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20 results on '"Garcon, M."'

1. Searching for Prompt and Long-Lived Dark Photons in Electro-Produced $e^+e^-$ Pairs with the Heavy Photon Search Experiment at JLab

Author

Adrian, P. H., Baltzell, N. A., Battaglieri, M., Bondi, M., Boyarinov, S., Bravo, C., Bueltmann, S., Butti, P., Burkert, V. D., Calvo, D., Cao, T., Carpinelli, M., Celentano, A., Charles, G., Colaneri, L., Cooper, W., Cuevas, C., D'Angelo, A., Dashyan, N., De Napoli, M., De Vita, R., Deur, A., Diamond, M., Dupre, R., Egiyan, H., Elouadrhiri, L., Essig, R., Fadeyev, V., Field, C., Filippi, A., Freyberger, A., Garcon, M., Gevorgyan, N., Girod, F. X., Graf, N., Graham, M., Griffioen, K. A., Grillo, A., Guidal, M., Herbst, R., Holtrop, M., Jaros, J., Johnson, R. P., Kalicy, G., Khandaker, M., Kubarovsky, V., Leonora, E., Livingston, K., Marsicano, L., Maruyama, T., McCarty, S., McCormick, J., McKinnon, B., Moffeit, K., Moreno, O., Camacho, C. Munoz, Nelson, T., Niccolai, S., Odian, A., Oriunno, M., Osipenko, M., Paremuzyan, R., Paul, S., Randazzo, N., Raydo, B., Reese, B., Rizzo, A., Schuster, P., Sharabian, Y. G., Simi, G., Simonyan, A., Sipala, V., Spellman, A., Sokhan, D., Solt, M., Stepanyan, S., Szumila-Vance, H., Toro, N., Uemura, S., Ungaro, M., Voskanyan, H., Weinstein, L. B., Wojtsekhowski, B., and Yale, B.

Subjects
High Energy Physics - Experiment
Abstract

The Heavy Photon Search experiment (HPS) at the Thomas Jefferson National Accelerator Facility searches for electro-produced dark photons. We report results from the 2016 Engineering Run consisting of 10608/nb of data for both the prompt and displaced vertex searches. A search for a prompt resonance in the $e^+e^-$ invariant mass distribution between 39 and 179 MeV showed no evidence of dark photons above the large QED background, limiting the coupling of {\epsilon}^2 {\geq} 10^-5, in agreement with previous searches. The search for displaced vertices showed no evidence of excess signal over background in the masses between 60 and 150 MeV, but had insufficient luminosity to limit canonical heavy photon production. This is the first displaced vertex search result published by HPS. HPS has taken high-luminosity data runs in 2019 and 2021 that will explore new dark photon phase space., Comment: 28 pages, 46 figures

Published
2022
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2. Exploring the Structure of the Bound Proton with Deeply Virtual Compton Scattering

Author

Hattawy, M., Baltzell, N. A., Dupré, R., Bültmann, S., De Vita, R., Alaoui, A. El, Fassi, L. El, Egiyan, H., Girod, F. X., Guidal, M., Hafidi, K., Jenkins, D., Liuti, S., Perrin, Y., Stepanyan, S., Torayev, B., Voutier, E., Adhikari, S., Angelini, Giovanni, Gayoso, C. Ayerbe, Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Bossù, F., Brooks, W., Cao, F., Carman, D. S., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Ehrhart, M., Eugenio, P., Fegan, S., Filippi, A., Forest, T. A., Fradi, A., Garçon, M., Gavalian, G., Gevorgyan, N., Gilfoyle, G. P., Giovanetti, K. L., Golovatch, E., Gothe, R. W., Griffioen, K. A., Harrison, N., Hauenstein, F., Hayward, T. B., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Johnston, S., Keller, D., Khachatryan, G., Khachatryan, M., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Lanza, L., Kabir, M. L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Mayer, M., McKinnon, B., Meziani, Z. E., Mineeva, T., Mirazita, M., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Niccolai, S., Ostrovidov, A. I., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Pogorelko, O., Poudel, J., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Sokhan, D., Soto, O., Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Tyler, N., Ungaro, M., Voskanyan, H., Wang, R., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this work, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering (DVCS) off a proton bound in $^4$He. The data used here were accumulated using a $6$ GeV longitudinally polarized electron beam incident on a pressurized $^4$He gaseous target placed within the CLAS spectrometer in Hall-B at the Thomas Jefferson National Accelerator Facility. The azimuthal angle ($\phi$) dependence of the BSA was studied in a wide range of virtual photon and scattered proton kinematics. The $Q^2$, $x_B$, and t dependencies of the BSA on the bound proton are compared with those on the free proton. In the whole kinematical region of our measurements, the BSA on the bound proton is smaller by 20\% to 40\%, indicating possible medium modification of its partonic structure.

Published
2018
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3. Search for a Dark Photon in Electro-Produced $e^{+}e^{-}$ Pairs with the Heavy Photon Search Experiment at JLab

Author

Adrian, P. H., Baltzell, N. A., Battaglieri, M., Bondí, M., Boyarinov, S., Bueltmann, S., Burkert, V. D., Calvo, D., Carpinelli, M., Celentano, A., Charles, G., Colaneri, L., Cooper, W., Cuevas, C., D'Angelo, A., Dashyan, N., De Napoli, M., De Vita, R., Deur, A., Dupre, R., Egiyan, H., Elouadrhiri, L., Essig, R., Fadeyev, V., Field, C., Filippi, A., Freyberger, A., Garçon, M., Gevorgyan, N., Girod, F. X., Graf, N., Graham, M., Griffioen, K. A., Grillo, A., Guidal, M., Herbst, R., Holtrop, M., Jaros, J., Kalicy, G., Khandaker, M., Kubarovsky, V., Leonora, E., Livingston, K., Maruyama, T., McCarty, K., McCormick, J., McKinnon, B., Moffeit, K., Moreno, O., Camacho, C. Munoz, Nelson, T., Niccolai, S., Odian, A., Oriunno, M., Osipenko, M., Paremuzyan, R., Paul, S., Randazzo, N., Raydo, B., Reese, B., Rizzo, A., Schuster, P., Sharabian, Y. G., Simi, G., Simonyan, A., Sipala, V., Sokhan, D., Solt, M., Stepanyan, S., Szumila-Vance, H., Toro, N., Uemura, S., Ungaro, M., Voskanyan, H., Weinstein, L. B., Wojtsekhowski, B., and Yale, B.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The Heavy Photon Search experiment took its first data in a 2015 engineering run using a 1.056 GeV, 50 nA electron beam provided by CEBAF at the Thomas Jefferson National Accelerator Facility, searching for an electro-produced dark photon. Using 1.7 days (1170 nb$^{-1}$) of data, a search for a resonance in the $e^{+}e^{-}$ invariant mass distribution between 19 and 81 MeV/c$^2$ showed no evidence of dark photon decays above the large QED background, confirming earlier searches and demonstrating the full functionality of the experiment. Upper limits on the square of the coupling of the dark photon to the Standard Model photon are set at the level of 6$\times$10$^{-6}$. In addition, a search for displaced dark photon decays did not rule out any territory but resulted in a reliable analysis procedure that will probe hitherto unexplored parameter space with future, higher luminosity runs., Comment: 8 pages, Proceedings of the 39th International Conference on High Energy Physics (ICHEP 2018), 4-11 July, 2018, Seoul, Korea

