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292 results on '"I. I. Strakovsky"'

1. 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

2. 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

3. Single $$\pi ^0$$ production off neutrons bound in deuteron with linearly polarized photons

Author

M. Günther, D. P. Watts, M. Bashkanov, R. A. Miskimen, S. Abt, C. S. Akondi, N. Jermann, Yu. A. Usov, O. Steffen, I. J. D. MacGregor, P. Pedroni, N. K. Walford, Nicholas Zachariou, Concettina Sfienti, S. N. Prakhov, D. Ghosal, S. Wagner, G. Reicherz, A. Powell, V. L. Kashevarov, A. Braghieri, Z. Ahmed, Th. Strub, Patrick Achenbach, Susanna Costanza, Andy Thomas, I. I. Strakovsky, M. Ostrick, M. Mocanu, Michaela Thiel, I. Supek, B. Krusche, J. Wettig, Lena Heijkenskjöld, J. R. M. Annand, R. Beck, K. Livingston, V. V. Kulikov, S. Lutterer, S. Fegan, S. Gardner, N. S. Borisov, I. Gorodnov, Ron L. Workman, C. Mullen, S. Kay, D. M. Manley, M. Korolija, A. B. Neganov, V. Sokhoyan, D. Hornidge, A. Thiel, A. G. Denig, M. Dieterle, K. Spieker, P. P. Martel, F. Afzal, Durga Paudyal, A. Kaeser, E. J. Downie, A. Lazarev, Lilian Witthauer, E. Mornacchi, W. Gradl, C. Meier, M. Wolfes, D. Werthmüller, M. Biroth, G. Gurevic, C. Collicott, P. B. Otte, P. Drexler, M. A. Martemianov, W. J. Briscoe, M. Unverzagt, T. Rostomyan, F. Cividini, Guy Ron, G. M. Huber, M. Oberle, D. I. Glazier, and M. I. Ferretti-Bondy

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Nuclear Theory, 010308 nuclear & particles physics, media_common.quotation_subject, Hadron, 01 natural sciences, Asymmetry, High Energy Physics - Experiment, High Energy Physics - Phenomenology, Pion, Isospin, 0103 physical sciences, Production (computer science), Center of mass, Nuclear Experiment, 010306 general physics, Crystal Ball, media_common
Abstract

The quasifree $\overrightarrow{\gamma} d\to\pi^0n(p)$ photon beam asymmetry, $\Sigma$, has been measured at photon energies, $E_\gamma$, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 to 148$^\circ$. In this kinematic region, polarization observables are sensitive to contributions from the $\Delta (1232)$ and $N(1440)$ resonances. The extracted values of $\Sigma$ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID, and Bonn-Gatchina analyses; while a revised SAID fit, including the new $\Sigma$ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict $\pi^0n$ photoproduction observables, based on fits to published data in the channels $\pi^0p$, $\pi^+n$, and $\pi^-p$., Comment: 11 pages, 9 figures, 5 tables; fixed 2 glitches

Published
2021

4. Observation of Beam Spin Asymmetries in the Process ep→e′π+π−X with CLAS12

Author

G. Niculescu, D. Bulumulla, G. Ciullo, Aditya R. Khanal, A. El Alaoui, S. Niccolai, E. L. Isupov, D. S. Carman, F. X. Girod, Nikos Sparveris, K. A. Griffioen, D. G. Ireland, V. I. Mokeev, M. Contalbrigo, V. Crede, Nicholas Zachariou, J. C. Carvajal, Sung-Sik Lee, X. Wei, S. Boiarinov, Andrea Bianconi, P. Lenisa, C. Dilks, Fatiha Benmokhtar, O. Soto, T. B. Hayward, M. Osipenko, R. Paremuzyan, L. Marsicano, Maxime Defurne, B. A. Clary, Latifa Elouadrhiri, A. Movsisyan, N. Tyler, N. Markov, P. L. Cole, N. Dashyan, K. Hicks, I. J. D. MacGregor, S. Strauch, D. I. Glazier, V. P. Kubarovsky, Michael Paolone, Krishna Neupane, H. Hakobyan, F. Bossu, R. Tyson, J. Ritman, Eugene Pasyuk, R. De Vita, D. Marchand, H. S. Jo, H. Avakian, Eric Voutier, L. Lanza, S. Diehl, C. Salgado, A. A. Golubenko, H. Atac, H. Voskanyan, G. Costantini, W. J. Briscoe, L. Barion, S. E. Kuhn, M. Hattawy, A. Vossen, M. Guidal, A. D'Angelo, Dustin Keller, M Ehrhart, P. Naidoo, T. Chetry, D. P. Watts, P. Chatagnon, Y. Prok, U. Shrestha, Michael Wood, F. Sabatié, M. Holtrop, Chaden Djalali, L. El Fassi, V. Mascagna, G. Gavalian, K. Hafidi, A. Filippi, B. A. Raue, Luciano Pappalardo, C. Ayerbe Gayoso, I. Bedlinskiy, Michael Dugger, W. Phelps, G. Angelini, P. Rossi, K. Wei, S. Joosten, S. Fegan, M. Leali, A. Celentano, R. W. Gothe, P. Nadel-Turonski, M. Khachatryan, N. A. Baltzell, K. Livingston, Alessandro Rizzo, Axel Schmidt, T. R. O'Connell, William Brooks, I. I. Strakovsky, F. Hauenstein, A. Kim, L. Venturelli, Jie Zhang, Y. Gotra, Z. E. Meziani, A. Deur, B. Yale, E.P. Segarra, S. Nanda, A. Kripko, T. A. Forest, S. Stepanyan, Y. G. Sharabian, M. Ripani, R. Dupré, M. Bondì, M. Battaglieri, O. Pogorelko, J. Rowley, Volker D. Burkert, A. S. Biselli, A. Hobart, S. Adhikari, B. McKinnon, M. Mirazita, Gerard Gilfoyle, D. Sokhan, M. Arratia, Hovanes Egiyan, C. Munoz Camacho, M. Ungaro, K. Joo, A. Thornton, and W. Kim

Subjects
Quark, Physics, Spectrometer, Proton, Nuclear Theory, General Physics and Astronomy, Deep inelastic scattering, 01 natural sciences, Gluon, Nuclear physics, 0103 physical sciences, Cathode ray, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Beam (structure), Spin-½
Abstract

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported for the first time. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first observation of a signal that can be used to extract the PDF $e(x)$ in a collinear framework and the helicity-dependent two-pion fragmentation function $G_1^\perp$.

Published
2021

5. 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

6. Photoproduction of the f2(1270) Meson Using the CLAS Detector

Author

V. Mokeev, P. Eugenio, Vincent Mathieu, D. Heddle, R. A. Schumacher, M. Battaglieri, K. A. Griffioen, R. Paremuzyan, Laura Clark, L. Marsicano, L. Lanza, M. J. Amaryan, M Carver, G. Angelini, D. P. Watts, Gerard Gilfoyle, M. Osipenko, N. Gevorgyan, P. Lenisa, M. Contalbrigo, H. Egiyan, K. Livingston, R. Tyson, D. Sokhan, S. Stepanyan, I. J. D. MacGregor, F. X. Girod, S. Adhikari, Dustin Keller, F. Sabatié, B. McKinnon, G. Niculescu, G. Rosner, B. A. Clary, D. G. Ireland, V. Crede, D. Bulumulla, William Brooks, E. Munevar, Jie Zhang, T. B. Hayward, K. Hafidi, A. Filippi, W. Phelps, Z. E. Meziani, B. Yale, Aditya R. Khanal, L. Venturelli, M. Ehrhart, M. Khandaker, E. L. Isupov, Friedrich Klein, Alessandro Rizzo, A. Kim, Michael Paolone, S. Boiarinov, Andrea Bianconi, G. Ciullo, A. Pilloni, C. W. Kim, A. Celentano, R. W. Gothe, Y. Prok, C. E. Hyde, I. Bedlinskiy, A. El Alaoui, N. A. Baltzell, F. Bossu, T. Chetry, D. S. Carman, Nicholas Zachariou, H. S. Jo, U. Shrestha, J. C. Carvajal, H. Voskanyan, Z. W. Zhao, Fatiha Benmokhtar, Nikos Sparveris, X. Wei, W. J. Briscoe, O. Soto, V. Mascagna, Maxime Defurne, M. Holtrop, S. Joosten, S. Niccolai, D. Protopopescu, E. Voutier, Luciano Pappalardo, A. Movsisyan, R. De Vita, H. Hakobyan, O. Pogorelko, S. Strauch, J. Ritman, J. Rowley, A. I. Ostrovidov, P. Chatagnon, K. Wei, S. Diehl, C. Salgado, S. Fegan, H. Atac, Volker D. Burkert, C. Munoz Camacho, Eugene Pasyuk, A. S. Biselli, G. Gavalian, V. P. Kubarovsky, Krishna Neupane, M. Ripani, M. Hattawy, K. Hicks, N. Dashyan, Michael Dugger, Yordanka Ilieva, L. Barion, Barry Ritchie, R. Dupre, D. Marchand, M. Ungaro, G. V. Fedotov, Q. Huang, K. P. Adhikari, K. Joo, D. G. Jenkins, M. Leali, Axel Schmidt, I. I. Strakovsky, P. Nadel-Turonski, A. Deur, Mark W. Bondi, M. E. McCracken, N. Tyler, C. Djalali, A. D'Angelo, L. El Fassi, A. Kripko, Y. G. Sharabian, and P. L. Cole

Subjects
Quark, Physics, Spectrometer, Meson, High Energy Physics::Lattice, Nuclear Theory, Quark model, Detector, General Physics and Astronomy, Quantum number, 01 natural sciences, 7. Clean energy, Resonance (particle physics), Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract

The quark structure of the f2(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq¯) resonance with quantum numbers JPC=2++. Recently, it was proposed that the f2(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π+π-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π0π0p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f2(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.

