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1. A multidimensional study of the structure function ratio σLT′/σ0 from hard exclusive π+ electro-production off protons in the GPD regime

Author: S. Diehl, A. Kim, K. Joo, P. Achenbach, Z. Akbar, M.J. Amaryan, H. Atac, H. Avagyan, C. Ayerbe Gayoso, L. Baashen, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, A.S. Biselli, M. Bondi, W.A. Booth, F. Bossù, S. Boiarinov, K.-Th. Brinkmann, W.J. Briscoe, S. Bueltmann, D. Bulumulla, V.D. Burkert, D.S. Carman, A. Celentano, P. Chatagnon, V. Chesnokov, T. Chetry, G. Ciullo, G. Clash, P.L. Cole, M. Contalbrigo, G. Costantini, A. D'Angelo, N. Dashyan, R. De Vita, M. Defurne, A. Deur, C. Djalali, R. Dupre, H. Egiyan, M. Ehrhart, A. El Alaoui, L. El Fassi, L. Elouadrhiri, S. Fegan, A. Filippi, G. Gavalian, Y. Ghandilyan, G.P. Gilfoyle, D.I. Glazier, A.A. Golubenko, G. Gosta, R.W. Gothe, Y. Gotra, K.A. Griffioen, M. Guidal, K. Hafidi, H. Hakobyan, M. Hattawy, T.B. Hayward, D. Heddle, A. Hobart, M. Holtrop, Y. Ilieva, D.G. Ireland, E.L. Isupov, H.S. Jo, M. Khachatryan, A. Khanal, W. Kim, A. Kripko, V. Kubarovsky, V. Lagerquist, J.-M. Laget, L. Lanza, M. Leali, S. Lee, P. Lenisa, X. Li, K. Livingston, I. .J .D. MacGregor, D. Marchand, V. Mascagna, B. McKinnon, Z.E. Meziani, S. Migliorati, T. Mineeva, M. Mirazita, V. Mokeev, E. Molina, R.A. Montgomery, C. Munoz Camacho, P. Nadel-Turonski, P. Naidoo, K. Neupane, S. Niccolai, M. Nicol, G. Niculescu, M. Osipenko, M. Ouillon, P. Pandey, M. Paolone, L.L. Pappalardo, R. Paremuzyan, E. Pasyuk, S.J. Paul, W. Phelps, N. Pilleux, M. Pokhrel, J. Poudel, J.W. Price, Y. Prok, T. Reed, J. Richards, M. Ripani, J. Ritman, P. Rossi, F. Sabatié, C. Salgado, S. Schadmand, A. Schmidt, Y. Sharabian, E.V. Shirokov, U. Shrestha, P. Simmerling, D. Sokhan, N. Sparveris, M. Spreafico, S. Stepanyan, I.I. Strakovsky, S. Strauch, J.A. Tan, N. Trotta, M. Turisini, R. Tyson, M. Ungaro, S. Vallarino, L. Venturelli, H. Voskanyan, E. Voutier, D.P. Watts, X. Wei, R. Williams, R. Wishart, M.H. Wood, N. Zachariou, J. Zhang, Z.W. Zhao, and M. Zurek
Subjects: Exclusive single pion, Eletroproduction, GPD, CLAS12, Physics, QC1-999
Abstract: A multidimensional extraction of the structure function ratio σLT′/σ0 from the hard exclusive e→p→e′nπ+ reaction above the resonance region has been performed. The study was done based on beam-spin asymmetry measurements using a 10.6 GeV incident electron beam on a liquid-hydrogen target and the CLAS12 spectrometer at Jefferson Lab. The measurements focus on the very forward regime (t/Q2 ≪ 1) with a wide kinematic range of xB in the valence regime (0.17 < xB < 0.55), and virtualities Q2 ranging from 1.5 GeV2 up to 6 GeV2. The results and their comparison to theoretical models based on Generalized Parton Distributions demonstrate the sensitivity to chiral-odd GPDs and the directly related tensor charge of the nucleon. In addition, the data is compared to an extension of a Regge formalism at high photon virtualities. It was found that the Regge model provides a better description at low Q2, while the GPD model is more appropriate at high Q2.
Published: 2023
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2. Measurement of the beam spin asymmetry of e→p→e′p′η in the deep-inelastic regime with CLAS

Author: B. Zhao, A. Kim, K. Joo, I. Bedlinskiy, W. Kim, V. Kubarovsky, M. Ungaro, S. Adhikari, Z. Akbar, G. Angelini, H. Avakian, J. Ball, N.A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, V. Batourine, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, D.S. Carman, A. Celentano, P. Chatagnon, T. Chetry, G. Ciullo, L. Clark, B.A. Clary, P.L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, S. Diehl, C. Djalali, R. Dupre, H. Egiyan, M. Ehrhart, A. El Alaoui, L. El Fassi, P. Eugenio, A. Filippi, T.A. Forest, G. Gavalian, Y. Ghandilyan, G.P. Gilfoyle, F.X. Girod, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, M. Holtrop, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H.S. Jo, S. Johnston, M.L. Kabir, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Klein, F.J. Klein, S.E. Kuhn, S.V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, D. Marchand, N. Markov, B. McKinnon, C.A. Meyer, Z.E. Meziani, M. Mirazita, V. Mokeev, R.A. Montgomery, C. Munoz Camacho, P. Nadel-Turonski, S. Niccolai, G. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, M. Ripani, A. Rizzo, G. Rosner, P. Rossi, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, J.A. Tan, H. Voskanyan, E. Voutier, R. Wang, X. Wei, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
Abstract: The beam spin asymmetry of the exclusive pseudoscalar channel e→p→e′p′η was measured for the first time in the deep-inelastic regime (W>2 GeV/c2 and Q2>1 GeV2/c2) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q2, xB, −t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin⁡ϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations. Keywords: Nucleon structure, CLAS collaboration, Deeply Virtual Meson Production, Chiral-odd generalized parton distributions
Published: 2019
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3. First results on nucleon resonance photocouplings from the γp → π+π−p reaction

Author: E. Golovatch, V.D. Burkert, D.S. Carman, R.W. Gothe, K. Hicks, B.S. Ishkhanov, V.I. Mokeev, E. Pasyuk, S. Adhikari, Z. Akbar, M.J. Amaryan, H. Avakian, J. Ball, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, F. Cao, A. Celentano, P. Chatagnon, T. Chetry, G. Ciullo, L. Clark, B.A. Clary, P.L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, S. Diehl, C. Djalali, M. Dugger, R. Dupre, H. Egiyan, M. Ehrhart, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, R. Fersch, A. Filippi, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, N. Harrison, M. Hattawy, D. Heddle, M. Holtrop, Y. Ilieva, D.G. Ireland, E.L. Isupov, D. Jenkins, H.S. Jo, S. Johnston, K. Joo, M.L. Kabir, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, D. Marchand, N. Markov, B. McKinnon, C.A. Meyer, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, S. Niccolai, G. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, M. Ripani, D. Riser, A. Rizzo, G. Rosner, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, I.I. Strakovsky, S. Strauch, M. Taiuti, J.A. Tan, N. Tyler, M. Ungaro, H. Voskanyan, E. Voutier, R. Wang, X. Wei, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
Abstract: We report the first experimental measurements of the nine 1-fold differential cross sections for the γp→π+π−p reaction, obtained with the CLAS detector at Jefferson Laboratory. The measurements cover the invariant mass range of the final state hadrons from 1.6 GeV
Published: 2019
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4. Beam–target helicity asymmetry E in K+Σ− photoproduction on the neutron

Author: N. Zachariou, D.P. Watts, J. Fleming, A.V. Sarantsev, V.A. Nikonov, A. D'Angelo, M. Bashkanov, C. Hanretty, T. Kageya, F.J. Klein, M. Lowry, H. Lu, A. Sandorfi, X. Wei, I. Zonta, K.P. Adhikari, S. Adhikari, M.J. Amaryan, G. Angelini, G. Asryan, H. Atac, L. Barion, C. Bass, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A.S. Biselli, F. Bossù, S. Boiarinov, W.J. Briscoe, W.K. Brooks, D. Bulumulla, V. Burkert, D.S. Carman, J.C. Carvajal, A. Celentano, G. Charles, P. Chatagnon, T. Chetry, G. Ciullo, P.L. Cole, M. Contalbrigo, N. Dashyan, R. De Vita, A. Deur, S. Diehl, C. Djalali, R. Dupre, H. Egiyan, M. Ehrhart, A. El Alaoui, P. Eugenio, S. Fegan, R. Fersch, A. Filippi, G. Gavalian, N. Gevorgyan, Y. Ghandilyan, G.P. Gilfoyle, F.X. Girod, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, K. Hafidi, H. Hakobyan, M. Hattawy, D. Heddle, K. Hicks, D. Ho, M. Holtrop, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H.S. Jo, K. Joo, S.J. Joosten, D. Keller, M. Khachatryan, A. Khanal, M. Khandaker, C.W. Kim, W. Kim, V. Kubarovsky, L. Lanza, M. Leali, P. Lenisa, K. Livingston, I.J.D. MacGregor, D. Marchand, N. Markov, L. Marsicano, V. Mascagna, M. Mayer, B. McKinnon, Z.E. Meziani, T. Mineeva, V. Mokeev, E. Munevar, C. Munoz Camacho, P. Nadel Turonski, T.R. O'Connell, M. Osipenko, A.I. Ostrovidov, M. Paolone, L.L. Pappalardo, K. Park, E. Pasyuk, P. Peng, W. Phelps, O. Pogorelko, J. Poudel, J.W. Price, Y. Prok, A.J.R. Puckett, B.A. Raue, M. Ripani, A. Rizzo, G. Rosner, C. Salgado, A. Schmidt, R.A. Schumacher, U. Shrestha, D. Sokhan, O. Soto, N. Sparveris, I.I. Strakovsky, S. Strauch, J.A. Tan, N. Tyler, M. Ungaro, L. Venturelli, H. Voskanyan, E. Voutier, N.K. Walford, C.S. Whisnant, M.H. Wood, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
Abstract: We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2− resonance, are also quantified.
Published: 2020
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5. Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

Author: S. Jawalkar, S. Koirala, H. Avakian, P. Bosted, K.A. Griffioen, C. Keith, S.E. Kuhn, K.P. Adhikari, S. Adhikari, D. Adikaram, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, J. Ball, N.A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, J. Brock, W.K. Brooks, S. Bültmann, V.D. Burkert, Frank Thanh Cao, C. Carlin, D.S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P.L. Cole, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, C. Djalali, G. Ddoge, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, R. Fersch, A. Filippi, J.A. Fleming, T.A. Forest, A. Fradi, M. Garçon, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, C. Gleason, W. Gohn, E. Golovatch, R.W. Gothe, M. Guidal, N. Guler, L. Guo, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, G. Hollis, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, K. Joo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, S.V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, N. Markov, M. Mayer, M.E. McCracken, B. McKinnon, C.A. Meyer, T. Mineeva, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, R. Paremuzyan, K. Park, E. Pasyuk, E. Phelps, W. Phelps, J. Pierce, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, D. Riser, A. Rizzo, G. Rosner, P. Rossi, F. Sabatié, C. Salgado, R.A. Schumacher, E. Seder, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, I. Stankovic, S. Strauch, M. Taiuti, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, L.B. Weinstein, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
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 14NH3 target, and extracted double and single target spin asymmetries for ep→e′π0X in multidimensional bins in four-momentum transfer (1.0
Published: 2018
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6. Differential cross section for γd → ωd using CLAS at Jefferson Lab

Author: T. Chetry, K. Hicks, N. Compton, M. Sargsian, S. Adhikari, J. Ball, I. Balossino, L. Barion, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, D.S. Carman, A. Celentano, G. Charles, G. Ciullo, L. Clark, Brandon A. Clary, P.L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, R. Fersch, A. Filippi, G. Gavalian, Y. Ghandilyan, K.L. Giovanetti, F.X. Girod, E. Golovatch, R.W. Gothe, K.A. Griffioen, L. Guo, K. Hafidi, N. Harrison, M. Hattawy, M. Holtrop, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, S. Johnston, M.L. Kabir, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, V. Mokeev, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, S. Niccolai, G. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, O. Pogorelko, J.W. Price, Y. Prok, M. Ripani, D. Riser, B.G. Ritchie, A. Rizzo, G. Rosner, C. Salgado, R.A. Schumacher, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, J.A. Tan, M. Ungaro, H. Voskanyan, E. Voutier, L.B. Weinstein, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
Abstract: The cross section for coherent ω-meson photoproduction off the deuteron has been measured for the first time as a function of the momentum transfer t=(Pγ−Pω)2 and photon energy Eγ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are measured in the energy range 1.4
Published: 2018
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7. Hard exclusive pion electroproduction at backward angles with CLAS

Author: K. Park, M. Guidal, R.W. Gothe, B. Pire, K. Semenov-Tian-Shansky, J.-M. Laget, K.P. Adhikari, S. Adhikari, Z. Akbar, H. Avakian, J. Ball, I. Balossino, N.A. Baltzell, L. Barion, M. Battaglieri, I. Bedlinskiy, A.S. Biselli, W.J. Briscoe, W.K. Brooks, V.D. Burkert, F.T. Cao, D.S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, P.L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, R. Fersch, A. Filippi, M. Garçon, Y. Ghandilyan, G.P. Gilfoyle, F.X. Girod, E. Golovatch, K.A. Griffioen, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, M. Holtrop, C.E. Hyde, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, S. Johnston, K. Joo, M.L. Kabir, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, W. Kim, F.J. Klein, V. Kubarovsky, S.E. Kuhn, L. Lanza, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, M. Mirazita, V. Mokeev, R.A. Montgomery, C. Munoz Camacho, P. Nadel-Turonski, S. Niccolai, G. Niculescu, M. Osipenko, M. Paolone, R. Paremuzyan, E. Pasyuk, W. Phelps, O. Pogorelko, J. Poudel, J.W. Price, Y. Prok, D. Protopopescu, M. Ripani, A. Rizzo, P. Rossi, F. Sabatié, C. Salgado, R.A. Schumacher, Y. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, J.A. Tan, M. Ungaro, H. Voskanyan, E. Voutier, X. Wei, N. Zachariou, and J. Zhang
Subjects: Physics, QC1-999
Abstract: We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep→e′nπ+, above the resonance region at backward pion center-of-mass angles. The φπ⁎-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs). These non-perturbative objects are defined as matrix elements of three-quark-light-cone-operators and characterize partonic correlations with a particular emphasis on baryon charge distribution inside a nucleon. Keywords: TDA, Exclusive single pion, Eletroproduction, CLAS
Published: 2018
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8. Photon beam asymmetry Σ in the reaction γ→p→pω for Eγ=1.152 to 1.876 GeV

Author: P. Collins, B.G. Ritchie, M. Dugger, F.J. Klein, A.V. Anisovich, E. Klempt, V.A. Nikonov, A. Sarantsev, K.P. Adhikari, S. Adhikari, D. Adikaram, Z. Akbar, S. Anefalos Pereira, H. Avakian, J. Ball, N.A. Baltzell, M. Bashkanov, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, Frank Thanh Cao, T. Cao, D.S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, P.L. Cole, M. Contalbrigo, O. Cortes, V. Crede, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, A. Filippi, J.A. Fleming, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, C. Gleason, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, G. Hollis, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, V. Kubarovsky, S.V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, Z.E. Meziani, T. Mineeva, V. Mokeev, R.A. Montgomery, A. Movsisyan, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, S. Procureur, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, A. Rizzo, G. Rosner, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, I. Stankovic, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao
Subjects: Physics, QC1-999
Abstract: Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ→p→ωp are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the JP=3/2+ partial wave), as well as the resonant portions of the smaller partial waves with JP=1/2−, 3/2−, and 5/2+. Keywords: Omega photoproduction, Polarization observable, Beam asymmetry
Published: 2017
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9. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

Author: P. Collins, B.G. Ritchie, M. Dugger, A.V. Anisovich, M. Döring, E. Klempt, V.A. Nikonov, D. Rönchen, D. Sadasivan, A. Sarantsev, K.P. Adhikari, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, H. Avakian, J. Ball, I. Balossino, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, A.S. Biselli, W.J. Briscoe, W.K. Brooks, V.D. Burkert, Frank Thanh Cao, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P.L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J.A. Fleming, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, C. Gleason, E. Golovatch, R.W. Gothe, K.A. Griffioen, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, D. Heddle, K. Hicks, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, Ye Tian, B. Torayev, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, X. Wei, N. Zachariou, and J. Zhang
Subjects: Physics, QC1-999
Abstract: Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(1895)1/2−, N(1900)3/2+, N(2100)1/2+ and N(2120)3/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process. Keywords: Meson photoproduction, Eta photoproduction, Eta-prime photoproduction, Polarization observable, Photon beam asymmetry
Published: 2017
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10. Differential cross sections and polarization observables from CLAS K⁎ photoproduction and the search for new N⁎ states

Author: A.V. Anisovich, K. Hicks, E. Klempt, V.A. Nikonov, A. Sarantsev, W. Tang, D. Adikaram, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, R.A. Badui, J. Ball, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, W.J. Briscoe, V.D. Burkert, D.S. Carman, A. Celentano, S. Chandavar, T. Chetry, G. Ciullo, L. Clark, P.L. Cole, N. Compton, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, M. Dugger, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J.A. Fleming, N. Gevorgyan, Y. Ghandilyan, K.L. Giovanetti, F.X. Girod, C. Gleason, R.W. Gothe, K.A. Griffioen, L. Guo, C. Hanretty, N. Harrison, M. Hattawy, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khandaker, W. Kim, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, E. Munevar, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, L.A. Net, A. Ni, S. Niccolai, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, P. Peng, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, A.J.R. Puckett, B.A. Raue, M. Ripani, B.G. Ritchie, G. Rosner, P. Roy, F. Sabatié, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, I. Stankovic, S. Stepanyan, S. Strauch, V. Sytnik, Ye. Tian, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, M.H. Wood, N. Zachariou, J. Zhang, and I. Zonta
Subjects: Physics, QC1-999
Abstract: The reaction γp→K⁎+Λ was measured using the CLAS detector for photon energies between the threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. For the first time, spin-density matrix elements have been extracted for this reaction. Differential cross sections, spin density matrix elements, and the Λ recoil polarization are compared with theoretical predictions using the BnGa partial wave analysis. The main result is the evidence for significant contributions from N(1895)1/2− and N(2100)1/2+ to the reaction. Branching ratios for decays into K⁎Λ for these resonances and further resonances are reported. Keywords: Baryon spectroscopy, Meson photoproduction, Polarization observables
Published: 2017
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11. Target and double spin asymmetries of deeply virtual π0 production with a longitudinally polarized proton target and CLAS