Published
2018

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

Author

Saylor, N. Hirlinger, Guegan, B., Burkert, V. D., Elouadrhiri, L., Garcon, M., Girod, F. X., Guidal, M., Jo, H. S., Kubarovsky, V., Niccolai, S., and Stoler, P.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Experiment
Abstract

This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data., Comment: 27 pages, 24 figures, Accepted for publication in PRC

Published
2018
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5. Measurement of the helicity asymmetry $E$ in $\omega\to\pi^+\pi^-\pi^0$ photoproduction

Author

Akbar, Z., Roy, P., Park, S., Crede, V., Anisovich, A. V., Denisenko, I., Klempt, E., Nikonov, V. A., Sarantsev, A. V., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Pereira, S. Anefalos, Avakian, H., Ball, J., Battaglieri, M., Batourine, V., Bedlinskiy, I., Boiarinov, S., Briscoe, W. J., Brock, J., Brooks, W. K., Burkert, V. D., Cao, F. T., Carlin, C., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Fassi, L. El, Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Garcon, M., Gevorgyan, N., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovach, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Hollis, G., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joosten, S., Keith, C. D., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Lanza, L., Livingston, K., MacGregor, I. J. D., Markov, N., McKinnon, B., Meekins, D. G., Mineeva, T., Mokeev, V., Movsisyan, A., Camacho, C. Munoz, Nadel-Turonski, P., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Sabatie, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sober, D. I., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Ungaro, M., Voskanyan, H., Voutier, E., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The double-polarization observable $E$ was studied for the reaction $\gamma p\to p\omega$ using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally-polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, $\omega\to\pi^+\pi^-\pi^0$, using a circularly-polarized tagged-photon beam with energies ranging from the $\omega$ threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the $3/2^+$ partial wave near threshold, which is identified with the sub-threshold $N(1720)\,3/2^+$ nucleon resonance. To describe the entire data set, which consisted of $\omega$ differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to non-resonant mechanisms, $\pi$ exchange in the $t$-channel was found to remain small across the analyzed energy range, while pomeron $t$-channel exchange gradually grew from the reaction threshold to dominate all other contributions above $W \approx 2$ GeV., Comment: 12 pages, 8 figures

Published
2017
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6. First Exclusive Measurement of Deeply Virtual Compton Scattering off $^4$He: Toward the 3D Tomography of Nuclei

Author

Hattawy, M., Baltzell, N. A., Dupré, R., Hafidi, K., Stepanyan, S., Bültmann, S., De Vita, R., Alaoui, A. El, Fassi, L. El, Egiyan, H., Girod, F. X., Guidal, M., Jenkins, D., Liuti, S., Perrin, Y., Torayev, B., Voutier, E., Adhikari, K. P., Adhikari, S., Adikaram, D., Akbar, Z., Amaryan, M. J., Pereira, S. Anefalos, Armstrong, Whitney R., Avakian, H., Ball, J., Bashkanov, M., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Cao, Frank Thanh, Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Sanctis, E., Deur, A., Djalali, C., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Fradi, A., Garçon, M., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Hakobyan, H., Hanretty, C., Harrison, N., Heddle, D., Hicks, K., Holtrop, M., Hughes, S. M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jiang, H., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I . J . D., Markov, N., Mayer, M., McCracken, M. E., McKinnon, B., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mirazita, M., Mokeev, V., Montgomery, R. A., Moutarde, H., Movsisyan, A, Camacho, C. Munoz, Nadel-Turonski, P., Net, L. A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, E., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Salgado, C., Schumacher, R. A., Seder, E., Sharabian, Y. G., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Strauch, S., Taiuti, M., Ungaro, M., Voskanyan, H., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment used the 6 GeV electron beam from the CEBAF accelerator at Jefferson Lab incident on a pressurized $^4$He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron was detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber was used to detect the recoiling $^4$He nuclei. We measured beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we were able to extract, in a model-independent way, the real and imaginary parts of the only $^4$He Compton form factor, $\cal H_A$. This first measurement of coherent deeply virtual Compton scattering on the $^4$He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

Published
2017
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7. Exclusive $\eta$ electroproduction at $W>2$ GeV with CLAS and transversity generalized parton distributions

Author

CLAS Collaboration, Bedlinskiy, I., Kubarovsky, V., Stoler, P., Adhikari, K. P., Akbar, Z., Pereira, S. Anefalos, Avakian, H., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Burkert, V. D., Cao, T., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dupre, R., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Garçon, M., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Hicks, K., Hughes, S. M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kuhn, S. E., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Markov, N., McKinnon, B., Meziani, Z. E., Mirazita, M., Mokeev, V., Montgomery, R. A., Movsisyan, A., Camacho, C. Munoz, Nadel-Turonski, P., Net, L. A., Ni, A., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Peng, P., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Puckett, A. J. R., Raue, B. A., Ripani, M., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Saini, M. S., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Ye, Torayev, B., Turisini, M., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Yurov, M., Zachariou, N., Zhang, J., and Zonta, I.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The cross section of the exclusive $\eta$ electroproduction reaction $ep\to e^\prime p^\prime \eta$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma/dtdQ^2dx_Bd\phi_\eta$ and structure functions $\sigma_U = \sigma_T+\epsilon\sigma_L, \sigma_{TT}$ and $\sigma_{LT}$, as functions of $t$ were obtained over a wide range of $Q^2$ and $x_B$. The $\eta$ structure functions are compared with those previously measured for $\pi^0$ at the same kinematics. At low $t$, both $\pi^0$ and $\eta$ are described reasonably well by generalized parton distributions (GPDs) in which chiral-odd transversity GPDs are dominant. The $\pi^0$ and $\eta$ data, when taken together, can facilitate the flavor decomposition of the transversity GPDs., Comment: 16 pages, 16 figures

Published
2017
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8. The E00-110 experiment in Jefferson Lab's Hall A: Deeply Virtual Compton Scattering off the Proton at 6 GeV

