stepanyan, L. Elouadrhiri, L. Lanza, Igor Strakovsky, Nikos Sparveris, A. Filippi, X. Wei, K. Hafidi, Y. Ghandilyan, H. Y. Lu, P. Stoler, E. Fanchini, M. Khandaker, A. Deur, Michael Paolone, E. Voutier, I. Bedlinskiy, A. Movsisyan, H. Avakian, D. G. Ireland, P. Bosted, P. Roy, V. Crede, P. Eugenio, M. Taiuti, D. Adikaram, Brian Raue, M. J. Amaryan, M. Osipenko, N. Dashyan, M. Guidal, R. Dupre, M. Battaglieri, F. X. Girod, D. I. Glazier, A. Kim, K. Hicks, G. Niculescu, E. Seder, R. A. Montgomery, H. Voskanyan, S. Bültmann, I. Stankovic, R. De Vita, M. Holtrop, W. J. Briscoe, E. Pasyuk, I. J. D. MacGregor, J. Zhang, Y. G. Sharabian, Iu. Skorodumina, A. Ni, W. Gohn, J. W. Price, Larry Weinstein, W. Kim, William Brooks, M. Ripani, S. Chandavar, S. Strauch, G. Khachatryan, S. Anefalos Pereira, S. Fegan, S. E. Kuhn, Laura Clark, M. Hattawy, L. Guo, M. Ungaro, S. M. Hughes, J. A. Fleming, V. P. Kubarovsky, W. Phelps, O. Cortes, V. Mokeev, E. L. Isupov, O. Pogorelko, A Klei, Ye Tian, P. Rossi, Andrew Puckett, S. Boiarinov, Martin K. Mayer, K. Joo, K. P. Adhikari, M. S. Saini, H. Hakobyan, H. S. Jo, M. Contalbrigo, Z. Akbar, M. E. McCracken, P. Nadel-Turonski, R. A. Badui, George Davey Smith, A. D'Angelo, A. Celentano, R. W. Gothe, L. El Fassi, N. K. Walford, R. G. Fersch, T. Cao, P. L. Cole, Z. W. Zhao, K. Livingston, N. Guler, D. Protopopescu, A. El Alaoui, Nicholas Zachariou, A. I. Ostrovidov, K. Park, B. McKinnon, H. Jiang, M. Mirazita, Volker D. Burkert, A. S. Biselli, C. Munoz Camacho, R. Paremuzyan, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, L. Colaneri, A. Fradi, N. Markov, and S. Pisano
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Resonance, Electron, 01 natural sciences, Nuclear physics, Pion, Amplitude, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Sign (mathematics), Spin-½
Abstract: Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive pi(0) electroproduction reaction. gamma(*) p -> p pi(0), expanding an analysis of the. gamma(*) p -> n pi(+) reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q(2) < 6 GeV2. Results were obtained for about 5700 bins in W, Q(2), cos(theta(*)), and phi(*). The beam-target asymmetries were found to generally be greater than zero, with relatively modest phi(*) dependence. The target asymmetries exhibit very strong phi(*) dependence, with a change in sign occurring between results at low W and high W, in contrast to pi(+) electroproduction. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but significant differences are seen at higherW. When combined with cross-sectional measurements, as well as pi(+) observables, the present results will provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q(2), for resonances with masses as high as 2.4 GeV.
Published: 2017

17. Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1GeV2 . I. ep→eπ+n

Author: Sylvester Joosten, P. Lenisa, B. McKinnon, I. Zonta, G. Ciullo, C. Djalali, J. P. Ball, Y. Prok, D. S. Carman, M. Mirazita, V. Crede, Nikos Sparveris, X. Wei, M. Osipenko, N. Gevorgyan, V. Batourine, H. Egiyan, R. A. Badui, M. Guidal, S. Niccolai, R. A. Montgomery, S. E. Kuhn, M. Hattawy, Brian Raue, K. A. Griffioen, J. A. Fleming, A. Filippi, M. Holtrop, G. Charles, Gerard Gilfoyle, D. Protopopescu, D. Sokhan, L. Colaneri, A. Fradi, Andrew Puckett, E. Voutier, W. Kim, S. Chandavar, I. Bedlinskiy, P. Eugenio, M. Taiuti, Laura Clark, M. Khandaker, R. W. Gothe, P. Rossi, E. Seder, P. L. Cole, Z. W. Zhao, I. Stankovic, K. Livingston, Yordanka Ilieva, Iu. Skorodumina, S. Pisano, K. Hicks, P. Peng, M. J. Amaryan, L. Lanza, C. Munoz Camacho, M. E. McCracken, S. Strauch, G. Murdoch, S. M. Hughes, P. Nadel-Turonski, M. Ripani, L. A. Net, S. Stepanyan, W. Phelps, C. Gleason, Larry Weinstein, S. Koirala, N. K. Walford, F. X. Girod, A. El Alaoui, I. J. D. MacGregor, Andrea Celentano, B. Torayev, A. I. Ostrovidov, K. Park, M. Contalbrigo, Nicholas Zachariou, C. A. Meyer, D. G. Ireland, H. Jiang, G. V. Fedotov, Volker D. Burkert, A. S. Biselli, H. Hakobyan, M. Battaglieri, H. S. Jo, W. Gohn, Victor Mokeev, L. Elouadrhiri, I. I. Strakovsky, E. Fanchini, A. Deur, J. Zhang, J. W. Price, M. Ungaro, E. Golovatch, R. Dupre, K. Joo, E. L. Isupov, Ye Tian, R. De Vita, S. Anefalos Pereira, E. De Sanctis, R. A. Schumacher, T. A. Forest, N. A. Baltzell, G. Khachatryan, W. J. Briscoe, G. Rosner, Y. Ghandilyan, A. Kim, E. Munevar, B. S. Ishkhanov, George Davey Smith, A. D'Angelo, Frank Klein, L. El Fassi, P. E. Bosted, H. Avakian, H. Voskanyan, S. Bültmann, E. Pasyuk, V. P. Kubarovsky, and O. Pogorelko
Subjects: Physics, Meson, 010308 nuclear & particles physics, Scattering, Form factor (quantum field theory), Resonance, Electron, 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Spin-½
Abstract: Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π 0 electroproduction reaction γ ∗ p → p π 0 , expanding an analysis of the γ ∗ p → n π + reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q 2 < 6 GeV 2 . Results were obtained for about 5700 bins in W , Q 2 , cos ( θ ∗ ) , and ϕ ∗ . The beam-target asymmetries were found to generally be greater than zero, with relatively modest ϕ ∗ dependence. The target asymmetries exhibit very strong ϕ ∗ dependence, with a change in sign occurring between results at low W and high W , in contrast to π + electroproduction. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but significant differences are seen at higher W . When combined with cross-sectional measurements, as well as π + observables, the present results will provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2 , for resonances with masses as high as 2.4 GeV.
Published: 2017

18. Target and double spin asymmetries of deeply virtual π 0 production with a longitudinally polarized proton target and CLAS

Author: E. Seder, G. V. Fedotov, K. P. Adhikari, D. G. Ireland, V. Sytnik, V. Crede, B. McKinnon, A. Kim, M. Ungaro, Dustin Keller, G. Khachatryan, W. Phelps, M. Contalbrigo, A. Fradi, D. P. Watts, A. D'Angelo, H. Egiyan, P. Nadel-Turonski, H. Y. Lu, P. Mattione, P. Bosted, P. Roy, E. De Sanctis, M. Osipenko, L. Colaneri, L. El Fassi, M. Battaglieri, Sylvester Joosten, H. S. Jo, S. Pisano, K. Hafidi, D. G. Jenkins, N. Compton, Michael Paolone, C. Hanretty, P. Lenisa, M. E. McCracken, V. Batourine, I. I. Strakovsky, I. J. D. MacGregor, B. S. Ishkhanov, Z. Akbar, K. Joo, W. Kim, N. Markov, F. X. Girod, Lorenzo Zana, K. A. Griffioen, R. A. Badui, G. D. Smith, M. Holtrop, S. E. Kuhn, L. Guo, Alessandro Rizzo, C. Djalali, Friedrich Klein, J. A. Fleming, Gerard Gilfoyle, P. Rossi, V. P. Kubarovsky, C. Salgado, D. Sokhan, M. Ripani, O. Pogorelko, E. Golovatch, A. Celentano, R. W. Gothe, L. Lanza, S. Chandavar, M. Garc con, J. W. Price, I. Bedlinskiy, R. G. Fersch, H. Avakian, A. I. Ostrovidov, R. De Vita, K. Park, Y. Prok, D. S. Carman, Iu. Skorodumina, P. L. Cole, J. Zhang, L. A. Net, O. Cortes, Nikos Sparveris, William Brooks, H. Voskanyan, H. Jiang, X. Wei, Taya Chetry, W. J. Briscoe, E. Pasyuk, S. Niccolai, G. Rosner, S. Boiarinov, S. Anefalos Pereira, A. Movsisyan, P. Eugenio, Volker D. Burkert, A. S. Biselli, N. Dashyan, M. Taiuti, Y. G. Sharabian, Y. Ghandilyan, T. Cao, R. A. Schumacher, M. Hattawy, W. Gohn, S. Bültmann, S. Stepanyan, E. Munevar, Avraham Klein, Sergey Kuleshov, V. Mokeev, G. Charles, S. Strauch, P. Stoler, K. Hicks, E. Voutier, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. Heddle, B. Torayev, A. Filippi, M. Khandaker, K. L. Giovanetti, Larry Weinstein, Institut de Physique Nucléaire d'Orsay (IPNO), 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and CLAS Collaboration
Subjects: Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, Deeply Virtual Meson Production, Virtual particle, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Nucleon structure, 0103 physical sciences, Chiral-odd generalized parton distributions, CLAS collaboration, Longitudinally polarized target, 010306 general physics, Nuclear Experiment, media_common, Physics, Spectrometer, 010308 nuclear & particles physics, lcsh:QC1-999, Pseudoscalar, Transverse plane, Amplitude, Phase space, High Energy Physics::Experiment, lcsh:Physics
Abstract: The target and double spin asymmetries of the exclusive pseudoscalar channel View the MathML source were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, −t and ϕ . Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs View the MathML source and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and View the MathML source. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.
Published: 2017