Author: A. Kim, H. Avakian, V. Burkert, K. Joo, W. Kim, K.P. Adhikari, Z. Akbar, S. Anefalos Pereira, R.A. Badui, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, P. Bosted, W.J. Briscoe, W.K. Brooks, S. Bültmann, T. Cao, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, L. Colaneri, P.L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, C. Djalali, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, R. Fersch, A. Filippi, J.A. Fleming, A. Fradi, M. Garc con, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, L. Guo, K. Hafidi, C. Hanretty, M. Hattawy, D. Heddle, K. Hicks, M. Holtrop, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, D. Jenkins, H. Jiang, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khandaker, A. Klein, F.J. Klein, V. Kubarovsky, S.E. Kuhn, S.V. Kuleshov, L. Lanza, P. Lenisa, H.Y. Lu, I.J.D. MacGregor, N. Markov, P. Mattione, M.E. McCracken, B. McKinnon, V. Mokeev, A. Movsisyan, E. Munevar, P. Nadel-Turonski, L.A. Net, S. Niccolai, M. Osipenko, A.I. Ostrovidov, M. Paolone, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, M. Ripani, A. Rizzo, G. Rosner, P. Rossi, P. Roy, C. Salgado, R.A. Schumacher, E. Seder, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, P. Stoler, I.I. Strakovsky, S. Strauch, V. Sytnik, M. Taiuti, B. Torayev, M. Ungaro, H. Voskanyan, E. Voutier, D.P. Watts, X. Wei, L.B. Weinstein, N. Zachariou, L. Zana, and J. Zhang
Subjects: Nucleon structure, CLAS collaboration, Deeply Virtual Meson Production, Chiral-odd generalized parton distributions, Longitudinally polarized target, Physics, QC1-999
Abstract: The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ0 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 H˜T and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and E¯T. 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
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12. First measurement of the helicity asymmetry E in η photoproduction on the proton

Author: I. Senderovich, B.T. Morrison, M. Dugger, B.G. Ritchie, E. Pasyuk, R. Tucker, J. Brock, C. Carlin, C.D. Keith, D.G. Meekins, M.L. Seely, D. Rönchen, M. Döring, P. Collins, K.P. Adhikari, D. Adikaram, Z. Akbar, M.D. Anderson, S. Anefalos Pereira, R.A. Badui, J. Ball, N.A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Colaneri, P.L. Cole, M. Contalbrigo, O. Cortes, V. Credé, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Filippi, J.A. Fleming, A. Fradi, B. Garillon, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, J.T. Goetz, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, M. Hattawy, K. Hicks, D. Ho, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, D. Jenkins, H. Jiang, H.S. Jo, K. Joo, S. Joosten, D. Keller, G. Khachatryan, M. Khandaker, A. Kim, F.J. Klein, V. Kubarovsky, M.C. Kunkel, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, P. Mattione, B. McKinnon, C.A. Meyer, T. Mineeva, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, K. Park, S. Park, P. Peng, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, A.J.R. Puckett, M. Ripani, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, D. Schott, R.A. Schumacher, E. Seder, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, N. Sparveris, S. Stepanyan, P. Stoler, I.I. Strakovsky, S. Strauch, V. Sytnik, Ye Tian, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, X. Wei, M.H. Wood, N. Zachariou, L. Zana, J. Zhang, Z.W. Zhao, and I. Zonta
Subjects: Physics, QC1-999
Abstract: Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γp→ηp. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the Jülich–Bonn model to examine the case for the existence of a narrow N⁎ resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances. Keywords: Eta photoproduction, Polarization observable, Helicity asymmetry
Published: 2016
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13. First measurement of the polarization observable E in the p→(γ→,π+)n reaction up to 2.25 GeV

Author: S. Strauch, W.J. Briscoe, M. Döring, E. Klempt, V.A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K.P. Adhikari, D. Adikaram, M.D. Anderson, S. Anefalos Pereira, A.V. Anisovich, R.A. Badui, J. Ball, V. Batourine, M. Battaglieri, I. Bedlinskiy, N. Benmouna, A.S. Biselli, J. Brock, W.K. Brooks, V.D. Burkert, T. Cao, C. Carlin, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Colaneri, P.L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, N. Dashyan, A. D'Angelo, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, M. Dugger, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Filippi, J.A. Fleming, T.A. Forest, A. Fradi, N. Gevorgyan, Y. Ghandilyan, K.L. Giovanetti, F.X. Girod, D.I. Glazier, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, K. Hicks, D. Ho, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, K. Joo, S. Joosten, C.D. Keith, D. Keller, G. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, S.E. Kuhn, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, N. Markov, B. McKinnon, D.G. Meekins, C.A. Meyer, V. Mokeev, R.A. Montgomery, C.I. Moody, H. Moutarde, A. Movsisyan, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, G. O'Rielly, M. Osipenko, A.I. Ostrovidov, K. Park, P. Peng, W. Phelps, J.J. Phillips, S. Pisano, O. Pogorelko, S. Pozdniakov, J.W. Price, S. Procureur, Y. Prok, D. Protopopescu, A.J.R. Puckett, B.A. Raue, M. Ripani, B.G. Ritchie, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, D. Schott, R.A. Schumacher, E. Seder, M.L. Seely, I. Senderovich, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, P. Stoler, S. Stepanyan, V. Sytnik, M. Taiuti, Ye Tian, A. Trivedi, R. Tucker, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, M.H. Wood, N. Zachariou, L. Zana, J. Zhang, Z.W. Zhao, and I. Zonta
Subjects: Baryon spectroscopy, Pion photoproduction, Polarization observables, FROST experiment, Physics, QC1-999
Abstract: First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction γ→p→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn–Gatchina, Jülich–Bonn, and SAID groups.
Published: 2015
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14. The Present and Future of QCD: QCD Town Meeting White Paper -- An INput to the 2023 NSAC Long Range Plan

Author: P Achenbach, D Adhikari, A Afanasev, F Afzal, C Aidala, A Al-bataineh, D Almaaloi, M Amaryan, D Androic, W Armstrong, M Arriatia, J Arrington, A Asaturyan, E Aschenauer, H Atac, H Avakian, T Averett, C Ayerbe Gayoso, X Bai, K Barish, N Barnea, G Basar, M Battaglieri, A Baty, I Bautista, A Bazilevsky, C Beattie, S Behera, V Bellini, R Bellwied, J Benesch, F Benmokhtar, C Bernardes, J Bernauer, H Bhatt, S Bhatta, M Boer, T Boettcher, S Bogacz, H Bossi, J Brandenburg, E Brash, R Briceno, W Briscoe, S Brodsky, D Brown, V Burkert, H Caines, I Cali, A Camsonne, D Carman, J Caylor, S Cerci, M Chamizo Llatas, J Chen, Y Chen, Y Chien, P Chou, X Chu, E Chudakov, E Cline, I Cloet, P Cole, M Conners, M Constantinou, W Cosyn, S Covrig Dusa, R Cruz-Torres, U D'Alesio, C da Silva, Z Davoudi, C Dean, D Dean, M Demarteau, A Deshpande, W Detmold, A Deur, B Devkota, S Dhital, M Diefenthaler, S Dobbs, M Doring, X Dong, R Dotel, K Dow, E Downie, J Drachenberg, A Dumitru, J Dunlop, R Dupre, J Durham, D Dutta, R Edwards, R Ehlers, L El Fassi, M Elaasar, L Elouadrhiri, M Engelhardt, R Ent, S Esumi, O Evdokimov, O Eyser, C Fanelli, R Fatemi, I Fernando, F Flor, N Fomin, A Frawley, T Federico, R Fries, C Gal, B Gamage, L Gamberg, H Gao, D Gaskell, F Geurts, Y Ghandilyan, R Gilman, C Gleason, K Gnanvo, R Gothe, S Greene, H Griesshammer, S Grossberndt, B Grube, D Hackett, T Hague, H Hakobyan, J Hansen, Y Hatta, M Hattawy, L Havener, O Hen, W Henry, D Higinbotham, T Hobbs, A Hodges, T Holmstrom, B Hong, T Horn, C Howell, H Huang, M Huang, S Huang, G Huber, C Hyde, E Isupov, P Jacobs, J Jalilian-Marian, A Jentsch, H Jheng, C Ji, X Ji, J Jia, D Jones, M Jones, N Kalantarians, G Kalicy, Z Kang, J Karthein, D Keller, C Keppel, V Khachartryan, D Kharzeev, M Kim, Y Kim, P King, E Kinney, S Klein, H Ko, V Koch, M Kohl, Y Kovchegov, G Krintiras, V Kubarovsky, S Kuhn, K Kumar, T Kutz, J Lajoie, J Lauret, I Lavrukhin, D Lawrence, J Lee, K Lee, S Lee, Y Lee, S Li, W Li, X Li, J Liao, H Lin, M Lisa, K Liu, M Liu, T Liu, S Liuti, N Liyanage, W Llope, C Loizides, R Longo, W Lorenzon, X Luo, R Ma, B McKinnon, D Meekins, Y Mehtar-Tani, W Melnitchouk, A Metz, C Meyer, Z Meziani, R Michaels, R Milner, H Mkrtchyan, P Mohanmurthy, B Mohanty, V Mokeev, I Mooney, C Morningstar, D Morrison, B Muller, S Mukherjee, J Mulligan, C Munoz Camacho, J Murillo Quijada, M Murray, S Nadeeshani, P Nadel-Turonski, J Nam, C Nattrass, G Nijs, J Norohna, J Noronha-Hostler, N Novitzky, M Nycz, F Olness, J Osborn, R Pak, B Pandey, M Paolone, Z Papandreou, J Paquet, S Park, K Paschke, B Pasquini, E Pasyuk, T Patel, A Patton, C Paudel, C Peng, J Peng, H Pereira Da Costa, D Perepelitsa, M Peters, P Petreczky, R Pisarski, D Pitonyak, M Ploskon, M Posik, J Poudel, R Pradhan, A Prokudin, C Pruneau, J Putschke, J Pybus, J Qiu, K Rajagopal, C Ratti, K Read, R Reed, D Richards, C Riedl, F Ringer, T Rinn, J Rittenhouse West, J Roche, A Rodas, G Roland, F Romero-Lopez, P Rossi, T Rostomyan, L Ruan, O Ruimi, N Saha, N Sahoo, T Sakaguchi, F Salazar, C Salgado, G Salme, S Salur, S Santiesteban, M Sargsian, M Sarsour, N Sato, T Satogata, S Sawada, T Schafer, B Scheihing-Hitschfeld, B Schenke, S Schindler, A Schmidt, R Seidl, M Sabestari, P Shanahan, C Shen, T Sheng, M Shepherd, A M Sickles, M Sievert, K Smith, Y Song, A Sorensen, P Souder, N Spareveris, S Srednyak, A Stahl Leiton, A Stasto, P Steinberg, S Stepanyan, M Stephanov, J Stevens, D Stewart, I Stewart, M Stojanovic, I Strakovsky, S Strauch, M Strickland, D Sunar Cerci, M Suresh, B Surrow, S Syritsyn, A Szczepaniak, A Tadepalli, A H Tang, J Tapia Takaki, T Tarnowsky, A Tawfik, M Taylor, C Tennant, A Thiel, D Thomas, Y Tian, A Timmins, P Tribedy, Z Tu, S Tuo, T Ullrich, E Umaka, N Ghimire, J Vary, J Velkovska, R Venugopalan, A Vijayakumar, I Vitev, W Vogelsang, R Vogt, A Vossen, E Voutier, V Vovchenko, A Walker-Loud, F Wang, J Wang, X Wang, L Weinstein, T Wenaus, S Weyhmiller, S Wissink, B Wojtsekhowski, C Wong, M Wood, Y Wunderlich, B Wyslouch, B Xiao, W Xie, W Xiong, N Xu, Q Xu, Z Xu, D Yaari, X Yao, Z Ye, C Yero, F Yuan, W Zajc, C Zhang, J Zhang, F Zhao, Y Zhao, Z Zhao, X Zheng, and J Zhou
Published: 2023

15. Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

Author: S.J. Paul, A. Peck, M. Arratia, Y. Gotra, V. Ziegler, R. De Vita, F. Bossù, M. Defurne, H. Atac, C. Ayerbe Gayoso, L. Baashen, N.A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A.S. Biselli, M. Bondi, S. Boiarinov, K.-Th. Brinkmann, W.J. Briscoe, W.K. Brooks, D. Bulumulla, V.D. Burkert, R. Capobianco, D.S. Carman, J.C. Carvajal, P. Chatagnon, V. Chesnokov, T. Chetry, G. Ciullo, P.L. Cole, G. Costantini, A. D’Angelo, N. Dashyan, A. Deur, S. Diehl, C. Djalali, R. Dupre, A. El Alaoui, L. El Fassi, L. Elouadrhiri, A. Filippi, K. Gates, G. Gavalian, Y. Ghandilyan, G.P. Gilfoyle, A.A. Golubenko, G. Gosta, R.W. Gothe, K. Griffioen, M. Guidal, H. Hakobyan, M. Hattawy, F. Hauenstein, T.B. Hayward, D. Heddle, A. Hobart, M. Holtrop, Y. Ilieva, D.G. Ireland, E.L. Isupov, H.S. Jo, R. Johnston, K. Joo, D. Keller, M. Khachatryan, A. Khanal, A. Kim, W. Kim, V. Klimenko, A. Kripko, L. Lanza, M. Leali, P. Lenisa, X. Li, I.J.D. MacGregor, D. Marchand, L. Marsicano, V. Mascagna, B. McKinnon, C. McLauchlin, S. Migliorati, T. Mineeva, M. Mirazita, V. Mokeev, C. Munoz Camacho, P. Nadel-Turonski, P. Naidoo, K. Neupane, D. Nguyen, S. Niccolai, M. Nicol, G. Niculescu, M. Osipenko, P. Pandey, M. Paolone, R. Paremuzyan, N. Pilleux, O. Pogorelko, M. Pokhrel, J. Poudel, J.W. Price, Y. Prok, T. Reed, M. Ripani, J. Ritman, F. Sabatié, S. Schadmand, A. Schmidt, E.V. Shirokov, U. Shrestha, P. Simmerling, D. Sokhan, N. Sparveris, M. Spreafico, I.I. Strakovsky, S. Strauch, J.A. Tan, R. Tyson, M. Ungaro, S. Vallarino, L. Venturelli, H. Voskanyan, E. Voutier, D.P. Watts, X. Wei, R. Wishart, M.H. Wood, N. Zachariou, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, data analysis method, Physics - Instrumentation and Detectors, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, tracking detector, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment (nucl-ex), numerical calculations, Nuclear Experiment, Instrumentation, Alignment, track data analysis, Settore FIS/04, Detector, Instrumentation and Detectors (physics.ins-det), detector: alignment, Kalman filter, cosmic radiation, semiconductor detector: microstrip, performance
Abstract: International audience; Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of l. 967 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.
Published: 2023

16. Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei

Author: S J, Paul, S, Morán, M, Arratia, A, El Alaoui, H, Hakobyan, W, Brooks, M J, Amaryan, W R, Armstrong, H, Atac, L, Baashen, N A, Baltzell, L, Barion, M, Bashkanov, M, Battaglieri, I, Bedlinskiy, B, Benkel, F, Benmokhtar, A, Bianconi, L, Biondo, A S, Biselli, M, Bondi, F, Bossù, S, Boiarinov, K-Th, Brinkmann, W J, Briscoe, D, Bulumulla, V D, Burkert, R, Capobianco, D S, Carman, A, Celentano, V, Chesnokov, T, Chetry, G, Ciullo, P L, Cole, M, Contalbrigo, G, Costantini, A, D'Angelo, N, Dashyan, R, De Vita, M, Defurne, A, Deur, S, Diehl, C, Dilks, C, Djalali, R, Dupre, H, Egiyan, L, El Fassi, P, Eugenio, S, Fegan, A, Filippi, G, Gavalian, Y, Ghandilyan, G P, Gilfoyle, A A, Golubenko, G, Gosta, R W, Gothe, K A, Griffioen, M, Guidal, M, Hattawy, T B, Hayward, D, Heddle, A, Hobart, M, Holtrop, Y, Ilieva, D G, Ireland, E L, Isupov, H S, Jo, R, Johnston, K, Joo, S, Joosten, D, Keller, A, Khanal, M, Khandaker, W, Kim, A, Kripko, V, Kubarovsky, V, Lagerquist, L, Lanza, M, Leali, S, Lee, P, Lenisa, X, Li, K, Livingston, I J D, MacGregor, D, Marchand, V, Mascagna, B, McKinnon, Z E, Meziani, S, Migliorati, R G, Milner, T, Mineeva, M, Mirazita, V I, Mokeev, P, Moran, C, Munoz Camacho, K, Neupane, D, Nguyen, S, Niccolai, G, Niculescu, M, Osipenko, A I, Ostrovidov, P, Pandey, M, Paolone, L L, Pappalardo, R, Paremuzyan, E, Pasyuk, W, Phelps, N, Pilleux, D, Pocanic, O, Pogorelko, M, Pokhrel, J, Poudel, J W, Price, Y, Prok, B A, Raue, T, Reed, M, Ripani, G, Rosner, F, Sabatié, C, Salgado, A, Schmidt, R A, Schumacher, Y G, Sharabian, E V, Shirokov, U, Shrestha, P, Simmerling, D, Sokhan, N, Sparveris, S, Stepanyan, I I, Strakovsky, S, Strauch, J A, Tan, R, Tyson, M, Ungaro, S, Vallarino, L, Venturelli, H, Voskanyan, E, Voutier, X, Wei, R, Wishart, M H, Wood, N, Zachariou, Z W, Zhao, V, Ziegler, M, Zurek, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: nucleus: size, carbon: target, lead: target, electron nucleus: scattering, Settore FIS/04, Nuclear Theory, hadron hadron: angular correlation, General Physics and Astronomy, nucleus: yield, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], multiple scattering, angular dependence, CLAS, deuterium: target, iron: target, High Energy Physics::Experiment, hadron, electron: beam, Nuclear Experiment (nucl-ex), Nuclear Experiment, nucleus: surface, experimental results
Abstract: We present the first measurement of di-hadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the GiBUU model, which suggests that hadrons form near the nuclear surface and undergo multiple-scattering in nuclei. These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei, Comment: 6 pages, 4 figures
Published: 2022