Published
2021

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

Author

E. S. Smith, T. Erbora, Ilya Larin, V. V. Tarasov, J. Schwiening, K. Luckas, B. E. Cannon, A. Austregesilo, C. Fanelli, A. Hurley, H. Marukyan, J. Fitches, R.S. Pedroni, W. McGinley, C. A. Meyer, L. Guo, J. Reinhold, A. Ali, T. D. Beattie, S. Furletov, M. M. Dalton, A. Smith, Z. Zhao, M. M. Ito, G. Rodriguez, F. Barbosa, D. Romanov, W. J. Briscoe, V. A. Matveev, A. M. Schertz, D. G. Ireland, V. Crede, T. Daniels, L. Gan, H. Egiyan, B. C.L. Sumner, A. LaDuke, G. J. Lolos, C. S. Akondi, V. Lyubovitskij, S. Somov, S. Fegan, R. Barsotti, S. Adhikari, M. R. Shepherd, A. Gasparian, E. Pooser, T. Whitlatch, N. Wickramaarachchi, Xiang Zhou, T. Britton, Sergey Kuleshov, B. Liu, M. Khatchatryan, H. Hakobyan, A. I. Ostrovidov, D. I. Lersch, K. Suresh, H. Li, P. Eugenio, W. B. Li, J. Barlow, Stephen Taylor, W. Phelps, J. Ritman, J. R. Stevens, M. McCaughan, Haiyan Gao, Mark Richard James Williams, Michael Dugger, Q. Zhou, Barry Ritchie, G. M. Huber, D. I. Sober, C. Gleason, K. Livingston, A. Thiel, A. Hamdi, I. I. Strakovsky, A. Schick, E. Barriga, V. S. Goryachev, A. Deur, Carlos A. Salgado, P. Pauli, V. Neelamana, Z. Baldwin, Z. Papandreou, O. Soto, R. Dzhygadlo, S. Schadmand, I. Jaegle, V. Khachatryan, J. Zarling, R. Dotel, Krisztian Peters, K. Goetzen, M. J. Amaryan, A. Asaturyan, F. Nerling, R. A. Schumacher, X. Shen, Christine Kourkoumelis, R. E. Mitchell, R. A. Miskimen, B. Zihlmann, L. Ng, A. Ernst, Zhiyong Zhang, V. V. Berdnikov, G. Vasileiadis, W.U. Boeglin, V. Kakoyan, D. J. Mack, D. Lawrence, Sean A Dobbs, A. Somov, William Brooks, Lubomir Pentchev, C. Paudel, A. M. Foda, G. Kalicy, N. S. Jarvis, A. Dolgolenko, S. Cole, O. Cortes, C.P. Romero, T. C. Black, R. T. Jones, M. E. McCracken, J. Zhou, K. Mizutani, M. Kamel, A. Teymurazyan, Y. Yang, and E. Chudakov

Subjects
Physics, Range (particle radiation), GlueX, Proton, Meson, 010308 nuclear & particles physics, media_common.quotation_subject, Momentum transfer, 01 natural sciences, Asymmetry, Pseudoscalar, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract

We report a measurement of the π − photoproduction beam asymmetry for the reaction → γ p → π − Δ + + using data from the GlueX experiment in the photon beam energy range 8.2–8.8 GeV. The asymmetry Σ is measured as a function of four-momentum transfer t to the Δ + + and compared to phenomenological models. We find that Σ varies as a function of t : negative at smaller values and positive at higher values of | t | . The reaction can be described theoretically by t -channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy.

Published
2021

8. 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

9. The GlueX beamline and detector

Author

T. Whitlatch, N. Wickramaarachchi, N. Cao, Ilya Larin, Michael Dugger, N. K. Walford, V. V. Tarasov, Gerard Visser, W. Phelps, J. Frye, B. Liu, J. Stewart, V. Razmyslovich, S. Schadmand, B. E. Cannon, C.P. Romero, O. Cortes, F. Nerling, S. Adhikari, M. M. Dalton, G. Voulgaris, C. S. Akondi, W. J. Briscoe, J. R. Stevens, W. D. Crahen, G.H. Biallas, H. Marukyan, R.S. Pedroni, C. Gleason, W. McGinley, P. Eugenio, E. Wolin, V. Crede, C. Carlin, L. A. Teigrob, F. Mokaya, T. C. Black, A. Toro, D. G. Meekins, I. A. Semenova, Elton Smith, A. Thiel, Kamal K. Seth, G. J. Lolos, A. M. Schertz, Todd Satogata, G. Kalicy, T. Daniels, N. S. Jarvis, A. Hamdi, I. I. Strakovsky, N. Qin, Mark Richard James Williams, I. Vega, A. Tsaris, Y. Yang, K. Goetzen, T. Erbora, J. Leckey, W. U. Boeglin, R. T. Jones, S. Fegan, D. S. Carman, K. Suresh, V. V. Berdnikov, Barry Ritchie, G. Vasileiadis, T. Carstens, E. Barriga, H. Al Ghoul, K. Moriya, J. Hardin, A. Gerasimov, M. E. McCracken, A. Deur, C. D. Keith, M. J. Staib, Hovanes Egiyan, A. Ali, Vladimir Popov, Jay Benesch, A. Hurley, C. Dickover, Viktor Matveev, Dmitri Romanov, A. Dolgolenko, B. Pratt, Justin I. McIntyre, C. A. Meyer, R. Mendez, A. R. Dzierba, C. Hutton, N. Sandoval, G. M. Huber, L. Guo, Z. Papandreou, Zhiyong Zhang, D. I. Sober, E. Pooser, J. Foote, J. Zarling, M. M. Ito, O. Chernyshov, Blake Leverington, S. Cole, P. Brindza, H. Hakobyan, A. Barnes, Sean A Dobbs, E. G. Anassontzis, T. D. Beattie, D. Werthmüller, X. Shen, Amiran Tomaradze, M. Patsyuk, J. Ritman, M. McCaughan, C. Fanelli, Yujie Qiang, R. A. Miskimen, A. Somov, R. Kliemt, F. Barbosa, A. Austregesilo, R. Dzhygadlo, C. Salgado, B. C.L. Sumner, L. Robison, Joerg Reinhold, Ting Xiao, A. Schick, V. Kakoyan, William Brooks, D. J. Mack, W. I. Levine, N. Gevorgyan, S. Katsaganis, E. Chudakov, Pavlos Ioannou, Lubomir Pentchev, A. Goncalves, A. Yu. Semenov, A. I. Ostrovidov, A. M. Foda, R. Dotel, M. Kamel, R. A. Schumacher, D. G. Ireland, W. B. Li, M. R. Shepherd, Ashot Gasparian, A. Teymurazyan, Krisztian Peters, J. Barlow, B. Zihlmann, Xiang Zhou, J. Pierce, S. Taylor, N. Sparks, L. Gan, S. Somov, L. Ng, A. Ernst, D. Kolybaba, K. Livingston, V. S. Goryachev, Cornelius Schwarz, P. Mattione, Y. Van Haarlem, P. Pauli, I. Tolstukhin, J. Schwiening, M. J. Amaryan, D. Lawrence, J. Brock, H. Ni, C. Stanislav, V. Lyubovitskij, S. Furletov, T. Britton, R. Barsotti, C. Paudel, Christine Kourkoumelis, Sergey Kuleshov, R. E. Mitchell, D. I. Lersch, C. L. Henschel, Q. Zhou, O. Soto, Friedrich Klein, and S.T. Krueger

Subjects
Nuclear and High Energy Physics, GlueX, детектор, Physics - Instrumentation and Detectors, Photon, Physics::Instrumentation and Detectors, фотонный пучок, FOS: Physical sciences, Scintillator, 01 natural sciences, Optics, Hodoscope, 0103 physical sciences, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Physics, GlueX, Spectrometer, Calorimeter (particle physics), 010308 nuclear & particles physics, business.industry, Detector, Instrumentation and Detectors (physics.ins-det), Beamline, High Energy Physics::Experiment, business
Abstract

The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 $\mu$s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation., Comment: Accepted by Nuclear Instruments and Methods A, 78 pages, 54 figures

Published
2021

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

Author

Anthony W. Thomas, M. Battaglieri, R. De Vita, D. Marchand, Latifa Elouadrhiri, S. Habet, Hubert Spiesberger, P. Gueye, David Hamilton, Giovanni Salmè, A. Filippi, Pete Markowitz, D. Perera, G. Kalicy, M. Muhoza, N. Kalantarians, H. Atac, M. Khandaker, J. Xie, F. Sabatié, M. Mazouz, Ashot Gasparian, I.P. Fernando, V. Klimenko, T. A. Forest, D. McNulty, Z. E. Meziani, M. Boer, M. McCaughan, A. Asaturyan, J. P. Chen, V. Kozhuharov, S. Stepanyan, Simonetta Liuti, T. Patel, Alberto Accardi, M. Spata, Andrew Puckett, Andreas Metz, Salina Ali, V. Bellini, L. Barion, V. V. Berdnikov, Alexandre Camsonne, P. E. Reimer, M. Shabestari, P. Bisio, Simon Širca, T. Averett, J. Kim, Nikolaos Sparveris, M. Poelker, M. Spreafico, H. F. Ibrahim, Dipangkar Dutta, V. Bertone, Bogdan Wojtsekhowski, Ross Milner, H. Avakian, C. E. Hyde, P. M. King, Marc Vanderhaeghen, A. Somov, Yulia Furletova, Miha Mihovilovič, V. Tadevosyan, P. Sznajder, S. Migliorati, R. S. Beminiwattha, T. Chetry, M. Guidal, Olfred Hansen, T. Kutz, Z. W. Zhao, Barbara Pasquini, Eric Voutier, L. Lanza, M. J. Amaryan, J. R. M. Annand, Fatiha Benmokhtar, T. Gautam, H. Voskanyan, Richard Trotta, Ian L. Pegg, J. F. Owens, W. J. Briscoe, Jingyi Zhou, P. Valente, M. N. H. Rashad, Gordan Krnjaic, P. Lenisa, Elena Santopinto, Joseph Grames, M. Leali, S. Zhamkochyan, M. Caudron, Kai-Thomas Brinkmann, Elton Smith, L. Marsicano, Andrei Afanasev, Luciano Pappalardo, M. Carmignotto, Donal Day, L. Venturelli, Eugene Pasyuk, M. Ungaro, C. Peng, L. Causse, D. Hasell, G. Costantini, Douglas Higinbotham, N. D’Hose, J. Murphy, P. Chatagnon, R. Dupré, M. Bondì, Alexander Ilyichev, Matteo Rinaldi, P. Stoler, Brian Raue, G. N. Grauvogel, R. Santos Estrada, Kondo Gnanvo, K. Price, Q. Liu, S. Diehl, J. Nazeer, Y. G. Sharabian, X. Zheng, S. Niccolai, P. G. Blunden, J. Arrington, Riad Suleiman, J. Erler, S. Joosten, Andrea Bianconi, H.-S. Ko, P. L. Cole, Nilanga Liyanage, I. Albayrak, K. Joo, Jan C. Bernauer, F.-X. Girod, D. Gaskell, A. Kim, Juliette Mammei, A. Italiano, M. Hattawy, C. Ayerbe Gayoso, I. I. Strakovsky, M. Yurov, N. Randazzo, A. Deur, Wally Melnitchouk, H.-G. Zaunick, Michael Kohl, A. D'Angelo, E. Nardi, M. Paolone, C. Zorn, L. El Fassi, B. T. Kriesten, L. Darmé, M. Rathnayake, A. Shahinyan, Jie Zhang, Alessandro Rizzo, D. Flay, W. Xiong, H. Dutrieux, V. Sergeyeva, S. Zhang, E. R. Kinney, Hervé Moutarde, B. Dongwi, Axel Schmidt, Rolf Ent, S. Zhao, Volker D. Burkert, A. S. Tadepalli, A. S. Biselli, Tanja Horn, G. Niculescu, T. Cao, A. Celentano, P. Nadel-Turonski, Ethan Cline, J. Roche, B. Karky, M. Contalbrigo, H. Szumila-Vance, S. Fucini, O. Rondon-Aramayo, M. De Napoli, V. Mascagna, E. Fuchey, L. Cardman, G. Ciullo, Haiyan Gao, Cynthia Keppel, M. Ehrhart, A. Movsisyan, R. Novotny, A. Hobart, Sergio Scopetta, B. McKinnon, S. A. Wood, H. Mkrtchyan, M. Tiefenback, C. Munoz Camacho, Xinzhan Bai, R. Paremuzyan, B. Sawatzky, D. Sokhan, M. Suresh, Markus Diefenthaler, Z. Ye, Mauro Raggi, M. Kerver, Y. Roblin, A. Mkrtchyan, V. P. Kubarovsky, R. Capobianco, T. J. Hague, Dustin Keller, Sonny Mantry, Vladimir Khachatryan, Peter Schweitzer, Michael Wood, Maxime Defurne, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
cross-section, ratio, Photon, parton distributions, elastic scattering, Parton, polarized beam, Electron, Leptons Accelerators, Structure of Nucleons, 7. Clean energy, 01 natural sciences, Dark photon, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Positron, Economica, electromagnetic form-factors, virtual compton-scattering, generalized, squared 4-momentum transfers, lepton-flavor, violation, electron-proton, parity violation, pair production, Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Elastic scattering, Dark sector, JLab, dark photon, Settore FIS/04, lepton: flavor: violation, nucleon: generalized parton distribution, 3. Good health, High Energy Physics - Phenomenology, Elastic and deep inelastic Scattering, Nucleon, Jefferson Lab, Nuclear and High Energy Physics, nucleon: form factor: electromagnetic, FOS: Physical sciences, Socio-culturale, helium: target, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, 0103 physical sciences, quantum chromodynamics, 010306 general physics, PE2_3, activity report, exchange: two-photon, electroweak interaction, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Ambientale, positron: beam, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], charge: asymmetry, Positron Beams, Physics::Accelerator Physics, proposal, High Energy Physics::Experiment
Abstract

Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab., Comment: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"

Published
2021

11. 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

12. Threshold Upsilon-meson Photoproduction at EIC and EicC

Author

I. I. Strakovsky, Lubomir Pentchev, W. J. Briscoe, and Axel Schmidt

Subjects
Quantum chromodynamics, Physics, Particle physics, Nuclear Theory, High Energy Physics::Lattice, Upsilon meson, High Energy Physics::Phenomenology, FOS: Physical sciences, Absolute value, Parton, Quarkonium, Omega, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), Amplitude, High Energy Physics - Phenomenology (hep-ph), Production (computer science), High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

High-accuracy $\Upsilon$-meson photoproduction data from EIC and EicC experiments will allow the measurement of the near-threshold total cross section of the reaction $\gamma p\to\Upsilon p$, from which the absolute value of the $\Upsilon p$ scattering length, $|\alpha_{\Upsilon p}|$, can be extracted using a Vector-Meson Dominance model. For this evaluation, we used $\Upsilon$-meson photoproduction quasi-data from the QCD approach (the production amplitude can be factorized in terms of gluonic generalized parton distributions and the quarkonium distribution amplitude). A comparative analysis of $|\alpha_{\Upsilon p}|$ with the recently determined scattering lengths for $\omega p$, $\phi p$, and $J/\psi p$ using the A2, CLAS, and GlueX experimental data are performed. The role of the "young" vector-meson effect is evaluated., Comment: 6 pages, 6 figures, 3 tables

Published
2021
Full Text
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13. Measurement of proton-proton elastic scattering into the Coulomb region at Pbeam = 2.5, 2.8 and 3.2 GeV/c

Author

Q. Hu, Frank Goldenbaum, James Ritman, D. Grzonka, Tobias Stockmanns, H. Xu, B. Lorentz, T. Sefzick, Ulf Bechstedt, I. I. Strakovsky, P. Wüstner, Ron L. Workman, A. Täschner, F. Klehr, Yong Zhou, A. Gillitzer, Colin Wilkin, S. Schadmand, D. Prasuhn, A. Khoukaz, and Jürgen Böker

Subjects
Physics, Elastic scattering, Nuclear and High Energy Physics, Range (particle radiation), Proton, Proton–proton elastic scattering, Four-momentum, FOS: Physical sciences, lcsh:QC1-999, Nuclear physics, Cross section (physics), Total cross section, Coulomb, Polar, ddc:530, Coulomb-nuclear interference, Nuclear Experiment (nucl-ex), Dispersion (water waves), Nuclear Experiment, lcsh:Physics
Abstract

The proton–proton elastic differential cross section at very small four momentum transfer squared has been measured at three different incident proton momenta in the range of 2.5 to 3.2 GeV/c by detecting the recoil proton at polar angles close to 90∘. The measurement was performed at COSY with the KOALA detector covering the Coulomb–nuclear interference region. The total cross section σtot, which has been determined precisely, is consistent with previous measurements. The values of the slope parameter B and the relative real amplitude ratio ρ determined in this experiment alleviate the lack of data in the relevant energy region. These precise data on ρ might be an important check for a new dispersion analysis.

Published
2021

14. Deeply virtual Compton scattering using a positron beam in Hall-C at Jefferson Lab

Author

Rolf Ent, M. Kerver, T. A. Forest, A. Mkrtchyan, M. J. Amaryan, P. Nadel-Turonski, Jie Zhang, M. McCaughan, V. V. Berdnikov, H. Rashad, J. Roche, Dustin Keller, A. Asaturyan, C. Munoz Camacho, K. Price, Donal Day, H.-S. Ko, B. McKinnon, S. A. Wood, I. Albayrak, V. Sergeyeva, A. Hobart, J. Murphy, S. Zhao, J. R. M. Annand, M. A. I. Fernando, Bogdan Wojtsekhowski, A. Somov, Tanja Horn, D. Marchand, S. Zhamkochyan, M. Defurne, H. Mkrtchyan, I. I. Strakovsky, S. Habet, V. Tadevosyan, R. Dupré, David Hamilton, Cynthia Keppel, R. Paremuzyan, H. Voskanyan, G. Kalicy, W. J. Briscoe, Dipangkar Dutta, P. Chatagnon, M. Caudron, S. Niccolai, V. Bellini, C. E. Hyde, Alexandre Camsonne, B. Sawatzky, Salina Ali, G. Niculescu, M. Ehrhart, Simon Širca, Eric Voutier, R. Rondon, E. R. Kinney, M. Muhoza, M. Guidal, P. Gueye, M. Mazouz, M. Carmignotto, Kai-Thomas Brinkmann, L. Causse, Carl Zorn, Andrei Afanasev, R. Novotny, S. Diehl, Richard Trotta, Ian L. Pegg, Joseph Grames, M. Boer, P. Markowitze, 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 Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Nuclear and High Energy Physics, Photon, interference, FOS: Physical sciences, Parton, Bethe-Heitler, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], momentum transfer dependence, 01 natural sciences, Nuclear physics, p: target, Cross section (physics), deeply virtual Compton scattering, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Neutral particle, Nuclear Experiment, Physics, Spectrometer, 010308 nuclear & particles physics, Compton scattering, photon: electroproduction, nucleon: generalized parton distribution, positron: beam, neutral particle, kinematics, momentum: high, High Energy Physics::Experiment, spectrometer, Nucleon, Beam (structure), Jefferson Lab, experimental results
Abstract

We propose to use the High Momentum Spectrometer of Hall C combined with the Neutral Particle Spectrometer (NPS) to perform high precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section using a beam of positrons. The combination of measurements with oppositely charged incident beams is the only unambiguous way to disentangle the contribution of the DVCS $$^2$$ term in the photon electroproduction cross section from its interference with the Bethe-Heitler amplitude. This provides a stronger way to constrain the Generalized Parton Distributions of the nucleon. A wide range of kinematics accessible with an 11 GeV beam off an unpolarized proton target will be covered. The $$Q^2-$$ dependence of each contribution will be measured independently.

Published
2021

15. Jülich-Bonn-Washington model for pion electroproduction multipoles

Author

Ron L. Workman, Ulf-G. Meißner, Maxim Mai, Carlos Granados, Helmut Haberzettl, I. I. Strakovsky, D. Rönchen, and Michael Döring

Subjects
Systematic error, Physics, Particle physics, Nuclear Theory, Proton, 010308 nuclear & particles physics, 01 natural sciences, High Energy Physics - Phenomenology, Amplitude, Pion, 0103 physical sciences, High Energy Physics::Experiment, ddc:530, Gauge theory, Nuclear Experiment, 010306 general physics, Parametrization, Nuclear theory
Abstract

Pion electroproduction off the proton is analyzed in a new framework based on a general parametrization of transition amplitudes, including constraints from gauge invariance and threshold behavior. Data with energies $1.13~{\rm GeV}, Comment: 27 pages, 14 figures

Published
2021

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

Author

I. Illari, R. A. Schumacher, U. Shrestha, M. Leali, S. Adhikari, B. McKinnon, C. A. Meyer, E. Munevar, P. Chatagnon, B. S. Ishkhanov, Aditya R. Khanal, G. V. Fedotov, P. Lenisa, J. Ritman, S. Stepanyan, N. Dashyan, D. P. Watts, Andrea Bianconi, M. Ungaro, K. P. Adhikari, A. El Alaoui, I. I. Strakovsky, G. Rosner, T. Chetry, A. Deur, C. W. Kim, Laura Clark, W. Phelps, M. Battaglieri, Nicholas Zachariou, J. C. Carvajal, Alexander Schmidt, M. J. Amaryan, William Brooks, Yordanka Ilieva, T. B. Hayward, V. Mascagna, B. A. Clary, E. L. Isupov, Y. G. Sharabian, H. Voskanyan, Friedrich Klein, W. J. Briscoe, P. Eugenio, S. Boiarinov, Brian Raue, G. Angelini, L. Barion, K. Joo, M. Guidal, Michael Paolone, Z. W. Zhao, F. X. Girod, F. Bossu, R. Cruz-Torres, E. Golovatch, M. Holtrop, R. Dupre, S. Strauch, Hovanes Egiyan, Maxime Defurne, K. A. Griffioen, Dustin Keller, C. Munoz Camacho, H. Hakobyan, Y. Prok, H. S. Jo, M. Hattawy, Michael Wood, K. Hafidi, D. G. Ireland, Luciano Pappalardo, V. Crede, A. Kim, D. I. Glazier, G. Ciullo, D. S. Carman, F. Sabatié, T. Hu, R. Paremuzyan, R. De Vita, D. Marchand, D. Protopopescu, Eugene Pasyuk, X. Wei, L. Venturelli, S. Diehl, Fatiha Benmokhtar, O. Soto, C. Salgado, E. Voutier, L. Lanza, Nicholas M. Harrison, Gerard Gilfoyle, A. Filippi, A. Movsisyan, J. W. Price, D. Sokhan, V. P. Kubarovsky, I. Bedlinskiy, M. Khandaker, M. Khachatryan, Nikolaos Sparveris, Z. E. Meziani, K. Wei, S. Niccolai, K. Livingston, N. Markov, Iu. Skorodumina, N. Tyler, C. Djalali, J. A. Tan, V. I. Mokeev, D. Heddle, Jie Zhang, G. Gavalian, D. G. Jenkins, R. Fersch, M. Ehrhart, M. Ripani, O. Pogorelko, P. L. Cole, J. Rowley, Tim O'Connell, A. I. Ostrovidov, Michael Dugger, T. Mineeva, P. Nadel-Turonski, H. Atac, A. S. Biselli, A. D'Angelo, L. Guo, Sylvester Joosten, Alessandro Rizzo, G. Asryan, L. El Fassi, C. Ayerbe Gayoso, M. E. McCracken, A. Hobart, C. Hanretty, W. Kim, G. Niculescu, P. Stoler, M. Osipenko, I. J. D. MacGregor, K. Hicks, M. Contalbrigo, J. Poudel, Z. Akbar, A. Celentano, and R. W. Gothe