19. Target and beam-target spin asymmetries in exclusive π+ and π− electroproduction with 1.6- to 5.7-GeV electrons

Author: N. Dashyan, Taya Chetry, I. Stankovic, Yordanka Ilieva, Sergey Kuleshov, C. Djalali, A. Filippi, H. Avakian, G. Charles, George Davey Smith, W. Gohn, N. A. Baltzell, D. G. Jenkins, I. I. Strakovsky, A. Deur, P. Bosted, P. Roy, D. Adikaram, F. X. Girod, R. A. Schumacher, S. Strauch, A. D'Angelo, B. McKinnon, E. Munevar, G. Niculescu, P. Eugenio, M. Taiuti, S. Joosten, M. Ungaro, D. Heddle, B. S. Ishkhanov, G. Ciullo, A. El Alaoui, Nicholas Zachariou, M. Holtrop, S. Bültmann, W. Kim, L. El Fassi, K. P. Adhikari, T. A. Forest, V. Crede, D. P. Watts, I. Zonta, S. Stepanyan, R. W. Gothe, Andrew Puckett, C. Gleason, J. Pierce, Avraham Klein, K. A. Griffioen, M. E. McCracken, P. Nadel-Turonski, E. Golovatch, R. Dupre, Carlos A. Salgado, K. Joo, M. Mirazita, B. Torayev, G. E. Dodge, H. Y. Lu, S. M. Hughes, K. Livingston, R. A. Badui, N. Gevorgyan, I. Bedlinskiy, H. S. Jo, A. Fradi, A. Simonyan, M. J. Amaryan, J. P. Ball, V. Sytnik, R. Fersch, D. S. Carman, M. Hattawy, M. Osipenko, N. Guler, Nikos Sparveris, P. Lenisa, W. J. Briscoe, I. Niculescu, X. Wei, E. Voutier, A. Movsisyan, S. L. Careccia, S. Niccolai, S. E. Kuhn, J. A. Fleming, V. P. Kubarovsky, S. Chandavar, V. Batourine, Victor Mokeev, A. Ni, D. Protopopescu, M. Garçon, A. Celentano, O. Pogorelko, Alessandro Rizzo, L. Lanza, Friedrich Klein, P. Rossi, K. L. Giovanetti, R. De Vita, E. Fanchini, E. Seder, P. Peng, Hovanes Egiyan, Larry Weinstein, C. Munoz Camacho, C. Hanretty, Brian Raue, M. Khandaker, M. Ripani, R. C. Minehart, S. Anefalos Pereira, C. A. Meyer, J. Zhang, R. Paremuzyan, H. Voskanyan, L. A. Net, G. V. Fedotov, J. W. Price, G. Rosner, S. Boiarinov, E. Pasyuk, Gerard Gilfoyle, Y. Ghandilyan, Dustin Keller, P. L. Cole, Z. W. Zhao, A. I. Ostrovidov, K. Park, Michael Wood, K. Hafidi, D. G. Ireland, H. Jiang, Y. G. Sharabian, Volker D. Burkert, X. Zheng, A. S. Biselli, L. Colaneri, N. Markov, S. Pisano, M. Battaglieri, S. Procureur, O. Cortes, E. L. Isupov, Ye Tian, Lorenzo Zana, L. Clark, K. Hicks, L. Guo, G. Asryan, N. Harrison, Iu. Skorodumina, W. Phelps, Y. Prok, F. Sabatié, M. Contalbrigo, Z. Akbar, N. K. Walford, T. Cao, and I. J. D. MacGregor
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Resonance, Electron, Polarization (waves), Deep inelastic scattering, 01 natural sciences, Particle identification, Nuclear physics, Amplitude, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Beam-target double spin asymmetries and target single-spin asymmetries in exclusive $\pi^+$ and $\pi^-$ electroproduction were obtained from scattering of 1.6 to 5.7 GeV longitudinally polarized electrons from longitudinally polarized protons (for $\pi^+$) and deuterons (for $\pi^-$) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is $1.1 1.5$ GeV. Very large target-spin asymmetries are observed for $W>1.6$ GeV. When combined with cross section measurements, the present results will provide powerful constraints on nucleon resonance amplitudes at moderate and large values of $Q^2$, for resonances with masses as high as 2.3 GeV.
Published: 2016

20. Photoproduction ofΛandΣ0hyperons using linearly polarized photons

Author: W. Kim, Michael Dugger, A. El Alaoui, Y. Ilieva, G. Niculescu, P. Peng, Hovanes Egiyan, C. Munoz Camacho, Nicholas Zachariou, R. A. Schumacher, D. G. Jenkins, V. P. Kubarovsky, A. I. Ostrovidov, K. Park, M. Contalbrigo, O. Pogorelko, S. M. Hughes, V. Crede, N. Compton, M. J. Amaryan, A. Ni, D. G. Ireland, H. Jiang, Dustin Keller, P. Lenisa, B. McKinnon, K. P. Adhikari, Volker D. Burkert, A. S. Biselli, J. A. Fleming, F. X. Girod, I. I. Strakovsky, I. Zonta, M. Taiuti, K. Hafidi, X. Wei, A. Deur, M. Osipenko, E. Munevar, Friedrich Klein, Iu. Skorodumina, Z. Akbar, M. Ungaro, Brian Raue, L. Clark, N. Gevorgyan, L. A. Net, H. Y. Lu, K. L. Giovanetti, W. K. Brooks, D. Protopopescu, R. A. Badui, P. Roy, C. Salgado, Y. G. Sharabian, C. Gleason, R. Paremuzyan, D. Adikaram, E. Voutier, H. Voskanyan, Andrew Puckett, J. W. Price, Barry Ritchie, W. J. Briscoe, R. Dupre, M. Hattawy, Gerard Gilfoyle, Nikolaos Sparveris, D. I. Glazier, A. Celentano, R. W. Gothe, A. Filippi, L. Guo, L. Colaneri, D. Sokhan, S. Niccolai, F. Sabatié, O. Cortes, E. L. Isupov, K. Livingston, G. D. Smith, M. Holtrop, M. Khandaker, S. Strauch, C. A. Paterson, Jie Zhang, N. Markov, R. De Vita, E. Seder, S. Pisano, G. V. Fedotov, P. Mattione, M. Ripani, D. P. Watts, K. Joo, N. K. Walford, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, I. Bedlinskiy, S. Anefalos Pereira, Eugene Pasyuk, A. Rizzo, V. Sytnik, N. Harrison, I. J. D. MacGregor, A. Movsisyan, B. Torayev, E. Fanchini, K. A. Griffioen, Taya Chetry, D. I. Sober, Sergey Kuleshov, Victor Mokeev, P. Nadel-Turonski, K. Hicks, L. Lanza, C. Djalali, M. Battaglieri, M. E. McCracken, A. D'Angelo, G. Khachatryan, L. El Fassi, C. A. Mayer, R. Tucker, P. L. Cole, N. A. Baltzell, B. S. Ishkhanov, L. Zana, G. Rosner, and Y. Ghandilyan
Subjects: Physics, Quantum chromodynamics, Particle physics, Photon, 010308 nuclear & particles physics, Linear polarization, Bremsstrahlung, Strangeness, 01 natural sciences, Particle identification, Nuclear physics, Baryon, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Background: Measurements of polarization observables for the reactions (gamma) over right arrowp -> K+ Lambda and (gamma) over right arrowp -> K+ Sigma(0) have been performed. This is part of a program of measurements designed to study the spectrum of baryon resonances in particular, and nonperturbative QCD in general. Purpose: The accurate measurement of several polarization observables provides tight constraints for phenomenological fits, which allow the study of strangeness in nucleon and nuclear systems. Beam-recoil observables for the (gamma) over right arrowp -> K+ Sigma(0) reaction have not been reported before now. Method: Themeasurements were carried out using linearly polarized photon beams incident on a liquid hydrogen target, and the CLAS detector at the Thomas Jefferson National Accelerator Facility. The energy range of the results is 1.71 < W < 2.19 GeV, with an angular range -0.75 < cos theta(K)* < +0.85. Results: The observables extracted for both reactions are beam asymmetry Sigma, target asymmetry T, and the beam-recoil double polarization observables O-x and O-z. Conclusions: Comparison with theoretical fits indicates that, in the regions where no previous data existed, the new data contain significant new information, and strengthen the evidence for the set of resonances used in the latest Bonn-Gatchina fit.
Published: 2016

21. Differential cross section of γn→K+Σ− on bound neutrons with incident photons from 1.1 to 3.6 GeV

Author: A. I. Ostrovidov, K. Park, M. E. McCracken, D. G. Ireland, Michael Dugger, Volker D. Burkert, A. S. Biselli, V. P. Kubarovsky, Lorenzo Zana, Sergey Kuleshov, H. S. Jo, C. Salgado, K. A. Griffioen, O. Pogorelko, D. Protopopescu, L. Guo, P. Nadel-Turonski, S. Fegan, R. De Vita, M. Osipenko, S. S. Stepanyan, S. Pozdniakov, W. Gohn, S. Procureur, C. Bookwalter, S. Anefalos Pereira, K. Mikhailov, F. Sabatié, M. Guidal, S. Dhamija, V. Crede, N. Dashyan, W. J. Briscoe, E. Pasyuk, Y. Perrin, T. Mineeva, R. W. Gothe, E. De Sanctis, S. L. Careccia, R. Dupre, M. Holtrop, A. Daniel, Gerard Gilfoyle, G. Ricco, M. Aghasyan, P. Eugenio, M. Battaglieri, J. Salamanca, Friedrich Klein, Brian Raue, K. Joo, D. Sokhan, E. Munevar, D. I. Sober, S. Pisano, B. S. Ishkhanov, B. Morrison, G. Gavalian, S. Tkachenko, W. Kim, B. Zhao, H. Baghdasaryan, M. Ripani, P. L. Cole, B. McKinnon, C. Djalali, G. Niculescu, A. El Alaoui, F. X. Girod, Y. Ilieva, K. L. Giovanetti, Michael Wood, D. Branford, P. Collins, D. Keller, M. Mirazita, E. Voutier, P. Khetarpal, G. Rosner, B. L. Berman, A. D'Angelo, S. S. Jawalkar, I. Niculescu, J. P. Ball, Y. Prok, M. Khandaker, C. Hanretty, D. S. Carman, J. W. Price, N. Hassall, R. A. Schumacher, S. Park, V. Mokeev, P. Rossi, T. A. Forest, S. Stepanyan, H. Moutarde, S. Strauch, P. Stoler, D. P. Watts, B. Dey, B. Moreno, K. Hicks, B. Vernarsky, K. Livingston, J. Zhang, R. Dickson, N. Guler, M. Y. Gabrielyan, H. Hakobyan, D. J. Tedeschi, V. Kuznetsov, S. Niccolai, E. Seder, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, M. S. Saini, Barry Ritchie, J. T. Goetz, I. I. Strakovsky, A. Deur, W. K. Brooks, Kei Moriya, C. A. Meyer, K. P. Adhikari, Michael Vineyard, D. P. Weygand, and D. Doughty
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, 010308 nuclear & particles physics, Hadron, Photon energy, Strangeness, 7. Clean energy, 01 natural sciences, Nuclear physics, Baryon, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Differential cross sections of the reaction γd → K+Σ–(p) have been measured with the CLAS detector at Jefferson Lab using incident photons with energies between 1.1 and 3.6 GeV. This is the first complete set of strangeness photoproduction data on the neutron covering a broad angular range. At energies close to threshold and up to Eγ ~ 1.8 GeV, the shape of the angular distribution is suggestive of the presence of s -channel production mechanisms. For Eγ > 1.8 GeV, a clear forward peak appears and becomes more prominent as the photon energy increases, suggesting contributions from t-channel production mechanisms. Furthermore, these data can be used to constrain future analysis of this reaction.
Published: 2010

22. 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

23. 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

24. Characterization of mixing enhancement in swirl-spray interactions in diesel engines

Author: M. E. Mccracken and J. Abraham
Subjects: business.industry, 020209 energy, General Chemical Engineering, Homogeneous charge compression ignition, Mixing (process engineering), General Physics and Astronomy, Energy Engineering and Power Technology, 02 engineering and technology, General Chemistry, Diesel cycle, Mechanics, Diesel engine, Combustion, Diesel fuel, 020303 mechanical engineering & transports, Fuel Technology, 0203 mechanical engineering, Internal combustion engine, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, Exhaust gas recirculation, business
Abstract: Swirl in diesel engines is known to be an important parameter that affects the mixing of fuel and air, heat release, emissions, and overall engine performance. In this study, a multidimensional model for flows, sprays, and combustion in engines is employed to study the interactions between swirl and the fuel spray in a diesel engine. It is generally believed that swirl enhances mixing in a diesel engine. Previous studies have suggested that there may be an optimal level of swirl at which the mixing in the chamber is maximized for a given set of engine operating conditions. This optimal level may result from a balance between increased jet surface area and utilization of air in the chamber. In this work, those trends are clarified through a detailed evaluation of the velocity flow patterns in the chamber and by relating such patterns to those published in the literature for jets in cross-flow. It is also shown that the optimal swirl ratio for enhanced mixing may be characterized by a nondimensional paramet...
Published: 2002