17. Measurement of deeply virtual Compton scattering off He4 with the CEBAF Large Acceptance Spectrometer at Jefferson Lab

Author: T. A. Forest, D. P. Watts, H. Egiyan, F. Sabatié, D. Bulumulla, A. Filippi, Aditya R. Khanal, M. Khandaker, G. Rosner, Andrea Bianconi, D. Payette, Jo H. S., Y. Ghandilyan, H. Voskanyan, W. Kim, R. A. Schumacher, P. Lenisa, S. Bültmann, W. J. Briscoe, E. Pasyuk, Maxime Defurne, N. Markov, B. Torayev, R. Dupre, D. G. Ireland, Carlos A. Salgado, V. Crede, B. A. Clary, M. Contalbrigo, K. Livingston, M. Battaglieri, M. J. Amaryan, B. Yale, G. Costantini, S. Stepanyan, V. P. Kubarovsky, A. Kim, R. De Vita, J. Rowley, Whitney Armstrong, Simonetta Liuti, Krishna Neupane, J. Poudel, O. Pogorelko, K. Wei, S. Fegan, P. Eugenio, Dustin Keller, R. Paremuzyan, G. Khachatryan, Volker D. Burkert, M. L. Kabir, H. Atac, T. B. Hayward, Paolo Rossi, A. S. Biselli, R. Wishart, A. Celentano, R. W. Gothe, M. Guidal, K. Hafidi, V. Mokeev, Larry Weinstein, Gerard Gilfoyle, L. Venturelli, Michael Paolone, E. L. Isupov, D. Sokhan, M. Ehrhart, M. Caudron, M. Osipenko, S. Boiarinov, I. J. D. MacGregor, F. Bossu, A. Vossen, G. Ciullo, Fatiha Benmokhtar, Y. Prok, D. S. Carman, M. Holtrop, O. Soto, N. A. Baltzell, Nikos Sparveris, X. Wei, H. Hakobyan, M. H. Wood, E. Voutier, J. Ritman, S. Diehl, N. Dashyan, A. El Alaoui, B. McKinnon, Luciano Pappalardo, M. Bondì, K. A. Griffioen, Yordanka Ilieva, C. Ayerbe Gayoso, Nicholas Zachariou, J. C. Carvajal, Y. Perrin, V. Chesnokov, L. Barion, U. Shrestha, M. Mirazita, L. Lanza, K. Hicks, W. Phelps, V. Mascagna, D. Marchand, S. Niccolai, Alessandro Rizzo, Alexander Schmidt, I. Bedlinskiy, M. Ripani, P. Chatagnon, M. Ungaro, K. Joo, V. Sergeyeva, J. Zhang, F. X. Girod, N. Tyler, C. Djalali, T. Chetry, S. Strauch, L. Elouadrhiri, S. Joosten, I. I. Strakovsky, A. Deur, D. G. Jenkins, A. Hobart, M. Leali, T. R. O'Connell, N. Pivnyuk, A. D'Angelo, L. El Fassi, S. E. Kuhn, M. Hattawy, P. L. Cole, Martin K. Mayer, A. Kripko, and Y. G. Sharabian
Subjects: Nuclear physics, Physics, Spectrometer, 010308 nuclear & particles physics, 0103 physical sciences, Compton scattering, Perturbative QCD, 010306 general physics, 01 natural sciences
Published: 2021

18. Measurement of the beam spin asymmetry of e→p→e′p′η in the deep-inelastic regime with CLAS

Author: M. Guidal, C. Djalali, J. A. Tan, A. I. Ostrovidov, K. Park, Z.W. Zhao, G. D. Smith, M. Holtrop, M. Hattawy, D. G. Ireland, Iu. Skorodumina, Volker D. Burkert, K. A. Griffioen, A. S. Biselli, Maxime Defurne, V. Mokeev, D. Marchand, X. Wei, M. Bashkanov, S. Adhikari, V. Crede, Rong Wang, B. McKinnon, P. Lenisa, L. Lanza, Taya Chetry, R. A. Montgomery, C. A. Meyer, N. A. Baltzell, Y. G. Sharabian, P. Chatagnon, M. Ehrhart, W. Kim, D. G. Jenkins, A. Kim, Y. Prok, M. Mirazita, Z. E. Meziani, A. Celentano, R. W. Gothe, R. De Vita, G. Niculescu, Sergey Kuleshov, F. Sabatié, N. Markov, F. X. Girod, V. Batourine, M. Ungaro, N. Dashyan, M. Khachatryan, V. P. Kubarovsky, H. S. Jo, R. Paremuzyan, K. Livingston, O. Pogorelko, L. Barion, G. Rosner, Nicholas M. Harrison, Gerard Gilfoyle, Friedrich Klein, M. Battaglieri, H. Avakian, K. Joo, S. Strauch, H. Hakobyan, D. Sokhan, I. Bedlinskiy, H. Voskanyan, Y. Ghandilyan, Laura Clark, B. S. Ishkhanov, H. Egiyan, Jie Zhang, S. Diehl, C. Salgado, M. Osipenko, K. Hicks, B. Zhao, G. Khachatryan, P. Nadel-Turonski, G. Ciullo, J. P. Ball, S. E. Kuhn, D. S. Carman, Dustin Keller, D. Heddle, Nikos Sparveris, E. De Sanctis, R. A. Schumacher, G. Angelini, P. Eugenio, S. Johnston, L. Guo, Alessandro Rizzo, S. Niccolai, Michael Wood, P. Rossi, C. Munoz Camacho, K. Hafidi, W. J. Briscoe, M. L. Kabir, E. Golovatch, R. Dupre, T. A. Forest, S. Stepanyan, A. Filippi, Avraham Klein, E. L. Isupov, G. Gavalian, I. J. D. MacGregor, M. Contalbrigo, M. Khandaker, I. I. Strakovsky, A. Deur, M. Ripani, S. Boiarinov, M. Taiuti, W. K. Brooks, B. A. Clary, Z. Akbar, Michael Paolone, J. W. Price, A. D'Angelo, D. Protopopescu, E. Voutier, L. El Fassi, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, and P. L. Cole
Subjects: Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Hadron, Virtual particle, Parton, 01 natural sciences, Asymmetry, Nuclear physics, Pseudoscalar, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Spin-½, media_common, Lepton
Abstract: The beam spin asymmetry of the exclusive pseudoscalar channel e → p → e ′ p ′ η was measured for the first time in the deep-inelastic regime ( W > 2 GeV / c 2 and Q 2 > 1 GeV 2 / c 2 ) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q 2 , x B , − t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin ⁡ ϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.
Published: 2019

19. Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

Author: K. Park, V. P. Kubarovsky, Krishna Neupane, C. W. Kim, H. Avakian, H. Voskanyan, W. J. Briscoe, Dustin Keller, P. Eugenio, Michael Wood, K. Hafidi, G. Gavalian, L. Marsicano, A Hobart, V. Mokeev, F. X. Girod, R. A. Schumacher, M. Battaglieri, I. I. Strakovsky, R. W. Gothe, T. Chetry, M. J. Amaryan, F. Sabatié, K. Wei, S. Fegan, N. Markov, L. Guo, Alessandro Rizzo, K. A. Griffioen, Fatiha Benmokhtar, Gerard Gilfoyle, R. Paremuzyan, E. L. Isupov, A. Deur, S. Pisano, V. Crede, Ross Milner, O. Soto, P. Lenisa, M. Contalbrigo, C. Dilks, L. Lanza, M. Ungaro, T. A. Forest, C. Mullen, W. K. Brooks, M. Guidal, Z. W. Zhao, S. Stepanyan, N. A. Baltzell, M. Holtrop, T. B. Hayward, Friedrich Klein, Andrea Celentano, O. Pogorelko, J. Poudel, A. Filippi, Brian Raue, K. Hicks, K. Joo, D. Marchand, M. Osipenko, Luciano Pappalardo, K. L. Giovanetti, Hovanes Egiyan, M. Ripani, C. Munoz Camacho, A. D'Angelo, B. Yale, S. Adhikari, L. Venturelli, B. McKinnon, M. Ehrhart, D. G. Ireland, Tim O'Connell, I. Bedlinskiy, D. I. Glazier, W. Phelps, D. G. Jenkins, N. Tyler, M. Leali, L. El Fassi, C. Djalali, Volker D. Burkert, W. Kim, T. Mineeva, D. Heddle, R. De Vita, G. Ciullo, V. Mascagna, H. S. Jo, A. S. Biselli, M. Mirazita, D. Bulumulla, Y. Prok, D. S. Carman, G. Niculescu, B. S. Ishkhanov, E. Pasyuk, Aditya R. Khanal, X. Wei, R. G. Fersch, Andrea Bianconi, H. Atac, P. L. Cole, N. Dashyan, G. Angelini, P. Chatagnon, B. A. Clary, P. Rossi, M. Defurne, Michael Paolone, L. Barion, Axel Schmidt, Aurore Courtoy, K. Livingston, M. Khandaker, Jie Zhang, I. J. D. MacGregor, E. Golovatch, R. Dupre, Y. Ghandilyan, Q. Huang, E. Voutier, A. Vossen, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, J. C. Carvajal, S. Strauch, D. P. Watts, F. Bossu, Nikolaos Sparveris, Dinko Pocanic, S. E. Kuhn, M. Hattawy, Y. G. Sharabian, S. Boiarinov, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, U. Shrestha, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: High Energy Physics::Lattice, Nuclear Theory, Hadron, parton: distribution function, General Physics and Astronomy, Parton, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Economica, higher-twist, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), electron: beam, Nuclear Experiment, dimension: 1, Physics, Quantum chromodynamics, deep inelastic scattering: semi-inclusive reaction, Settore FIS/04, nucleon, kinematics, Quarks and Gluons, helicity distributions, quark: valence, Nucleon, Jefferson Lab, Quark, Particle physics, polarization: longitudinal, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Transversity Distributions, hadron: electroproduction, hadron: pair production, Pion, CLAS, Hadron Physics, quantum chromodynamics, 0103 physical sciences, ddc:530, 010306 general physics, High Energy Physics::Phenomenology, Ambientale, Deep inelastic scattering, spin: asymmetry: measured, Distribution function, Elementary Particles and Fields, QCD Dynamics, High Energy Physics::Experiment, pi: pair production, experimental results
Abstract: Physical review letters 126(6), 062002 (2021). doi:10.1103/PhysRevLett.126.062002, Published by APS, College Park, Md.
Published: 2021

20. Measurement of the proton spin structure at long distances

Author: P. Eugenio, J. Brock, N. Dashyan, I. Bedlinskiy, S. Choi, P. Nadel-Turonski, A. Hobart, M. Defurne, S. E. Kuhn, Latifa Elouadrhiri, P. Chatagnon, M. Ripani, C. D. Keith, D. Bulumulla, Aditya R. Khanal, S. Adhikari, B. McKinnon, T. Holmstrom, V. Mokeev, G. V. Fedotov, H. S. Jo, L. Guo, Alessandro Rizzo, Andrea Bianconi, L. Barion, M. Mirazita, K. Livingston, M. Hattawy, N. Markov, G. Rosner, Simon Širca, S. Fegan, Y. Ghandilyan, Jie Zhang, P. Bosted, Michael Paolone, C. Carlin, M. Guidal, M. L. Seely, E. Pasyuk, D. P. Watts, F. Bossu, Laura Clark, S. Niccolai, N. Guler, M. Holtrop, B. Yale, R. A. Schumacher, P. Rossi, W. Phelps, V. Mascagna, S. Joosten, Axel Schmidt, Alexandre Deur, Luciano Pappalardo, Nikolaos Sparveris, V. Crede, I. I. Strakovsky, W. Kim, Fatiha Benmokhtar, M. Ehrhart, D. I. Glazier, V. P. Kubarovsky, T. A. Forest, O. Pogorelko, Z. W. Zhao, J. Rowley, S. Stepanyan, A. I. Ostrovidov, K. Park, Krishna Neupane, R. De Vita, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. G. Ireland, C. W. Kim, H. Avakian, C. Mullen, W. K. Brooks, A. Kripko, Andrea Celentano, Volker D. Burkert, A. S. Biselli, J. C. Carvajal, V. Sulkosky, H. Atac, Karl Slifer, M. Leali, F. Sabatié, L. Venturelli, Y. G. Sharabian, X. Zheng, M. Bondì, H. Voskanyan, P. Lenisa, W. J. Briscoe, I. J. D. MacGregor, M. Contalbrigo, S. K. Phillips, T. Mineeva, T. B. Hayward, Friedrich Klein, Brian Raue, J. Poudel, N. Tyler, C. Djalali, G. Ciullo, M. Osipenko, Y. Prok, D. S. Carman, X. Wei, K. A. Griffioen, E. Voutier, Dustin Keller, S. Strauch, L. Lanza, R. W. Gothe, Michael Wood, T. Chetry, K. Hafidi, R. Dupre, M. Battaglieri, Gerard Gilfoyle, E. L. Isupov, V. A. Drozdov, S. Boiarinov, H. Kang, U. Shrestha, F.-X. Girod, K. P. Adhikari, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, R. G. Fersch, M. Ungaro, E. Long, J. P. Chen, D. Heddle, P. L. Cole, D. G. Meekins, A. D'Angelo, K. Hicks, L. El Fassi, K. Joo, M. Khandaker, M. J. Amaryan, A. Filippi, K. L. Giovanetti, Larry Weinstein, L. Marsicano, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: polarizabilities, Photon, Proton, High Energy Physics::Lattice, Nuclear Theory, General Physics and Astronomy, polarized target, polarized beam, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, High Energy Physics - Experiment, Theoretical Nuclear Physics, Experimental Nuclear Physics, High Energy Physics - Experiment (hep-ex), effective field theory, Economica, Proton spin crisis, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Experimental particle Physics, order, Nuclear Experiment (nucl-ex), Nuclear Experiment, Spin-½, Quantum chromodynamics, Physics, Settore FIS/04, nucleon, virtual compton-scattering, chiral perturbation-theory, sum-rule, moments, evolution, sum rule, kinematics, Quantum electrodynamics, nuclear matter, Nucleon, nucleon: structure, Strong interaction, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], p: spin, PE2_2, momentum transfer: low, PE2_1, CLAS, 0103 physical sciences, quantum chromodynamics, ddc:530, 010306 general physics, PE2_3, quark gluon, Coupling constant, nuclear force, scattering, Ambientale, Physics::Accelerator Physics, nucleon: spin, High Energy Physics::Experiment, experimental results
Abstract: Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV$^2$. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, e.g. in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections., Published version. 10 pages, 5 figures. 20 pages of supplementary material (data tables and a figure)
Published: 2021

21. Extraction of beam-spin asymmetries from the hard exclusive π+ channel off protons in a wide range of kinematics

Author: Y. G. Sharabian, K. Tezgin, S. E. Kuhn, M. Hattawy, S. Adhikari, M. Khachatryan, M. J. Amaryan, N. Tyler, P. Lenisa, C. Dilks, J. A. Tan, C. W. Kim, H. Avakian, B. McKinnon, Maxime Defurne, Laura Clark, K. A. Griffioen, Chaden Djalali, D. Bulumulla, T. Mineeva, L. Guo, G. Angelini, D. I. Glazier, B. S. Ishkhanov, S. Strauch, Aditya R. Khanal, F. X. Girod, T. B. Hayward, M. Guidal, D. P. Watts, K. L. Giovanetti, P. L. Cole, E. L. Isupov, E. Golovatch, G. Asryan, L. Lanza, R. De Vita, Alessandro Rizzo, Z. W. Zhao, V. Crede, R. Dupre, H. Voskanyan, Andrea Bianconi, N. Markov, Brian Raue, Y. Ghandilyan, S. Boiarinov, A. D'Angelo, M. Mirazita, M. Ehrhart, W. Phelps, W. J. Briscoe, A. Filippi, M. Holtrop, Victor Mokeev, U. Shrestha, L. El Fassi, H. Atac, P. Nadel-Turonski, M. Khandaker, Luciano Pappalardo, P. Eugenio, J. W. Price, O. Pogorelko, I. J. D. MacGregor, T. Chetry, M. Osipenko, J. Rowley, M. Ripani, Fatiha Benmokhtar, H. Hakobyan, O. Soto, M. Battaglieri, S. Diehl, Paolo Rossi, K. Park, Michael Paolone, A. Celentano, R. W. Gothe, D. Heddle, F. Bossu, D. G. Ireland, Hovanes Egiyan, C. Munoz Camacho, W. Kim, Axel Schmidt, G. Niculescu, P. Stoler, Volker D. Burkert, M. Contalbrigo, A. S. Biselli, M. Ungaro, I. I. Strakovsky, K. Hicks, A. Deur, Nicholas M. Harrison, Gerard Gilfoyle, D. Marchand, V. Mascagna, Eugene Pasyuk, W. K. Brooks, D. G. Jenkins, S. Joosten, L. Marsicano, V. P. Kubarovsky, K. P. Adhikari, M. Leali, D. Riser, Z. E. Meziani, Y. Prok, F. Sabatié, I. Bedlinskiy, P. Kroll, K. Joo, Dustin Keller, Michael Wood, A. Kim, K. Livingston, Jie Zhang, H. S. Jo, C. Salgado, A. El Alaoui, Y. Ilieva, P. Chatagnon, Nicholas Zachariou, J. C. Carvajal, K. Semenov-Tian-Shansky, N. Dashyan, E. Voutier, L. Venturelli, L. Barion, R. A. Schumacher, G. Ciullo, D. S. Carman, Nikos Sparveris, X. Wei, T. A. Forest, S. Stepanyan, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: Particle physics, generalized parton distribution, Partons, Nucleons, Compton Scattering, media_common.quotation_subject, General Physics and Astronomy, parton: distribution function, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Resonance (particle physics), Asymmetry, High Energy Physics - Experiment, Pion, PE2_2, PE2_1, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Nuclear Experiment, PE2_3, Spin-½, media_common, Physics, Settore FIS/04, electroproduction, moment, Moment (mathematics), distribution amplitude, High Energy Physics - Phenomenology, Amplitude, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Elementary Particles and Fields, High Energy Physics::Experiment, Center of mass, asymmetry, experimental results
Abstract: We have measured beam-spin asymmetries to extract the \ud sin\ud ϕ\ud moment \ud A\ud sin\ud ϕ\ud L\ud U\ud from the hard exclusive \ud →\ud e\ud p\ud →\ud e\ud ′\ud n\ud π\ud +\ud reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The \ud A\ud sin\ud ϕ\ud L\ud U\ud moment has been measured up to \ud 6.6\ud \ud \ud GeV\ud 2\ud in \ud −\ud t\ud , covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found \ud A\ud sin\ud ϕ\ud L\ud U\ud to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.
Published: 2020