Author

Defurne, M., Amaryan, M., Aniol, K. A., Beaumel, M., Benaoum, H., Bertin, P., Brossard, M., Camsonne, A., Chen, J. -P., Chudakov, E., Craver, B., Cusanno, F., de Jager, C. W., Deur, A., Feuerbach, R., Ferdi, C., Fieschi, J. -M., Frullani, S., Fuchey, E., Garcon, M., Garibaldi, F., Gayou, O., Gavalian, G., Gilman, R., Gomez, J., Gueye, P., Guichon, P. A. M., Guillon, B., Hansen, O., Hayes, D., Higinbotham, D., Holmstrom, T., Hyde, C. E., Ibrahim, H., Igarashi, R., Jiang, X., Jo, H. S., Kaufman, L. J., Kelleher, A., Keppel, C., Kolarkar, A., Kuchina, E., Kumbartzki, G., Laveissière, G., LeRose, J. J., Lindgren, R., Liyanage, N., Lu, H. -J., Margaziotis, D. J., Mazouz, M., Meziani, Z. -E., McCormick, K., Michaels, R., Michel, B., Moffit, B., Monaghan, P., Camacho, C. Muñoz, Nanda, S., Nelyubin, V., Paremuzyan, R., Potokar, M., Qiang, Y., Ransome, R. D., Réal, J. -S., Reitz, B., Roblin, Y., Roche, J., Sabatié, F., Saha, A., Sirca, S., Slifer, K., Solvignon, P., Subedi, R., Sulkosky, V., Ulmer, P. E., Voutier, E., Wang, K., Weinstein, L. B., Wojtsekhowski, B., Zheng, X., and Zhu, L.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We present final results on the photon electroproduction ($\vec{e}p\rightarrow ep\gamma$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Results of the $Q^2$- and $x_B$-dependences of both the helicity-dependent and helicity-independent cross sections are discussed. The $Q^2$-dependence illustrates the dominance of the twist-2 handbag amplitude in the kinematics of the experiment, as previously noted. Thanks to the excellent accuracy of this high luminosity experiment, it becomes clear that the unpolarized cross section shows a significant deviation from the Bethe-Heitler process in our kinematics, compatible with a large contribution from the leading twist-2 DVCS$^2$ term to the photon electroproduction cross section. The necessity to include higher-twist corrections in order to fully reproduce the shape of the data is also discussed. The DVCS cross sections in this paper represent the final set of experimental results from E00-110, superseding the previous publication., Comment: 48 pages, 32 figures

Published
2015
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9. Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

Author

Jo, H. S., Girod, F. X., Avakian, H., Burkert, V. D., Garçon, M., Guidal, M., Kubarovsky, V., Niccolai, S., Stoler, P., and Collaboration, the CLAS

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

Unpolarized and beam-polarized four-fold cross sections $\frac{d^4 \sigma}{dQ^2 dx_B dt d\phi}$ for the $ep\to e^\prime p^\prime \gamma$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon., Comment: 7 pages, 5 figures

Published
2015
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10. The DarkLight Experiment: A Precision Search for New Physics at Low Energies

Author

Balewski, J., Bernauer, J., Bessuille, J., Corliss, R., Cowan, R., Epstein, C., Fisher, P., Hasell, D., Ihloff, E., Kahn, Y., Kelsey, J., Milner, R., Steadman, S., Thaler, J., Tschalaer, C., Vidal, C., Benson, S., Boyce, J., Douglas, D., Evtushenko, P., Hernandez-Garcia, C., Keith, C., Tennant, C., Zhang, S., Alarcon, R., Blyth, D., Dipert, R., Ice, L., Randall, G., Dongwi, B., Kalantarians, N., Kohl, M., Liyanage, A., Nazeer, J., Garcon, M., Cervantes, R., Dehmelt, K., Deshpande, A., Feege, N., and Surrow, B.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We describe the current status of the DarkLight experiment at Jefferson Laboratory. DarkLight is motivated by the possibility that a dark photon in the mass range 10 to 100 MeV/c$^2$ could couple the dark sector to the Standard Model. DarkLight will precisely measure electron proton scattering using the 100 MeV electron beam of intensity 5 mA at the Jefferson Laboratory energy recovering linac incident on a windowless gas target of molecular hydrogen. The complete final state including scattered electron, recoil proton, and e+e- pair will be detected. A phase-I experiment has been funded and is expected to take data in the next eighteen months. The complete phase-II experiment is under final design and could run within two years after phase-I is completed. The DarkLight experiment drives development of new technology for beam, target, and detector and provides a new means to carry out electron scattering experiments at low momentum transfers., Comment: Whitepaper submitted to Town Meeting on Fundamental and Symmetries and Neutrinos, O'Hare airport, Chicago, IL

Published
2014

11. Exclusive ${\pi}^0$ electroproduction at $W>2$ GeV with CLAS

Author

Bedlinskiy, I., Kubarovsky, V., Niccolai, S., Stoler, P., Adhikari, K. P., Anderson, M. D., Pereira, S. Anefalos, Avakian, H., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Biselli, A. S., Boiarinov, S., Bono, J., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Colaneri, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Doughty, D., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Fleming, J. A., Forest, T. A., Garillon, B., Garçon, M., Gavalian, G., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guegan, B., Guo, L., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Keller, D., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Koirala, S., Kuhn, S. E., Kuleshov, S. V., Lenisa, P., Levine, W. I., Livingston, K., Lu, H. Y., MacGregor, I . J . D., Markov, N., Mayer, M., McKinnon, B., Mirazita, M., Mokeev, V., Montgomery, R. A., Moody, C. I., Moutarde, H., Movsisyan, A, Camacho, C. Munoz, Nadel-Turonski, P., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Pappalardo, L. L., Park, K., Park, S., Pasyuk, E., Phelps, E., Phelps, W., Phillips, J. J., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Procureur, S., Puckett, A. J. R., Raue, B. A., Ripani, M., Ritchie, B. G., Rizzo, A., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schott, D., Schumacher, R. A., Seder, E., Senderovich, I., Sharabian, Y. G., Simonyan, A., Smith, G. D., Sober, D. I., Sokhan, D., Stepanyan, S. S., Strauch, S., Sytnik, V., Tang, W., Tian, Ye, Ungaro, M., Vlassov, A. V., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D., Wei, X., Weinstein, L. B., Yurov, M., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., and Zonta, I.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Exclusive neutral-pion electroproduction ($ep\to e^\prime p^\prime \pi^0$) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma/dtdQ^2dx_Bd\phi_\pi$ and structure functions $\sigma_T+\epsilon\sigma_L, \sigma_{TT}$ and $\sigma_{LT}$ as functions of $t$ were obtained over a wide range of $Q^2$ and $x_B$. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found that the inclusion of vector meson rescattering processes is necessary to bring the magnitude of the calculated and measured structure functions into rough agreement. In the handbag framework, there are two independent calculations, both of which appear to roughly explain the magnitude of the structure functions in terms of transversity generalized parton distributions., Comment: 28 pages, 25 figures, Submitted to Phys. Rev. C