25. Energy-independent PWA of the reaction γp → K+Λ

Author: M. E. McCracken, A. V. Anisovich, R. A. Schumacher, A. V. Sarantsev, R. Beck, Eberhard Klempt, U. Thoma, Volker D. Burkert, and V. A. Nikonov
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Observable, Lambda, Energy (signal processing), Spin-½
Abstract: Using all recent data on the differential cross sections and spin observables for the reaction $\gamma p \to K^+ \Lambda$, an energy-independent partial-wave analysis is performed. The analysis requires multipoles up to $L = 2$; there is no evidence that the fit requires multipoles with $L=3$. At present the available data allow us to extract the dominant multipoles only. These are compatible with the multipoles obtained in the energy-dependent fit. This result supports the reliability of the Bonn-Gatchina energy-dependent results.
Published: 2014

26. 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

27. Differential photoproduction cross sections of theΣ0(1385),Λ(1405), andΛ(1520)

Author: H. Y. Lu, Jie Zhang, H. Avakian, M. F. Vineyard, R. Fersch, N. Guler, M. J. Amaryan, N. K. Walford, S. Fegan, H. Voskanyan, H. Seraydaryan, J. P. Ball, D. S. Carman, I. Zonta, R. De Vita, W. J. Briscoe, E. Pasyuk, E. Voutier, Friedrich Klein, H. Moutarde, I. Niculescu, Brian Raue, K. L. Giovanetti, Y. G. Sharabian, A. Kubarovsky, S. Anefalos Pereira, Larry Weinstein, A. Deur, R. A. Schumacher, F. Sabatié, B. Vernarsky, V. P. Kubarovsky, D. Doughty, S. Tkachenko, P. Eugenio, L. Guo, G. Niculescu, Andrew Puckett, Martin K. Mayer, O. Pogorelko, D. Adikaram, W. K. Brooks, D. Heddle, D. Protopopescu, M. Guidal, S. Pozdniakov, S. Park, E. Munevar, S. Niccolai, S. Chandavar, E. Seder, B. S. Ishkhanov, E. De Sanctis, C. E. Taylor, J. J. Phillips, P. Rossi, M. S. Saini, Michael Wood, M. Aghasyan, Z. W. Zhao, David M. Keller, D. I. Sober, M. Holtrop, S. Stepanyan, I. J. D. MacGregor, H. Hakobyan, D. Ho, V. Crede, Y. Ilieva, Kei Moriya, C. A. Meyer, G. V. Fedotov, E. Golovatch, C. Hanretty, Nicholas Zachariou, M. Khandaker, M. Contalbrigo, C. S. Nepali, Luciano Pappalardo, S. Strauch, D. P. Watts, R. A. Montgomery, S. Lewis, M. D. Mestayer, B. McKinnon, J. A. Fleming, O. Cortes, T. Mineeva, D. Rimal, P. Stoler, M. Taiuti, E. L. Isupov, W. Tang, J. Bono, P. Nadel-Turonski, Ye Tian, Michael L. Williams, K. P. Adhikari, B. Dey, M. Osipenko, Diane Schott, G. Rosner, R. Nasseripour, A. I. Ostrovidov, K. Park, S. Boiarinov, K. Hicks, I. Bedlinskiy, D. G. Ireland, D. Martinez, Volker D. Burkert, A. S. Biselli, M. Mirazita, Barry Ritchie, F. X. Girod, A. Celentano, R. W. Gothe, Sergey Kuleshov, J. T. Goetz, V. Mokeev, W. Gohn, N. Gevorgyan, V. Batourine, C. Djalali, J. W. Price, S. Koirala, R. Paremuzyan, Lorenzo Zana, E. Phelps, S. Pisano, H. S. Jo, Gerard Gilfoyle, C. Salgado, D. Sokhan, Hovanes Egiyan, C. Munoz Camacho, R. P. Bennett, P. Collins, N. A. Baltzell, K. A. Griffioen, S. Taylor, Avraham Klein, M. Ungaro, M. Ripani, Michael Dugger, K. Joo, M. Bellis, R. Dupre, M. Battaglieri, S. Procureur, George Davey Smith, A. D'Angelo, L. El Fassi, M. E. McCracken, K. Livingston, and N. Dashyan
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Current (mathematics), 010308 nuclear & particles physics, Theoretical models, Hyperon, Sigma, Lambda, 01 natural sciences, Nuclear physics, Isospin, 0103 physical sciences, Effective lagrangian, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Differential (mathematics)
Abstract: We report the exclusive photoproduction cross sections for the Sigma(1385), Lambda(1405), and Lambda(1520) in the reactions gamma + p -> K+ + Y* using the CLAS detector for energies from near the respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential cross sections are integrated to give the total exclusive cross sections for each hyperon. Comparisons are made to current theoretical models based on the effective Lagrangian approach and fitted to previous data. The accuracy of these models is seen to vary widely. The cross sections for the Lambda(1405) region are strikingly different for the Sigma+pi-, Sigma0 pi0, and Sigma- pi+ decay channels, indicating the effect of isospin interference, especially at W values close to the threshold.
Published: 2013

28. 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

29. 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

30. PWA prospects for K+Λ and K+Σ0 photoproduction

Author: C. A. Meyer, B. Dey, and M. E. McCracken
Subjects: Nuclear physics, Physics, High energy, Particle physics, Polarization observables, Photon beams, DESY, Strangeness, Photon beam
Abstract: We present a status update on the CMU group PWA efforts in the strangeness (K+Λ/K+Σ0) sector. The bulk of the currently available data comes from recently published CLAS g11a results [1, 2], with extensive polarization data expected soon from the CLAS g8 and g9 set of experiments. We give a brief description of issues pertaining to different sign conventions for the polarization observables in the literature [3], and normalization discrepancies between the CLAS-g11a results and older high energy data from SLAC/CEA/DESY that used an untagged photon beam.
Published: 2012

31. 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

32. Absorption of the ω and ϕ Mesons in Nuclei

Author: R. Nasseripour, K. Livingston, George Davey Smith, A. D'Angelo, P. L. Cole, L. El Fassi, M. E. McCracken, R. Dickson, V. Kuznetsov, V. Crede, R. Dupre, M. Battaglieri, B. McKinnon, W. Tang, William Brooks, A. I. Ostrovidov, F. X. Girod, B. Zhao, B. L. Berman, E. De Sanctis, S. S. Stepanyan, K. Park, M. Osipenko, E. Munevar, S. S. Jawalkar, D. Branford, D. G. Ireland, B. S. Ishkhanov, D. I. Sober, M. Mirazita, R. A. Schumacher, D. Martinez, Michael Vineyard, Volker D. Burkert, A. S. Biselli, S. L. Careccia, S. Dhamija, S. Niccolai, A. Kim, L. Graham, J. W. Price, V. Batourine, R. W. Gothe, M. R. Niroula, P. Konczykowski, S. Procureur, P. Eugenio, M. Taiuti, A. Ni, S. Strauch, A. El Alaoui, K. L. Giovanetti, D. P. Watts, Larry Weinstein, S. Stepanyan, M. Ripani, H. Egiyan, S. Park, Avraham Klein, D. Doughty, H. Hakobyan, R. De Vita, N. Hassall, M. Bellis, F. Sabatié, S. Fegan, P. Rossi, P. Collins, Z. W. Zhao, T. Mineeva, W. Kim, H. S. Jo, G. Niculescu, D. J. Tedeschi, B. Moreno, M. Paolone, P. Khetarpal, M. Y. Gabrielyan, G. Rosner, C. Salgado, D. Protopopescu, Y. Ilieva, S. Anefalos Pereira, I. Bedlinskiy, S. Pozdniakov, M. Garçon, I. Niculescu, S. Tkachenko, D. Keller, Friedrich Klein, Brian Raue, L. Guo, R. Paremuzyan, D. Schott, M. Guidal, M. Ungaro, B. Vernarsky, S. Pisano, M. Khandaker, Gerard Gilfoyle, G. Ricco, K. Joo, M. Holtrop, J. P. Ball, D. Sokhan, D. S. Carman, A. Daniel, P. Stoler, J. Zhang, B. Dey, K. Hicks, Sergey Kuleshov, C. Hanretty, Victor Mokeev, E. Seder, Y. Prok, Kei Moriya, C. A. Meyer, K. P. Adhikari, D. P. Weygand, E. Voutier, W. Gohn, I. I. Strakovsky, A. Deur, C. E. Taylor, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, M. S. Saini, J. T. Goetz, C. Djalali, J. McAndrew, Michael Wood, J. Salamanca, B. Morrison, P. Nadel-Turonski, K. Hafidi, W. J. Briscoe, E. Pasyuk, V. P. Kubarovsky, and O. Pogorelko
Subjects: Nuclear reaction, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Elementary particle, PROPAGATION, MASS, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, 0103 physical sciences, RHO-MESON, Nuclear Experiment, 010306 general physics, Absorption (electromagnetic radiation), MATTER, PHOTOPRODUCTION, PHOTON, DECAY, Physics, 010308 nuclear & particles physics, Nuclear matter, Antimatter, High Energy Physics::Experiment, Atomic physics, Lepton
Abstract: Because of their long lifetimes, the ω and ϕ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e+e- channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the ω meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.
Published: 2010

33. 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

34. Differential cross section and recoil polarization measurements for theγp→K+Λreaction using CLAS at Jefferson Lab

Author: P. Eugenio, R. De Vita, S. Anefalos Pereira, M. Taiuti, E. Munevar, E. De Sanctis, M. Ungaro, D. I. Sober, W. Kim, Kei Moriya, D. Doughty, C. A. Meyer, S. S. Stepanyan, B. P. Quinn, S. Pisano, Y. Perrin, F. X. Girod, G. Niculescu, Martin K. Mayer, B. McKinnon, D. Protopopescu, S. Fegan, S. Strauch, J. Salamanca, S. Procureur, S. Pozdniakov, H. Hakobyanm, Friedrich Klein, P. Collins, I. Niculescu, D. P. Watts, Brian Raue, K. P. Adhikari, D. J. Tedeschi, D. P. Weygand, B. Morrison, V. P. Kubarovsky, V. Crede, T. Mineeva, D. Branford, M. Bellis, F. Sabatié, M. S. Saini, O. Pogorelko, D. Schott, R. A. Schumacher, M. Mirazita, A. El Alaoui, Y. Ilieva, J. W. Price, P. Khetarpal, P. Nadel-Turonski, H. Moutarde, A. Fradi, J. P. Ball, Y. Prok, B. Vernarsky, Michael Dugger, S. Dhamija, D. S. Carman, M. Y. Gabrielyan, N. Hassall, C. Hanretty, A. I. Ostrovidov, K. Park, S. L. Careccia, R. W. Gothe, Sergey Kuleshov, V. Kuznetsov, J. T. Goetz, H. S. Jo, E. Seder, A. D'Angelo, D. G. Ireland, W. J. Briscoe, E. Pasyuk, K. L. Giovanetti, S. Niccolai, B. Moreno, K. Livingston, M. Guidal, Larry Weinstein, C. Djalali, Volker D. Burkert, M. Battaglieri, A. S. Biselli, N. Dashyan, R. Dickson, D. Keller, K. A. Griffioen, B. L. Berman, G. Rosner, J. McAndrew, E. Voutier, Avraham Klein, Michael Wood, M. Holtrop, Barry Ritchie, A. Daniel, K. Hafidi, M. Khandaker, S. Park, G. Ricco, S. Tkachenko, D. Sokhan, P. Rossi, M. Ripani, M. Osipenko, M. E. McCracken, M. F. Vineyard, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, V. Mokeev, P. L. Cole, P. Stoler, B. Dey, A. Deur, W. K. Brooks, K. Hicks, W. Gohn, Lorenzo Zana, M. D. Mestayer, Michael L. Williams, and R. Dupre
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Lambda baryon, Lambda, 7. Clean energy, 01 natural sciences, Baryon, Nuclear physics, Pion, Recoil, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.
Published: 2010

35. Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

Author: D. G. Ireland, M. E. McCracken, C. A. Meyer, and B. Dey
Subjects: Density matrix, Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Meson, FOS: Physical sciences, Elementary particle, 20399 Classical Physics not elsewhere classified, Polarization (waves), Baryon, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Covariant transformation, Nuclear Experiment (nucl-ex), Scalar meson, Nuclear Experiment, Boson
Abstract: The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab., Comment: 11 pages, 2 figures
Published: 2010
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36. Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

Author: Latifa Elouadrhiri, C. A. Meyer, K. P. Adhikari, E. Seder, K. Livingston, N. Dashyan, Y. Prok, H. S. Jo, P. Collins, P. Eugenio, M. Mayer, V. Kuznetsov, S. Niccolai, Daniel S. Carman, M. J. Amaryan, Y. Ilieva, R. G. Fersch, Z. W. Zhao, A. Deur, N. Guler, G. E. Dodge, H. Baghdasaryan, M. Guidal, H. Moutarde, J. Zhang, P. Rossi, P. Konczykowski, J. Salamanca, J. Ball, F. X. Girod, S. Park, Larry Weinstein, H. Seraydaryan, B. Vernarsky, D. Heddle, I. Niculescu, S. Procureur, D. Protopopescu, Michael Vineyard, B. Morrison, D. P. Watts, E. De Sanctis, S. Dhamija, Y. G. Sharabian, D. Martinez, S. Fegan, R. A. Schumacher, V. Crede, S. Stepanyan, R. Dickson, E. Voutier, M. Aghasyan, M. Taiuti, R. W. Gothe, B. Dey, N. Markov, H. Hakobyan, S. Anefalos Pereira, L. Guo, D. Doughty, M. Ungaro, D. Keller, R. Nasseripour, J. W. Price, S. S. Stepanyan, E. Pasyuk, M. R. Niroula, A. El Alaoui, B. A. Raue, M. Y. Gabrielyan, T. A. Forest, P. Nadel-Turonski, B. Zhao, S. Tkachenko, G. Ricco, Philip L. Cole, Avraham Klein, M. Ripani, T. Mineeva, S. S. Jawalkar, M. S. Saini, G. Rosner, G. Gavalian, D. J. Tedeschi, Friedrich Klein, I. Bedlinskiy, P. Bosted, E. Munevar, B. Moreno, M. Mirazita, M. Holtrop, C. Salgado, A. Daniel, Chaden Djalali, D. G. Crabb, S. E. Kuhn, M. E. McCracken, M. Anghinolfi, L. Casey, K. Moriya, N. Hassall, C. Hanretty, Y. Perrin, F. Sabatié, W. J. Briscoe, Victor Mokeev, K. Joo, K. L. Giovanetti, S. V. Kuleshov, H. Y. Lu, D. P. Weygand, M. Battaglieri, M. Osipenko, W. Kim, G. Niculescu, A. I. Ostrovidov, K. Park, D. G. Ireland, P. Khetarpal, Volker D. Burkert, A. S. Biselli, A. Fradi, R. De Vita, R. Suleiman, S. Pisano, K.H. Hicks, D. I. Sober, P. Stoler, K. A. Griffioen, S. Strauch, R. Paremuzyan, Gerard Gilfoyle, D. Sokhan, B. McKinnon, D. Branford, N. Gevorgyan, H. Avakian, W. K. Brooks, V. P. Kubarovsky, Annalisa D'Angelo, J. McAndrew, Michael Wood, K. Hafidi, E. L. Isupov, W. Gohn, R. Dupre, O. Pogorelko, M. Khandaker, 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, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), 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), Institut de Physique Nucléaire d'Orsay (IPNO), 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), CLAS, 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), and 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)
Subjects: Particle physics, Meson, DRELL-YAN, Hadron, General Physics and Astronomy, FOS: Physical sciences, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, DEPENDENCE, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], SCATTERING, DISTRIBUTIONS, Nuclear Experiment (nucl-ex), 010306 general physics, FINAL-STATE INTERACTIONS, TRANSVERSE-MOMENTUM, AZIMUTHAL ASYMMETRIES, DRELL-YAN, SCATTERING, DISTRIBUTIONS, QUARK, DEPENDENCE, CLAS, QCD, Nuclear Experiment, Spin-½, Physics, FINAL-STATE INTERACTIONS, 010308 nuclear & particles physics, QUARK, TRANSVERSE-MOMENTUM, Deep inelastic scattering, AZIMUTHAL ASYMMETRIES, QCD, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, Lepton
Abstract: We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes phi have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q(2). A significant nonzero sin2 phi single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.
Published: 2010

37. 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

38. Differential cross sections and spin density matrix elements for the reactionγp→pω

Author: V. Crede, Gerard Gilfoyle, K. Park, H. Hakobyan, D. Sokhan, S. S. Stepanyan, D. J. Tedeschi, B. McKinnon, I. Bedlinskiy, Barry Ritchie, Y. Perrin, W. Gohn, V. Kuznetsov, S. Niccolai, C. Djalali, M. Mirazita, S. Fegan, N. Gevorgyan, C. Bookwalter, S. Strauch, D. Applegate, S. L. Careccia, P. Nadel-Turonski, I. I. Strakovsky, A. Deur, M. Guidal, M. Holtrop, F. Sabatié, Y. Ilieva, E. Voutier, S. Procureur, Michael Dugger, K. A. Griffioen, W. K. Brooks, A. Daniel, K. L. Giovanetti, Latifa Elouadrhiri, Kei Moriya, C. A. Meyer, E. De Sanctis, Larry Weinstein, S. Park, G. V. Fedotov, D. Doughty, H. S. Jo, Z. Krahn, E. Golovatch, D. I. Sober, G. Ricco, B. L. Berman, K. P. Adhikari, B. Zhao, D. P. Weygand, H. Baghdasaryan, P. Rossi, A. I. Ostrovidov, C. Salgado, Sergey Kuleshov, F. X. Girod, J. Salamanca, D. G. Ireland, B. Moreno, M. Y. Gabrielyan, S. S. Jawalkar, K. Livingston, Volker D. Burkert, B. Morrison, Elton Smith, A. S. Biselli, R. Dickson, J. P. Ball, D. S. Carman, P. Eugenio, Friedrich Klein, M. Anghinolfi, M. Taiuti, N. Hassall, M. Bellis, Brian Raue, J. W. Price, H. Seraydaryan, A. Fradi, D. Keller, S. Dhamija, S. Tkachenko, Y. G. Sharabian, R. W. Gothe, P. Collins, M. Ripani, S. Pisano, E. Munevar, M. Khandaker, Martin K. Mayer, B. S. Ishkhanov, M. S. Saini, R. Dupre, M. Battaglieri, D. Protopopescu, R. De Vita, S. Pozdniakov, M. Garçon, M. R. Niroula, Michael Vineyard, M. Paris, R. A. Schumacher, S. Anefalos Pereira, E. L. Isupov, Avraham Klein, Michael L. Williams, G. E. Dodge, H. Y. Lu, H. Moutarde, I. Niculescu, R. A. Niyazov, D. Schott, L. Guo, D. P. Watts, M. Ungaro, K. Joo, J. Zhang, C. Hanretty, J. R. Johnstone, V. P. Kubarovsky, O. Pogorelko, W. J. Briscoe, E. Pasyuk, G. Rosner, A. El Alaoui, J. McAndrew, Michael Wood, K. Hafidi, P. Stoler, A. D'Angelo, B. Dey, M. E. McCracken, K. Hicks, K. Mikhailov, W. Kim, P. L. Cole, G. Niculescu, P. Khetarpal, C. S. Nepali, V. Mokeev, and M. Osipenko
Subjects: Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Elementary particle, Omega baryon, 01 natural sciences, Omega, Nuclear physics, Baryon, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Energy (signal processing)
Abstract: High-statistics differential cross sections and spin-density matrix elements for the reaction {gamma}p{yields}p{omega} have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos{theta}{sub c.m.}{sup {omega}} bins of width 0.1. These are the most precise and extensive {omega} photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.
Published: 2009

39. Differential cross sections for the reactionsγp→pηandγp→pη'

Author: G. E. Dodge, H. Y. Lu, J. Salamanca, R. De Vita, B. Morrison, E. Munevar, A. I. Ostrovidov, K. Park, B. S. Ishkhanov, I. Niculescu, R. A. Niyazov, G. Rosner, D. Applegate, D. G. Ireland, Volker D. Burkert, V. Kuznetsov, S. Anefalos Pereira, D. Schott, A. S. Biselli, D. Keller, Z. Krahn, Michael Vineyard, F. X. Girod, W. Kim, P. L. Cole, M. R. Niroula, G. Niculescu, J. McAndrew, N. Hassall, M. Bellis, V. Crede, M. Guidal, C. Djalali, Michael Wood, K. Hafidi, M. Khandaker, K. Mikhailov, M. E. McCracken, P. Khetarpal, A. Fradi, S. Niccolai, C. S. Nepali, S. Strauch, M. Holtrop, Gerard Gilfoyle, J. W. Price, F. Sabatié, E. De Sanctis, D. Sokhan, D. P. Watts, V. P. Kubarovsky, D. Doughty, I. I. Strakovsky, D. I. Sober, H. Hakobyan, A. Deur, O. Pogorelko, P. Stoler, H. S. Jo, Barry Ritchie, A. Daniel, A. D'Angelo, J. Zhang, B. Dey, P. Nadel-Turonski, C. Salgado, B. McKinnon, W. K. Brooks, S. Pisano, R. A. Schumacher, K. Hicks, L. Guo, M. Ungaro, Y. Perrin, M. Osipenko, D. J. Tedeschi, P. Eugenio, M. Y. Gabrielyan, W. J. Briscoe, E. Pasyuk, M. Mirazita, M. Taiuti, B. L. Berman, K. A. Griffioen, G. Ricco, E. Golovatch, I. Bedlinskiy, S. Park, S. L. Careccia, K. Livingston, Sergey Kuleshov, K. Joo, R. Dickson, P. Rossi, K. L. Giovanetti, Larry Weinstein, Avraham Klein, P. Collins, N. Guler, Friedrich Klein, D. Pieschacon, T. Mineeva, Brian Raue, W. Gohn, S. S. Stepanyan, V. Mokeev, S. Dhamija, Latifa Elouadrhiri, Kei Moriya, C. Hanretty, A. El Alaoui, C. A. Meyer, Y. Ilieva, R. W. Gothe, J. R. Johnstone, R. Dupre, M. Battaglieri, K. P. Adhikari, D. P. Weygand, E. L. Isupov, Michael L. Williams, B. Zhao, D. Protopopescu, S. Pozdniakov, M. Garçon, S. S. Jawalkar, S. Procureur, J. P. Ball, Y. Prok, D. S. Carman, E. Voutier, H. Baghdasaryan, S. Fegan, C. Bookwalter, Michael Dugger, S. Tkachenko, M. Ripani, Elton Smith, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, and M. S. Saini
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Elementary particle, 7. Clean energy, 01 natural sciences, Baryon, Nuclear physics, Isospin, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Boson
Abstract: High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.
Published: 2009