22. Exclusive π0p electroproduction off protons in the resonance region at photon virtualities 0.4GeV2≤Q2≤1GeV2

Author: P. Eugenio, M. Taiuti, Carlos A. Salgado, L. C. Smith, I. I. Strakovsky, B. S. Ishkhanov, R. Dupre, M. Battaglieri, Aditya R. Khanal, A. Deur, R. A. Schumacher, M. Contalbrigo, Michael Paolone, F. Bossu, C. Evans, Maxime Defurne, N. Tyler, C. Djalali, J. A. Tan, K. A. Griffioen, Pawel Nadel-Turonski, Fatiha Benmokhtar, O. Soto, R. De Vita, M. Ungaro, S. Niccolai, L. Lanza, A. D'Angelo, A. Kim, Alessandro Rizzo, T. Mineeva, S. Stepanyan, W. Kim, U. Shrestha, V. Crede, L. El Fassi, T. B. Hayward, H. Atac, R. Paremuzyan, P. Stoler, K. Joo, D. G. Jenkins, M. Leali, K. Hicks, G. Ciullo, William Brooks, N. Markov, M. Guidal, G. Niculescu, Y. Prok, L. Venturelli, W. Phelps, E. De Sanctis, V. Mascagna, I. Bedlinskiy, E. Golovatch, D. S. Carman, A. Celentano, R. W. Gothe, E. L. Isupov, M. Holtrop, Nikos Sparveris, C. W. Kim, Luciano Pappalardo, X. Wei, F. X. Girod, S. Boiarinov, G. Angelini, H. Avakian, J. W. Price, P. L. Cole, G. Rosner, N. A. Baltzell, T. Chetry, J. Rowley, K. Park, D. Sokhan, Y. Ghandilyan, F. Sabatié, Y. G. Sharabian, H. Hakobyan, H. S. Jo, E. Voutier, S. Diehl, D. G. Ireland, I. J. D. MacGregor, N. Dashyan, Volker D. Burkert, A. S. Biselli, S. Strauch, S. Adhikari, M. H. Wood, M. Osipenko, P. Chatagnon, B. McKinnon, Yordanka Ilieva, V. Mokeev, M. Mirazita, Rong Wang, M. Ehrhart, L. Barion, M. Hattawy, H. Voskanyan, S. K. Nanda, M. Ripani, M. Khachatryan, W. J. Briscoe, D. Marchand, E. Pasyuk, V. P. Kubarovsky, D. Riser, A. El Alaoui, C. Ayerbe Gayoso, Nicholas Zachariou, J. C. Carvajal, O. Pogorelko, D. Protopopescu, Frank Klein, Dustin Keller, K. Livingston, K. Hafidi, M. J. Amaryan, A. Filippi, and M. Khandaker
Subjects: Physics, Range (particle radiation), Photon, Proton, 010308 nuclear & particles physics, Resonance, 01 natural sciences, Nuclear physics, Cross section (physics), Isospin, 0103 physical sciences, Invariant mass, 010306 general physics, Legendre polynomials
Abstract: The exclusive electroproduction process ep→e′p′π0 was measured in the range of photon virtualities Q2=0.4–1.0GeV2 and the invariant mass range of the pπ0 system of W=1.1–1.8 GeV. These kinematics are covered in exclusive π0 electroproduction off the proton with nearly complete angular coverage in the pπ0 center-of-mass system and with high statistical accuracy. Nearly 36 000 cross-section points were measured, and the structure functions σT+eσL,σLT, and σTT, were extracted via fitting the ϕπ0 dependence of the cross section. A Legendre polynomial expansion analysis demonstrates the sensitivity of our data to high-lying N* and Δ* resonances with M>1.6 GeV. As part of a broad effort to determine the electrocouplings of the N* and Δ* resonances using both single- and double-pion electroproduction, this dataset is crucial for the reliable extraction of the high-lying resonance electrocouplings from the combined isospin analysis of the Nπ and π+π−p channels.
Published: 2020

23. Beam–target helicity asymmetry $E$ in $K^+$ $\Sigma^-$ photoproduction on the neutron

Author: R. De Vita, D. Marchand, H. Atac, H. S. Jo, A. Filippi, L. Marsicano, N. K. Walford, O. Soto, M. Khandaker, I. J. D. MacGregor, K. Hicks, W. Phelps, R. A. Schumacher, Michael Paolone, H. Hakobyan, W. Kim, G. Charles, F. Bossu, H. Lu, S. Joosten, J. W. Price, S. Diehl, C. Salgado, William Brooks, L. Venturelli, D. Heddle, V. P. Kubarovsky, I. Bedlinskiy, Z. E. Meziani, V. Mascagna, A. Celentano, R. W. Gothe, N. Markov, Alessandro Rizzo, W. Gohn, G. Asryan, Axel Schmidt, Dustin Keller, M. Ungaro, M. Guidal, M. Contalbrigo, M. Osipenko, Z. W. Zhao, Fatiha Benmokhtar, E. L. Isupov, Y. Prok, J. Poudel, O. Pogorelko, A. I. Ostrovidov, K. Park, M. J. Amaryan, Michael Wood, K. Hafidi, M. Holtrop, M. Ehrhart, C.D. Bass, V. A. Nikonov, A. D'Angelo, D. G. Jenkins, D. G. Ireland, G. Rosner, S. Boiarinov, E. Golovatch, P. Eugenio, K. Livingston, Luciano Pappalardo, K. Joo, M. Leali, Jie Zhang, T. Kageya, Volker D. Burkert, Y. Ghandilyan, A. S. Biselli, C. W. Kim, G. Gavalian, U. Shrestha, F.-X. Girod, Gerard Gilfoyle, M. Ripani, R. G. Fersch, H. Voskanyan, A. El Alaoui, G. Angelini, Nicholas Zachariou, J. C. Carvajal, W. J. Briscoe, P. L. Cole, T. Chetry, N. Gevorgyan, D. Ho, I. I. Strakovsky, A. M. Sandorfi, A. Deur, Victor Mokeev, D. Sokhan, T. R. O'Connell, Chaden Djalali, P. Nadel Turonski, T. Mineeva, M. Bashkanov, S. Adhikari, D. Bulumulla, E. Munevar, B. McKinnon, B. S. Ishkhanov, Aditya R. Khanal, Andrea Bianconi, I. Zonta, X. Wei, P. Peng, Hovanes Egiyan, C. Munoz Camacho, P. Lenisa, M. Hattawy, J. A. Fleming, Friedrich Klein, Brian Raue, Andrew Puckett, E. Voutier, Martin K. Mayer, M. Khachatryan, K. A. Griffioen, Nikolaos Sparveris, K. P. Adhikari, C. S. Whisnant, C. Hanretty, L. Lanza, R. Dupre, M. Battaglieri, M. Lowry, S. Strauch, Eugene Pasyuk, N. Dashyan, Yordanka Ilieva, L. Barion, G. Ciullo, D. S. Carman, S. Fegan, D. P. Watts, A. V. Sarantsev, N. Tyler, J. A. Tan, P. Chatagnon, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: Nuclear and High Energy Physics, Socio-culturale, nucleon resonance, Nucleons, Photoproduction, Mesons, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, K+: photoproduction, Particle identification, Nuclear physics, chemistry.chemical_compound, PE2_2, PE2_1, CLAS, 0103 physical sciences, Neutron, Hydrogen deuteride, n: target, 010306 general physics, Nuclear Experiment, PE2_3, photon: beam, Physics, 010308 nuclear & particles physics, nucleus: target, Settore FIS/04, Resonance, helicity: asymmetry, Observable, Sigma-: photoproduction, Helicity, lcsh:QC1-999, chemistry, Excited state, spectrometer, Nucleon, lcsh:Physics, Jefferson Lab, experimental results
Abstract: We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2− resonance, are also quantified.
Published: 2020

24. 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

25. Photon beam asymmetry Σ in the reaction γ→p→pω for E= 1.152 to 1.876 GeV

Author: G. Khachatryan, W. Kim, M. Battaglieri, N. K. Walford, G. Niculescu, L. Lanza, Michael Paolone, M. Bashkanov, S. Adhikari, H. Avakian, F. X. Girod, W. J. Briscoe, Laura Clark, B. McKinnon, P. Lenisa, T. Cao, M. Ungaro, I. J. D. MacGregor, F. Sabatié, I. I. Strakovsky, H. Voskanyan, A. Kim, E. De Sanctis, V. A. Nikonov, A. Deur, E. Pasyuk, J. W. Price, N. Dashyan, C. Gleason, G. Rosner, K. Hicks, V. Mokeev, P. Nadel-Turonski, V. Batourine, I. Bedlinskiy, D. I. Sober, S. Strauch, V. Crede, William Brooks, Dustin Keller, M. Defurne, Y. Ghandilyan, D. P. Watts, Barry Ritchie, Brian Raue, Alessandro Rizzo, C. Hanretty, H. Egiyan, E. Golovatch, R. Dupre, R. A. Montgomery, A. Celentano, R. W. Gothe, M. Khachatryan, Sylvester Joosten, B. S. Ishkhanov, G. Charles, Michael Wood, J. Ball, K. Hafidi, W. Phelps, H. S. Jo, A. V. Sarantsev, G. Ciullo, Y. Prok, D. I. Glazier, D. S. Carman, A. Simonyan, O. Cortes, N. A. Baltzell, C. Munoz Camacho, Nikos Sparveris, F. J. Klein, M. Ripani, M. Contalbrigo, Z. E. Meziani, E. L. Isupov, S. Niccolai, D. G. Jenkins, M. Osipenko, K. A. Griffioen, R. Paremuzyan, Eberhard Klempt, S. Boiarinov, N. Markov, V. P. Kubarovsky, A. Movsisyan, R. De Vita, Nicholas M. Harrison, O. Pogorelko, Gerard Gilfoyle, J. Zhang, S. M. Hughes, X. Wei, S. Pisano, D. Sokhan, I. Stankovic, A. V. Anisovich, C. A. Meyer, Z. Akbar, G. V. Fedotov, I. Niculescu, C. Salgado, P. L. Cole, A. I. Ostrovidov, K. Park, R. A. Schumacher, D. G. Ireland, H. Jiang, H. Hakobyan, S. Anefalos Pereira, Volker D. Burkert, A. S. Biselli, L. El Fassi, K. P. Adhikari, S. Stepanyan, E. Munevar, L. A. Net, Avraham Klein, Y. G. Sharabian, J. A. Fleming, Iu. Skorodumina, D. Heddle, G. Hollis, P. Eugenio, M. Taiuti, P. Collins, S. Procureur, K. L. Giovanetti, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, A. Filippi, M. Khandaker, K. Livingston, M. Hattawy, D. Protopopescu, Z. W. Zhao, E. Voutier, Chaden Djalali, Michael Dugger, T. Mineeva, F. Cao, D. Adikaram, M. Guidal, G. D. Smith, M. Holtrop, Taya Chetry, and Sergey Kuleshov
Subjects: Physics, Nuclear and High Energy Physics, Photon, Meson, Proton, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Photon energy, 01 natural sciences, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ → p → ω p are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the J P = 3 / 2 + partial wave), as well as the resonant portions of the smaller partial waves with J P = 1 / 2 − , 3 / 2 − , and 5 / 2 + .
Published: 2017

26. First results on nucleon resonance photocouplings from the γp → π+π−p reaction

Author: I. Bedlinskiy, J. Ball, F. Cao, E. De Sanctis, M. Guidal, R. Paremuzyan, N. Markov, Y. G. Sharabian, D. I. Sober, Maxime Defurne, D. I. Glazier, I. J. D. MacGregor, R. De Vita, P. Eugenio, I. I. Strakovsky, D. Protopopescu, G. D. Smith, M. Holtrop, Z. W. Zhao, Nicholas M. Harrison, Gerard Gilfoyle, M. Taiuti, E. Voutier, A. Deur, M. Contalbrigo, M. Khachatryan, D. Sokhan, Latifa Elouadrhiri, M. L. Kabir, M. J. Amaryan, G. Ciullo, C. A. Meyer, M. Khandaker, P. Chatagnon, Y. Prok, D. S. Carman, G. V. Fedotov, Z. Akbar, F. X. Girod, Sandra K. Johnston, K. Livingston, M. Hattawy, Nikos Sparveris, K. A. Griffioen, E. Golovatch, R. Dupre, A. I. Ostrovidov, K. Park, Jie Zhang, S. Niccolai, Hovanes Egiyan, Taya Chetry, C. Munoz Camacho, A. Movsisyan, D. G. Ireland, V. Crede, F. Sabatié, Volker D. Burkert, A. S. Biselli, P. Lenisa, M. Bashkanov, S. Adhikari, B. McKinnon, K. L. Giovanetti, S. Strauch, L. Lanza, J. W. Price, V. I. Mokeev, M. Ripani, R. A. Montgomery, D. Marchand, X. Wei, D. Heddle, A. El Alaoui, Y. Ilieva, M. Battaglieri, B. A. Clary, Nicholas Zachariou, Friedrich Klein, Iu. Skorodumina, H. Hakobyan, Michael Paolone, D. G. Jenkins, N. Dashyan, S. Diehl, C. Salgado, H. S. Jo, A. Filippi, Laura Clark, L. Barion, E. L. Isupov, Michael Dugger, S. Boiarinov, R. A. Schumacher, Avraham Klein, P. Nadel-Turonski, M. Ungaro, K. Joo, N. Tyler, C. Djalali, J. A. Tan, Dustin Keller, B. S. Ishkhanov, Michael Wood, K. Hafidi, H. Avakian, H. Voskanyan, E. Pasyuk, V. P. Kubarovsky, D. Riser, O. Pogorelko, G. Khachatryan, W. J. Briscoe, G. Rosner, Y. Ghandilyan, K. Hicks, L. Guo, Alessandro Rizzo, R. G. Fersch, P. L. Cole, A. D'Angelo, L. El Fassi, M. Osipenko, Rong Wang, M. Ehrhart, W. Kim, G. Niculescu, A. Celentano, and R. W. Gothe
Subjects: Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, Two pion photoproduction, Socio-culturale, Elementary particle, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Particle decay, Pion, 0103 physical sciences, Invariant mass, Resonance photocouplings, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Resonance, lcsh:QC1-999, Baryon state, High Energy Physics::Experiment, Nucleon, lcsh:Physics
Abstract: We report the first experimental measurements of the nine 1-fold differential cross sections for the γp→π+π−p reaction, obtained with the CLAS detector at Jefferson Laboratory. The measurements cover the invariant mass range of the final state hadrons from 1.6 GeV Δ(1620)1/2−, Δ(1700)3/2−, N(1720)3/2+, and Δ(1905)5/2+ resonances, which have dominant decays into the ππN final states rather than the more extensively studied single meson decay channels.
Published: 2019