Published
2014
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12. Measurement of Exclusive $\pi^0$ Electroproduction Structure Functions and their Relationship to Transversity GPDs

Author

CLAS Collaboration, Bedlinskiy, I., Kubarovsky, V., Niccolai, S., Stoler, P., Adhikari, K. P., Aghasyan, M., Amaryan, M. J., Anghinolfi, M., Avakian, H., Baghdasaryan, H., Ball, J., Baltzell, N. A., Battaglieri, M., Bennett, R. P., Biselli, A. S., Bookwalter, C., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Contalbrigo, M., Crede, V., D'Angelo, A., Daniel, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Doughty, D., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Fleming, J. A., Forest, T. A., Garçon, M., Gevorgyan, N., Giovanetti, K. L., Girod, F. X., Gohn, W., Gothe, R. W., Graham, L., Griffioen, K. A., Guegan, B., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jo, H. S., Joo, K., Keller, D., Khandaker, M., Khetarpal, P., Kim, A., Kim, W., Klein, F. J., Koirala, S., Kubarovsky, A., Kuhn, S. E., Kuleshov, S. V., Kvaltine, N. D., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Mao, Y., Markov, N., Martinez, D., Mayer, M., McKinnon, B., Meyer, C. A., Mineeva, T., Mirazita, M., Mokeev, V., Moutarde, H., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Pappalardo, L. L., Paremuzyan, R., Park, K., Park, S., Pasyuk, E., Pereira, S. Anefalos, Phelps, E., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Puckett, A. J. R., Raue, B. A., Ricco, G., Rimal, D., Ripani, M., Rosner, G., Rossi, P., Sabatié, F., Saini, M. S., Salgado, C., Saylor, N., Schott, D., Schumacher, R. A., Seder, E., Seraydaryan, H., Sharabian, Y. G., Smith, G. D., Sober, D. I., Sokhan, D., Stepanyan, S. S., Stepanyan, S., Strauch, S., Taiuti, M., Tang, W., Taylor, C. E., Tian, Ye, Tkachenko, S., Ungaro, M., Vineyard, M. F., Vlassov, A., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Weinstein, L. B., Weygand, D. P., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., and Zonta, I.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Experiment
Abstract

Exclusive $\pi^0$ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in $Q^2$, $x_B$, $t$, and $\phi_\pi$, in the $Q^2$ range from 1.0 to 4.6 GeV$^2$,\ $-t$ up to 2 GeV$^2$, and $x_B$ from 0.1 to 0.58. Structure functions $\sigma_T +\epsilon \sigma_L, \sigma_{TT}$ and $\sigma_{LT}$ were extracted as functions of $t$ for each of 17 combinations of $Q^2$ and $x_B$. The data were compared directly with two handbag-based calculations including both longitudinal and transversity GPDs. Inclusion of only longitudinal GPDs very strongly underestimates $\sigma_T +\epsilon \sigma_L$ and fails to account for $\sigma_{TT}$ and $\sigma_{LT}$, while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity flip and helicity non-flip processes. The results confirm that exclusive $\pi^0$ electroproduction offers direct experimental access to the transversity GPDs., Comment: 6 pages, 2 figures

Published
2012
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13. Comment on the narrow structure reported by Amaryan et al

Author

Anghinolfi, M., Ball, J., Baltzell, N. A., Battaglieri, M., Bedlinskiy, I., Bellis, M., Biselli, A. S., Bookwalter, C., Boiarinov, S., Bosted, P., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Cole, P. L., Crede, V., De Vita, R., De Sanctis, E., Dey, B., Dickson, R., Doughty, D., Dugger, M., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Gabrielyan, M. Y., Garcon, M., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Goetz, J. T., Golovatch, E., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Heddle, D., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jo, H. S., Joo, K., Khetarpal, P., Kim, A., Kim, W., Kubarovsky, V., Kuleshov, S. V., Lu, H. Y., MacGregor, L. J. D., Markov, N., McCracken, M. E., McKinnon, B., Mestayer, M. D., Meyer, C. A., Mirazita, M., Mokeev, V., Moriya, K., Morrison, B., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I, Park, K., Park, S., Pereira, S. Anefalos, Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Ricco, G., Ripani, M., Ritchie, B. G., Rossi, P., Schott, D., Schumacher, R. A., Seder, E., Sharabian, Y. G., Smith, E. S., Sober, D. I, Stepanyan, S. S., Stoler, P., Tang, W., Ungaro, M., Vernarsky, B., Vineyard, M. F., Weygand, D. P., Wood, M. H., Zachariou, N., and Zhao, B.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

The CLAS Collaboration provides a comment on the physics interpretation of the results presented in a paper published by M. Amaryan et al. regarding the possible observation of a narrow structure in the mass spectrum of a photoproduction experiment., Comment: to be published in Physical Review C

Published
2012

14. Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive $\pi^0$ production

Author

Aghasyan, M., Avakian, H., Rossi, P., De Sanctis, E., Hasch, D., Mirazita, M., Adikaram, D., Amaryan, M. J., Anghinolfi, M., Baghdasaryan, H., Ball, J., Battaglieri, M., Batourine, V., Bedlinskiy, I., Bennett, R. P., Biselli, A. S., Branford, D., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Chandavar, S., Cole, P. L., Collins, P., Contalbrigo, M., Crede, V., D'Angelo, A., Daniel, A., Dashyan, N., De Vita, R., Deur, A., Dey, B., Dickson, R., Djalali, C., Dodge, G. E., Doughty, D., Dupre, R., Egiyan, H., Alaoui, A. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Fradi, A., Gabrielyan, M. Y., Garçon, M., Gevorgyan, N., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Goetz, J. T., Gohn, W., Golovatch, E., Gothe, R. W., Graham, L., Griffioen, K. A., Guegan, B., Guidal, M., Guler, N., Guo, L., Hafidi, K., Hanretty, C., Hicks, K., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jawalkar, S. S., Jenkins, D., Jo, H. S., Joo, K., Keller, D., Khandaker, M., Khetarpal, P., Kim, A., Kimy, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Kuznetsov, V., Kvaltine, N. D., Livingston, K., Lu, H. Y., MacGregor, I . J . D., Markov, N., Mayer, M., McAndrew, J., McKinnon, B., Meyer, C. A., Micherdzinska, A. M., Mokeev, V., Moreno, B., Moutarde, H., Munevar, E., Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L., Paremuzyan, R., Park, K., Park, S., Pasyuk, E., Pereira, S. Anefalos, Phelps, E., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Raue, B. A., Ricco, G., Rimal, D., Ripani, M., Rosner, G., Sabatié, F., Saini, M. S., Salgado, C., Schott, D., Schumacher, R. A., Seder, E., Seraydaryan, H., Sharabian, Y. G., Smith, G. D., Sober, D. I., Stepanyan, S. S., Stepanyan, S., Stoler, P., Strakovsky, I., Strauch, S., Taiuti, M., Tang, W., Taylor, C. E., Tkachenko, S., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D., Weinstein, L. B., Weygand, D. P., Wood, M. H., Zana, L., Zhang, J., Zhao, B., and Zhao, Z. W.