40. Photodisintegration ofHe4intop+t

Author: A. I. Ostrovidov, K. Park, G. E. Dodge, H. Y. Lu, Volker D. Burkert, K. Livingston, A. S. Biselli, R. Dickson, L. Guo, G. Rosner, R. Fersch, M. Ungaro, I. Niculescu, A. Fradi, M. Osipenko, R. Dupre, S. Pisano, M. Battaglieri, E. De Sanctis, C. E. Hyde, R. Nasseripour, Marco Ripani, C. Djalali, D. I. Sober, B. McKinnon, K. A. Griffioen, B. Zhao, D. P. Watts, E. Wolin, V. Kuznetsov, D. Branford, A. Deur, J. M. Laget, W. J. Briscoe, E. Pasyuk, P. L. Cole, P. Ambrozewicz, Paolo Rossi, S. S. Jawalkar, Y. Ilieva, J. P. Ball, Y. Prok, D. S. Carman, W. K. Brooks, S. Procureur, S. Niccolai, M. Y. Gabrielyan, P. Stoler, Friedrich Klein, Z. W. Zhao, R. De Vita, R. A. Schumacher, S. Dhamija, M. J. Amaryan, A. D'Angelo, Brian Raue, B. Dey, Gerard Gilfoyle, K. Hicks, P. Nadel-Turonski, R. W. Gothe, V. P. Kubarovsky, S. Strauch, H. Hakobyan, S. Park, D. Sokhan, B. L. Berman, M. Taiuti, S. Anefalos Pereira, M. E. McCracken, O. Pogorelko, W. Kim, D. J. Tedeschi, R. Suleiman, G. Niculescu, W. Gohn, F. X. Girod, N. Hassall, D. Protopopescu, I. Bedlinskiy, Michael Wood, S. L. Careccia, P. Khetarpal, S. Pozdniakov, P. Collins, S. Fegan, C. S. Nepali, P. Corvisiero, S. Stepanyan, Giovanni Ricco, E. Golovatch, J. W. Price, D. G. Ireland, E. Munevar, C. Bookwalter, Avraham Klein, N. Dashyan, F. Sabatié, M. R. Niroula, H. Baghdasaryan, K. L. Giovanetti, K. Joo, J. Salamanca, Larry Weinstein, B. Morrison, D. Doughty, T. Mineeva, D. Heddle, C. Salgado, S. Tkachenko, N. Benmouna, D. Keller, E. L. Isupov, Michael L. Williams, M. Khandaker, S. E. Kuhn, Michael Vineyard, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, M. S. Saini, J. T. Goetz, M. Mirazita, S. S. Stepanyan, Sergey Kuleshov, M. Guidal, A. Daniel, Barry Ritchie, Kei Moriya, G. V. Fedotov, K. P. Adhikari, D. P. Weygand, J. Zhang, C. Hanretty, Victor Mokeev, and J. R. Johnstone
Subjects: Nuclear physics, Nuclear reaction, Physics, Nuclear and High Energy Physics, Proton, Photodisintegration, Helium-3, Hadron, Bremsstrahlung, Nucleon, Isotopes of helium
Abstract: The two-body photodisintegration of {sup 4}He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid {sup 4}He target. This is the first measurement of the photodisintegration of {sup 4}He above 0.4 GeV. The differential cross sections for the {gamma}{sup 4}He{yields}pt reaction were measured as a function of photon-beam energy and proton-scattering angle and are compared with the latest model calculations by J.-M. Laget. At 0.6-1.2 GeV, our data are in good agreement only with the calculations that include three-body mechanisms, thus confirming their importance. These results reinforce the conclusion of our previous study of the three-body breakup of {sup 3}He that demonstrated the great importance of three-body mechanisms in the energy region 0.5-0.8 GeV.
Published: 2009

41. Measurement of the Differential Cross Section for the Reactionγn→π−pfrom Deuterium

Author: S. Park, M. J. Amaryan, D. P. Watts, H. Egiyan, S. L. Careccia, M. Ungaro, P. Rossi, K. L. Giovanetti, Larry Weinstein, C. Djalali, Michael Wood, B. S. Ishkhanov, D. Keller, A. Yegneswaran, M. Battaglieri, P. Eugenio, M. R. Niroula, M. Khandaker, S. Tkachenko, M. E. McCracken, W. Gohn, Tsutomu Mibe, M. Taiuti, M. Ripani, K. Hicks, S. E. Kuhn, W. J. Briscoe, S. Strauch, W. Kim, W. Chen, J. Salamanca, D. Doughty, D. Heddle, G. Ricco, T. Mineeva, Dipangkar Dutta, J. Zhang, P. Khetarpal, P. Collins, Y. Ilieva, D. Protopopescu, P. Nadel-Turonski, V. Crede, L. Casey, N. Hassall, M. Bellis, R. Nasseripour, S. Pozdniakov, M. Garçon, I. I. Strakovsky, C. Hanretty, A. Deur, Friedrich Klein, M. Osipenko, V. P. Kubarovsky, F. Sabatié, W. K. Brooks, O. Pogorelko, K. A. Griffioen, Brian Raue, J. R. Johnstone, R. De Vita, V. Kuznetsov, S. Procureur, Barry Ritchie, P. L. Cole, M. Anghinolfi, V. Mokeev, B. L. Berman, Kei Moriya, S. Anefalos Pereira, C. A. Meyer, G. V. Fedotov, C. E. Hyde, Y. G. Sharabian, D. P. Weygand, E. De Sanctis, D. I. Sober, M. S. Saini, S. Niccolai, H. Hakobyan, D. J. Tedeschi, B. Moreno, K. Livingston, R. Dickson, R. A. Schumacher, G. Rosner, S. Stepanyan, Avraham Klein, G. E. Dodge, H. Y. Lu, I. Niculescu, K. Joo, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, B. Zhao, A. S. Biselli, Laird Kramer, Sergey Kuleshov, D. S. Carman, F. X. Girod, Haiyan Gao, J. W. Price, N. Dashyan, A. Fradi, N. Markov, S. S. Stepanyan, S. Dhamija, R. W. Gothe, H. Bagdasaryan, Gerard Gilfoyle, Michael Vineyard, M. Guidal, D. Sokhan, M. Holtrop, A. Daniel, B. McKinnon, D. Branford, C. Bookwalter, M. Mirazita, J. M. Laget, H. S. Jo, C. Salgado, and E. L. Isupov
Subjects: Massless particle, Physics, Particle physics, Pion, Meson, Photodisintegration, Hadron, General Physics and Astronomy, High Energy Physics::Experiment, Elementary particle, Nuclear Experiment, Energy (signal processing), Boson
Abstract: We report a measurement of the differential cross section for the $$\gamma n \to \pi^- p$$ process from the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles ($$\theta_{c.m.}$$) between 50$$^\circ$$ and 115$$^\circ$$. We confirm a previous indication of a broad enhancement around a c.m. energy ($$\sqrt{s}$$) of 2.2 GeV at $$\theta_{c.m.}=90^\circ$$ in the scaled differential cross section, $$s^7 {\frac{d\sigma}{dt}}$$. Our data show the angular dependence of this enhancement as the scaling region is approached in the kinematic region from 70$$^\circ$$ to 105$$^\circ$$.
Published: 2009

42. π+photoproduction on the proton for photon energies from 0.725 to 2.875 GeV

Author: W. Kim, P. Khetarpal, S. Tkachenko, G. Rosner, V. Mokeev, F. X. Girod, A. Fradi, E. L. Isupov, R. De Vita, K. Joo, C. Hanretty, P. Eugenio, Gerard Gilfoyle, J. R. Johnstone, J. P. Ball, S. S. Stepanyan, E. Pasyuk, B. L. Berman, D. Doughty, D. Sokhan, M. Taiuti, S. Anefalos Pereira, Michael Vineyard, B. McKinnon, D. Heddle, D. S. Carman, H. Bagdasaryan, M. Osipenko, O. Pogorelko, J. W. Price, D. P. Watts, R. A. Schumacher, H. Hakobyan, M. Ripani, G. Ricco, D. Branford, Chaden Djalali, V. P. Kubarovsky, Michael Dugger, Y. Ilieva, J. Salamanca, K. L. Giovanetti, E. De Sanctis, B. Moreno, B. S. Ishkhanov, S. Dhamija, R. W. Gothe, K. Livingston, S. Park, D. J. Tedeschi, D. I. Sober, R. Dickson, Friedrich Klein, D. Keller, Brian Raue, M. R. Niroula, P. Collins, F. Sabatié, Sergey Kuleshov, W. J. Briscoe, D. G. Ireland, V. Crede, S. Stepanyan, Avraham Klein, V. Kuznetsov, M. Khandaker, A. Yegneswaran, A. I. Ostrovidov, M. Guidal, P. Rossi, I. I. Strakovsky, G. E. Dodge, H. Y. Lu, Michael Wood, K. Hafidi, M. Holtrop, D. Protopopescu, A. Daniel, S. Pozdniakov, A. Deur, Volker D. Burkert, A. S. Biselli, M. J. Amaryan, S. Niccolai, S. L. Careccia, W. K. Brooks, I. Niculescu, Larry Weinstein, Laird Kramer, W. Gohn, P. Corvisiero, K. Hicks, M. Battaglieri, M. E. McCracken, K. A. Griffioen, C. Bookwalter, R. Nasseripour, R. A. Arndt, P. Nadel-Turonski, S. Procureur, Ron L. Workman, P. L. Cole, S. Strauch, N. Dashyan, N. Hassall, M. Bellis, Barry Ritchie, Kei Moriya, C. A. Meyer, G. V. Fedotov, D. P. Weygand, C. Salgado, Charles Hyde, M. S. Saini, M. Mirazita, J. R. Ficenec, M. Anghinolfi, and Y. G. Sharabian
Subjects: Physics, Nuclear physics, Massless particle, Baryon, Nuclear and High Energy Physics, Particle physics, Pion, Proton, Meson, Hadron, Elementary particle, Nuclear Experiment, Nucleon
Abstract: Differential cross sections for the reaction $$\gamma p \to n \pi^+$$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID and MAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the world data set, significant changes have occurred in the high-energy behavior of the SAID cross-section predictions and amplitudes.
Published: 2009

43. Beam-recoil polarization transfer in the nucleon resonance region in the exclusivee→p→e'K+Λ→ande→p→e'K+Σ→0reactions at the CLAS spectrometer

Author: M. J. Amaryan, W. Kim, K. L. Giovanetti, P. Khetarpal, M. Holtrop, H. Hakobyan, M. Bellis, R. A. Schumacher, A. Fradi, A. Daniel, M. Ungaro, N. Dashyan, P. Eugenio, D. Protopopescu, D. J. Tedeschi, S. Dhamija, W. J. Briscoe, S. Stepanyan, D. I. Sober, Barry Ritchie, T. Mineeva, J. W. Price, D. Sayre, Y. Ilieva, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, E. De Sanctis, R. W. Gothe, M. E. McCracken, S. Park, V. Mokeev, S. Niccolai, V. Kuznetsov, K. Mikhailov, F. X. Girod, G. Ricco, J. Zhang, Michael Wood, B. Zhao, G. Rosner, D. Branford, G. V. Fedotov, M. Taiuti, P. Nadel-Turonski, G. E. Dodge, V. Crede, M. Y. Gabrielyan, Atilla Gonenc, Michael Vineyard, M. Osipenko, K. P. Adhikari, C. Hanretty, S. S. Stepanyan, E. Pasyuk, K. Moriya, N. Hassall, W. Gohn, J. R. Johnstone, V. P. Kubarovsky, P. L. Cole, M. Ripani, H. S. Jo, M. R. Niroula, K. Hicks, S. Strauch, D. Schott, A. Deur, D. Sokhan, B. Moreno, O. Pogorelko, R. De Vita, W. K. Brooks, K. Livingston, M. Battaglieri, Brian Raue, P. Collins, P. Rossi, Maryam Moteabbed, E. Wolin, Chaden Djalali, D. S. Carman, H. Baghdasaryan, S. Fegan, F. Sabatié, C. Bookwalter, S. Tkachenko, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, C. Salgado, Martin K. Mayer, C. A. Meyer, M. S. Saini, and M. Mirazita
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, Momentum transfer, Lambda baryon, Sigma baryon, Nuclear physics, Baryon, Recoil, Pair production, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract: Beam-recoil transferred polarizations for the exclusive $$\vec{e}p \to e'K^+ \vec{\Lambda},\vec{\Sigma}^0$$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754~GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4~GeV$^2$, invariant energy $W$ from 1.6 to 2.6~GeV, and the full center-of-mass angular range of the $K^+$ meson. These new data add to the existing CLAS $$K^+\Lambda$$ measurements at 2.567~GeV, and provide the first-ever data for the $$K^+\Sigma^0$$ channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to $s$-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the $$s\bar{s}$$ quark-pair creation dynamics.
Published: 2009