27. Ξ* photoproduction from threshold to W=3.3GeV

Author: Frank Klein, Dustin Keller, K. Hafidi, E. Golovatch, Y. G. Sharabian, K. Hicks, M. Ripani, C. Bookwalter, K. A. Griffioen, L. Lanza, H. Egiyan, V. Crede, I. J. D. MacGregor, M. Contalbrigo, S. Adhikari, M. Hattawy, C. Munoz Camacho, M. H. Wood, B. McKinnon, I. Bedlinskiy, D. Protopopescu, Michael Dugger, M. Osipenko, L. Elouadrhiri, M. Khachatryan, M. S. Saini, G. Ciullo, P. Eugenio, M. Taiuti, A. El Alaoui, Carlos A. Salgado, F. Cao, W. Kim, I. I. Strakovsky, Maxime Defurne, A. Deur, J. T. Goetz, Y. Prok, D. S. Carman, M. Mirazita, Nikos Sparveris, B. S. Ishkhanov, Nicholas Zachariou, M. L. Kabir, Diane Schott, Michael Paolone, C. A. Meyer, A. I. Ostrovidov, K. Park, X. Wei, N. Gevorgyan, D. I. Glazier, P. Chatagnon, G. V. Fedotov, D. G. Ireland, R. De Vita, M. Guidal, E. Voutier, A. Movsisyan, J. Zhang, F. Sabatié, G. Niculescu, S. Chandavar, V. P. Kubarovsky, Volker D. Burkert, A. S. Biselli, K. Livingston, J. W. Price, A. Celentano, R. W. Gothe, S. Anefalos Pereira, R. Paremuzyan, D. Riser, V. Mokeev, D. P. Weygand, A. Filippi, M. C. Kunkel, Brian Raue, O. Pogorelko, Nicholas M. Harrison, Rong Wang, M. Holtrop, S. Niccolai, R. Dupre, M. Battaglieri, M. Khandaker, Alessandro Rizzo, D. Sokhan, D. I. Sober, L. Guo, M. Ehrhart, M. Ungaro, Pawel Nadel-Turonski, H. Voskanyan, W. J. Briscoe, E. Pasyuk, Iu. Skorodumina, D. Heddle, Taya Chetry, William Brooks, P. L. Cole, Z. W. Zhao, R. A. Schumacher, A. D'Angelo, F. X. Girod, L. El Fassi, S. Strauch, E. L. Isupov, S. Boiarinov, H. Hakobyan, H. S. Jo, S. Diehl, Sylvester Joosten, C. Djalali, J. A. Tan, G. Khachatryan, N. Dashyan, A. Kim, G. Rosner, and Y. Ghandilyan
Subjects: Quark, Physics, Particle physics, 010308 nuclear & particles physics, Nuclear Theory, Quark model, Lattice field theory, 01 natural sciences, Xi baryon, Baryon, Lattice (order), Excited state, 0103 physical sciences, High Energy Physics::Experiment, Gauge theory, Nuclear Experiment, 010306 general physics
Abstract: The doubly strange Xi baryons provide an effective way to study a puzzle called the missing-baryons problem where both quark models and lattice guage theory predict more baryon excited states than are seen experimentally. However, few of these excited states have been observed with any certainty. Here, high-mass Xi* states have been searched for in photoproduction with the detector of the CLAS collaboration, and upper limits for the total cross sections have been established from threshold to W = 3.3 GeV. In addition, the total cross sections of the ground-state Xi(-)(1320) and first excited state Xi(-)(1530) are presented, extending significantly the centre-of-mass energy range of previous data.
Published: 2018

28. The CLAS12 forward electromagnetic calorimeter

Author: G. Asryan, Sh. Chandavar, T. Chetry, N. Compton, A. Daniel, N. Dashyan, N. Gevorgyan, Y. Ghandilyan, K. Giovanetti, K. Griffioen, K. Hicks, D. Kashy, G. Khachatryan, M. Khandaker, W. Phelps, J. Riso, A. Simonyan, C. Salgado, C. Smith, S. Stepanyan, W. Tang, H. Voskanyan, and M. Yurov
Subjects: Nuclear and High Energy Physics, Instrumentation
Published: 2020

29. Beam-target helicity asymmetry E in K0Λ and K0Σ0 photoproduction on the neutron

Author: P. Lenisa, M. Ungaro, D. G. Ireland, C. A. Meyer, R. Dupre, V. Crede, C.D. Bass, V. A. Nikonov, M. Battaglieri, P. Chatagnon, G. V. Fedotov, R. A. Montgomery, Ron L. Workman, R. Paremuzyan, R. A. Schumacher, C. S. Whisnant, K. P. Adhikari, A. Fradi, M. Osipenko, D. G. Jenkins, Nicholas M. Harrison, N. Markov, Martin K. Mayer, K. A. Griffioen, I. Zonta, I. J. D. MacGregor, A. Kim, H. Hakobyan, M. Khachatryan, D. Sokhan, H. S. Jo, Tim O'Connell, D. Marchand, S. Diehl, M. Bashkanov, B. McKinnon, A. I. Ostrovidov, K. Park, V. Mokeev, G. Khachatryan, L. Lanza, Eberhard Klempt, P. Collins, S. Niccolai, F. X. Girod, M. Contalbrigo, Sandra K. Johnston, P. Eugenio, T. Chetry, Volker D. Burkert, A. S. Biselli, Pawel Nadel-Turonski, M. Mirazita, J. Zhang, Rong Wang, J. W. Price, Alessandro Rizzo, S. Strauch, Iu. Skorodumina, C. Hanretty, George Davey Smith, M. Taiuti, C. Djalali, J. A. Tan, E. Golovatch, Y. G. Sharabian, M. Lowry, G. Charles, K. L. Giovanetti, I. Bedlinskiy, M. Rehfuss, K. Hicks, S. Adhikari, M. L. Kabir, M. Ehrhart, F. Sabatié, Andreas Klein, V. Laine, F. Cao, D. Adikaram, M. Guidal, W. Kim, Larry Weinstein, Z. Akbar, G. Rosner, P. Peng, C. Munoz Camacho, M. H. Wood, M. Hattawy, G. Niculescu, J. A. Fleming, I. I. Strakovsky, M. Holtrop, A. Filippi, A. D'Angelo, M. Ripani, Y. Ghandilyan, Carlos A. Salgado, B. A. Clary, A. M. Sandorfi, B. S. Ishkhanov, M. Khandaker, D. I. Sober, A. Deur, Hong Lu, Michael Paolone, D. Ho, S. Fegan, A. Celentano, R. W. Gothe, D. Heddle, Maxime Defurne, E. L. Isupov, W. Gohn, S. Boiarinov, R. De Vita, T. Kageya, L. El Fassi, N. K. Walford, R. G. Fersch, Frank Klein, P. L. Cole, Z. W. Zhao, Dustin Keller, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, X. Wei, K. Hafidi, E. Voutier, A. Movsisyan, Yordanka Ilieva, L. Barion, V. P. Kubarovsky, D. Riser, A. El Alaoui, Nicholas Zachariou, O. Pogorelko, K. Livingston, H. Voskanyan, D. Protopopescu, W. J. Briscoe, E. Pasyuk, D. P. Watts, H. Egiyan, A. V. Sarantsev, and S. Chandavar
Subjects: Physics, Strange quark, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Quark model, Hyperon, 01 natural sciences, Helicity, Asymmetry, Pseudoscalar meson, Nuclear physics, 13. Climate action, Isospin, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, media_common
Abstract: We report the first measurements of the E beam-target helicity asymmetry for the γn→K0Λ and K0Σ0 channels in the energy range 1.70≤W≤2.34 GeV. The CLAS system at Jefferson Lab uses a circularly polarized photon beam and a target consisting of longitudinally polarized solid molecular hydrogen deuteride with low background contamination for the measurements. The multivariate analysis method boosted decision trees is used to isolate the reactions of interest. Comparisons with predictions from the KaonMAID, SAID, and Bonn-Gatchina models are presented. These results will help separate the isospin I=0 and I=1 photocoupling transition amplitudes in pseudoscalar meson photoproduction.
Published: 2018

30. Center of Mass Motion of Short-Range Correlated Nucleon Pairs studied via the A(e,e′pp) Reaction

Author: D. Protopopescu, Z. W. Zhao, E. Voutier, M. Duer, D. Marchand, X. Wei, Dustin Keller, P. Eugenio, I. J. D. MacGregor, G. Ciullo, M. Taiuti, C. Djalali, J. A. Tan, W. Kim, Y. Prok, F. Sabatié, L. Lanza, J. P. Ball, D. S. Carman, G. Niculescu, M. L. Kabir, P. Lenisa, S. Strauch, Michael Wood, K. Hafidi, B. A. Clary, K. Livingston, D. G. Jenkins, S. Niccolai, A. Movsisyan, Jie Zhang, Michael Paolone, D. Heddle, A. Celentano, R. W. Gothe, N. Dashyan, Maxime Defurne, H. Avakian, S. E. Kuhn, Friedrich Klein, M. Contalbrigo, A. Beck, Hovanes Egiyan, C. Munoz Camacho, M. Osipenko, M. Ungaro, Eli Piasetzky, H. Voskanyan, R. Fersch, Or Hen, Z. Akbar, L. Barion, R. De Vita, P. Nadel-Turonski, V. Crede, Alessandro Rizzo, Eliahu Cohen, E. Golovatch, R. Dupre, W. J. Briscoe, E. Pasyuk, A. El Alaoui, R. A. Montgomery, R. Paremuzyan, V. Mokeev, M. Battaglieri, M. Ripani, F. Hauenstein, B. S. Ishkhanov, Nicholas M. Harrison, Nicholas Zachariou, Rong Wang, D. Sokhan, Alexander Schmidt, D. P. Watts, S. Adhikari, K. Hicks, B. McKinnon, E. De Sanctis, S. Mey-Tal Beck, A. Kim, V. P. Kubarovsky, Y. G. Sharabian, D. Riser, A. I. Ostrovidov, A. Filippi, P. Rossi, X. Zheng, M. Ehrhart, O. Pogorelko, M. Mirazita, A. Deur, D. G. Ireland, I. Bedlinskiy, M. Khachatryan, M. Khandaker, Nikolaos Sparveris, Volker D. Burkert, A. S. Biselli, M. J. Amaryan, Sandra K. Johnston, K. L. Giovanetti, Larry Weinstein, B. Schmookler, C. A. Meyer, P. Chatagnon, G. V. Fedotov, F. Cao, I. Korover, B. Mustapha, M. Holtrop, Taya Chetry, G. Charles, E. L. Isupov, S. Boiarinov, R. Cruz Torres, H. Hakobyan, S. Diehl, F. X. Girod, J. W. Price, R. A. Schumacher, S. Stepanyan, Avraham Klein, H. S. Jo, A. D'Angelo, L. El Fassi, G. Khachatryan, G. Rosner, Y. Ghandilyan, and K. A. Griffioen
Subjects: Physics, Range (particle radiation), 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Momentum, medicine.anatomical_structure, Quantum state, 0103 physical sciences, medicine, Nuclear force, Center of mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Fermi Gamma-ray Space Telescope
Abstract: Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.
Published: 2018

31. Measurements of the γvp→p′π+π− cross section with the CLAS detector for 0.4GeV2<Q2<1.0GeV2 and 1.3GeV<W<1.825GeV

Author: Z. W. Zhao, S. Strauch, Whitney Armstrong, M. Battaglieri, K. Park, Volker D. Burkert, H. Hakobyan, R. A. Schumacher, A. S. Biselli, P. Eugenio, T. Mineeva, Barry Ritchie, M. Khandaker, Y. Ilieva, M. Khachatryan, S. Johnston, N. Markov, M. Hattawy, I. Bedlinskiy, Nicholas Zachariou, M. L. Kabir, Maxime Defurne, F. X. Girod, G. Khachatryan, G. Charles, D. G. Ireland, P. Nadel-Turonski, B. A. Clary, Y. Prok, F. Sabatié, X. Wei, R. De Vita, K. Hicks, Michael Paolone, S. Procureur, M. Ungaro, R. A. Montgomery, Sylvester Joosten, M. Osipenko, K. Livingston, J. W. Price, G. Ciullo, J. P. Ball, D. S. Carman, D. Heddle, K. A. Griffioen, I. I. Strakovsky, G. D. Smith, M. Holtrop, S. Niccolai, I. J. D. MacGregor, Jie Zhang, Avraham Klein, Nikos Sparveris, A. Deur, Hovanes Egiyan, C. Munoz Camacho, A. D'Angelo, V. Mokeev, E. De Sanctis, Y. Ghandilyan, N. Dashyan, G. V. Fedotov, A. Celentano, R. W. Gothe, R. Paremuzyan, Taya Chetry, L. Lanza, P. Lenisa, W. K. Brooks, Nicholas M. Harrison, Gerard Gilfoyle, D. I. Sober, M. Ripani, A. Kim, D. Sokhan, G. Gavalian, Y. G. Sharabian, D. G. Jenkins, M. Bashkanov, S. Adhikari, Iu. Skorodumina, B. McKinnon, L. Guo, Sergey Kuleshov, W. Kim, G. Niculescu, E. Golovatch, R. Dupre, L. El Fassi, Alessandro Rizzo, V. Batourine, L. Barion, Friedrich Klein, M. Contalbrigo, N. Tyler, C. Djalali, J. A. Tan, C. Hanretty, H. S. Jo, B. S. Ishkhanov, M. Taiuti, R. G. Fersch, P. L. Cole, C. Salgado, O. Cortes, E. L. Isupov, S. Boiarinov, D. Protopopescu, E. Voutier, I. Balossino, Dustin Keller, Michael Wood, K. Hafidi, H. Avakian, H. Voskanyan, W. J. Briscoe, E. Pasyuk, V. P. Kubarovsky, D. Riser, and O. Pogorelko
Subjects: Physics, Photon, 010308 nuclear & particles physics, Detector, 01 natural sciences, Nuclear physics, Cross section (physics), Reaction model, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: New results on the single-differential and fully integrated cross sections for the process γvp→p′π+π- are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q2 from 0.4 to 1.0 GeV2. The cross sections were obtained in narrow Q2 bins (0.05 GeV2) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in agreement with previously available data where they overlap. A preliminary interpretation of the extracted cross sections, which was based on a phenomenological meson-baryon reaction model, revealed substantial relative contributions from nucleon resonances. The data offer promising prospects to improve knowledge on the Q2 evolution of the electrocouplings of most resonances with masses up to ∼1.8 GeV.
Published: 2018

32. Exclusive photoproduction of π0 up to large values of Mandelstam variables s,t, and u with CLAS

Author: S. Adhikari, S. E. Kuhn, M. Hattawy, P. Eugenio, Taya Chetry, E. Golovatch, M. Taiuti, D. Lersch, M. L. Kabir, E. De Sanctis, Carlos A. Salgado, Michael Paolone, S. Procureur, D. I. Sober, D. Protopopescu, G. V. Fedotov, A. Roy, M. Ripani, M. Khachatryan, D. P. Weygand, R. Dupre, M. Battaglieri, Maxime Defurne, M. C. Kunkel, J. Ritman, F. Cao, M. Guidal, Michael Dugger, G. Gavalian, V. P. Kubarovsky, O. Pogorelko, D. I. Glazier, G. Niculescu, P. Lenisa, A. El Alaoui, Barry Ritchie, Iu. Skorodumina, I. Balossino, D. G. Ireland, V. Crede, Frank Klein, I. Bedlinskiy, K. A. Griffioen, R. De Vita, W. Gohn, V. Mokeev, M. Holtrop, L. Elouadrhiri, Y. G. Sharabian, Andreas Klein, Nicholas Zachariou, G. Mbianda Njencheu, W. Phelps, R. A. Schumacher, Dustin Keller, I. I. Strakovsky, A. Filippi, A. Deur, C. Djalali, R. A. Montgomery, K. Hafidi, V. Batourine, H. Avakian, J. A. Tan, L. Lanza, A. D'Angelo, D. P. Watts, D. G. Jenkins, H. Voskanyan, K. Livingston, F. Sabatié, H. Egiyan, M. Khandaker, S. Niccolai, J. Zhang, S. Bültmann, W. J. Briscoe, E. Pasyuk, Alessandro Rizzo, L. El Fassi, J. W. Price, C. E. Hyde, F. X. Girod, L. Guo, M. Ungaro, T. Mineeva, R. G. Fersch, Pawel Nadel-Turonski, P. L. Cole, Z. W. Zhao, K. Hicks, Laura Clark, W. Kim, K. Joo, S. Strauch, G. Charles, B. S. Ishkhanov, O. Cortes, G. Ciullo, E. L. Isupov, J. P. Ball, Y. Prok, D. S. Carman, D. Payette, M. Osipenko, S. Boiarinov, Nikos Sparveris, X. Wei, I. J. D. MacGregor, K. P. Adhikari, A. Kim, E. Voutier, A. Movsisyan, N. Dashyan, H. Hakobyan, S. Stepanyan, L. Barion, M. J. Amaryan, K. L. Giovanetti, Larry Weinstein, G. Khachatryan, S. Schadmand, William Brooks, G. Rosner, S. Ghosh, Y. Ghandilyan, P. V. Degtyarenko, A. Celentano, R. W. Gothe, M. Contalbrigo, C. Munoz Camacho, J. Poudel, B. McKinnon, J. M. Laget, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Fradi, N. Markov, A. I. Ostrovidov, K. Park, G. R. Goldstein, Volker D. Burkert, and A. S. Biselli
Subjects: Quark, Quantum chromodynamics, Physics, Meson, 010308 nuclear & particles physics, Perturbative QCD, Parton, Mandelstam variables, Photon energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Sum rule in quantum mechanics, 010306 general physics
Abstract: Exclusive photoproduction cross sections have been measured for the process γ p → p π 0 [ e + e − ( γ ) ] with the Dalitz decay final state using tagged photon energies in the range of E γ = 1.275 – 5.425 GeV. The complete angular distribution of the final state π 0 , for the entire photon energy range up to large values of t and u , has been measured for the first time. The data obtained show that the cross section d σ / d t , at mid to large angles, decreases with energy as s − 6.89 ± 0.26 . This is in agreement with the perturbative QCD quark counting rule prediction of s − 7 . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s = 11 GeV 2 . At the same time, the Regge-exchange-based models for π 0 photoproduction are more consistent with experimental data.
Published: 2018