Subjects
Physics, Particle physics, Range (particle radiation), Photon, Proton, Meson, 010308 nuclear & particles physics, Sigma, Photon energy, 01 natural sciences, 7. Clean energy, Resonance (particle physics), 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Photoproduction cross sections are reported for the reaction $\gamma p\to p\eta$ using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The $\eta$ mesons are detected in their dominant charged decay mode, $\eta\to \pi^+\pi^-\pi^0$, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new $\eta$ photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are compared with the experimental results from several other experiments, and with predictions of $\eta$ MAID\,2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections $d\sigma/dt$ are presented for incident photon energies $E_\gamma > 2.9$ GeV ($W > 2.5$ GeV), and compared with predictions which are based on Regge trajectories exchange in the $t$-channel (Regge models). The data confirm the expected dominance of $\rho$, $\omega$ vector-meson exchange in an analysis by the Joint Physics Analysis Center.

Published
2020

17. 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

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

Author

J. Rowley, A. I. Ostrovidov, Volker D. Burkert, A. S. Biselli, W. Phelps, K. A. Griffioen, V. Mascagna, N. Markov, M. E. McCracken, A. Hobart, Carlos A. Salgado, A. Filippi, A. Pilloni, Frank Klein, Dustin Keller, P. Eugenio, L. Marsicano, Sylvester Joosten, Maxime Defurne, M. Khandaker, M. Khachatryan, M. Osipenko, Pawel Nadel-Turonski, Michael Paolone, Alexander Schmidt, D. I. Glazier, D. Bulumulla, E. Munevar, B. S. Ishkhanov, Aditya R. Khanal, Nikolaos Sparveris, M. Ungaro, K. Hafidi, F. Bossu, M. Guidal, G. Niculescu, L. Lanza, D. G. Jenkins, I. J. D. MacGregor, R. De Vita, M. Leali, Laura Clark, M. J. Amaryan, Andrea Bianconi, C. W. Kim, W. Kim, W. Gohn, F. X. Girod, N. Tyler, C. Djalali, J. A. Tan, P. Chatagnon, G. V. Fedotov, H. Voskanyan, A. D'Angelo, T. Chetry, I. Bedlinskiy, L. Elouadrhiri, M. Holtrop, F. Hauenstein, W. J. Briscoe, E. Pasyuk, S. Strauch, K. Joo, H. Atac, D. P. Watts, H. Egiyan, G. Angelini, L. El Fassi, I. I. Strakovsky, R. Dupre, M. Battaglieri, F. Sabatié, Luciano Pappalardo, D. Heddle, A. Deur, M. Ripani, G. Gavalian, V. Mokeev, D. Marchand, V. Lucherini, V. P. Kubarovsky, Michael Dugger, Fatiha Benmokhtar, Krishna Neupane, R. G. Fersch, O. Pogorelko, O. Soto, S. Niccolai, Vincent Mathieu, P. L. Cole, Z. W. Zhao, Alessandro Rizzo, E. Golovatch, P. Lenisa, K. Hicks, M. Ehrhart, S. Adhikari, T. B. Hayward, J. Zhang, M. Hattawy, J. W. Price, N. Dashyan, Yordanka Ilieva, L. Barion, G. Rosner, William Brooks, G. Ciullo, Y. Prok, L. Venturelli, D. S. Carman, R. A. Schumacher, A. El Alaoui, X. Wei, Nicholas Zachariou, J. C. Carvajal, S. Stepanyan, E. Voutier, A. Movsisyan, Adam P. Szczepaniak, D. Sokan, Z. E. Meziani, K. Livingston, K. P. Adhikari, H. Hakobyan, H. S. Jo, A. Kim, J. Ritman, S. Diehl, D. G. Ireland, V. Crede, O. Cortes, E. L. Isupov, R. Paremuzyan, S. Boiarinov, R. Cruz-Torres, Nicholas M. Harrison, U. Shrestha, M. Contalbrigo, C. Munoz Camacho, M. H. Wood, B. McKinnon, A. Celentano, R. W. Gothe, M. Mirazita, and N. Gevorgyan

Subjects
Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Sigma, Photon energy, 01 natural sciences, Nuclear physics, Amplitude, 0103 physical sciences, Invariant mass, Nuclear Experiment, 010306 general physics, Phenomenology (particle physics)
Abstract

We present the first measurement of the exclusive reaction $\gamma p \rightarrow a_2(1320)^0 \, p$ in the photon energy range $3.5$-$5.5$ GeV and four-momentum transfer squared $0.2

Published
2020

19. Extracting the spin polarizabilities of the proton by measurement of Compton double-polarization observables

Author

Susanna Costanza, A. G. Denig, V. L. Kashevarov, V. Metag, C. Sfienti, W. Gradl, G. M. Huber, M. Oberle, D. Werthmüller, J. Wettig, M. Biroth, F. Afzal, P. B. Otte, V. Lisin, A. Polonski, V. Sokhoyan, A. B. Lazarev, Anthony W. Thomas, D. I. Glazier, K. Livingston, S. Lutterer, K. Spieker, J. Mancell, S. Gardner, N. S. Borisov, A. Käser, D. Hornidge, C. Collicott, A. Braghieri, A. B. Neganov, Th. Strub, A. Rajabi, D. P. Watts, Patrick Achenbach, J. R. M. Annand, H. J. Arends, P. Drexler, M. Ostrick, R. Kondratiev, Michaela Thiel, Lena Heijkenskjöld, M. I. Ferretti-Bondy, D. Glowa, M. Bashkanov, R. A. Miskimen, M. Korolija, S. N. Prakhov, Yu. A. Usov, O. Steffen, A. Thiel, G. M. Gurevich, David Manley, P. Pedroni, Lorenzo Zana, P. P. Martel, S. Garni, A. Neiser, I. Keshelashvili, David Hamilton, W. Meyer, B. Krusche, J. Linturi, M. Dieterle, Lilian Witthauer, S. Kay, S. Günther, S. Wagner, G. Reicherz, S. Abt, C. S. Akondi, A. J. Sarty, Reinhard Beck, I. Supek, I. Gorodnov, M. H. Sikora, Roderick M. Macrae, W. J. Briscoe, A. N. Mushkarenkov, T. Rostomyan, Guy Ron, E. J. Downie, M. Unverzagt, F. Cividini, P. Adlarson, Z. Ahmed, I. I. Strakovsky, C. Mullen, Durga Paudyal, M. Wolfes, A. Powell, N. K. Walford, E. Mornacchi, and I. J. D. MacGregor

Subjects
Nuclear reaction, Physics, Chiral perturbation theory, Proton, 010308 nuclear & particles physics, Resonance, 16. Peace & justice, 01 natural sciences, Baryon, 0103 physical sciences, Proton spin crisis, Atomic physics, 010306 general physics, Microtron, Spin-½
Abstract

The Compton double-polarization observable \ud Σ\ud 2\ud z\ud has been measured for the first time in the \ud Δ\ud (\ud 1232\ud )\ud resonance region using a circularly polarized photon beam incident on a longitudinally polarized proton target at the Mainz Microtron. This paper reports these results, together with the model-dependent extraction of four proton spin polarizabilities from fits to additional asymmetry data using either a dispersion relation calculation or a baryon chiral perturbation theory calculations with the weighted average of these two fits resulting in \ud γ\ud E\ud 1\ud E\ud 1\ud =\ud −\ud 2.87\ud ±\ud 0.52\ud ,\ud \ud γ\ud M\ud 1\ud M\ud 1\ud =\ud 2.70\ud ±\ud 0.43\ud ,\ud \ud γ\ud E\ud 1\ud M\ud 2\ud =\ud −\ud 0.85\ud ±\ud 0.72\ud , and \ud γ\ud M\ud 1\ud E\ud 2\ud =\ud 2.04\ud ±\ud 0.43\ud , in units of \ud 10\ud −\ud 4\ud fm\ud 4\ud .

Published
2020

20. Threshold $$\pi ^-$$ photoproduction on the neutron

Author

A. E. Kudryavtsev, Ron L. Workman, W. J. Briscoe, I. I. Strakovsky, and V. E. Tarasov

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Hadron, 01 natural sciences, Pion, Deuterium, 0103 physical sciences, Elementary reaction, Pi, Nuclear fusion, Neutron, Nuclear Experiment, 010306 general physics, Multipole expansion
Abstract

Recent data from the PIONS@MAX-lab Collaboration, measuring the total cross section of the incoherent pion photoproduction reaction, $$\gamma d\rightarrow \pi ^- pp$$ , near threshold, have been used to extract the $$E_{0+}$$ multipole and total cross section of the reaction $$\gamma n\rightarrow \pi ^-p$$ , also near threshold. These are the first measurements of the reaction $$\gamma d\rightarrow \pi ^- pp$$ in the threshold region. The value of $$E_{0+}$$ is extracted through a fit to the deuteron data in a photoproduction model accounting for final-state interactions. The model takes an S-wave approximation for the elementary reaction $$\gamma n\rightarrow \pi ^-p$$ with $$\hbox {E}_{0+} = $$ const in the threshold region. The fit over all the 6 deuteron data points gives the value $$E_{0+} = -\,31.86\pm 0.8$$ (in units $$10^{-3}/m_\pi $$ ). We explore the dependence of our results on the choice of data subsets included in the fit. The obtained values of $$E_{0+}$$ , for different subsets, have overlapping errors and agree with previous determinations.