44. Precise Measurement of the Neutron Magnetic Form FactorGMnin the Few-GeV2Region

Author: R. J. Feuerbach, J. P. Cummings, L. C. Smith, E. Munevar, R. De Masi, D. Keller, M. Kossov, B. S. Ishkhanov, I. Popa, K. S. Egiyan, G. Ricco, K. Mikhailov, L. Cheng, M. Khandaker, M. Garçon, J. Shaw, Michael Wood, P. Nadel-Turonski, Nikolay Shvedunov, M. R. Niroula, K. Hafidi, R. Nasseripour, S. McAleer, Friedrich Klein, B. P. Quinn, Brian Raue, V. S. Serov, L. Casey, F. X. Girod, Susan Taylor, Marco A. Huertas, M. Lowry, V. Sapunenko, D. P. Watts, L. C. Dennis, B. E. Bonner, Hartmuth Arenhövel, Dinko Pocanic, H. Egiyan, R. G. Fersch, H. Avakian, D. Doughty, B. B. Niczyporuk, G. S. Adams, S. Park, D. Sharov, N. Kalantarians, P. L. Cole, Sylvain Bouchigny, Sabine Jeschonnek, R. C. Minehart, Kei Moriya, D. Heddle, P. Rossi, J. Lachniet, H. G. Juengst, C. A. Meyer, N. Pivnyuk, K. Joo, W. J. Briscoe, B. L. Berman, A. Tkabladze, G. V. Fedotov, E. Pasyuk, D. Rowntree, A. Coleman, L. M. Qin, M. Y. Gabrielyan, S. E. Kuhn, S. A. Dytman, V. Crede, Y. Ilieva, J. R. Calarco, T. Mineeva, J. W. Price, M. J. Amaryan, C. Paterson, S. Strauch, M. MacCormick, A.V. Stavinsky, M. Klusman, I. Hleiqawi, V. P. Kubarovsky, K. P. Adhikari, S. L. Careccia, A. Empl, L. El Fassi, O. Pogorelko, B. Moreno, D. P. Weygand, J. Salamanca, R. Suleiman, M. E. McCracken, Elton Smith, K. L. Giovanetti, B. Asavapibhop, G. V. O'Rielly, Tsutomu Mibe, Larry Weinstein, Z. W. Zhao, J. W C McNabb, D. J. Tedeschi, D. Protopopescu, D. G. Jenkins, Barry Ritchie, M. Anghinolfi, James Mueller, S. Malace, S. A. Morrow, P. Rubin, I. Bedlinskiy, G. S. Mutchler, Konstantin Stopani, S. Pozdniakov, V. Gyurjyan, M. M. Ito, C. Djalali, Y. G. Sharabian, G. Rosner, T. Kageya, K. Livingston, D. S. Dale, X. Wei, R. Dickson, V. Kuznetsov, C. E. Hyde-Wright, H. Denizli, N. Guler, N. A. Baltzell, P. Mattione, K. A. Griffioen, M. S. Saini, A. V. Skabelin, P. Dragovitsch, J. Zhang, S. Barrow, E. De Sanctis, S. Niccolai, J. T. Goetz, E. Polli, H. Bagdasaryan, R. A. Miskimen, J. D. Kellie, B. McKinnon, Sergey Kuleshov, M. Bektasoglu, J. Hardie, M. Nozar, W. Kim, Laird Kramer, G. Niculescu, D. I. Sober, D. Branford, M. Guidal, R. A. Schumacher, H. Hakobyan, M. Mirazita, P. Khetarpal, C. Hanretty, J. M. Laget, M. Holtrop, Victor Mokeev, L. Graham, J. R. Johnstone, N. Gevorgyan, L. Guo, M. Ungaro, M. Osipenko, F. Sabatié, A. Daniel, K. Beard, Kalvir S. Dhuga, S. Bültmann, A. I. Ostrovidov, J. Yun, D. Cords, V. Batourine, T. A. Forest, A. Yegneswaran, A. C S Lima, A. Sandorfi, K. Park, R. Fatemi, S. Stepanyan, A. V. Vlassov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, J. Pierce, Avraham Klein, B. Zhao, J. Langheinrich, R. De Vita, A. Fradi, S. S. Stepanyan, S. A. Philips, William Brooks, N. Markov, P. Konczykowski, B. E. Stokes, J. J. Manak, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, N. Dashyan, Maryam Moteabbed, P. V. Degtyarenko, K. V. Dharmawardane, I. Niculescu, D. Lawrence, D. Schott, F. W. Hersman, M. Battaglieri, N. Baillie, P. Stoler, K. Hicks, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, R. Bradford, B. A. Mecking, K. Lukashin, E. Wolin, Gerard Gilfoyle, M. Guillo, D. Sokhan, W. Gohn, N. Hassall, M. Bellis, E. Golovatch, J. P. Ball, J. Hu, Y. Prok, D. S. Carman, S. Dhamija, M. D. Mestayer, L. Elouadrhiri, I. I. Strakovsky, E. L. Isupov, R. W. Gothe, G. Gavalian, S. Tkachenko, A. Deur, Michael L. Williams, J. Kuhn, N. Benmouna, J. P. Santoro, Andrei Afanasev, M. Ripani, D. G. Crabb, K. Y. Kim, Roy Thompson, Cynthia Marie Hadjidakis, S. Boiarinov, Michael Dugger, B. M. Preedom, Douglas Higinbotham, M. Yurov, Lorenzo Zana, H. S. Jo, C. Bookwalter, C. Salgado, Kwangsoo Kim, G. Riccardi, P. Eugenio, A. Starostin, M. Taiuti, Michael Vineyard, and P. Collins
Subjects: Physics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, General Physics and Astronomy, Scintillator, 7. Clean energy, 01 natural sciences, Nuclear physics, Dipole, Deuterium, 0103 physical sciences, Magnetic form factor, Neutron detection, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Electron scattering
Abstract: The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.
Published: 2009

45. Measurement of Directf0(980)Photoproduction on the Proton

Author: S. Park, Sylvain Bouchigny, V. Crede, J. R. Calarco, E. Wolin, C. E. Hyde, R. A. Schumacher, V. Sapunenko, Dinko Pocanic, P. Nadel-Turonski, L. Casey, V. Mokeev, D. Lawrence, J. P. Cummings, H. G. Juengst, B. E. Stokes, Cynthia Marie Hadjidakis, J. P. Ball, D. S. Carman, A. Fradi, A. V. Vlassov, P. Konczykowski, M. J. Amaryan, S. Dhamija, Michael Dugger, K. Livingston, D. S. Dale, T. Lee, Maryam Moteabbed, M. Kossov, S. E. Kuhn, L. Graham, Ashot Gasparian, B. B. Niczyporuk, C. I O Gordon, M. MacCormick, R. W. Gothe, Z. W. Zhao, R. Dickson, N. Gevorgyan, T. Kageya, H. Avakian, I. Hleiqawi, K. V. Dharmawardane, A.V. Stavinsky, J. Donnelly, G. Asryan, N. Pivnyuk, D. G. Crabb, J. Kuhn, M. E. McCracken, R. De Vita, S. Strauch, E. Clinton, S. Bültmann, S. L. Careccia, D. G. Jenkins, O. P. Dzyubak, D. P. Watts, H. Egiyan, Gerard Gilfoyle, G. Ricco, Lorenzo Zana, J. P. Santoro, C. Tur, L. Gan, Tsutomu Mibe, W. Gohn, T. A. Forest, D. J. Tedeschi, N. Markov, D. Sokhan, D. Sharov, W. Kim, S. Anefalos Pereira, S. Stepanyan, G. Niculescu, M. Yurov, J. Goett, R. A. Miskimen, I. Bedlinskiy, B. McKinnon, M. Y. Gabrielyan, J. Pierce, K. L. Giovanetti, F. X. Girod, Sergey Kuleshov, Avraham Klein, Shifeng Chen, N. Guler, E. Golovatch, Friedrich Klein, Larry Weinstein, N. A. Baltzell, G. E. Dodge, P. Khetarpal, K. A. Stopani, Brian Raue, D. Keller, H. Y. Lu, M. Nozar, D. Branford, J. Salamanca, H. S. Jo, C. Bookwalter, E. De Sanctis, L. Lesniak, G. Riccardi, J. M. Laget, V. V. Mochalov, P. Mattione, K. A. Griffioen, M. Aghasyan, X. Wei, V. Kuznetsov, M. S. Saini, P. V. Degtyarenko, A. I. Ostrovidov, D. I. Sober, A. Sandorfi, K. Park, P. Eugenio, Adam P. Szczepaniak, V. Batourine, C. Hanretty, A. Starostin, M. Guidal, N. Dashyan, M. Taiuti, W. J. Briscoe, E. Pasyuk, H. Hakobyan, S. A. Morrow, G. Rosner, J. T. Goetz, M. Mirazita, C. Djalali, Paolo Rossi, M. Khandaker, L. Bibrzycki, I. Niculescu, J. Lachniet, A. Tkabladze, Y. Ilieva, J. W. Price, M. Holtrop, R. A. Niyazov, Elton Smith, D. G. Ireland, A. Daniel, A. Teymurazyan, I. I. Strakovsky, G. Gavalian, N. Hassall, M. Bellis, P. Ambrozewicz, P. Collins, B. Zhao, R. De Masi, S. Tkachenko, D. Schott, M. Ripani, D. Doughty, P. Stoler, J. J. Melone, S. Niccolai, Z. Krahn, Volker D. Burkert, A. S. Biselli, M. Anghinolfi, C. Salgado, N. Benmouna, J. Langheinrich, S. S. Stepanyan, D. Heddle, J. D. Kellie, A. Deur, N. Baillie, T. Mineeva, S. Malace, Mark W. Paris, J. R. Johnstone, Hall Crannell, M. Osipenko, V. P. Kubarovsky, Y. G. Sharabian, Laird Kramer, L. Cheng, W. K. Brooks, J. Hardie, F. W. Hersman, R. S. Hakobyan, L. Guo, M. Ungaro, B. Moreno, O. Pogorelko, G. S. Mutchler, K. Hicks, Nikolay Shvedunov, D. Protopopescu, B. L. Berman, K. S. Egiyan, L. El Fassi, S. Pozdniakov, M. Garçon, Michael Wood, K. Mikhailov, K. Hafidi, V. S. Serov, M. Battaglieri, N. Kalantarians, R. Bradford, B. A. Mecking, R. Nasseripour, K. Joo, A. Yegneswaran, Michael Vineyard, V. Gyurjyan, J. Zhang, H. Bagdasaryan, L. Todor, R. G. Fersch, C. Paterson, Ji Li, P. L. Cole, M. D. Mestayer, E. L. Isupov, Michael L. Williams, M. M. Ito, S. Boiarinov, F. Sabatié, L. C. Smith, E. Munevar, B. S. Ishkhanov, M. R. Niroula, M. Lowry, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, K. P. Adhikari, D. P. Weygand, O. Glamazdin, Alexei V. Klimenko, Y. Prok, Barry Ritchie, and I. Nakagawa
Subjects: Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, General Physics and Astronomy, Resonance, 01 natural sciences, 7. Clean energy, Nuclear physics, Particle decay, Pion, 0103 physical sciences, 010306 general physics, Nucleon
Abstract: We report on the results of the first measurement of exclusive f{sub 0}(980) meson photoproduction on protons for E{sub {gamma}}=3.0-3.8 GeV and -t=0.4-1.0 GeV{sup 2}. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the {pi}{sup +}{pi}{sup -} channel by performing a partial wave analysis of the reaction {gamma}p{yields}p{pi}{sup +}{pi}{sup -}. Clear evidence of the f{sub 0}(980) meson was found in the interference between P and S waves at M{sub {pi}{sup +}}{sub {pi}{sup -}}{approx}1 GeV. The S-wave differential cross section integrated in the mass range of the f{sub 0}(980) was found to be a factor of about 50 smaller than the cross section for the {rho} meson. This is the first time the f{sub 0}(980) meson has been measured in a photoproduction experiment.
Published: 2009