33. Differential cross section for γd → ωd using CLAS at Jefferson Lab

Author: R. W. Gothe, I. J. D. MacGregor, M. Contalbrigo, K. A. Griffioen, S. Adhikari, S. Strauch, V. Crede, Taya Chetry, A. Filippi, I. I. Strakovsky, A. Deur, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, E. Voutier, Misak Sargsian, M. Khandaker, L. Lanza, S. Niccolai, A. El Alaoui, Y. Ilieva, N. Compton, A. Movsisyan, M. Khachatryan, E. De Sanctis, Nicholas Zachariou, I. Bedlinskiy, W. K. Brooks, B. McKinnon, E. L. Isupov, M. Battaglieri, Iu. Skorodumina, P. Eugenio, M. Osipenko, M. Taiuti, R. A. Schumacher, Laura Clark, P. Lenisa, D. I. Sober, S. Boiarinov, M. L. Kabir, G. Charles, A. Kim, K. Livingston, M. Hattawy, A. D'Angelo, E. Golovatch, D. G. Jenkins, G. D. Smith, R. Dupre, N. Markov, Jie Zhang, M. Holtrop, Friedrich Klein, K. L. Giovanetti, Andrea Celentano, S. Stepanyan, Larry Weinstein, G. V. Fedotov, R. De Vita, C. Salgado, V. Batourine, L. El Fassi, P. Nadel-Turonski, N. Dashyan, G. Gavalian, V. Mokeev, Z. W. Zhao, R. Paremuzyan, Nicholas M. Harrison, F. X. Girod, L. Barion, S. Johnston, J. W. Price, M. Ripani, B. A. Clary, Michael Paolone, Barry Ritchie, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, C. Djalali, J. A. Tan, D. Sokhan, W. Kim, C. Munoz Camacho, G. Niculescu, R. G. Fersch, P. L. Cole, M. Ungaro, H. Voskanyan, B. S. Ishkhanov, E. Pasyuk, V. P. Kubarovsky, D. Riser, O. Pogorelko, I. Balossino, G. Khachatryan, Dustin Keller, W. J. Briscoe, Michael Wood, K. Hafidi, L. Guo, Alessandro Rizzo, K. Hicks, W. Phelps, G. Rosner, and Y. Ghandilyan
Subjects: Vector Meson Dominance, Nuclear and High Energy Physics, Meson, Nuclear Theory, Socio-culturale, Double scattering, Photon energy, 01 natural sciences, 7. Clean energy, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Cross section (physics), 0103 physical sciences, 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Scattering, Momentum transfer, Differential cross section, Single scattering, Vector meson dominance, lcsh:QC1-999, Deuterium, High Energy Physics::Experiment, lcsh:Physics
Abstract: The cross section for coherent ω-meson photoproduction off the deuteron has been measured for the first time as a function of the momentum transfer t=(Pγ−Pω)2 and photon energy Eγ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are measured in the energy range 1.4
Published: 2018

34. Measurement of the Q2 Dependence of the Deuteron Spin Structure Function g1 and its Moments at Low Q2 with CLAS

Author: I. Balossino, K. Kovacs, C. E. Hyde, Taya Chetry, P. Lenisa, Friedrich Klein, E. De Sanctis, D. G. Meekins, R. A. Schumacher, R. W. Gothe, L. El Fassi, Latifa Elouadrhiri, Y. Prok, Michael Paolone, L. Lanza, V. Crede, K. Park, C. A. Meyer, C. Munoz Camacho, J. Brock, G. V. Fedotov, J. P. Chen, K. Livingston, V. P. Kubarovsky, X. Zheng, A. D'Angelo, D. Heddle, B. McKinnon, M. Battaglieri, P. L. Cole, V. A. Drozdov, S. Bültmann, Maxime Defurne, G. Khachatryan, H. Avakian, M. Hattawy, J. A. Tan, K. P. Adhikari, N. Markov, M. Mirazita, Martin K. Mayer, H. Kang, K. Hafidi, S. Strauch, K. Joo, J. Pierce, Avraham Klein, K. Hicks, M. J. Amaryan, H. Hakobyan, J. W. Price, P. Bosted, H. S. Jo, W. Kim, M. Khachatryan, W. J. Briscoe, Nikolaos Sparveris, R. De Vita, M. Guidal, G. Niculescu, E. Pasyuk, K. A. Griffioen, G. E. Dodge, N. Dashyan, S. K. Phillips, C. Carlin, R. Paremuzyan, W. Phelps, A. Filippi, G. D. Smith, M. Holtrop, I. Bedlinskiy, M. Osipenko, Y. Ilieva, H. Egiyan, Larry Weinstein, D. Payette, E. L. Isupov, E. Golovatch, R. Dupre, Z. W. Zhao, I. J. D. MacGregor, P. Nadel-Turonski, Nicholas M. Harrison, Gerard Gilfoyle, S. E. Kuhn, F. Thanh Cao, S. Stepanyan, N. Guler, S. Johnston, D. Sokhan, Laura Clark, M. Ungaro, A. I. Ostrovidov, Luciano Pappalardo, E. Long, Sylvester Joosten, D. G. Jenkins, M. Khandaker, B. A. Raue, M. Contalbrigo, D. G. Ireland, Chaden Djalali, X. Wei, T. Shigeyuki, C. D. Keith, G. Rosner, Volker D. Burkert, P. Eugenio, M. Taiuti, S. Choi, T. Mineeva, A. S. Biselli, L. Guo, Y. Ghandilyan, P. Rossi, M. L. Kabir, S. Niccolai, A. El Alaoui, P. Konczykowski, Andrea Celentano, Karl Slifer, C. Salgado, L. Barion, J. Poudel, O. Pogorelko, C. Hanretty, M. Ripani, Z. Akbar, I. I. Strakovsky, A. Simonyan, G. Ciullo, J. P. Ball, D. S. Carman, A. Rizzo, A. Deur, A. Movsisyan, Victor Mokeev, J. Zhang, D. Protopopescu, S. Adhikari, E. Voutier, Y. G. Sharabian, G. Charles, V. Sulkosky, F. Sabatié, David M. Keller, and Iu. Skorodumina
Subjects: Physics, Quantum chromodynamics, Nuclear reaction, Chiral perturbation theory, Magnetic moment, 010308 nuclear & particles physics, General Physics and Astronomy, Spin structure, 01 natural sciences, Nuclear magnetic resonance, Polarizability, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: We measured the g 1 spin structure function of the deuteron at low Q 2 , where QCD can be approximated with chiral perturbation theory ( χ PT ). The data cover the resonance region, up to an invariant mass of W ≈ 1.9 GeV . The generalized Gerasimov-Drell-Hearn sum, the moment Γ d 1 and the spin polarizability γ d 0 are precisely determined down to a minimum Q 2 of 0.02 GeV 2 for the first time, about 2.5 times lower than that of previous data. We compare them to several χ PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χ PT domain.
Published: 2018

35. 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

36. First measurement of $\Xi^-$ polarization in photoproduction

Author: K. Livingston, M. Hattawy, Taya Chetry, Jie Zhang, A. Kim, L. Guo, Alessandro Rizzo, W. Kim, G. Niculescu, R. Paremuzyan, Lorenzo Zana, N. Dashyan, Nicholas M. Harrison, R. A. Schumacher, Maxime Defurne, Yordanka Ilieva, C. Djalali, J. A. Tan, K. A. Griffioen, C. Salgado, V. Crede, D. Sokhan, D. I. Glazier, L. Barion, P. Eugenio, Michael Dugger, R. A. Montgomery, R. De Vita, E. Golovatch, A. El Alaoui, M. Taiuti, Nicholas Zachariou, M. Osipenko, J. Bono, A. Fradi, M. L. Kabir, H. Egiyan, F. Cao, I. Bedlinskiy, Iu. Skorodumina, S. Stepanyan, G. Charles, M. Ungaro, E. L. Isupov, B. A. Clary, C. Munoz Camacho, G. Rosner, X. Wei, P. Lenisa, Y. Prok, S. Strauch, M. Battaglieri, F. Sabatié, W. Gohn, D. Protopopescu, Z. W. Zhao, N. Markov, K. Hicks, M. Bashkanov, S. Adhikari, B. McKinnon, W. Phelps, G. D. Smith, M. Holtrop, N. Gevorgyan, Avraham Klein, Y. Ghandilyan, Michael Paolone, A. Celentano, R. W. Gothe, I. I. Strakovsky, E. Voutier, Rong Wang, A. Deur, M. Khachatryan, G. Ciullo, J. P. Ball, M. C. Kunkel, A. I. Ostrovidov, K. Park, D. S. Carman, G. V. Fedotov, Nikos Sparveris, D. G. Ireland, Friedrich Klein, V. Batourine, Volker D. Burkert, A. S. Biselli, T. Mineeva, William Brooks, Brian Raue, K. P. Adhikari, F. X. Girod, G. Gavalian, Y. G. Sharabian, S. Johnston, M. Ripani, H. S. Jo, G. Khachatryan, M. Contalbrigo, J. W. Price, Z. Akbar, I. J. D. MacGregor, V. P. Kubarovsky, A. D'Angelo, O. Pogorelko, L. El Fassi, Dustin Keller, Michael Wood, K. Hafidi, M. J. Amaryan, P. L. Cole, H. Voskanyan, D. Heddle, E. Pasyuk, S. Diehl, A. Filippi, M. Khandaker, 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, Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay ( IPNO ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), and 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, Photon, Meson, Hadron, Nuclear Theory, Cascade, Hyperon spectroscopy, Photoproduction, Polarization, Strange, Xi, Socio-culturale, Elementary particle, Xi-: polarization, Photon energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Computer Science::Digital Libraries, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, photoproduction: (cascade), Particle decay, polarization: measured, excited state: spectrum, CLAS, meson: exchange, 0103 physical sciences, Xi-: photoproduction, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Hyperon, hyperon: (nucleon resonance), photon: energy, Baryon, Xi-: (recoil), High Energy Physics::Experiment, polarization: induced, hyperon: photoproduction, decay: weak interaction, +K%2B+K-+Xi%22">photon p --> K+ K- Xi, 5.45 GeV, Jefferson Lab
Abstract: Despite decades of studies of the photoproduction of hyperons, both their production mechanisms and their spectra of excited states are still largely unknown. While the parity-violating weak decay of hyperons offers a means of measuring their polarization, which could help discern their production mechanisms and identify their excitation spectra, no such study has been possible for doubly strange baryons in photoproduction, due to low production cross sections. However, by making use of the reaction $\gamma p \to K^+ K^+ \Xi^-$, we have measured, for the first time, the induced polarization, $P$, and the transferred polarization from circularly polarized real photons, characterized by $C_x$ and $C_z$, to recoiling $\Xi^-$s. The data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab for photon energies from just over threshold (2.4 GeV) to 5.45 GeV. These first-time measurements are compared, and are shown to broadly agree, with model predictions in which cascade photoproduction proceeds through the decay of intermediate hyperon resonances that are produced via relativistic meson exchange, offering a new step forward in the understanding of the production and polarization of doubly-strange baryons., Comment: 9 pages, 7 figures
Published: 2018

37. Probing high-momentum protons and neutrons in neutron-rich nuclei

Author: D. Bulumulla, B. S. Ishkhanov, B. A. Clary, C. E. Hyde, T. Mineeva, Adi Ashkenazi, P. Eugenio, Alexander Schmidt, K. Livingston, Pawel Nadel-Turonski, M. Taiuti, J. Arrington, Y. Prok, A. I. Ostrovidov, G. Gavalian, M. Contalbrigo, Michael Paolone, R. A. Schumacher, M. L. Kabir, A. D'Angelo, C. Munoz-Camacho, A. Beck, G. Ciullo, J. P. Ball, G. Laskaris, D. S. Carman, L. Lanza, Shalev Gilad, G. Khachatryan, A. Rizzo, F. Hauenstein, D. G. Ireland, R. G. Fersch, E. De Sanctis, S. Mey-Tal Beck, A. Movsisyan, M. Battaglieri, P. L. Cole, Z. W. Zhao, S. Stepanyan, George Davey Smith, Volker D. Burkert, A. S. Biselli, G. Charles, Nicholas M. Harrison, Gerard Gilfoyle, Y. Ilieva, Andreas Klein, J. Poudel, D. Sokhan, M. Patsyuk, K. Hicks, D. P. Watts, Taya Chetry, B. McKinnon, H. Egiyan, S. Nadeeshani, X. Wei, P. Lenisa, N. Markov, W. J. Briscoe, W. Kim, K. P. Adhikari, Douglas Higinbotham, M. Mirazita, Maxime Defurne, R. Cruz-Torres, I. Bedlinskiy, S. Niccolai, Chaden Djalali, M. Osipenko, L. El Fassi, L. Guo, D. Payette, Or Hen, Eliahu Cohen, K.A. Griffoen, B. Schmookler, M. Braverman, L. Barion, R. De Vita, A. El Alaoui, G. E. Dodge, Andrea Celentano, K. Hafidi, M. Khandaker, S. Procureur, Friedrich Klein, T. A. Forest, F. X. Girod, M. J. Amaryan, Nicholas Zachariou, F. Cao, M. Ripani, I. J. D. MacGregor, E.P. Segarra, Eli Piasetzky, I. Korover, Afroditi Papadopoulou, S. Strauch, J. W. Price, G. Rosner, A. Filippi, M. Duer, K. L. Giovanetti, O. Pogorelko, Larry Weinstein, B. Mustapha, G. Niculescu, E. Pasyuk, W. Phelps, N. Dashyan, E. L. Isupov, O. Cortes, R. W. Gothe, S. Boiarinov, Y. Ghandilyan, M. Holtrop, S. Bueltmann, Victor Mokeev, M. Ungaro, J. Zhang, D. Protopopescu, K. Joo, E. Voutier, Y. G. Sharabian, A. Kim, William Brooks, C. Marchand, V. Batourine, F. Sabatié, David M. Keller, J. A. Tan, V. Crede, R. A. Montgomery, H. Hakobyan, Laura Clark, P. Rossi, X. Zheng, M. Khachatryan, Nikolaos Sparveris, S. E. Kuhn, M. Hattawy, A. Deur, S. Adhikari, E. Golovatch, R. Dupre, K. Park, I. Balossino, H. Voskanyan, Carlos A. Salgado, 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: Quark, Multidisciplinary matter, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Astrophysics::High Energy Astrophysical Phenomena, EMC effect, Nuclear Theory, momentum spectrum, Socio-culturale, parton: distribution function, Electron, 7. Clean energy, 01 natural sciences, nucleon: momentum, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, CLAS, 0103 physical sciences, Neutron, 010306 general physics, Nuclear Experiment, neutron star, p nucleus: scattering, Physics, Multidisciplinary, 010308 nuclear & particles physics, electron nucleus: scattering, quantum mechanics, Nuclear shell model, shell model, correlation, Atomic nucleus, Nucleon
Abstract: International audience; The atomic nucleus is one of the densest and most complex quantum-mechanical systems in nature. Nuclei account for nearly all the mass of the visible Universe. The properties of individual nucleons (protons and neutrons) in nuclei can be probed by scattering a high-energy particle from the nucleus and detecting this particle after it scatters, often also detecting an additional knocked-out proton. Analysis of electron- and proton-scattering experiments suggests that some nucleons in nuclei form close-proximity neutron–proton pairs 1$^{–}$12 with high nucleon momentum, greater than the nuclear Fermi momentum. However, how excess neutrons in neutron-rich nuclei form such close-proximity pairs remains unclear. Here we measure protons and, for the first time, neutrons knocked out of medium-to-heavy nuclei by high-energy electrons and show that the fraction of high-momentum protons increases markedly with the neutron excess in the nucleus, whereas the fraction of high-momentum neutrons decreases slightly. This effect is surprising because in the classical nuclear shell model, protons and neutrons obey Fermi statistics, have little correlation and mostly fill independent energy shells. These high-momentum nucleons in neutron-rich nuclei are important for understanding nuclear parton distribution functions (the partial momentum distribution of the constituents of the nucleon) and changes in the quark distributions of nucleons bound in nuclei (the EMC effect) 1$^{,}$13$^{,}$14 . They are also relevant for the interpretation of neutrino-oscillation measurements 15 and understanding of neutron-rich systems such as neutron stars 3$^{,}$16 .
Published: 2018

38. 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

39. Determination of the proton spin structure functions for 0.05<Q2<5GeV2 using CLAS

Author: N. Harrison, V. Crede, Y. Prok, A. Simonyan, R. A. Montgomery, P. Lenisa, N. Zachariou, H. Egiyan, L. Clark, N. K. Walford, M. Ungaro, N. Dashyan, R. W. Gothe, A. D'Angelo, G. P. Gilfoyle, C. Salgado, L. Colaneri, P. Bosted, P. Eugenio, I. Balossino, R. G. Fersch, Friedrich Klein, E. L. Isupov, M. Taiuti, W. Phelps, M. Contalbrigo, G. Gavalian, F. Cao, K. Hicks, G. Murdoch, P. Roy, M. Guidal, Taya Chetry, G. E. Dodge, C. Hanretty, M. Khandaker, M. Holtrop, M. Garçon, K. Hafidi, I. Bedlinskiy, J. A. Fleming, J. Ball, M. Hattawy, M. Osipenko, Iu. Skorodumina, B. S. Ishkhanov, D. Protopopescu, D. Heddle, D. Keller, Z. Akbar, Marco Ripani, J. Zhang, Michael Paolone, C. Djalali, C. A. Meyer, E. Voutier, G. V. Fedotov, O. Cortes, D. P. Watts, K. Griffioen, H. Voskanyan, V. Kubarovsky, C. Keith, W. K. Brooks, P. Rossi, Ye Tian, F. Sabatié, L. B. Weinstein, S. L. Careccia, I. I. Strakovsky, A. Rizzo, A. Deur, C. Gleason, R. Paremuzyan, W. Kim, D. Sokhan, S. Pisano, L. Elouadrhiri, G. Niculescu, S. E. Kuhn, D. Riser, A. El Alaoui, S. Stepanyan, O. Pogorelko, H. Avakian, B. A. Raue, A. I. Ostrovidov, G. Asryan, D. G. Ireland, Y. Ilieva, Volker D. Burkert, A. S. Biselli, R. Dupre, K. L. Giovanetti, G. Ciullo, D. A. Jenkins, K. Livingston, D. S. Carman, Nikos Sparveris, S. Niccolai, X. Wei, L. Lanza, V. G. Lagerquist, B. Torayev, E. Pasyuk, I. Stankovic, A. Movsisyan, N. Guler, M. Mirazita, C. Munoz Camacho, N. Compton, Hrachya Hakobyan, B. McKinnon, E. De Sanctis, A. Klein, H. Y. Lu, R. De Vita, S. Anefalos Pereira, K. Joo, S. Chandavar, A. Filippi, M. J. Amaryan, E. Fanchini, L. Guo, J. W. Price, S. M. Hughes, R. Minehart, R. A. Schumacher, V. Mokeev, K. P. Adhikari, T. A. Forest, J. Pierce, S. Bultmann, E. Golovatch, P. Nadel-Turonski, I. Niculescu, S. Adhikari, G. Khachatryan, W. J. Briscoe, G. Charles, L. El Fassi, P. L. Cole, Andrea Celentano, A. Kim, G. D. Smith, F. X. Girod, S. Strauch, M. Khachatryan, Y. G. Sharabian, G. Rosner, N. A. Baltzell, Y. Ghandilyan, K. Park, and M. Battaglieri
Subjects: Quantum chromodynamics, Physics, Particle physics, Proton, 010308 nuclear & particles physics, Virtual particle, Parton, Deep inelastic scattering, 01 natural sciences, Nuclear physics, 0103 physical sciences, Proton spin crisis, High Energy Physics::Experiment, Operator product expansion, Nuclear Experiment, 010306 general physics, Spin-½
Abstract: We present the results of our final analysis of the full data set of g1p(Q2), the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000–2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets (NH315 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries A1p and A2p and spin structure functions g1p and g2p over a wide kinematic range (0.05 GeV2
Published: 2017