Published
2020

21. Differential cross sections for neutron-proton scattering in the region of the d*(2380) dibaryon resonance

Author

C.-O. Gullström, Markus Büscher, D. Pszczel, P. Podkopał, Pawel Marciniewski, S. Sawant, Paweł Moskal, R. Varma, P. Fedorets, I. Ozerianska, R. Maier, A. Švarc, J. Ritman, W. Eyrich, T. Sefzick, V. Serdyuk, P. Goslawski, E. Stephan, Jerzy Smyrski, P. Kulessa, N. Hüsken, B. Kamys, V. Hejny, K. Föhl, R. Engels, A. Pricking, P. Wüstner, H. Clement, Günter Kemmerling, A. Kupść, M. Mikirtychiants, A. Pyszniak, W. Augustyniak, D. Lersch, Izabela Ciepał, A. Goswami, Magdalena Skurzok, M. Bashkanov, Frank Goldenbaum, M. Krapp, K. Demmich, K. Pysz, B. Kłos, A. Magiera, Ferdous Khan, J. Zabierowski, Akira Yamamoto, Hans Stockhorst, M. Berłowski, A. Erven, H. Ströher, W. Erven, G. Sterzenbach, Antoni Szczurek, B. Lorentz, Rolf Stassen, Tord Johansson, K. Fransson, H. P. Morsch, Zbigniew Rudy, T. Skorodko, V. Sopov, H. Ohm, K. Grigoryev, A. Trzcinski, A. Khoukaz, S. Schadmand, P. Żuprański, A. Zink, Jozef Zlomanczuk, B. Mariański, R. Siudak, A. Täschner, I. I. Strakovsky, E. Doroshkevich, Aleksandra Wrońska, A. Jany, K. Lalwani, Eryk Czerwiński, Hans Calén, Stanisław Kistryn, W. Bardan, W. J. Briscoe, E. Perez del Rio, Ankhi Roy, Wojciech Krzemien, M. Hodana, J. Stepaniak, C. F. Redmer, F. S. Bergmann, Magnus Wolke, Harald Kleines, Di. Kirillov, F. Hauenstein, Lena Heijkenskjöld, D. Prasuhn, P. Wurm, Patrik Adlarson, Bo Höistad, D. Coderre, L. Yurev, Benedykt R. Jany, Himani Bhatt, N.M. Piskunov, Ron L. Workman, M. Żurek, and Marcin Zieliński

Subjects
Physics, Nuclear physics, Range (particle radiation), Hydrogen, chemistry, Deuterium, Scattering, chemistry.chemical_element, Neutron, Nuclear Experiment, Resonance (particle physics), Beam (structure), Differential (mathematics)
Abstract

Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized np scattering performed in the energy region of the d*(2380) dibaryon resonance covering the range of beam energies Tn=0.98−1.29 GeV (s=2.32−2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp→np+pspectator. In this way the np differential cross section σ(Θ) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power Ay(Θ) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D33-G33 waves.

Published
2020

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

Author

T. D. Beattie, K. Goetzen, W. J. Briscoe, P. Pauli, G. M. Huber, D. I. Sober, M. J. Amaryan, V. Crede, M. M. Dalton, V. S. Goryachev, Christine Kourkoumelis, A. Hurley, R. E. Mitchell, G. Kalicy, N. S. Jarvis, C. A. Meyer, L. Ng, D. Lawrence, A. Ernst, H. Hakobyan, V. Lyubovitskij, G. J. Lolos, I. Larin, C. Salgado, R. Barsotti, S. Adhikari, O. Cortes, Sean A Dobbs, T. Britton, A. Somov, A. Ali, Sergey Kuleshov, C.P. Romero, P. Eugenio, R. A. Schumacher, D. I. Lersch, K. Livingston, M. M. Ito, Barry Ritchie, N. Cao, Ashot Gasparian, A. Hamdi, Krisztian Peters, Michael Dugger, T. C. Black, I. I. Strakovsky, J. Barlow, Joerg Reinhold, S. Fegan, A. Deur, S. Cole, J. Frye, E. Pooser, V. A. Matveev, N. Qin, J. Schwiening, O. Soto, A. M. Schertz, T. Whitlatch, L. Robison, T. Daniels, B. E. Cannon, T. Erbora, H. Ni, Z. Papandreou, Ting Xiao, V. V. Berdnikov, William Brooks, J. R. Stevens, M. McCaughan, Mark Richard James Williams, Lubomir Pentchev, C. Gleason, S. Furletov, Q. Zhou, A. M. Foda, Dmitri Romanov, H. Marukyan, R.S. Pedroni, W. U. Boeglin, W. McGinley, E. Chudakov, N. Wickramaarachchi, A. Thiel, K. K. Seth, C. Fanelli, M. Kamel, W. Phelps, F. Nerling, Elton Smith, B. Liu, G. Vasileiadis, A. Austregesilo, Zhiyong Zhang, M. R. Shepherd, A. Teymurazyan, R. T. Jones, Y. Yang, M. E. McCracken, Xiang Zhou, S. Taylor, L. Gan, S. Somov, L. Guo, J. Zarling, C. Paudel, A. Dolgolenko, V. V. Tarasov, E. Barriga, M. Patsyuk, J. Foote, X. Shen, K. Suresh, Hovanes Egiyan, R. A. Miskimen, R. Dzhygadlo, F. Barbosa, V. Kakoyan, D. J. Mack, A. Goncalves, R. Dotel, B. Zihlmann, A. I. Ostrovidov, H. Li, D. G. Ireland, and W. B. Li

Subjects
Physics, Range (particle radiation), GlueX, Spectrometer, 010308 nuclear & particles physics, Linear polarization, media_common.quotation_subject, Theoretical models, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Photon beam, Nuclear Experiment, 010306 general physics, Beam (structure), media_common
Abstract

We report measurements of the photon beam asymmetry Σ for the reaction γp→K+Σ0 (1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2–8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Σ was measured as a function of the Mandelstam variable t , and a single value of Σ was extracted for events produced in the u channel. These are the first exclusive measurements of the photon beam asymmetry Σ for the reaction in this energy range. For the t channel, the measured beam asymmetry is close to unity over the t range studied, − t = ( 0.1 – 1.4 ) ( GeV / c ) 2 , with an average value of Σ = 1.00 ± 0.05 . This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K ∗ (892) Regge trajectory. A value of Σ = 0.41 ± 0.09 is obtained for the u channel integrated up to − u = 2.0 ( GeV / c ) 2 .

Published
2020

23. Comparative analysis of ωp , ϕp , and J/ψp scattering lengths from A2, CLAS, and GlueX threshold measurements

Author

I. I. Strakovsky, Lubomir Pentchev, and Alexander I. Titov

Subjects
Physics, Particle physics, GlueX, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Hadron, Scattering length, Absolute value (algebra), 01 natural sciences, Omega, Cross section (physics), 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nuclear theory
Abstract

The high accuracy $\phi $-meson photoproduction data from the CLAS experiment in Hall~B of Jefferson Laboratory allow us to determine the near-threshold total cross section of the $\gamma p\to\phi p$ reaction and use it for evaluating the $\phi p$ scattering length $\alpha_{\phi p}$. These data result in an absolute value of $|\alpha_{\phi p}| = (0.063\pm 0.010)$~fm, which is smaller than the typical hadron size. A comparative analysis of $\alpha_{\phi p}$ with the previously determined scattering lengths for $\omega p$ and $J/\psi p$ from the A2 and GlueX experiments is performed.

Published
2020

24. J/ψp scattering length from GlueX threshold measurements

Author

Denis Epifanov, I. I. Strakovsky, and Lubomir Pentchev

Subjects
Physics, Particle physics, GlueX, Nuclear Theory, 010308 nuclear & particles physics, Scattering length, Vector meson dominance, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Phenomenology, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nuclear theory, Energy (signal processing)
Abstract

The quality of the recent GlueX $J/\psi $ photoproduction data from Hall~D at Jefferson Laboratory, and the proximity of the data to the energy threshold, gives access to a variety of interesting physics aspects. As an example, an estimation of the $J/\psi$-nucleon scattering length $\alpha_{J/\psi p}$ is provided within the vector meson dominance model. It results in $|\alpha_{J/\psi p}| = (3.08\pm 0.55 ({\rm stat.}) \pm 0.45 ({\rm syst.}))$~mfm., Comment: 5 pages, 2 figures, v1 had a typo

Published
2020

25. Signatures of the d*(2380) Hexaquark in d(γ,pn→)

Author

M. Bashkanov, R. A. Miskimen, M. Biroth, Yu. A. Usov, O. Steffen, P. Pedroni, P. B. Otte, Michaela Thiel, S. Abt, C. S. Akondi, A. B. Lazarev, A. Braghieri, Th. Strub, Concettina Sfienti, L.A. Zana, M. Korolija, K. Livingston, S. Lutterer, David Manley, V. L. Kashevarov, W. Gradl, S. Gardner, N. S. Borisov, D. Hornidge, P. P. Martel, Z. Ahmed, N. K. Walford, J. Wettig, S. Fegan, I. I. Strakovsky, F. Cividini, Susanna Costanza, H. J. Arends, D. Ghosal, Guy Ron, S. Wagner, K. Spieker, A. Käser, V. Sokhoyan, C. Mullen, R. Beck, P. Adlarson, A. Fix, A. G. Denig, M. Ostrick, Durga Paudyal, Nicholas Zachariou, D. P. Watts, Patrick Achenbach, A. Neiser, E. J. Downie, D. Gurevich, M. Wolfes, I. Supek, C. Collicott, I. Gorodnov, A. Thiel, F. Afzal, W. J. Briscoe, A. B. Neganov, D. Werthmüller, M. Günther, Lena Heijkenskjöld, I. J. D. MacGregor, P. Drexler, S. N. Prakhov, J. R. M. Annand, Andy Thomas, G. M. Huber, D. I. Glazier, S. Kay, A. Powell, A. Sarty, E. Mornacchi, and B. Krusche

Subjects
Physics, Photon, Spin polarization, Nuclear Theory, General Physics and Astronomy, Photon energy, 01 natural sciences, Nuclear physics, Recoil, Photodisintegration, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Crystal Ball
Abstract

We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570 MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d^{*}(2380) hexaquark.

Published
2020

26. 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

27. 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

28. Cross section for γn→π0n measured at the Mainz A2 experiment

Author

K. Livingston, S. Lutterer, S. Gardner, N. S. Borisov, M. Unverzagt, V. V. Kulikov, H. J. Arends, A. B. Lazarev, A. Neiser, Alfred Švarc, F. Cividini, A. Braghieri, F. Afzal, D. G. Middleton, B. Oussena, C. Collicott, D. P. Watts, K. Spieker, K. Bantawa, M. Bashkanov, R. A. Miskimen, M. Ostrick, S. Kay, C. Sfienti, V. E. Tarasov, Patrick Achenbach, Yu. A. Usov, G. M. Huber, A. E. Kudryavtsev, A. Käser, O. Steffen, P. Aguar-Bartolomé, V. L. Kashevarov, A. G. Denig, E. J. Downie, N. K. Walford, J. Wettig, E. Mornacchi, A. Thiel, J. Stahov, S. Fegan, Durga Paudyal, J. C. McGeorge, Nicholas Zachariou, V. Sokhoyan, I. J. D. MacGregor, M. I. Ferretti Bondy, M. A. Martemianov, D. Gurevich, D. Hornidge, D. Ghosal, S. Wagner, M. Wolfes, Anthony W. Thomas, D. I. Glazier, Guy Ron, Z. Ahmed, Susanna Costanza, Michaela Thiel, W. J. Briscoe, A. Powell, M. Günther, L. Tiator, I. I. Strakovsky, A. N. Mushkarenkov, S. A. Bulychjov, D. M. Manley, Lena Heijkenskjöld, P. P. Martel, R. Omerović, M. Korolija, R. Beck, C. Mullen, J. R. M. Annand, D. Werthmüller, M. Biroth, M. Hadžimehmedović, P. B. Otte, A. B. Neganov, P. Pedroni, W. Gradl, S. N. Prakhov, B. Krusche, P. Drexler, H. Osmanović, T. Rostomyan, I. Supek, I. Gorodnov, Ron L. Workman, Roderick M. Macrae, S. Abt, C. S. Akondi, and A. J. Sarty

Subjects
Physics, 010308 nuclear & particles physics, Nuclear Theory, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Nuclear physics, Cross section (physics), Pion, Amplitude, Deuterium, Reaction dynamics, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Microtron
Abstract

The γ n → π 0 n differential cross section evaluated for 27 energy bins span the photon-energy range 290–813 MeV ( W = 1.195 –1.553 GeV) and the pion c.m. polar production angles, ranging from 18 ∘ to 162 ∘ , making use of model-dependent nuclear corrections to extract π 0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883 MeV electron beam of the Mainz Microtron MAMI was used for the π 0 -meson production. Our accumulation of 3.6 × 10 6 γ n → π 0 n events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared with predictions of previous said, maid, and BnGa partial-wave analyses and to the latest said fit MA19 that included our data. Selected photon-decay amplitudes N ∗ → γ n at the resonance poles are determined for the first time.