Subjects
High Energy Physics - Experiment
Abstract

We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial $\sin \phi_h$ amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle $\phi_h$ of the produced neutral pion. The dependence of this amplitude on Bjorken $x$ and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations., Comment: to be submitted PLB

Published
2011
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15. Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction $\gamma p \rightarrow \phi p$

Author

Dey, B., Voutier, E., Ball, J., Garcon, M., Moutarde, H., Procureur, S., Sabatie, F., Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)

Subjects
High Energy Physics - Phenomenology, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, High Energy Physics - Experiment
Abstract

High-statistics measurements of differential cross sections and spin density matrix elements for the reaction $\gamma p \to \phi p$ have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.97 to 2.84 GeV, with an extensive coverage in the $\phi$ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the $\phi$ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- ($\phi \to K^+ K^-$) and neutral- ($\phi \to K^0_S K^0_L$) $K\overline{K}$ decay modes of the $\phi$. Further, for the charged mode, we differentiate between the cases where the final $K^-$ track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed $\phi$ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide $\sqrt{s}$ bins for the charged- and the neutral-mode, respectively. Possible effects from $K^+ \Lambda^\ast$ channels with $p K\overline{K}$ final-states are discussed. These present results constitute the most precise and extensive $\phi$ photoproduction measurements to date and in conjunction with the $\omega$ photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction., Comment: 38 pages, 36 figures. arXiv admin note: substantial text overlap with arXiv:1006.0374

Published
2014

16. Cross sections and beam asymmetries for $\vev{e}p \to en\pi^+$ in the nucleon resonance region for $1.7 \le Q^2 \le 4.5 (GeV)^2$

Author

Park, K., Burkert, V.D., Kim, W., Aznauryan, I.G., Minehart, R., Smith, L.C., Joo, K., Elouadrhiri, L., Adams, G., Amaryan, M.J., Ambrozewicz, P., Anghinol_, M., Asryan, G., Avakian, H., Bagdasaryan, H., Baillie, N., Ball, J.P., Baltzell, N.A., Barrow, S., Batourine, V., Battaglieri, M., Bedlinskiy, I., Bektasoglu, M., Bellis, M., Benmouna, N., Berman, B.L., Biselli, A.S., Blaszczyk, L., Bonner, B.E., Bookwalter, C., Bouchigny, S., Boiarinov, S., Bradford, R., Branford, D., Briscoe, W.J., Brooks, W.K., Bultmann, S., Butuceanu, C., Calarco, J.R., Careccia, S.L., Carman, D.S., Casey, L., Cazes, A., Chen, Si, Cheng, L., Cole, P.L., Collins, P., Coltharp, P., Cords, D., Corvisiero, P., Crabb, D., Crede, V., Cummings, J.P., Dale, D., Dashyan, N., De Masi, R., De Vita, R., De Sanctis, E., Degtyarenko, P.V., Denizli, H., Dennis, L., Deur, A., Dhamija, S., Dharmawardane, K.V., Dhuga, K.S., Dickson, R., Djalali, C., Dodge, G.E., Donnelly, J., Doughty, D., Dugger, M., Dytman, S., Dzyubak, O.P., Egiyan, H., Egiyan, K.S., El Fassi, L., Eugenio, P., Fatemi, R., Fedotov, G., Feldman, G., Feuerbach, R.J., Forest, T.A., Fradi, A., Funsten, H., Gabrielyan, M.Y., Garcon, M., Gavalian, G., Gevorgyan, N., Gilfoyle, G.P., Giovanetti, K.L., Girod, F.X., Goetz, J.T., Gohn, W., Golovatch, E., Gonenc, A., Gordon, C.I.O., Gothe, R.W., Graham, L., Grioen, K.A., Guidal, M., Guillo, M., Guler, N., Guo, L., Gyurjyan, V., Hadjidakis, C., Hadi, K., Hafnaoui, K., Hakobyan, H., Hakobyan, R.S., Hanretty, C., Hardie, J., Hassall, N., Heddle, D., Hersman, F.W., Hicks, K., Hleiqawi, I., Holtrop, M., Hyde-Wright, C.E., Ilieva, Y., Ireland, D.G., Ishkhanov, B.S., Isupov, E.L., Ito, M.M., Jenkins, D., Jo, H.S., Johnstone, J.R., Juengst, H.G., Kalantarians, N., Keller, D., Kellie, J.D., Khandaker, M., Kim, K.Y., Klein, A., Klein, F.J., Klimenko, A.V., Klusman, M., Kossov, M., Krahn, Z., Kramer, L.H., Kubarovsky, V., Kuhn, J., Kuhn, S.E., Kuleshov, S.V., Kuznetsov, V., Lachniet, J., Laget, J.M., Langheinrich, J., Lawrence, D., Lee, T., Li, Ji, Lima, A.C.S., Livingston, K., Lu, H.Y., Lukashin, K., MacCormick, M., Markov, N., Mattione, P., McAleer, S., Mckinnon, B., McNabb, J.W.C., Mecking, B.A., Mehrabyan, S., Melone, J.J., Mestayer, M.D., Meyer, C.A., Mibe, T., Mikhailov, K., Mirazita, M., Miskimen, R., Mokeev, V., Morand, L., Moreno, B., Moriya, K., Morrow, S.A., Moteabbed, M., Mueller, J., Munevar, E., Mutchler, G.S., Nadel-Turonski, P., Nasseripour, R., Niccolai, S., Niculescu, G., Niculescu, I., Niczyporuk, B.B., Niroula, M.R., Niyazov, R.A., Nozar, M., O'Rielly, G.V., Osipenko, M., Ostrovidov, A.I., Park, S., Pasyuk, E., Paterson, C., Anefalos Pereira, S., Philips, S.A., Pierce, J., Pivnyuk, N., Pocanic, D., Pogorelko, O., Polli, E., Popa, I., Pozdniakov, S., Preedom, B.M., Price, J.W., Prok, Y., Protopopescu, D., Qin, L.M., Raue, B.A., Riccardi, G., Ricco, G., Ripani, M., Ritchie, B.G., Ronchetti, F., Rosner, G., Rossi, P., Rowntree, D., Rubin, P.D., Sabatie, F., Saini, M.S., Salamanca, J., Salgado, C., Santoro, J.P., Sapunenko, V., Schott, D., Schumacher, R.A., Serov, V.S., Sharabian, Y.G., Sharov, D., Shaw, J., Shvedunov, N.V., Skabelin, A.V., Smith, E.S., Sober, D.I., Sokhan, D., Stavinsky, A., Stepanyan, S.S., Stepanyan, S., Stokes, B.E., Stoler, P., Strakovsky, I.I., Strauch, S., Suleiman, R., Taiuti, M., Takeuchi, T., Tedeschi, D.J., Tkabladze, A., Tkachenko, S., Todor, L., Tur, C., Ungaro, M., Vineyard, M.F., Vlassov, A.V., Watts, D.P., Weinstein, L.B., Weygand, D.P., Williams, M., Wolin, E., Wood, M.H., Yegneswaran, A., Yun, J., Yurov, M., Zana, L., Zhang, B., Zhang, J., Zhao, B., Zhao, Z.W., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
High Energy Physics - Phenomenology, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, High Energy Physics - Experiment
Abstract