40. Measurement of the differential and total cross sections of the γd→K0Λ(p) reaction within the resonance region

Author: H. Hakobyan, M. Taiuti, Dustin Keller, N. Compton, N. Dashyan, D. I. Glazier, R. De Vita, Michael Wood, K. Hafidi, Laura Clark, Yordanka Ilieva, X. Wei, C. E. Hyde, A. Simonyan, M. Osipenko, L. Guo, Alessandro Rizzo, S. Anefalos Pereira, K. Hicks, R. Paremuzyan, R. A. Schumacher, W. Phelps, V. P. Kubarovsky, V. Crede, A. El Alaoui, J. A. Fleming, O. Pogorelko, S. M. Hughes, P. Nadel-Turonski, G. Murdoch, R. A. Montgomery, Michael Paolone, G. Gavalian, N. K. Walford, M. Camp, G. Charles, V. Mokeev, C. Gleason, Nicholas Zachariou, E. De Sanctis, K. P. Adhikari, Nicholas M. Harrison, T. Cao, H. Avakian, H. S. Jo, F. X. Girod, N. Markov, I. J. D. MacGregor, D. Heddle, C. Hanretty, Barry Ritchie, H. Voskanyan, S. Pisano, P. Lenisa, M. Contalbrigo, Avraham Klein, D. Sokhan, F. Sabatié, H. Y. Lu, G. Rosner, M. Khachatryan, I. Stankovic, Philip L. Cole, Z. Akbar, S. Adhikari, B. McKinnon, Nikolaos Sparveris, I. Bedlinskiy, E. Munevar, W. Kim, P. L. Cole, K. Livingston, Y. Ghandilyan, I. Niculescu, Friedrich Klein, D. G. Jenkins, G. Niculescu, B. S. Ishkhanov, A. D'Angelo, Taya Chetry, R. W. Gothe, Eberhard Klempt, M. Mirazita, L. El Fassi, V. Batourine, J. Zhang, S. Stepanyan, G. Khachatryan, Brian Raue, J. W. Price, Latifa Elouadrhiri, C. A. Meyer, Sergey Kuleshov, M. Ripani, M. Ungaro, A. I. Ostrovidov, K. Park, G. V. Fedotov, F. Cao, D. G. Ireland, V. A. Nikonov, Volker D. Burkert, A. S. Biselli, W. J. Briscoe, K. Joo, C. Munoz Camacho, I. I. Strakovsky, M. Guidal, Y. G. Sharabian, G. Ciullo, Y. Prok, T. Mineeva, D. S. Carman, D. Protopopescu, A. Deur, E. Voutier, S. Niccolai, A. Movsisyan, Iu. Skorodumina, W. K. Brooks, G. D. Smith, M. Holtrop, C. E. Taylor, E. Golovatch, R. Dupre, S. Strauch, D. P. Watts, H. Egiyan, A. V. Sarantsev, M. Battaglieri, B. Torayev, K. L. Giovanetti, A. Filippi, M. Khandaker, O. Cortes, E. L. Isupov, A. Fradi, Sylvester Joosten, L. Lanza, Eugene Pasyuk, Andrea Celentano, C. Djalali, N. A. Baltzell, C. Salgado, K. A. Griffioen, A. Trivedi, and P. Eugenio
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Partial wave analysis, Quark model, Gamma ray, Bremsstrahlung, Resonance, Lambda, 01 natural sciences, Particle identification, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: We report the first measurement of differential and total cross sections for the $\ensuremath{\gamma}d\ensuremath{\rightarrow}{K}^{0}\mathrm{\ensuremath{\Lambda}}(p)$ reaction, using data from the CLAS detector at the Thomas Jefferson National Accelerator Facility. Data collected during two separate experimental runs were studied with photon-energy coverage 0.8--3.6 GeV and 0.5-- 2.6 GeV, respectively. The two measurements are consistent giving confidence in the method and determination of systematic uncertainties. The cross sections are compared with predictions from the KAON-MAID theoretical model (without kaon exchange), which deviate from the data at higher $W$ and at forward kaon angles. These data, along with previously published cross sections for ${K}^{+}\mathrm{\ensuremath{\Lambda}}$ photoproduction, provide essential constraints on the nucleon resonance spectrum. A first partial wave analysis was performed that describes the data without the introduction of new resonances.
Published: 2017

41. First measurement of the polarization observable E in the p→(γ→,π+)n reaction up to 2.25 GeV

Author: I. Zonta, William Brooks, X. Wei, P. Lenisa, K. Livingston, D. P. Watts, Friedrich Klein, A. V. Sarantsev, D. Rönchen, P. Nadel-Turonski, Z. W. Zhao, Eberhard Klempt, W. Gohn, F. Sabatié, R. A. Badui, H. Y. Lu, I. Niculescu, I. I. Strakovsky, B. A. Raue, R. A. Schumacher, A. El Alaoui, Barry Ritchie, J. W. Price, A. Deur, Nicholas Zachariou, K. A. Griffioen, S. Chandavar, A. V. Anisovich, L. Guo, M. Ungaro, M. Ripani, R. W. Gothe, Michael Döring, T. A. Forest, S. Stepanyan, E. Munevar, Avraham Klein, Iu. Skorodumina, P. Eugenio, C. I. Moody, M. Taiuti, V. Crede, V. A. Nikonov, Latifa Elouadrhiri, G. Khachatryan, C. A. Meyer, G.V. O'Rielly, A. Trivedi, K. Joo, G. V. Fedotov, Andrea Celentano, Andrew Puckett, R. A. Montgomery, A. Kim, E. Golovatch, R. Dupre, S. Procureur, D. Keller, R. De Vita, D. Protopopescu, M. Contalbrigo, D. G. Jenkins, S. Pozdniakov, I. Bedlinskiy, K. P. Adhikari, N. Benmouna, F. X. Girod, J. Brock, H. S. Jo, N. Compton, Jian Zhang, C. Carlin, A. Filippi, Nikolaos Sparveris, N. Gevorgyan, W. Kim, S. Strauch, D. S. Carman, Victor Mokeev, G. Niculescu, D. Ho, K. Park, L. Colaneri, M. Khandaker, John Phillips, A. Simonyan, E. Seder, N. Markov, S. Pisano, N. K. Walford, M. Hattawy, D. I. Glazier, E. Voutier, T. Cao, A. Fradi, O. Pogorelko, D. G. Meekins, Diane Schott, G. Rosner, I. J. D. MacGregor, A. I. Ostrovidov, M. Osipenko, D. G. Ireland, H. Moutarde, M. Battaglieri, Y. Ghandilyan, H. Jiang, B. S. Ishkhanov, Volker D. Burkert, S. E. Kuhn, A. S. Biselli, K. L. Giovanetti, J. A. Fleming, L. El Fassi, P. Peng, Hovanes Egiyan, Chaden Djalali, Michael Dugger, Hrachya Hakobyan, Y. Ilieva, C. Munoz Camacho, R. Tucker, Ron L. Workman, P. L. Cole, B. McKinnon, L. A. Net, S. Fegan, Eugene Pasyuk, S. Anefalos Pereira, Y. G. Sharabian, W. Phelps, V. Batourine, M. L. Seely, D. Sokhan, E. De Sanctis, C. D. Keith, J. P. Ball, Y. Prok, D. I. Sober, A. Rizzo, S. Niccolai, C. Hanretty, V. Sytnik, N. Harrison, A. Movsisyan, N. Dashyan, P. Stoler, I. Senderovich, K. Hicks, G. Charles, P. Roy, D. Adikaram, M. Guidal, S. Joosten, G. D. Smith, M. Holtrop, H. Voskanyan, W. J. Briscoe, V. P. Kubarovsky, Annalisa D'Angelo, S. M. Hughes, Michael Wood, K. Hafidi, O. Cortes, E. L. Isupov, Ye Tian, Lorenzo Zana, and C. Salgado
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Photon, Pion, Meson, Bremsstrahlung, Observable, Photon energy, Nuclear Experiment, Multipole expansion, Nucleon
Abstract: First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction (p) over right arrow((gamma) over right arrow, pi(+))n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, Jfilich-Bonn, and SAID groups. (C) 2015 The Authors. Published by Elsevier B.V.
Published: 2015

42. 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

43. Differential cross section measurements for γn→π−p above the first nucleon resonance region

Author: P. Eugenio, W. Kim, G. Niculescu, B. S. Ishkhanov, A. E. Kudryavtsev, A. Simonyan, Z. E. Meziani, V. P. Kubarovsky, S. M. Hughes, D. Adikaram, M. Guidal, X. Wei, K. Livingston, D. P. Watts, Michael Paolone, I. Bedlinskiy, H. Voskanyan, H. S. Jo, C. Salgado, A. Celentano, R. W. Gothe, R. A. Schumacher, Maxime Defurne, Dustin Keller, P. Lenisa, Jie Zhang, Michael Wood, K. Hafidi, P. Mattione, R. Fersch, G. D. Smith, M. Holtrop, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, R. Paremuzyan, M. Osipenko, Alfred Švarc, Nicholas M. Harrison, Gerard Gilfoyle, Nikos Sparveris, I. I. Strakovsky, R. De Vita, S. V. Kuleshov, E. Voutier, K. P. Adhikari, D. Sokhan, S. Stepanyan, K. L. Giovanetti, N. Markov, A. Deur, D. G. Jenkins, A. Movsisyan, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, Friedrich Klein, G. Rosner, N. K. Walford, T. Cao, S. Pisano, F. X. Girod, I. J. D. MacGregor, Laura Clark, Avraham Klein, P. L. Cole, Brian Raue, M. Bashkanov, S. Adhikari, B. McKinnon, S. Anefalos Pereira, S. Niccolai, M. Contalbrigo, O. Pogorelko, Z. W. Zhao, Victor Mokeev, A. I. Ostrovidov, A. Filippi, M. Ungaro, K. Park, I. Niculescu, J. W. Price, M. Taiuti, M. Ripani, D. Protopopescu, D. G. Ireland, V. Batourine, M. Khandaker, Z. Akbar, H. Jiang, E. De Sanctis, A. D'Angelo, Y. Ghandilyan, Volker D. Burkert, A. S. Biselli, O. Cortes, V. Crede, H. Hakobyan, K. Joo, L. El Fassi, Hovanes Egiyan, C. Munoz Camacho, E. L. Isupov, D. Heddle, E. Golovatch, G. Khachatryan, K. Hicks, R. A. Montgomery, P. Nadel-Turonski, Chaden Djalali, S. Boiarinov, Michael Dugger, T. Mineeva, G. Hollis, Taya Chetry, W. Phelps, W. J. Briscoe, Alessandro Rizzo, C. Hanretty, S. Procureur, A. Fradi, Ron L. Workman, S. Strauch, L. Lanza, Eugene Pasyuk, L. A. Net, N. A. Baltzell, R. Dupre, M. Battaglieri, K. A. Griffioen, Y. G. Sharabian, M. Khachatryan, G. Charles, J. A. Fleming, F. Sabatié, C. A. Meyer, G. V. Fedotov, Iu. Skorodumina, G. Murdoch, C. Gleason, Barry Ritchie, M. Hattawy, Sylvester Joosten, A. Kim, N. Dashyan, I. Stankovic, and V. E. Tarasov
Subjects: Physics, Particle physics, Photon, 010308 nuclear & particles physics, Bremsstrahlung, Resonance, State (functional analysis), 01 natural sciences, Particle identification, Pion, Amplitude, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon
Abstract: The quasifree $\ensuremath{\gamma}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}p(p)$ differential cross section has been measured with CLAS at photon beam energies ${E}_{\ensuremath{\gamma}}$ from 0.445 to 2.510 GeV (corresponding to $W$ from 1.311 to 2.366 GeV) for pion center-of-mass angles $cos{\ensuremath{\theta}}_{\ensuremath{\pi}}^{c.m.}$ from $\ensuremath{-}0.72$ to 0.92. A correction for final state interactions has been applied to these data to extract the $\ensuremath{\gamma}n\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}p$ differential cross sections. These cross sections are quoted in 8428 $({E}_{\ensuremath{\gamma}},cos{\ensuremath{\theta}}_{\ensuremath{\pi}}^{c.m.})$ bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of ${N}^{*}$ resonances and extract their properties. Selected photon decay amplitudes ${N}^{*}\ensuremath{\rightarrow}\ensuremath{\gamma}n$ at the resonance poles are determined for the first time and are reported here.
Published: 2017

44. Measurements of ep→e′π+π−p′ cross sections with CLAS at 1.40GeV<W<2.0 GeV and 2.0GeV2<Q2<5.0GeV2

Author: Y. Ilieva, W. Kim, Nicholas Zachariou, G. Niculescu, L. Colaneri, C. Salgado, J. W. Price, Latifa Elouadrhiri, H. Y. Lu, I. Stankovic, H. Hakobyan, D. Protopopescu, M. Garçon, E. Voutier, G. V. Fedotov, B. G. Ritchie, R. G. Fersch, Taya Chetry, K. Park, V. I. Mokeev, C. Munoz Camacho, G. Murdoch, M. Osipenko, D. Heddle, C. Gleason, D. G. Ireland, P. L. Cole, H. Jiang, P. Eugenio, O. Cortes, E. L. Isupov, Laura Clark, M. Hattawy, P. Lenisa, Volker D. Burkert, Ye Tian, A. S. Biselli, W. Phelps, I. Niculescu, D. I. Glazier, Sergey Kuleshov, K. Livingston, S. Adhikari, R. De Vita, B. McKinnon, B. Torayev, X. Wei, Jie Zhang, D. Adikaram, M. Guidal, G. Gavalian, M. J. Amaryan, Eugene Pasyuk, S. Anefalos Pereira, G. D. Smith, M. Holtrop, M. Mirazita, I. I. Strakovsky, V. Batourine, V. Crede, A. Deur, Y. G. Sharabian, Michael Paolone, R. A. Schumacher, E. De Sanctis, S. Niccolai, R. Paremuzyan, R. A. Montgomery, K. L. Giovanetti, A. Kim, Nicholas M. Harrison, Gerard Gilfoyle, W. K. Brooks, J. A. Fleming, D. Sokhan, N. Markov, S. Bültmann, A. D'Angelo, D. G. Jenkins, K. P. Adhikari, T. A. Forest, E. Munevar, Avraham Klein, F. X. Girod, A. Filippi, L. El Fassi, M. Ungaro, K. Hicks, A. Trivedi, M. Khandaker, M. Ripani, I. Bedlinskiy, Friedrich Klein, T. Mineeva, Brian Raue, Iu. Skorodumina, L. Guo, E. Golovatch, R. Dupre, Alessandro Rizzo, K. Joo, C. Hanretty, G. Charles, C. Djalali, F. Sabatié, G. Khachatryan, K. A. Griffioen, P. Nadel-Turonski, B. S. Ishkhanov, W. J. Briscoe, Sylvester Joosten, L. Lanza, S. Procureur, M. C. Kunkel, S. Strauch, M. Battaglieri, Y. Ghandilyan, M. Contalbrigo, M. Taiuti, Z. Akbar, N. K. Walford, T. Cao, I. J. D. MacGregor, A. Celentano, R. W. Gothe, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, N. A. Baltzell, Nikos Sparveris, Dustin Keller, A. Movsisyan, N. Dashyan, Michael Wood, K. Hafidi, A. Simonyan, V. P. Kubarovsky, D. Riser, O. Pogorelko, S. M. Hughes, H. Avakian, H. Voskanyan, and A. El Alaoui
Subjects: Nuclear physics, Baryon, Scattering cross-section, Physics, Particle physics, 010308 nuclear & particles physics, 0103 physical sciences, Pi interaction, 010306 general physics, Nucleon, 01 natural sciences, Resonance (particle physics), Energy (signal processing)
Abstract: This paper reports new exclusive cross sections for $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{p}^{\ensuremath{'}}$ using the CLAS detector at Jefferson Laboratory. These results are presented for the first time at photon virtualities $2.0\phantom{\rule{0.16em}{0ex}}{\mathrm{GeV}}^{2}\phantom{\rule{4pt}{0ex}}l{Q}^{2}l5.0\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$ in the center-of-mass energy range 1.4 GeV $lWl$ 2.0 GeV, which covers a large part of the nucleon resonance region. Using a model developed for the phenomenological analysis of electroproduction data, we see strong indications that the relative contributions from the resonant cross sections at $Wl1.74$ GeV increase with ${Q}^{2}$. These data considerably extend the kinematic reach of previous measurements. Exclusive $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{p}^{\ensuremath{'}}$ cross section measurements are of particular importance for the extraction of resonance electrocouplings in the mass range above 1.6 GeV.
Published: 2017

45. Differential cross sections and polarization observables from CLAS K* photoproduction and the search for new N* states