Published
2019

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

Author

A. Hurley, L. Gan, C. A. Meyer, J. Frye, C. Paudel, V. V. Tarasov, A. Dolgolenko, H. Hakobyan, C. Salgado, A. M. Schertz, E. Barriga, T. Daniels, C. Fanelli, R. T. Jones, W. Phelps, F. Nerling, M. E. McCracken, Krisztian Peters, Michael Dugger, V. Kakoyan, M. J. Staib, B. E. Cannon, T. Erbora, E. Pooser, I. A. Semenova, Z. Zhang, V. A. Matveev, A. Barnes, Dmitri Romanov, Sean A Dobbs, V. V. Berdnikov, A. Hamdi, J. Barlow, I. I. Strakovsky, Mark Richard James Williams, K. Suresh, T. Whitlatch, A. Somov, T. C. Black, D. Lawrence, A. Thiel, M. M. Dalton, H. Marukyan, Hovanes Egiyan, L. Ng, A. Ernst, M. McCaughan, R.S. Pedroni, W. McGinley, G. M. Huber, D. I. Sober, L. Robison, K. Livingston, V. Lyubovitskij, A. Deur, Ting Xiao, Q. Zhou, R. A. Miskimen, William Brooks, X. Zhou, P. Eugenio, G. Zhao, N. Wickramaarachchi, O. Cortes, N. Qin, L. Guo, E. Chudakov, R. Barsotti, Lubomir Pentchev, N. Cao, O. Soto, K. K. Seth, R. Dzhygadlo, F. Barbosa, B. Zihlmann, S. Fegan, M. Kamel, A. M. Foda, D. J. Mack, R. A. Schumacher, N. Gevorgyan, T. Britton, A. I. Ostrovidov, B. Liu, V. Crede, C.P. Romero, G. J. Lolos, I. Larin, G. Vasileiadis, H. Li, Ashot Gasparian, Sergey Kuleshov, D. I. Lersch, D. G. Ireland, A. Goncalves, Z. Papandreou, V. S. Goryachev, M. J. Amaryan, P. Mattione, S. Adhikari, M. Patsyuk, W. B. Li, A. Yu. Semenov, R. Dotel, Elton Smith, J. Schwiening, Barry Ritchie, J. R. Stevens, S. Somov, M. Boer, J. Foote, J. Zarling, M. R. Shepherd, A. Teymurazyan, C. Gleason, G. Kalicy, N. S. Jarvis, X. Shen, A. Austregesilo, S. Cole, Christine Kourkoumelis, Joerg Reinhold, A. Ali, R. E. Mitchell, W. U. Boeglin, Y. Yang, M. M. Ito, P. Pauli, S. Furletov, W. J. Briscoe, T. D. Beattie, and K. Goetzen

Subjects
Physics, GlueX, Meson, 010308 nuclear & particles physics, Linear polarization, media_common.quotation_subject, Momentum transfer, Parity (physics), 01 natural sciences, 7. Clean energy, Asymmetry, 0103 physical sciences, Quasiparticle, Atomic physics, Photon beam, 010306 general physics, media_common
Abstract

We report on the measurement of the beam asymmetry Σ for the reactions → γ p → p η and → γ p → p η ′ from the GlueX experiment using an 8.2–8.8-GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Laboratory. These measurements are made as a function of momentum transfer − t with significantly higher statistical precision than our earlier η measurements and are the first measurements of η ′ in this energy range. We compare the results to theoretical predictions based on t -channel quasiparticle exchange. We also compare the ratio of Σ η to Σ η ′ to these models as this ratio is predicted to be sensitive to the amount of s ¯ s exchange in the production. We find that photoproduction of both η and η ′ is dominated by natural parity exchange with little dependence on − t .

Published
2019

30. Neutral Pion Photoproduction on Neutron

Author

V. V. Kulikov, I. I. Strakovsky, A. E. Kudryavtsev, W. J. Briscoe, M. A. Martem’yanov, S. A. Bulychev, and V. E. Tarasov

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Atomic and Molecular Physics, and Optics, Complement (complexity), Nuclear physics, Pion, Deuterium, 0103 physical sciences, Electromagnetic coupling, Neutron, Nuclear Experiment, 010306 general physics, Crystal Ball
Abstract

The reaction γn → π0n is investigated both theoretically and experimentally as an important step toward determining the electromagnetic coupling constants of the N* and Δ* resonances [1]. We analyze the data on the collisions of γ quanta with energies between 200 and 800 MeV with a deuterium target collected by the A2 experiment in Mainz, Germany. These complement the data for neutral-pion photoproduction on protons obtained by the same experiment [2].

Published
2017

31. 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

32. 12C(e,e'pN) measurements of short range correlations in the tensor-to-scalar interaction transition region

Author

M. J. Amaryan, P. Lenisa, Jie Zhang, A. Beck, L. Marsicano, T. B. Hayward, U. Shrestha, Larry Weinstein, S. Strauch, Maxime Defurne, K. A. Griffioen, D. P. Watts, Friedrich Klein, R. Paremuzyan, Brian Raue, O. Pogorelko, J. Rowley, A. I. Ostrovidov, R. A. Schumacher, F. X. Girod, M. Duer, A. Denniston, E. Golovatch, R. Dupre, Nicholas M. Harrison, R. De Vita, I. I. Strakovsky, P. Eugenio, A. Deur, W. K. Brooks, A. Filippi, D. Sokhan, B. A. Clary, D. Protopopescu, Volker D. Burkert, A. S. Biselli, L. Lanza, M. Khandaker, N. Tyler, C. Djalali, E. Voutier, Michael Paolone, Y. G. Sharabian, X. Zheng, H. Atac, J. A. Tan, Y. Prok, D. S. Carman, I. Bedlinskiy, W. Phelps, V. Lucherini, M. Battaglieri, A. El Alaoui, Y. Ilieva, E. L. Isupov, Nicholas Zachariou, X. Wei, S. Mey-Tal Beck, S. Boiarinov, Hovanes Egiyan, F. Hauenstein, C. Munoz Camacho, J. W. Price, Taofeng Wang, Fatiha Benmokhtar, M. Khachatryan, Nikolaos Sparveris, N. Markov, A. Movsisyan, R. Cruz-Torres, T. A. Forest, O. Soto, D. Heddle, M. Ungaro, K. P. Adhikari, Douglas Higinbotham, Latifa Elouadrhiri, D. Marchand, P. Nadel-Turonski, S. Adhikari, B. McKinnon, M. Ripani, A. Kim, S. Stepanyan, I. Korover, M. Hattawy, M. Guidal, B. Mustapha, Z. W. Zhao, T. Mineeva, Or Hen, H. Hakobyan, M. Mirazita, J. Ritman, L. Barion, J.R. Pybus, M. Holtrop, S. Diehl, R. G. Fersch, C. Salgado, K. Joo, Luciano Pappalardo, T. Chetry, E.P. Segarra, H. S. Jo, D. G. Jenkins, M. Leali, Eugene Pasyuk, P. L. Cole, M. Ehrhart, G. Rosner, P. Chatagnon, A. D'Angelo, L. El Fassi, V. P. Kubarovsky, L. Venturelli, Krishna Neupane, C. W. Kim, H. Voskanyan, W. J. Briscoe, Dustin Keller, E. Piasetzky, D. Bulumulla, Michael Wood, K. Hafidi, Aditya R. Khanal, Andrea Bianconi, G. Niculescu, Alexander Schmidt, G. Gavalian, M. Osipenko, I. J. D. MacGregor, F. Sabatié, D. G. Ireland, V. Crede, M. Contalbrigo, Laura Clark, G. Angelini, K. Hicks, A. Celentano, R. W. Gothe, Alessandro Rizzo, V. Mascagna, S. Joosten, K. Livingston, 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 The Clas Collaboration

Subjects
Nuclear and High Energy Physics, Nuclear Theory, dependence, CLAS, dynamics, isospin, energy, system, Astronomy & Astrophysics, Physics, QC1-999, Scalar (mathematics), FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Astrophysics, 01 natural sciences, Nuclear Theory (nucl-th), Momentum, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, ddc:530, Tensor, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Nuclear theory, [PHYS]Physics [physics], Range (particle radiation), 010308 nuclear & particles physics, Settore FIS/04, Nuclear interaction, High Energy Physics - Phenomenology, Astronomy &amp, Atomic physics, Nucleon
Abstract

High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pN)$ reactions (where $N$ is either $n$ or $p$), at high-$Q^2$ and $x_B>1.1$. The data span a missing-momentum range of 300--1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon ($NN$) interaction models. This agreement suggests that the measured high missing-momentum protons up to $1000$ MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured $^{12}$C$(e,e'pN)$ / $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pp)$ / $^{12}$C$(e,e'pn)$ cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor $NN$ interaction at $\sim 400$ MeV/c to an isospin-independent scalar interaction at high-momentum around $\sim 800$ MeV/c as predicted by theoretical calculation., Accepted for publication in Physics Letters B. 7 pages, 3 figures, and online supplementary materials

Published
2021

33. First Measurements of the Double-Polarization Observables F , P , and H in ω Photoproduction off Transversely Polarized Protons in the N* Resonance Region