46. Measurement of the differential cross section for the reaction gamman--pi- p from deuterium

Author: W, Chen, T, Mibe, D, Dutta, H, Gao, J M, Laget, M, Mirazita, P, Rossi, S, Stepanyan, I I, Strakovsky, M J, Amaryan, M, Anghinolfi, H, Bagdasaryan, M, Battaglieri, M, Bellis, B L, Berman, A S, Biselli, C, Bookwalter, D, Branford, W J, Briscoe, W K, Brooks, V D, Burkert, S L, Careccia, D S, Carman, L, Casey, P L, Cole, P, Collins, V, Crede, A, Daniel, N, Dashyan, R, De Vita, E, De Sanctis, A, Deur, S, Dhamija, R, Dickson, C, Djalali, G E, Dodge, D, Doughty, H, Egiyan, P, Eugenio, G, Fedotov, A, Fradi, M, Garçon, G P, Gilfoyle, K L, Giovanetti, F X, Girod, W, Gohn, R W, Gothe, K A, Griffioen, M, Guidal, H, Hakobyan, C, Hanretty, N, Hassall, D, Heddle, K, Hicks, M, Holtrop, C E, Hyde, Y, Ilieva, D G, Ireland, B S, Ishkhanov, E L, Isupov, H S, Jo, J R, Johnstone, K, Joo, D, Keller, M, Khandaker, P, Khetarpal, W, Kim, A, Klein, F J, Klein, L H, Kramer, V, Kubarovsky, S E, Kuhn, S V, Kuleshov, V, Kuznetsov, K, Livingston, H Y, Lu, N, Markov, M E, McCracken, B, McKinnon, C A, Meyer, T, Mineeva, V, Mokeev, B, Moreno, K, Moriya, P, Nadel-Turonski, R, Nasseripour, S, Niccolai, I, Niculescu, M R, Niroula, M, Osipenko, A I, Ostrovidov, K, Park, S, Park, S Anefalos, Pereira, O, Pogorelko, S, Pozdniakov, J W, Price, S, Procureur, D, Protopopescu, B A, Raue, G, Ricco, M, Ripani, B G, Ritchie, G, Rosner, F, Sabatié, M S, Saini, J, Salamanca, C, Salgado, R A, Schumacher, Y G, Sharabian, D I, Sober, D, Sokhan, S S, Stepanyan, S, Strauch, M, Taiuti, D J, Tedeschi, S, Tkachenko, M, Ungaro, M F, Vineyard, D P, Watts, L B, Weinstein, D P, Weygand, M H, Wood, A, Yegneswaran, J, Zhang, and B, Zhao
Abstract: We report a measurement of the differential cross section for the gamman--pi- p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (thetac.m.) between 50 degrees and 115 degrees. We confirm a previous indication of a broad enhancement around a c.m. energy ([sqrt]s) of 2.1 GeV at thetac.m.=90 degrees in the scaled differential cross section s7dsigma/dt and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for thetac.m. from 70 degrees to 105 degrees.
Published: 2009

47. Electroproduction ofpπ+π−off protons at0.2<Q2<0.6GeV2and1.3<W<1.57GeV with the CLAS detector

Author: P. Stoler, N. A. Baltzell, V. Crede, K. Hicks, J. R. Calarco, K. A. Griffioen, K. S. Egiyan, J. D. Kellie, C. Paterson, H. Denizli, S. Strauch, M. Klusman, M. Guidal, J. W C McNabb, K. Livingston, Nikolay Shvedunov, G. S. Mutchler, R. Dickson, Shifeng Chen, M. Osipenko, M. Holtrop, G. E. Dodge, V. Gyurjyan, P. Eugenio, P. V. Degtyarenko, Laird Kramer, J. Donnelly, G. Asryan, C. E. Hyde, O. P. Dzyubak, M. Taiuti, Marco A. Huertas, G. Rosner, T. Mineeva, J. Zhang, N. Guler, F. X. Girod, J. Langheinrich, I. Niculescu, V. Batourine, B. Carnahan, R. A. Niyazov, E. De Sanctis, Hovhannes Baghdasaryan, Sylvain Bouchigny, L. C. Smith, J. T. Goetz, J. P. Cummings, D. Lawrence, A.V. Stavinsky, B. B. Niczyporuk, P. Corvisiero, L. Guo, P. Rossi, B. S. Ishkhanov, M. Ungaro, R. A. Miskimen, B. McKinnon, H. G. Juengst, Susan Taylor, E. Wolin, D. I. Sober, J. W. Price, Konstantin Stopani, D. J. Tedeschi, V. Sapunenko, N. Pivnyuk, K. Mikhailov, Y. Prok, D. Branford, Dinko Pocanic, M. Mirazita, H. Egiyan, E. Golovatch, William Brooks, J. M. Laget, L. Todor, S. E. Kuhn, R. Fatemi, J. P. Ball, I. Bedlinskiy, Sergey Kuleshov, Rakhsha Nasseripour, Hall Crannell, M. Bektasoglu, A. Yegneswaran, B. E. Stokes, D. Protopopescu, S. Pozdniakov, A. V. Vlassov, K. V. Dharmawardane, D. S. Carman, G. S. Adams, C. Tur, T. Lee, G. Ricco, K. Joo, J. Kuhn, D. G. Jenkins, A. I. Ostrovidov, Roy Thompson, G. V. O'Rielly, K. Park, R. De Vita, R. A. Schumacher, Elton Smith, R. J. Feuerbach, Victor Mokeev, J. Shaw, Y. Ilieva, S. A. Morrow, C. Djalali, G. Niculescu, M. Anghinolfi, Michael Wood, D. G. Ireland, D. G. Crabb, M. D. Mestayer, P. Coltharp, Friedrich Klein, James Mueller, N. Dashyan, S. Bültmann, T. A. Forest, Brian Raue, G. Gavalian, N. Hassall, M. Bellis, M. Guillo, S. Stepanyan, S. Niccolai, M. M. Ito, E. L. Isupov, Volker D. Burkert, J. Pierce, Avraham Klein, A. S. Biselli, P. D. Rubin, J. Hardie, J. Hu, P. Ambrozewicz, M. Battaglieri, V. S. Serov, L. C. Dennis, Michael L. Williams, B. E. Bonner, R. Bradford, B. A. Mecking, S. Tkachenko, N. Benmouna, F. Sabatié, Y. G. Sharabian, H. Avakian, Kwangsoo Kim, C. Butuceanu, M. Ripani, N. Markov, S. Boiarinov, D. Sharov, Cynthia Marie Hadjidakis, Michael Dugger, H. O. Funsten, E. Pasyuk, S. A. Dytman, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, A. Tkabladze, G. V. Fedotov, Michael Vineyard, D. P. Weygand, Alexei V. Klimenko, V. P. Kubarovsky, Barry Ritchie, O. Pogorelko, Lorenzo Zana, J. P. Santoro, H. S. Jo, D. Doughty, C. Salgado, M. E. McCracken, P. Nadel-Turonski, Tsutomu Mibe, M. Khandaker, N. Gevorgyan, Z. Krahn, J. Lachniet, N. Baillie, Gerard Gilfoyle, D. Rowntree, M. J. Amaryan, R. W. Gothe, I. Hleiqawi, K. Y. Kim, S. L. Careccia, P. L. Cole, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, F. W. Hersman, and W. Kim
Subjects: Baryon, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Meson, Hadron, Elementary particle, Invariant mass, Sensitivity (control systems), Nucleon
Abstract: This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep{yields}e{sup '}p{pi}{sup +}{pi}{sup -}. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2
Published: 2009

48. Photoproduction of pi+pi- meson pairs on the proton

Author: A. V. Vlassov, M. J. Amaryan, S. L. Careccia, E. Golovatch, W. Kim, R. De Vita, K. L. Giovanetti, D. Protopopescu, Martin K. Mayer, Larry Weinstein, D. P. Watts, H. Egiyan, S. Pozdniakov, M. Garçon, P. Khetarpal, Lorenzo Zana, G. E. Dodge, H. Y. Lu, Adam P. Szczepaniak, A. D'Angelo, I. Niculescu, C. S. Nepali, J. T. Goetz, K. Livingston, D. S. Dale, H. Hakobyan, L. Gan, M. Battaglieri, E. De Sanctis, Saini, Diane Schott, A. Deur, C. Hanretty, I. Nakagawa, A. I. Ostrovidov, B. Zhao, S. Fegan, D. I. Sober, K. Park, M. Y. Gabrielyan, L. Bibrzycki, A.V. Stavinsky, M. Khandaker, C. Bookwalter, D. G. Ireland, K. Moriya, P. Stoler, D. J. Tedeschi, Volker D. Burkert, A. S. Biselli, E. Wolin, Sergey Kuleshov, M. Osipenko, K. A. Griffioen, D. Doughty, Y. Prok, Gerard Gilfoyle, D. S. Carman, P. Eugenio, M. Taiuti, O. Glamazdin, K. Hicks, I. Bedlinskiy, A. Fradi, A. Gasparian, M. Kossov, Andreas Klein, D. Sokhan, N. Dashyan, J. Goett, B. McKinnon, Mokeev, M. Guidal, Barry Ritchie, Yordanka Ilieva, N. Hassall, M. Bellis, S. Park, K. Mikhailov, W. Gohn, S. Dhamija, D. Branford, S. Pisano, P. Collins, M. Mirazita, A. Teymurazyan, H. Baghdasaryan, R. W. Gothe, Leonard Lesniak, F. Sabatié, P. Rossi, J. M. Laget, Niroula, M. Holtrop, A. Daniel, E. L. Isupov, Crede, SA Pereira, Michael L. Williams, C. A. Meyer, G. V. Fedotov, S. Niccolai, S. Tkachenko, Mark W. Paris, M. Ripani, Carlos A. Salgado, Mochalov, M. Anghinolfi, K. P. Adhikari, Kuznetsov, D. P. Weygand, N. Pivnyuk, Michael Vineyard, C. Djalali, Drozdov, H. Seraydaryan, Y. G. Sharabian, P. L. Cole, Z. W. Zhao, M. E. McCracken, P. Nadel-Turonski, L. Guo, M. Ungaro, K. Joo, S. S. Stepanyan, C. E. Hyde, G. Rosner, J. Zhang, J. W. Price, R. A. Schumacher, G. Ricco, S. Stepanyan, W. J. Briscoe, E. Pasyuk, Brian Raue, Frank Klein, E. Munevar, Dustin Keller, A. Kubarovsky, Johnstone, Strakovsky, E. Clinton, Michael Wood, K. Hafidi, T. Mineeva, O. Pogorelko, Kubarovsky, F. X. Girod, S. Strauch, 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), 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), CLAS, and 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)
Subjects: PI-PI-DYNAMICS, COUPLED-CHANNEL, DIFFRACTION DISSOCIATION, POLARIZED PHOTONS, HIGH-STATISTICS, GEV-C, SYSTEM, MODEL, CLAS, CHAMBER, Nuclear and High Energy Physics, Particle physics, Meson, Proton, PI-PI-DYNAMICS, Photon energy, 01 natural sciences, 7. Clean energy, POLARIZED PHOTONS, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Particle decay, Pion, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Nuclear Experiment, Physics, Luminosity (scattering theory), 010308 nuclear & particles physics, DIFFRACTION DISSOCIATION, Momentum transfer, COUPLED-CHANNEL, HIGH-STATISTICS, GEV-C, SYSTEM, MODEL, CHAMBER, Production (computer science), High Energy Physics::Experiment
Abstract: The exclusive reaction $$\gamma p \to p \pi^+ \pi^-$$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4
Published: 2009

49. Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

Author: L. Guo, M. Ungaro, D. P. Watts, H. Egiyan, L. C. Smith, E. Munevar, B. S. Ishkhanov, R. Nasseripour, R. A. Schumacher, P. Nadel-Turonski, D. Keller, M. E. McCracken, K. L. Giovanetti, S. V. Kuleshov, Daniel S. Carman, A. Deur, Gerard Gilfoyle, M. Y. Gabrielyan, P. Eugenio, O. Pogorelko, J. Zhang, F. X. Girod, V. E. Kuznetsov, H. Seraydaryan, Philip L. Cole, J. Salamanca, M. Khandaker, R. Dupré, Y. Ilieva, D. Sokhan, M. R. Niroula, T. A. Forest, F. Sabatié, Nikolay Shvedunov, Latifa Elouadrhiri, H. S. Jo, C. A. Meyer, B. Morrison, S. Procureur, S. Niccolai, N. Hassall, M. Bellis, A. I. Ostrovidov, K. Park, S. L. Careccia, G. V. Fedotov, B. McKinnon, B. Zhao, Friedrich Klein, J. Ball, Avraham Klein, C. Hanretty, V. Batourine, S. E. Kuhn, E. Golovatch, Charles Hyde, E. L. Isupov, D. G. Ireland, M. Taiuti, S. Park, Victor Mokeev, D. Branford, K. Joo, S. Fegan, S. S. Jawalkar, Volker D. Burkert, A. S. Biselli, Chaden Djalali, M. Osipenko, Inna Aznauryan, M. S. Saini, H. Hakobyan, S. Anefalos Pereira, C. Bookwalter, M. Anghinolfi, D. Heddle, M. Battaglieri, J. T. Goetz, V. Crede, M. Mirazita, J. W. Price, B. A. Raue, R. Suleiman, D. P. Weygand, S. Dhamija, H. Avakian, E. De Sanctis, D. I. Sober, G. Ricco, K. Moriya, R. W. Gothe, S. S. Stepanyan, E. Pasyuk, M. Mayer, R. De Vita, T. Mineeva, W. J. Briscoe, S. Pisano, Igor Strakovsky, K.H. Hicks, I. Niculescu, J. R. Johnstone, Laird Kramer, Y. Prok, H. Moutarde, Barry Ritchie, H. Y. Lu, D. J. Tedeschi, I. Bedlinskiy, S. Strauch, Larry Weinstein, M. Holtrop, W. Kim, G. Niculescu, P. Khetarpal, W. Gohn, Michael L. Williams, C. S. Nepali, L. Zana, G. Rosner, M. Ripani, B. Moreno, D. Protopopescu, S. Pozdniakov, K. Livingston, M. Guidal, P. Rossi, A. Daniel, P. Stoler, S. Tkachenko, R. Dickson, B. Dey, D. Doughty, W. K. Brooks, A. El Alaoui, J. McAndrew, Michael Wood, K. Hafidi, V. P. Kubarovsky, Annalisa D'Angelo, P. Collins, Michael Vineyard, K. P. Adhikari, 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), CLAS, and 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)
Subjects: Nuclear and High Energy Physics, Roper resonance, Particle physics, Meson, Nuclear Theory, Hadron, FOS: Physical sciences, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, TRANSITION FORM-FACTORS, RELATIVISTIC QUARK-MODEL, LIGHT-FRONT DYNAMICS, GAMMA-ASTERISK, NEUTRAL PIONS, HIGH-ENERGIES, REGION, PHOTOPRODUCTION, Q2, MESONS, Delta baryon, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Pion, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, TRANSITION FORM-FACTORS, RELATIVISTIC QUARK-MODEL, LIGHT-FRONT DYNAMICS, GAMMA-ASTERISK, NEUTRAL PIONS, HIGH-ENERGIES, REGION, PHOTOPRODUCTION, Q2, MESONS, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Branching fraction, High Energy Physics - Phenomenology, High Energy Physics::Experiment, Nucleon
Abstract: We present results on the electroexcitation of the low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of JLab-CLAS data on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for pion electroproduction off the proton. The data were analysed using two conceptually different approaches, fixed-t dispersion relations and a unitary isobar model, allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the Delta(1232)P33} show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q2 N(1520)D13 and N(1535)S11 longitudinal helicity amplitudes with good precision., 23 pages, 17 figures
Published: 2009
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50. Measurement of semi-inclusive pi+ electroproduction off the proton

Author: L. C. Smith, E. Munevar, M. H. Wood, Y. Ilieva, M. E. McCracken, P. Nadel-Turonski, E. Wolin, R. J. Feuerbach, B. S. Ishkhanov, G. E. Dodge, Tsutomu Mibe, P. V. Degtyarenko, J. P. Ball, Y. Prok, D. S. Carman, M. R. Niroula, Alexander Ilyichev, O. P. Dzyubak, I. I. Strakovsky, Paolo Rossi, K. S. Egiyan, P. L. Cole, Z. W. Zhao, J. Lachniet, A. Tkabladze, W. Kim, I. Niculescu, R. A. Niyazov, D. G. Crabb, R. S. Hakobyan, L. El Fassi, Elton Smith, A. Deur, G. Niculescu, R. De Masi, B. L. Berman, J. Kuhn, B. McKinnon, W. K. Brooks, G. P. Gilfoyle, K. Livingston, R. Fatemi, N. Markov, A. V. Vlassov, J. P. Cummings, M. Anghinolfi, G. Ricco, B. Zhao, D. J. Tedeschi, S. Niccolai, R. Dickson, Ji Li, Y. G. Sharabian, S. Strauch, D. P. Watts, H. Egiyan, L. M. Qin, C. Paterson, L. Zana, D. Branford, J. M. Laget, M. Khandaker, G. Riccardi, N. Hassall, M. Bellis, Cynthia Marie Hadjidakis, R. De Vita, A. I. Ostrovidov, K. A. Griffioen, N. Guler, F. W. Hersman, J. Hardie, C. Butuceanu, M. J. Amaryan, M. Kossov, Shifeng Chen, E. N. Golovach, Volker D. Burkert, A. S. Biselli, Michael Dugger, J. Langheinrich, H. O. Funsten, H. G. Juengst, Luca Trentadue, M. MacCormick, I. Hleiqawi, M. D. Mestayer, C. Djalali, H. Denizli, P. Eugenio, S. Dytman, A. V. Skabelin, S. L. Careccia, I. Popa, P. Coltharp, R. A. Schumacher, P. Mattione, M. Osipenko, S. Barrow, M. Taiuti, A.V. Stavinsky, S. Anefalos Pereira, P. D. Rubin, R. W. Gothe, Laird Kramer, E. L. Isupov, D. Lawrence, D. Sokhan, M. M. Ito, H. Hakobyan, A. Cazes, J. R. Calarco, C. I O Gordon, K. L. Giovanetti, S. Mehrabyan, Alexei V. Klimenko, J. T. Goetz, R. Miskimen, C. Hanretty, G. V. O'Rielly, E. Polli, Michael L. Williams, Larry Weinstein, M. Mirazita, Kalvir S. Dhuga, J. D. Kellie, P. Collins, Friedrich Klein, F. Sabatié, Nikolay Shvedunov, J. J. Melone, V. Sapunenko, Sylvain Bouchigny, S. Bültmann, L. Todor, Barry Ritchie, Dinko Pocanic, Victor Mokeev, Brian Raue, G. Asryan, E. De Sanctis, M. Battaglieri, I. Bedlinskiy, V. A. Drozdov, S. Stepanyan, S. E. Kuhn, N. A. Baltzell, D. Protopopescu, S. Pozdniakov, M. Garçon, M. F. Vineyard, J. Pierce, Avraham Klein, Z. Krahn, N. Dashyan, S. Boiarinov, U. Thoma, D. I. Sober, R. Bradford, N. Kalantarians, Latifa Elouadrhiri, V. Gyurjyan, G. S. Mutchler, D. G. Ireland, V. Crede, N. Baillie, B. B. Niczyporuk, R. C. Minehart, Kei Moriya, S. McAleer, N. Pivnyuk, B. E. Stokes, J. Napolitano, G. S. Adams, J. Zhang, B. M. Preedom, F. X. Girod, L. Blaszczyk, H. Bagdasaryan, J. P. Santoro, C. Tur, C. A. Meyer, L. Guo, M. Ungaro, G. Gavalian, J. Donnelly, S. Tkachenko, D. Heddle, J. Salamanca, N. Benmouna, G. V. Fedotov, M. Ripani, J. W C McNabb, D. Jenkins, R. Nasseripour, S. A. Morrow, K. Joo, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, A. Yegneswaran, Atilla Gonenc, P. Ambrozewicz, J. W. Price, M. Holtrop, D. P. Weygand, P. Corvisiero, H. S. Jo, Gerald Feldman, Federico A. Ceccopieri, C. Salgado, G. Rosner, M. Guillo, K. Mikhailov, M. Guidal, H. Y. Lu, C. E. Hyde-Wright, P. Stoler, Sergey Kuleshov, M. Bektasoglu, M. Nozar, K. Hicks, S. S. Stepanyan, S. A. Philips, J. Mueller, K. Hafidi, V. S. Serov, K. Park, V. P. Kubarovsky, O. Pogorelko, L. C. Dennis, B. E. Bonner, H. Avakian, W. J. Briscoe, E. Pasyuk, D. Doughty, Institut de Physique Nucléaire d'Orsay (IPNO), 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), 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, CLAS, and 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)
Subjects: Particle physics, Nuclear and High Energy Physics, Proton, DEEP-INELASTIC-SCATTERING, TARGET FRAGMENTATION REGION, TRANSVERSE-MOMENTUM, PARTON DISTRIBUTIONS, AZIMUTHAL ASYMMETRY, PION ELECTROPRODUCTION, CHARGED HADRONS, HARD PROCESSES, LEADING ORDER, CROSS-SECTION, TARGET FRAGMENTATION REGION, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Nuclear physics, Pion, Factorization, 0103 physical sciences, 010306 general physics, Nuclear Experiment, PION ELECTROPRODUCTION, Physics, DEEP-INELASTIC-SCATTERING, 010308 nuclear & particles physics, LEADING ORDER, TRANSVERSE-MOMENTUM, Azimuth, Diquark, CHARGED HADRONS, HARD PROCESSES, PARTON DISTRIBUTIONS, Cathode ray, AZIMUTHAL ASYMMETRY, High Energy Physics::Experiment, CROSS-SECTION
Abstract: Semi-inclusive {pi}{sup +} electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range including the complete range of azimuthal angles between hadronic and leptonic planes, {phi}, enabling us to separate the {phi}-dependent terms. Our measurements of the {phi}-independent term of the cross section at low Bjorken x were found to be in fairly good agreement with pQCD calculations. Indeed, the conventional current fragmentation calculation can account for almost all of the observed cross section, even at small {pi}{sup +} momentum. The measured center-of-momentum spectra are in qualitative agreement with high-energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the antiquark fragmentation measured in e{sup +}e{sup -} collisions. We have observed that the two {phi}-dependent terms of the cross section are small. Within our precision the cos2{phi} term is compatible with zero, except for the low-z region, and the measured cos{phi} term is much smaller in magnitude than the sum of the Cahn and Berger effects.
Published: 2009

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