Author: G. Khachatryan, W. J. Briscoe, R. A. Schumacher, G. Rosner, Y. Ghandilyan, Andrew Puckett, P. Lenisa, C. Hanretty, N. K. Walford, Michael Dugger, C. A. Meyer, Nikolaos Sparveris, I. J. D. MacGregor, R. A. Badui, C. Djalali, V. Crede, R. W. Gothe, A. I. Ostrovidov, K. Park, W. Phelps, M. J. Amaryan, F. Sabatié, L. El Fassi, G. V. Fedotov, D. A. Jenkins, Friedrich Klein, M. Battaglieri, Brian Raue, E. Fanchini, R. A. Montgomery, P. Peng, I. Zonta, Hovanes Egiyan, C. Munoz Camacho, D. G. Ireland, Eberhard Klempt, L. A. Net, E. De Sanctis, J. W. Price, L. Clark, H. Jiang, Z. Akbar, K. L. Giovanetti, I. Bedlinskiy, A. Deur, R. Paremuzyan, H. S. Jo, F. X. Girod, N. Compton, Volker D. Burkert, A. S. Biselli, Nicholas M. Harrison, Y. G. Sharabian, M. Ripani, D. Sokhan, L. Guo, B. McKinnon, A. Ni, A. Filippi, M. Contalbrigo, I. Stankovic, P. Nadel-Turonski, Michael Paolone, E. Munevar, M. Ungaro, B. S. Ishkhanov, M. Mirazita, M. Khandaker, R. Dupre, I. Niculescu, W. Tang, Sylvester Joosten, K. A. Griffioen, V. Batourine, P. L. Cole, R. De Vita, M. Osipenko, E. L. Isupov, Iu. Skorodumina, V. A. Nikonov, Ye Tian, J. A. Fleming, W. Kim, S. Anefalos Pereira, A. D'Angelo, L. Lanza, V. Sytnik, K. Hicks, P. Eugenio, N. Markov, S. Pisano, Victor Mokeev, G. Murdoch, Andrea Celentano, P. Roy, D. Adikaram, N. Gevorgyan, C. Gleason, Barry Ritchie, J. Ball, M. Hattawy, G. D. Smith, M. Holtrop, Taya Chetry, N. Dashyan, K. Livingston, Jie Zhang, S. Stepanyan, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, E. Voutier, V. P. Kubarovsky, O. Pogorelko, S. M. Hughes, Dustin Keller, Michael Wood, H. Voskanyan, E. Pasyuk, G. Ciullo, Y. Prok, D. S. Carman, S. Strauch, D. P. Watts, S. Niccolai, A. Movsisyan, A. V. Sarantsev, S. Chandavar, A. V. Anisovich, 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, Université Paris-Sud - Paris 11 (UP11), 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)-Université Grenoble Alpes (UGA), CLAS, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and 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])
Subjects: Polarization observables, Photon, experimental methods, magnetic field, 01 natural sciences, B004:Desig=16, Settore FIS/04 - Fisica Nucleare e Subnucleare, Recoil, electron: recoil, B016.178, N(2100), B144:Desig=19, B071:Desig=179, electron: beam, photon: tagged beam, spin: density matrix, B132:Desig=13, Nuclear Experiment, B087.14, Physics, B005.22, B144.19, Bremsstrahlung, Lambda: polarization, B004.16, Polarization (waves), Breit-Wigner, B005:Desig=22, lcsh:QC1-999, Meson photoproduction, resonance, differential cross section, Baryon spectroscopy, branching ratio, missing-mass, Jefferson Lab, B016:Desig=178, Nuclear and High Energy Physics, Particle physics, B006.21, Partial wave analysis, B006:Desig=21, Socio-culturale, Photon energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], polarization: recoil, bremsstrahlung, Nuclear physics, CLAS, 0103 physical sciences, B024.15, 010306 general physics, 010308 nuclear & particles physics, Branching fraction, Resonance, B132.13, partial wave analysis, B087:Desig=14, meson: photoproduction, B024:Desig=15, 4.02 GeV, baryon: hadron spectroscopy, High Energy Physics::Experiment, B071.179, lcsh:Physics, dipole, experimental results
Abstract: The reaction γp→K⁎+Λ was measured using the CLAS detector for photon energies between the threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. For the first time, spin-density matrix elements have been extracted for this reaction. Differential cross sections, spin density matrix elements, and the Λ recoil polarization are compared with theoretical predictions using the BnGa partial wave analysis. The main result is the evidence for significant contributions from N(1895)1/2− and N(2100)1/2+ to the reaction. Branching ratios for decays into K⁎Λ for these resonances and further resonances are reported.
Published: 2017

46. Beam-Target Helicity Asymmetry for γ→n→→π−p in the N* Resonance Region

Author: C. Gleason, Barry Ritchie, G. V. Fedotov, K. P. Adhikari, J. Ball, M. Hattawy, D. P. Watts, Marco Ripani, H. Hakobyan, G. Rosner, S. Fegan, F. X. Girod, M. Ungaro, K. A. Griffioen, I. I. Strakovsky, K. Livingston, R. Paremuzyan, C. Djalali, X. Wei, A. V. Sarantsev, A. Deur, L. Elouadrhiri, Y. Ghandilyan, R. A. Schumacher, Nicholas M. Harrison, Gerard Gilfoyle, Z. Akbar, V. Crede, L. Lanza, D. I. Glazier, M. Osipenko, Jie Zhang, E. Pasyuk, G. Khachatryan, R. A. Montgomery, P. Lenisa, P. L. Cole, G. Ciullo, D. Sokhan, N. Markov, D. S. Carman, W. Phelps, V. P. Kubarovsky, D. Riser, P. Eugenio, L. Clark, M. Bashkanov, V. Laine, O. Pogorelko, W. J. Briscoe, F. J. Klein, S. Niccolai, R. Fersch, S. M. Hughes, B. McKinnon, Nikolaos Sparveris, A. Movsisyan, M. M. Lowry, I. Zonta, R. De Vita, N. Dashyan, H. S. Jo, C. Salgado, Avraham Klein, Ron L. Workman, F. Sabatié, I. Bedlinskiy, L. Colaneri, Andrea Celentano, C. Bass, Dustin Keller, H. Y. Lu, Yordanka Ilieva, E. Golovatch, S. Strauch, N. K. Walford, R. Dupre, G. Charles, Alfred Švarc, S. Procureur, L. El Fassi, Victor Mokeev, Z. W. Zhao, J. A. Fleming, J. W. Price, D. Ho, Michael Wood, T. Kageya, A. M. Sandorfi, Y. G. Sharabian, Taya Chetry, S. Anefalos Pereira, I. J. D. MacGregor, W. Kim, P. Collins, G. Niculescu, V. A. Nikonov, A. D'Angelo, R. W. Gothe, C. S. Whisnant, E. L. Isupov, M. Battaglieri, Ye Tian, H. Voskanyan, A. Fradi, K. Joo, K. Hicks, E. De Sanctis, V. Batourine, D. A. Jenkins, Sergey Kuleshov, D. G. Ireland, H. Jiang, C. S. Nepali, P. Peng, K. Park, D. I. Sober, Volker D. Burkert, C. Munoz Camacho, A. S. Biselli, Tim O'Connell, Eberhard Klempt, B. S. Ishkhanov, D. Adikaram, T. Mineeva, M. Guidal, L. Guo, Alessandro Rizzo, S. Joosten, G. D. Smith, M. Holtrop, D. Protopopescu, C. Hanretty, A. Kim, W. Gohn, E. Voutier, A. El Alaoui, Nicholas Zachariou, B. Torayev, M. J. Amaryan, H. Avakian, M. Contalbrigo, M. Khandaker, A. Filippi, M. Paolone, Iu. Skorodumina, and G. Murdoch
Subjects: Physics, Photon, 010308 nuclear & particles physics, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Helicity, Nuclear physics, Deuterium, Solid hydrogen, Isospin, 0103 physical sciences, Neutron, Invariant mass, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: We report the first beam-target double-polarization asymmetries in the γ þ nðpÞ → π− þ pðpÞ reaction spanning the nucleon resonance region from invariant mass W ¼ 1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN* resonance photocouplings.
Published: 2017

47. Measurement of two-photon exchange effect by comparing elastic e±p cross sections

Author: V. Crede, D. A. Jenkins, Lorenzo Zana, Y. G. Sharabian, L. Lanza, Hovanes Egiyan, C. Munoz Camacho, K. Livingston, L. Clark, G. V. Fedotov, P. Lenisa, C. Salgado, L. El Fassi, H. Voskanyan, K. A. Griffioen, Jie Zhang, B. McKinnon, M. D. Mestayer, O. Cortes, E. L. Isupov, Andrei Afanasev, S. Boiarinov, M. Taiuti, K. P. Adhikari, L. Guo, M. Mirazita, Z. Akbar, R. Fersch, Alessandro Rizzo, S. E. Kuhn, A. I. Ostrovidov, S. Stepanyan, N. Gevorgyan, V. Batourine, F. X. Girod, C. Hanretty, G. Khachatryan, J. A. Fleming, K. Park, N. Compton, C. Gleason, P. Eugenio, D. G. Ireland, K. L. Giovanetti, H. Jiang, W. Gohn, Larry Weinstein, V. P. Kubarovsky, W. J. Briscoe, Volker D. Burkert, R. Paremuzyan, J. W. Price, V. I. Mokeev, A. Ni, O. Pogorelko, S. M. Hughes, J. Ball, W. Kim, A. S. Biselli, M. Hattawy, Friedrich Klein, E. Golovatch, G. Niculescu, Gerard Gilfoyle, Taya Chetry, D. Heddle, D. Protopopescu, R. Dupre, E. Voutier, Michael Paolone, S. Strauch, D. Sokhan, Dustin Keller, I. Bedlinskiy, Brian Raue, P. Rossi, R. De Vita, Z. W. Zhao, A. D'Angelo, I. Zonta, F. Sabatié, Michael Wood, K. Hafidi, K. Hicks, Eugene Pasyuk, X. Wei, B. Torayev, P. L. Cole, N. K. Walford, S. Anefalos Pereira, E. Seder, W. Phelps, Andrew Puckett, D. Rimal, A. Filippi, Sergey Kuleshov, A. Deur, A. El Alaoui, M. Osipenko, M. Contalbrigo, Y. Ilieva, M. Khandaker, Nikolaos Sparveris, N. A. Baltzell, A. Fradi, Nicholas Zachariou, I. J. D. MacGregor, R. A. Badui, G. Rosner, V. Sytnik, L. Colaneri, Y. Ghandilyan, N. Markov, S. Pisano, N. Dashyan, P. Roy, Chaden Djalali, D. Adikaram, Iu. Skorodumina, I. Stankovic, R. W. Gothe, G. D. Smith, M. Holtrop, B. S. Ishkhanov, G. Ciullo, Y. Prok, D. S. Carman, N. Harrison, S. Niccolai, A. Movsisyan, P. Nadel-Turonski, Sylvester Joosten, M. Battaglieri, M. Ungaro, R. A. Schumacher, S. Bültmann, T. A. Forest, E. Munevar, Avraham Klein, William Brooks, Andrea Celentano, H. Y. Lu, I. Niculescu, J. Arrington, E. Fanchini, D. P. Watts, 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: ratio, Proton, radiative-corrections, Socio-culturale, FOS: Physical sciences, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Electron-proton scattering, Nuclear physics, 0103 physical sciences, form-factors, positron-proton, 4-momentum transfers, clas, hydrogen, beam, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Elastic scattering, Physics, 010308 nuclear & particles physics, Scattering, Electric form factor, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, Electron scattering, Beam (structure), Lepton
Abstract: [Background] The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer ($Q^{2}$). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. [Purpose] We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. [Methods] We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron/positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm long liquid hydrogen (LH$_2$) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented., Comment: 21 pages, 22 figures
Published: 2017

48. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

Author: K. A. Griffioen, I. I. Strakovsky, S. Strauch, H. Egiyan, Michael Dugger, Sylvester Joosten, Latifa Elouadrhiri, C. A. Meyer, Michael Paolone, P. Eugenio, M. Taiuti, A. Deur, K. Livingston, G. V. Fedotov, R. A. Schumacher, N. Markov, W. Phelps, W. K. Brooks, M. Osipenko, S. Pisano, F. X. Girod, E. Golovatch, R. Dupre, M. Ungaro, A. V. Sarantsev, X. Wei, G. Murdoch, M. Ripani, V. Crede, P. Collins, Iu. Skorodumina, M. Khachatryan, P. Nadel-Turonski, F. Sabatié, L. Lanza, C. Gleason, Michael Döring, D. Heddle, K. P. Adhikari, D. Sadasivan, R. Paremuzyan, N. K. Walford, A. Kim, J. W. Price, V. A. Nikonov, A. I. Ostrovidov, K. Park, Taya Chetry, S. Stepanyan, D. I. Glazier, G. Khachatryan, Barry Ritchie, G. Charles, R. A. Montgomery, Avraham Klein, C. Djalali, A. El Alaoui, Y. Ilieva, J. Ball, W. Kim, D. G. Ireland, G. Niculescu, V. P. Kubarovsky, R. De Vita, Volker D. Burkert, Nicholas Zachariou, H. S. Jo, S. Chandavar, A. V. Anisovich, A. S. Biselli, I. Bedlinskiy, I. J. D. MacGregor, M. Battaglieri, W. J. Briscoe, N. Compton, O. Pogorelko, S. M. Hughes, Nicholas M. Harrison, Gerard Gilfoyle, K. Hicks, B. Torayev, D. G. Jenkins, E. Fanchini, Y. G. Sharabian, H. Avakian, M. J. Amaryan, S. Anefalos Pereira, I. Niculescu, P. Lenisa, D. Sokhan, L. Guo, H. Hakobyan, O. Cortes, E. L. Isupov, Alessandro Rizzo, Laura Clark, H. Voskanyan, Eberhard Klempt, V. Mokeev, Ye Tian, D. Protopopescu, E. De Sanctis, M. Bashkanov, M. Contalbrigo, P. L. Cole, J. A. Fleming, E. Pasyuk, E. Voutier, C. Hanretty, J. Zhang, B. McKinnon, G. Ciullo, Friedrich Klein, Brian Raue, F. Cao, P. Roy, Y. Prok, D. S. Carman, K. L. Giovanetti, Nikos Sparveris, I. Balossino, G. Rosner, D. Rönchen, Dustin Keller, M. Mirazita, S. Niccolai, A. Movsisyan, B. S. Ishkhanov, C. Salgado, N. Dashyan, A. D'Angelo, A. Filippi, Z. Akbar, Y. Ghandilyan, K. Hafidi, M. Khandaker, G. D. Smith, M. Holtrop, A. Celentano, R. W. Gothe, L. El Fassi, C. Munoz Camacho, and L. Colaneri
Subjects: Nuclear and High Energy Physics, Photon, Proton, Meson, Meson photoproduction, Eta photoproduction, Eta-prime photoproduction, Polarization observable, Photon beam asymmetry, Nuclear Theory, Photon energy, 01 natural sciences, Particle identification, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Bremsstrahlung, Particle Data Group, lcsh:QC1-999, High Energy Physics::Experiment, Atomic physics, Nucleon, lcsh:Physics
Abstract: Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(1895)1/2−, N(1900)3/2+, N(2100)1/2+ and N(2120)3/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.
Published: 2017

49. Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region

Author: D, Ho, P, Peng, C, Bass, P, Collins, A, D'Angelo, A, Deur, J, Fleming, C, Hanretty, T, Kageya, M, Khandaker, F J, Klein, E, Klempt, V, Laine, M M, Lowry, H, Lu, C, Nepali, V A, Nikonov, T, O'Connell, A M, Sandorfi, A V, Sarantsev, R A, Schumacher, I I, Strakovsky, A, Švarc, N K, Walford, X, Wei, C S, Whisnant, R L, Workman, I, Zonta, K P, Adhikari, D, Adikaram, Z, Akbar, M J, Amaryan, S, Anefalos Pereira, H, Avakian, J, Ball, M, Bashkanov, M, Battaglieri, V, Batourine, I, Bedlinskiy, A, Biselli, W J, Briscoe, V D, Burkert, D S, Carman, A, Celentano, G, Charles, T, Chetry, G, Ciullo, L, Clark, L, Colaneri, P L, Cole, M, Contalbrigo, V, Crede, N, Dashyan, E, De Sanctis, R, De Vita, C, Djalali, R, Dupre, A, El Alaoui, L, El Fassi, L, Elouadrhiri, P, Eugenio, G, Fedotov, S, Fegan, R, Fersch, A, Filippi, A, Fradi, Y, Ghandilyan, G P, Gilfoyle, F X, Girod, D I, Glazier, C, Gleason, W, Gohn, E, Golovatch, R W, Gothe, K A, Griffioen, M, Guidal, L, Guo, H, Hakobyan, N, Harrison, M, Hattawy, K, Hicks, M, Holtrop, S M, Hughes, Y, Ilieva, D G, Ireland, B S, Ishkhanov, E L, Isupov, D, Jenkins, H, Jiang, H S, Jo, K, Joo, S, Joosten, D, Keller, G, Khachatryan, A, Kim, W, Kim, A, Klein, V, Kubarovsky, S V, Kuleshov, L, Lanza, P, Lenisa, K, Livingston, I J D, MacGregor, N, Markov, B, McKinnon, T, Mineeva, V, Mokeev, R A, Montgomery, A, Movsisyan, C, Munoz Camacho, G, Murdoch, S, Niccolai, G, Niculescu, M, Osipenko, M, Paolone, R, Paremuzyan, K, Park, E, Pasyuk, W, Phelps, O, Pogorelko, J W, Price, S, Procureur, D, Protopopescu, M, Ripani, D, Riser, B G, Ritchie, A, Rizzo, G, Rosner, F, Sabatié, C, Salgado, Y G, Sharabian, Iu, Skorodumina, G D, Smith, D I, Sober, D, Sokhan, N, Sparveris, S, Strauch, Ye, Tian, B, Torayev, M, Ungaro, H, Voskanyan, E, Voutier, D P, Watts, M H, Wood, N, Zachariou, J, Zhang, and Z W, Zhao
Abstract: We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.
Published: 2017

50. 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

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