Author

Eberhard Klempt, O. Cortes, C. Hanretty, K. A. Griffioen, M. Ungaro, V. A. Nikonov, X. Wei, B. S. Ishkhanov, O. Soto, C. D. Keith, S. Strauch, G. Khachatryan, F. X. Girod, M. Osipenko, A. D'Angelo, Eugene Pasyuk, H. S. Jo, A. El Alaoui, W. J. Briscoe, Y. Ilieva, Aditya R. Khanal, Dustin Keller, L. Barion, F. Sabatié, I. I. Strakovsky, L. Guo, Alessandro Rizzo, A. V. Anisovich, L. Lanza, J. Brock, V. Mokeev, E. L. Isupov, Nicholas Zachariou, K Nakayama, M. C. Kunkel, P. Nadel-Turonski, Rong Wang, R. De Vita, A. Deur, R. A. Schumacher, Michael Wood, P. Lenisa, W. Phelps, Barry Ritchie, S. Boiarinov, K. Hafidi, G. Ciullo, Y. Prok, Iu. Skorodumina, S Niccolai, P. Eugenio, W. Kim, G. Niculescu, D. S. Carman, W. K. Brooks, I. Bedlinskiy, C. A. Meyer, D. Payette, K. Livingston, Sylvester Joosten, G. Rosner, H. Egiyan, Andrea Celentano, T. B. Hayward, J. Pierce, Jie Zhang, S. Adhikari, Friedrich Klein, D. G. Jenkins, M. Taiuti, K. P. Adhikari, Brian Raue, D. P. Watts, D. Marchand, Y. G. Sharabian, A. Movsisyan, S. Diehl, M. Ripani, C. Salgado, C. Carlin, S. Fegan, M. L. Kabir, A. V. Sarantsev, M. Battaglieri, N. Tyler, B. Duran, V. P. Kubarovsky, E. Voutier, J. A. Tan, U. Shrestha, V. Crede, D. Riser, Chaden Djalali, O. Pogorelko, M. Khachatryan, Michael Dugger, T. Mineeva, H. Avakian, E. Golovatch, A Fradi, R. Dupre, H. Voskanyan, Nikolaos Sparveris, F. Cao, P. Roy, N C Wei, N. K. Walford, R. A. Montgomery, M. Guidal, E. De Sanctis, N. Dashyan, A. Kim, P. Chatagnon, I. J. D. MacGregor, Michael Paolone, M. Holtrop, M. Hattawy, R. W. Gothe, M Ehrhart, K. Hicks, Luciano Pappalardo, S. Park, Taya Chetry, M. Contalbrigo, G. Angelini, Sergey Kuleshov, D. G. Meekins, L. El Fassi, A. I. Ostrovidov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, M. Khandaker, B. McKinnon, D. Heddle, P. L. Cole, M. L. Seely, B. Torayev, Feng Huang, R. Paremuzyan, Sandra K. Johnston, D. Protopopescu, Z. W. Zhao, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Filippi, and C. Munoz Camacho

Subjects
Physics, Photon, Spectrometer, Proton, Linear polarization, media_common.quotation_subject, Nuclear Theory, General Physics and Astronomy, Resonance, Polarization (waves), 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics, Nucleon, media_common
Abstract

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables. The results are included in two partial-wave analyses and reveal significant contributions from several nucleon (N^{*}) resonances. In particular, contributions from new N^{*} resonances listed in the Review of Particle Properties are observed, which aid in reaching the goal of mapping out the nucleon resonance spectrum.

Published
2019

34. 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

35. 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

36. Near-threshold $\pi^-$ photoproduction on the deuteron

Author

B. Seitz, K. Hamilton, Michael A. Kovash, A. E. Kudryavtsev, M. Meshkian, Vadim Lensky, I. I. Strakovsky, B. Oussena, Kurt Hansen, D. O'donnell, M. F. Taragin, M. F. Preston, R. Al Jebali, Laura Clark, Lennart Isaksson, V. E. Tarasov, W. J. Briscoe, S. Lipschutz, F. Cividini, L.S. Myers, K. England, D. I. Glazier, Mikael Lundin, Bent Schröder, D. G. Middleton, E. J. Downie, J. R. M. Annand, J. Brudvik, Gerald Feldman, Grant O'Rielly, B. Strandberg, and Kevin Fissum

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Radiative capture, Nuclear Theory, Theoretical models, 01 natural sciences, 3. Good health, Nuclear physics, Near threshold, Cross section (physics), Deuterium, 0103 physical sciences, Elementary reaction, 010306 general physics, Nuclear Experiment, Beam (structure)
Abstract

The first experimental investigation of the near-threshold cross section for incoherent $\pi^-$ photoproduction on the deuteron $\gamma$ d -> $\pi^-$ pp is presented. The experimental technique involved detection of the ~131 MeV gamma ray resulting from the radiative capture of photoproduced $\pi^-$ in the target. The total cross section has been measured using an unpolarized tagged-photon beam, a liquid-deuterium target, and three very large NaI(Tl) spectrometers. The data are compared to theoretical models that give insight into the elementary reaction $\gamma$ n -> $\pi^-$ p and pion-nucleon and nucleon-nucleon final-state interactions., Comment: 8 pages, 6 figures, to be submitted to Physical Review C

Published
2018

37. 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

38. On the extraction of cross sections for π0 and η photoproduction off neutrons from deuteron data

Author

M. Ostrick, I. I. Strakovsky, W. J. Briscoe, V. E. Tarasov, M. Dieterle, B. Krusche, and A. E. Kudryavtsev

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Proton, Meson, FOS: Physical sciences, 01 natural sciences, Resonance (particle physics), High Energy Physics - Experiment, Nuclear Theory (nucl-th), Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Pion, 0103 physical sciences, Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Atomic and Molecular Physics, and Optics, High Energy Physics - Phenomenology, Isospin, Atomic nucleus, Nucleon
Abstract

We discuss the procedure of extracting the photoproduction cross section for neutral pseudoscalar mesons off neutrons from deuteron data. The main statement is that the final-state interaction (FSI) corrections for the proton and neutron target are in general not equal, but for pi0 production there are special cases were they have to be identical and there are large regions in the parameter space of incident photon energy and pion polar angle, \theta^*, where they happen to be quite similar. The corrections for both target nucleons are practically identical for $\pi_0$ production in the energy range of the Delta(1232)3/2+ resonance due to the specific isospin structure of this excitation. Also above the $\Delta$-isobar range large differences between proton and neutron correction factors are only predicted for extreme forward angles ($\theta^*$ < 20 deg), but the results are similar for larger angles. Numerical results for the gp-->pi0p and gn-->pi0n correction factors are discussed. Also the model description for the available data on the differential gd-->pi0pn cross sections are given., Comment: 16 pages, 5 figures; v2 fixed several minor typos

Published
2016

39. 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

40. Measurement of the doubly-polarized He3→(γ→,n)pp reaction at 16.5 MeV and its implications for the GDH sum rule

Author

M. Meziane, X. Yan, J.N. Heideman, M. W. Ahmed, P. H. Chu, W. Xiong, Jacek Golak, T. Averett, Henryk Witała, G. Laskaris, H. R. Weller, I. I. Strakovsky, W.R. Zimmerman, A. Deltuva, R. Skibiński, C. Flower, A. C. Fonseca, Jonathan Mueller, P. U. Sauer, Ying Wu, Haiyan Gao, and Hugon J Karwowski

Subjects
Physics, Nuclear and High Energy Physics, High intensity, Nuclear Theory, Polarization observables, Photon energy, Standard deviation, Nuclear physics, Cross section (physics), Photodisintegration, Coulomb, Sum rule in quantum mechanics, Atomic physics, Nuclear Experiment
Abstract

We report new measurements of the double-polarized photodisintegration of 3 He at an incident photon energy of 16.5 MeV, carried out at the High Intensity γ -ray Source (HI γ S) facility located at Triangle Universities Nuclear Laboratory (TUNL). The spin-dependent double-differential cross sections and the contribution from the three-body channel to the Gerasimov–Drell–Hearn (GDH) integrand were extracted and compared with the state-of-the-art three-body calculations. The calculations, which include the Coulomb interaction and are in good agreement with the results of previous measurements at 12.8 and 14.7 MeV, deviate from the new cross section results at 16.5 MeV. The GDH integrand was found to be about one standard deviation larger than the maximum value predicted by the theories.

Published
2015

41. A conceptual design study of a Compact Photon Source (CPS) for Jefferson Lab

Author

Rolf Ent, Dustin Keller, David Hamilton, G. Niculescu, Pavel Degtiarenko, Tanja Horn, Jie Zhang, I. I. Strakovsky, Donal Day, Sean A Dobbs, P. Reid, Cynthia Keppel, and Bogdan Wojtsekhowski

Subjects
Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Photon, 010308 nuclear & particles physics, business.industry, Scattering, Radiation dose, Bremsstrahlung, Photon source, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Optics, Conceptual design, 0103 physical sciences, 010306 general physics, Nucleon, business, Instrumentation, Intensity (heat transfer)
Abstract

This document describes the technical design concept of a compact high intensity, multi-GeV photon source. Capable of producing 10^12 equivalent photons per second this novel device will provide unprecedented access to physics processes with very small scattering probabilities such as hard exclusive reactions on the nucleon. When combined with dynamic nuclear polarized targets, its deployment will result in a large gain in polarized experiment figure-of-merit compared to all previous measurements. Compared to a traditional bremsstrahlung photon source the proposed concept presents several advantages, most significantly in providing a full intensity in a small spot at the target and in taking advantage of the narrow angular spread associated with high energy bremsstrahlung compare to the wide angular distribution of the secondary radiation to minimize the operational prompt and activation radiation dose rates., 16 pages, 20 figures

Published
2020

42. Measurement of the beam-helicity asymmetry in photoproduction of π0η pairs on carbon, aluminum, and lead

Author

R. A. Miskimen, A. G. Denig, Durga Paudyal, M. Wolfes, I. Keshelashvili, Yu. A. Usov, O. Steffen, K. Spieker, P. Pedroni, Susanna Costanza, P. Aguar-Bartolomé, Concettina Sfienti, A. N. Mushkarenkov, M. Ostrick, D. G. Middleton, M. Günther, S. Garni, A. Powell, I. Supek, A. Käser, R. Beck, I. Gorodnov, M. Unverzagt, V. L. Kashevarov, F. Cividini, Roderick M. Macrae, L. V. Fil'kov, P. Adlarson, M. Oberle, S. Abt, E. J. Downie, Patrick Achenbach, D. P. Watts, S. Cherepnya, A. J. Sarty, K. Bantawa, G. M. Huber, Z. Ahmed, S. Kay, I. I. Strakovsky, T. Rostomyan, K. Livingston, S. Lutterer, B. Strandberg, S. Gardner, N. S. Borisov, C. Mullen, Guy Ron, D. I. Glazier, S. Wagner, H. J. Arends, W. J. Briscoe, A. B. Lazarev, Michaela Thiel, A. Neiser, A. Fix, A. Braghieri, Th. Strub, P. Drexler, F. Afzal, A. B. Neganov, Nicholas Zachariou, W. Gradl, J. Wettig, J. C. McGeorge, V. Sokhoyan, P. P. Martel, J. R. M. Annand, D. Hornidge, E. Mornacchi, I. J. D. MacGregor, M. Korolija, David Manley, N. K. Walford, B. Krusche, K. Altangerel, E. Rickert, M. Biroth, P. B. Otte, R. Kondratiev, G. M. Gurevich, S. N. Prakhov, Lilian Witthauer, M. Dieterle, Lena Heijkenskjöld, M. I. Ferretti Bondy, Andy Thomas, A. Thiel, D. Werthmüller, C. Collicott, and M. Bashkanov