The exclusive electroproduction process $\vec{e}p \to e^\prime n \pi^+$ was measured in the range of the photon virtuality $Q^2 = 1.7 - 4.5 \rm{GeV^2}$, and the invariant mass range for the $n\pi^+$ system of $W = 1.15 - 1.7 \rm{GeV}$ using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive $\pi^+$ production from protons with nearly full coverage in the azimuthal and polar angles of the $n\pi^+$ center-of-mass system. The $n\pi^+$ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the $p\pi^0$ final state will serve to determine the transition form factors of a large number of resonances. The largest discrepancy between these results and present modes was seen in the $\sigma_{LT'}$ structure function. In this experiment, 31,295 cross section and 4,184 asymmetry data points were measured. Because of the large volume of data, only a reduced set of structure functions and Legendre polynomial moments can be presented that are obtained in model-independent fits to the differential cross sections.

Published
2007

17. Separated Structure Functions for the Exclusive Electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ Final States

Author

Ambrozewicz, P, Carman, Ds, Feuerbach, Rj, Mestayer, Md, Raue, Ba, Schumacher, Ra, Tkabladze, A, Amarian, Mj, Anghinolfi, Marco, Asavapibhop, B, Asryan, G, Avakian, H, Bagdasaryan, H, Baillie, N, Ball, Jp, Baltzell, Na, Barrow, S, Batourine, V, Battaglieri, Marco, Beard, K, Bedlinskiy, I, Bektasoglu, M, Bellis, M, Benmouna, N, Berman, Bl, Bianchi, Nicola, Biselli, As, Bonner, Be, Bouchigny, S, Boiarinov, S, Bradford, R, Branford, D, Briscoe, Wj, Brooks, Wk, Bultmann, S, Burkert, Vd, Butuceanu, C, Calarco, Jr, Careccia, Sl, Cetina, C, Chen, S, Cole, Pl, Collins, P, Coltharp, P, Cords, D, Corvisiero, Pietro, Crabb, D, Crede, V, Cummings, Jp, Dashyan, N, De Masi, R, De Vita Raffaella, De Sanctis Enzo, Degtyarenko, Pv, Dennis, L, Deur, A, Dhuga, Ks, Dickson, R, Djalali, C, Dodge, Ge, Donnelly, J, Doughty, D, Dragovitsch, P, Dugger, M, Dytman, S, Dzyubak, Op, Egiyan, H, Egiyan, Ks, El Fassi, L, Elouadrhiri, L, Empl, A, Eugenio, P, Farhi, L, Fatemi, R, Fedotov, G, Feldman, Gerald, Forest, Ta, Frolov, V, Funsten, H, Garcon, M, Gavalian, G, Gilfoyle, Gp, Giovanetti, Kl, Girard, P, Girod, Fx, Goetz, Jt, Gonenc, A, Gothe, Rw, Griffioen, Ka, Guidal, M, Guillo, M, Guler, N, Guo, L, Gyurjyan, V, Hafidi, K, Hakobyan, H, Hardie, J, Heddle, D, Hersman, Fw, Hicks, K, Hleiqawi, I, Holtrop, M, Hu, J, Hyde Wright CE, Ilieva, Y, Ireland, Dg, Ishkhanov, Bs, Isupov, El, Ito, Mm, Jenkins, D, Jo, Hs, Joo, K, Juengst, Hg, Kalantarians, N, Kellie, Jd, Khandaker, M, Kim, Ky, Kim, K, Kim, W, Klein, A, Klein, Fj, Klusman, M, Kossov, M, Kramer, Lh, Kubarovsky, V, Kuhn, J, Kuhn, Se, Kuleshov, Sv, Lachniet, J, Laget, Jm, Langheinrich, J, Lawrence, D, Livingston, K, Lu, Hy, Lukashin, K, Maccormick, M, Manak, Jj, Markov, N, Mcaleer, S, Mckinnon, B, Mcnabb, Jwc, Mecking, Ba, Meyer, Ca, Mibe, T, Mikhailov, K, Minehart, R, Mirazita, Marco, Miskimen, R, Mokeev, V, Moriya, K, Morrow, Sa, Moteabbed, M, Muccifora, Valeria, Mueller, J, Mutchler, Gs, Nadel Turonski, P, Napolitano, J, Nasseripour, R, Niccolai, S, Niculescu, G, Niculescu, I, Niczyporuk, Bb, Niroula, Mr, Niyazov, Ra, Nozar, M, O'Rielly, Gv, Osipenko, Mikhail, Ostrovidov, Ai, Park, K, Pasyuk, E, Paterson, C, Philips, Sa, Pierce, J, Pivnyuk, N, Pocanic, D, Pogorelko, O, Polli, Ermanno, Pozdniakov, S, Preedom, Bm, Price, Jw, Prok, Y, Protopopescu, D, Qin, Lm, Riccardi, G, Ricco, Giovanni, Ripani, Marco, Ritchie, Bg, Ronchetti, Federico, Rosner, G, Rossi, Patrizia, Rowntree, D, Rubin, Pd, Sabatie, F, Salamanca, J, Salgado Lopez Carlos Alberto, Santoro, Joseph, Sapunenko, Vladimir, Sayre, D, Serov, Vs, Shafi, A, Sharabian, Yg, Shvedunov, Nv, Simionatto, S, Skabelin, Av, Smith, Es, Smith, Lc, Sober, Di, Sokhan, D, Stavinsky, A, Stepanyan, Ss, Stepanyan, S, Stokes, Be, Stoler, P, Strakovsky, Ii, Strauch, S, Taiuti, MAURO GINO, Taylor, S, Tedeschi, Dj, Thompson, R, Tkachenko, S, Tur, C, Ungaro, M, Vineyard, Mf, Vlassov, Av, Wang, K, Watts, Dp, Weinstein, Lb, Weygand, Dp, Williams Meurig Crispin Stowe, Wolin, E, Wood, Mh, Yegneswaran, A, Yun, J, Zana, L, Zhang, J, Zhao, B, Zhao, Zw, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Thomas Jefferson National Accelerator Laboraory (TJNAL), Thomas Jefferson National Accelerator Laboratory, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
KAON PHOTOPRODUCTION, PHOTON ENERGIES, CLAS, RESONANCES, MESONS, SCATTERING, DIRECTION, K&LAMBDA, P(GAMMA, LAMBDA, P(GAMMA, MESONS, LAMBDA, High Energy Physics - Experiment, CLAS, K&LAMBDA, PHOTON ENERGIES, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], SCATTERING, KAON PHOTOPRODUCTION, High Energy Physics::Experiment, Nuclear Experiment, RESONANCES, DIRECTION
Abstract

We report measurements of the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ were extracted from the $\Phi$- and $\epsilon$-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first $\sigma_L/\sigma_T$ separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from $0.5\leq Q^2\leq 2.8$ GeV$^2$ and invariant energy from $1.6\leq W\leq 2.4$ GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the $\Lambda$ and $\Sigma^0$ hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production., Comment: 61 pages, 26 figures, 5 tables

Published
2006

18. Deeply virtual and exclusive electroproduction of $\omega$-mesons

Author

Morand, L, Dore, D, Garcon, M, Guidal, M, Laget, Jm, Morrow, S, Sabatie, F, Smith, E, Adams, G, Arnbrozewicz, P, Anghinolfi, Marco, Asryan, G, Audit, G, Avakian, H, Bagdasaryan, H, Ball, J, Ball, Jp, Baltzell, Na, Barrow, S, Batourine, V, Battaglieri, Marco, Bektasoglu, M, Bellis, M, Benmouna, N, Berman, Bl, Biselli, As, Boiarinov, S, Bonner, Be, Bouchigny, S, Bradford, R, Branford, D, Briscoe, Wj, Brooks, Wk, Bultmann, S, Burkert, Vd, Butuceanu, C, Calarco, Jr, Careccia, Sl, Carman, Ds, Cazes Antoine Jacques, Chen, S, Cole, Pl, Cords, D, Corvisiero, Pietro, Crabb, D, Cummings, Jp, De Sanctis Enzo, Devita, R, Degtyarenko, Pv, Denizli, H, Dennis, L, Deur, A, Dharmawardane, Kv, Dhuga, Ks, Djalali, C, Dodge, Ge, Donnelly, J, Doughty, D, Dugger, M, Dytman, S, Dzyubak, Op, Egiyan, H, Egiyan, Ks, Elouadrhiri, L, Eugenio, P, Fatemi, R, Feldman, Gerald, Fersch, Rg, Feuerbach, Rj, Funsten, H, Gavalian, G, Gilfoyle, Gp, Giovanetti, Kl, Girod, Fx, Goetz, Jt, Gordon, Cio, Gothe, Rw, Griffioen, Ka, Guillo, M, Guler, N, Guo, L, Gyurjyan, V, Hadjidakis, Cynthia, Hakobyan, Rs, Hardie, J, Heddle, D, Hersman, Fw, Hicks, K, Hleiqawi, I, Holtrop, M, Hyde Wright CE, Ilieva, Y, Ireland, Dg, Ito, Mm, Jenkins, D, Jo, Hs, Joo, K, Juengst, Hg, Kellie, Jd, Khandaker, M, Kim, W, Klein, A, Klein, Fj, Klimenko, Av, Kossov, M, Kubarovski, V, Kramer, Lh, Kuhn, Se, Kuhn, J, Lachniet, J, Langhenirich, J, Lawrence, D, Lee, T, Jun, Li, Livingston, K, Marchand, C, Maximon, Lc, Mcaleer, S, Mckinnon, B, Mcnabb, Jwc, Mecking, Ba, Mehrabyan, S, Melone, Jj, Mestayer, Md, Meyer, Ca, Mikhailov, K, Minehart, R, Mirazita, Marco, Miskimen, R, Mokeev, V, Mueller, J, Mutchler, Gs, Napolitano, J, Nasseripour, R, Niccolai, S, Niculescu, G, Niculescu, I, Niczyporuk, Bb, Niyazov, Ra, Nozar, M, O'Rielly, Gv, Osipenko, Mikhail, Ostrovidov, Ai, Park, K, Pasyuk, E, Philips, Sa, Pivnyuk, N, Pocanic, D, Pogorelko, O, Polli, Ermanno, Popa, I, Pozdniakov, S, Preedom, Bm, Price, Jw, Prok, Y, Protopopescu, D, Raue, Ba, Riccardi, G, Ricco, Giovanni, Ripani, Marco, Ritchie, Bg, Ronchetti, Federico, Rosner, G, Rossi, Patrizia, Rubin, Pd, Salgado Lopez Carlos Alberto, Santoro, Joseph, Sapunenko, Vladimir, Schumacher, Ra, Serov, Vs, Sharabian, Yg, Shaw, J, Skabelin, Av, Smith, Lc, Sober, Di, Stavinsky, A, Stepanyan, S, Stepanyan, Ss, Stokes, Be, Stoler, P, Strakovsky, Ii, Strauch, S, Taiuti, MAURO GINO, Tedeschi, Dj, Thoma, U, Tkabladze, A, Todor, L, Tur, C, Ungaro, M, Vineyard, Mf, Vlassov, Av, Weinstein, Lb, Weygand, Dp, Williams Meurig Crispin Stowe, Wolin, E, Wood, Mh, Yegneswaran, A, Zana, L., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and CLAS

Subjects
Nuclear and High Energy Physics, Particle physics, Photon, Meson, Proton, Nuclear Theory, FOS: Physical sciences, Parton, 13.60.Le - 12.40.Nn -12.38.Bx, 01 natural sciences, Omega, Resonance (particle physics), High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), GENERALIZED PARTON DISTRIBUTIONS, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], SCATTERING, 010306 general physics, Nuclear Experiment, Coupling, Physics, 010308 nuclear & particles physics, HYDROGEN, PHOTON, SPIN, GENERALIZED PARTON DISTRIBUTIONS, VECTOR-MESONS, SCATTERING, PHOTON, HYDROGEN, SPIN, CLAS, High Energy Physics::Experiment, Nucleon, VECTOR-MESONS
Abstract

The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the interference terms sigma_TT and sigma_TL to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit., 15 pages,19 figures