Subjects
Nuclear and High Energy Physics, Proton, media_common.quotation_subject, Nuclear Theory, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Asymmetry, Nuclear physics, Aluminium, 0103 physical sciences, Intermediate state, Nuclear Experiment, 010306 general physics, QC, media_common, Physics, 010308 nuclear & particles physics, Helicity, lcsh:QC1-999, 3. Good health, chemistry, High Energy Physics::Experiment, Nucleon, Carbon, lcsh:Physics, Beam (structure)
Abstract

The beam-helicity asymmetry was measured, for the first time, in photoproduction of $\pi^{0}\eta$ pairs on carbon, aluminum, and lead, with the A2 experimental setup at MAMI. The results are compared to an earlier measurement on a free proton and to the corresponding theoretical calculations. The Mainz model is used to predict the beam-helicity asymmetry for the nuclear targets. The present results indicate that the photoproduction mechanism for $\pi^{0}\eta$ pairs on nuclei is similar to photoproduction on a free nucleon. This process is dominated by the $D_{33}$ partial wave with the $\eta\Delta(1232)$ intermediate state., Comment: Accepted for publication in Physics Letters B (2020)

Published
2020

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

Author

G. Ricco, R. A. Schumacher, K. Mikhailov, L. Bibrzycki, P. Stoler, A. D'Angelo, K. Hicks, H. Hakobyan, Ashot Gasparian, L. Gan, V. Mokeev, A.V. Stavinsky, K. Livingston, D. S. Dale, S. Anefalos Pereira, A. V. Vlassov, D. J. Tedeschi, V. V. Mochalov, K. A. Griffioen, S. Fegan, E. Clinton, Michael Wood, N. Hassall, M. Bellis, K. Hafidi, Michael Vineyard, R. De Vita, S. Stepanyan, C. Bookwalter, P. Nadel-Turonski, M. Kossov, Avraham Klein, T. Mineeva, V. Drozdov, S. Strauch, V. Kuznetsov, Friedrich Klein, D. P. Watts, E. L. Isupov, E. Munevar, H. Egiyan, I. Nakagawa, I. Bedlinskiy, Brian Raue, W. J. Briscoe, Michael L. Williams, A. Kubarovsky, W. Gohn, E. Wolin, Lorenzo Zana, M. Y. Gabrielyan, C. E. Hyde, O. Glamazdin, M. R. Niroula, Z. W. Zhao, S. Niccolai, Y. Prok, D. S. Carman, M. Battaglieri, Barry Ritchie, N. Pivnyuk, I. I. Strakovsky, D. Protopopescu, C. Salgado, E. De Sanctis, M. Garçon, S. Pozdniakov, A. Deur, G. E. Dodge, Martin K. Mayer, G. Rosner, H. Y. Lu, Kei Moriya, C. A. Meyer, M. Osipenko, N. Dashyan, D. I. Sober, F. X. Girod, E. Pasyuk, G. V. Fedotov, S. Tkachenko, Adam P. Szczepaniak, M. S. Saini, I. Niculescu, P. Eugenio, H. Baghdasaryan, K. P. Adhikari, D. P. Weygand, E. Golovatch, M. Taiuti, J. T. Goetz, D. Schott, J. W. Price, C. Djalali, F. Sabatié, V. P. Kubarovsky, O. Pogorelko, W. Kim, P. Collins, M. Anghinolfi, Leonard Lesniak, H. Seraydaryan, J. Zhang, P. Khetarpal, Y. G. Sharabian, C. S. Nepali, M. Ripani, V. Crede, C. Hanretty, J. R. Johnstone, L. Guo, M. Ungaro, S. Park, P. Rossi, K. Joo, M. Guidal, M. Holtrop, A. Daniel, A. I. Ostrovidov, K. Park, Sergey Kuleshov, D. G. Ireland, S. S. Stepanyan, Mark W. Paris, B. Zhao, Volker D. Burkert, A. S. Biselli, S. Dhamija, R. W. Gothe, A. Fradi, M. J. Amaryan, J. Goett, B. McKinnon, D. Branford, S. Pisano, M. Mirazita, S. L. Careccia, J. M. Laget, K. L. Giovanetti, Larry Weinstein, D. Keller, Gerard Gilfoyle, M. Khandaker, M. E. McCracken, Y. Ilieva, D. Sokhan, D. Doughty, A. Teymurazyan, and P. L. Cole

Subjects
Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Particle decay, Pion, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The exclusive reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ was studied in the photon energy range 3.0--3.8 GeV and the momentum transfer range $0.4l\ensuremath{-}tl1.0\text{ }\text{ }{\mathrm{GeV}}^{2}$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range, the integrated luminosity was about $20\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. The reaction was isolated by detecting the ${\ensuremath{\pi}}^{+}$ and proton in CLAS, and reconstructing the ${\ensuremath{\pi}}^{\ensuremath{-}}$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves, in the ${M}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}$ mass range 0.4--1.4 GeV, were derived performing a partial wave expansion of the extracted moments. Beside the dominant contribution of the $\ensuremath{\rho}(770)$ meson in the $P$-wave, evidence for the ${f}_{0}(980)$ and the ${f}_{2}(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\ensuremath{\sigma}/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the ${f}_{0}(980)$ has been measured in a photoproduction experiment.

Published
2018

44. 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

45. 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

46. 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

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

Author

William Brooks, George Davey Smith, R. A. Schumacher, A. El Alaoui, S. Stepanyan, J. Pierce, H. Y. Lu, P. Eugenio, G. Gavalian, I. Denisenko, N. Dashyan, Taya Chetry, M. Taiuti, A. Filippi, A. Fradi, D. P. Watts, K. A. Griffioen, Friedrich Klein, V. Crede, M. Khandaker, D. G. Meekins, Brian Raue, A. D'Angelo, A. V. Sarantsev, Yordanka Ilieva, Nicholas Zachariou, E. Pasyuk, V. Mokeev, V. Batourine, R. Paremuzyan, R. De Vita, N. Markov, L. Lanza, G. Rosner, E. Golovatch, K. Hicks, W. Kim, Sergey Kuleshov, M. Ripani, R. A. Montgomery, F. Sabatié, S. Niccolai, Carlos A. Salgado, C. D. Keith, Pawel Nadel-Turonski, D. G. Jenkins, Eberhard Klempt, B. A. Clary, J. Brock, Alessandro Rizzo, R. Dupre, M. Battaglieri, J. Zhang, C. Djalali, J. A. Tan, L. El Fassi, J. W. Price, S. Anefalos Pereira, K. Livingston, C. Hanretty, C. Carlin, M. Guidal, L. Guo, M. Ungaro, Gerard Gilfoyle, A. I. Ostrovidov, A. V. Anisovich, K. Park, G. Charles, G. Niculescu, V. A. Nikonov, G. Ciullo, J. P. Ball, B. Torayev, Y. Prok, F. X. Girod, M. E. McCracken, D. S. Carman, D. G. Ireland, M. Holtrop, K. Joo, I. Bedlinskiy, V. P. Kubarovsky, D. Riser, M. Osipenko, Andreas Klein, Nikos Sparveris, X. Wei, T. Mineeva, D. Sokhan, O. Pogorelko, S. Procureur, W. Gohn, A. Kim, Z. E. Meziani, W. Phelps, Volker D. Burkert, M. Bashkanov, A. S. Biselli, B. S. Ishkhanov, L. Elouadrhiri, K. L. Giovanetti, I. Balossino, S. Strauch, Michael Dugger, D. I. Sober, E. Voutier, I. I. Strakovsky, A. Movsisyan, B. McKinnon, Dustin Keller, S. Park, A. Deur, K. Hafidi, Iu. Skorodumina, Sylvester Joosten, S. Fegan, G. Khachatryan, P. L. Cole, Z. W. Zhao, E. Phelps, N. Gevorgyan, D. Protopopescu, W. J. Briscoe, C. Munoz Camacho, M. H. Wood, A. Celentano, R. W. Gothe, M. Contalbrigo, Z. Akbar, N. K. Walford, I. J. D. MacGregor, S. Adhikari, M. Hattawy, Martin K. Mayer, Y. G. Sharabian, C. Gleason, Barry Ritchie, P. Roy, C. A. Meyer, G. V. Fedotov, E. L. Isupov, S. Boiarinov, K. P. Adhikari, H. Hakobyan, and P. Lenisa

Subjects
Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, media_common.quotation_subject, Nuclear Theory, Bremsstrahlung, Observable, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Asymmetry, Baryon, Nuclear physics, 13. Climate action, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract

The photoproduction of ω mesons off the proton has been studied in the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω→π+π-π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.

Published
2018

48. 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

49. 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

50. Deuteron photodisintegration by polarized photons in the region of the $d^*(2380)$

Author

A. Powell, I. Gorodnov, Roderick M. Macrae, W. J. Briscoe, M. Biroth, P. B. Otte, S. Abt, C. S. Akondi, A. Käser, A. B. Lazarev, Concettina Sfienti, A. Thiel, E. J. Downie, D. P. Watts, E. Mornacchi, W. Gradl, Z. Ahmed, David Manley, Lena Heijkenskjöld, A. Braghieri, Th. Strub, A. Sarty, I. J. D. MacGregor, I. I. Strakovsky, S. Wagner, K. Livingston, S. Lutterer, M. Ostrick, V. L. Kashevarov, M. Günther, P. P. Martel, N. S. Borisov, Michaela Thiel, T. Rostomyan, F. Cividini, N. K. Walford, J. Wettig, M. Bashkanov, R. A. Miskimen, H. J. Arends, M. Korolija, P. Adlarson, Yu. A. Usov, O. Steffen, C. Collicott, F. Afzal, C. Mullen, S. Kay, B. Krusche, V. Sokhoyan, A. B. Neganov, S. Costanza, P. Pedroni, A. G. Denig, Reinhard Beck, Durga Paudyal, A. Neiser, Guy Ron, S. Garni, D. Gurevich, M. Wolfes, K. Spieker, L.A. Zana, J. R. M. Annand, D. I. Glazier, G. M. Huber, D. Werthmüller, Patrick Achenbach, D. Hornidge, S. N. Prakhov, Andy Thomas, P. Drexler, and I. Supek

Subjects
Nuclear and High Energy Physics, Photon, media_common.quotation_subject, Nuclear Theory, Hexaquark, FOS: Physical sciences, Photon energy, 01 natural sciences, Asymmetry, Resonance (particle physics), Nuclear physics, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, Range (particle radiation), 010308 nuclear & particles physics, lcsh:QC1-999, Deuterium, Photodisintegration, lcsh:Physics, proton polarization, cross-section, disintegration, asymmetry, energies
Abstract

We report the first large-acceptance measurement of the beam–spin asymmetry for deuteron photodisintegration (γ→d→pn) in the photon energy range 420

Published
2018
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