Published
2005

19. Tensor polarization of the $\phi$ meson photoproduced at high $t$

Author

McCormick, K., Audit, G., Laget, J.M., Guo, L., Weygand, D.P., Niyazov, R.A., Weinstein, L.B., Carman, D.S., Joo, K., Mestayer, M.D., Raue, B.A., De Vita, R., Anghinolfi, M., Burkert, V.D., Dodge, G.E., Minehart, R., Taiuti, M., Weller, H., Adams, G., Amaryan, M.J., Anciant, E., Armstrong, D.S., Asavapibhop, B., Asryan, G., Auger, T., Avakian, H., Bagdasaryan, H., Ball, J.P., Barrow, S., Battaglieri, M., Beard, K., Bektasoglu, M., Bianchi, N., Biselli, A.S., Boiarinov, S., Bonner, B.E., Bosted, P., Bouchigny, S., Branford, D., Brooks, W.K., Bueltmann, S., Calarco, J.R., Capitani, G.P., Carnahan, B., Cazes, A., Ciciani, L., Cole, P.L., Coleman, A., Connelly, J., Cords, D., Corvisiero, P., Crabb, D., Crannell, H., Cummings, J.P., De-Sanctis, E., Degtyarenko, P.V., Demirchyan, R., Denizli, H., Dennis, L., Dharmawardane, K.V., Dhuga, K.S., Djalali, C., Doughty, D., Dragovitsch, P., Dugger, M., Dytman, S., Eckhause, M., Egiyan, H., Egiyan, K.S., Elouadrhiri, L., Empl, A., Farhi, L., Fatemi, R., Feuerbach, R.J., Ficenec, J., Forest, T.A., Frolov, V., Funsten, H., Gaff, S.J., Gai, M., Garcon, M., Gavalian, G., Gilad, S., Gilfoyle, G.P., Giovanetti, K.L., Girard, Pascal, Golovatch, E., Griffioen, K., Guidal, M., Guillo, M., Gyurjyan, V., Hadjidakis, C., Hancock, D., Hardie, J., Heddle, D., Heimberg, P., Hersman, F.W., Hicks, K., Hicks, R.S., Holtrop, M., Hu, J., Hyde-Wright, C.E., Ishkanov, B.S., Ito, M.M., Jenkins, D., Kelley, J.H., Kellie, J.D., Khandaker, M., Kim, K.Y., Kim, K., Kim, W., Klein, A., Klein, F.J., Klusman, M., Kossov, M., Kramer, L.H., Kuang, Y., Kuhn, S.E., Lachniet, J., Lawrence, D., Li, J., Livingston, K., Longhi, A., Loukachine, K., Lucas, M., Major, W., Manak, J.J., Marchand, C., McAleer, S., McCarthy, J., McNabb, J.W.C., Mecking, B.A., Meyer, C.A., Mikhailov, K.., Mirazita, M., Miskimen, R., Mokeev, V., Muccifora, V., Mueller, J., Mutchler, G.S., Napolitano, J., Nelson, S.O., Niculescu, G., Niculescu, I., Niczyporuk, B.B., Opper, A.K., O'Rielly, G.V., Osipenko, M., Park, K., Pasyuk, E., Peterson, G., Philips, S.A., Pivnyuk, N., Pocanic, D., Pogorelko, O., Polli, E., Pozdniakov, S., Preedom, B.M., Price, J.W., Prok, Y., Protopopescu, D., Qin, L.M., Reolon, A.R., Riccardi, G., Ricco, G., Ripani, M., Ritchie, B.G., Rock, S., Ronchetti, F., Rossi, P., Rowntree, D., Rubin, P.D., Sabatie, F., Sabourov, K., Salgado, C., Sapunenko, V., Sargsyan, M., Schumacher, R.A., Serov, V.S., Shafi, A., Sharabian, Y.G., Shaw, J., Skabelin, A.V., Smith, E.S., Smith, T., Smith, L.C., Sober, D.I., Sorrell, L., Spraker, M., Stavinsky, A., Stepanyan, S., Stoler, P., Strakovsky, I.I., Taylor, S., Tedeschi, D.J., Thompson, R., Todor, L., Ungaro, M., Vineyard, M.F., Vlassov, A.V., Wang, K., Weisberg, A., Whisnant, C.S., Wolin, E., Yegneswaran, A., Yun, J., Zhang, B., Zhao, J., Zhou, Z., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and CLAS

Subjects
EXCHANGE-POTENTIAL APPROACH, FOS: Physical sciences, High Energy Physics - Experiment, NUCLEON-SCATTERING, High Energy Physics - Experiment (hep-ex), EXCHANGE-POTENTIAL APPROACH, BARYON-BARYON SCATTERING, LARGE MOMENTUM-TRANSFER, VECTOR-MESONS, NUCLEON-SCATTERING, CLAS, SYSTEM, LARGE MOMENTUM-TRANSFER, CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nuclear Experiment, BARYON-BARYON SCATTERING, VECTOR-MESONS, SYSTEM
Abstract

As part of a measurement of the cross section of $\phi$ meson photoproduction to high momentum transfer, we measured the polar angular decay distribution of the outgoing $K^+$ in the channel $\phi \to K^+K^-$ in the $\phi$ center-of-mass frame (the helicity frame). We find that s-channel helicity conservation (SCHC) holds in the kinematical range where $t$-channel exchange dominates (up to $-t \sim 2.5$ GeV$^2$ for $E_{\gamma}$=3.6 GeV). Above this momentum, $u$-channel production of a $\phi$ meson dominates and induces a violation of SCHC. The deduced value of the $\phi NN$ coupling constant lies in the upper range of previously reported values., Comment: 6 pages; 5 figures

Published
2004

20. Comment on the narrow structure reported by Amaryan et al

Author

Anghinolfi, M., Ball, J., Baltzell, N. A., Battaglieri, M., Bedlinskiy, I., Bellis, M., Biselli, A. S., Bookwalter, C., Boiarinov, S., Bosted, P., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Cole, P. L., Crede, V., Vita, R., Sanctis, E., Dey, B., Dickson, R., Doughty, D., Dugger, M., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Gabrielyan, M. Y., Garcon, M., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Goetz, J. T., Golovatch, E., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Heddle, D., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jo, H. S., Joo, K., Khetarpal, P., Kim, A., Kim, W., Kubarovsky, V., Kuleshov, S. V., Lu, H. Y., Macgregor, L. J. D., Markov, N., Mccracken, M. E., Mckinnon, B., Mestayer, M. D., Curtis Meyer, Mirazita, M., Mokeev, V., Moriya, K., Morrison, B., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Park, K., Park, S., Pereira, S. Anefalos, Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Ricco, G., Ripani, M., Ritchie, B. G., Rossi, P., Schott, D., Schumacher, R. A., Seder, E., Sharabian, Y. G., Smith, E. S., Sober, D. I., Stepanyan, S. S., Stoler, P., Tang, W., Ungaro, M., Vernarsky, B., Vineyard, M. F., Weygand, D. P., Wood, M. H., Zachariou, N., Zhao, B., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and CLAS

Subjects
High Energy Physics - Experiment (hep-ex), [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract

The CLAS Collaboration provides a comment on the physics interpretation of the results presented in a paper published by M. Amaryan et al. regarding the possible observation of a narrow structure in the mass spectrum of a photoproduction experiment., Comment: to be published in Physical Review C

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