Author: "~Sharabian, Y. G." / Publisher: american physical society - Searchworks@Jio Institute Digital Library Search Results

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76 results on '"~Sharabian, Y. G."'

1. Polarized structure function σLT′ from π0p electroproduction data in the resonance region at 0.4GeV2<Q2<1.0GeV2

Author: Isupov, E. L., Burkert, V. D., Golubenko, A. A., Joo, K., Markov, N. S., Mokeev, V. I., Smith, L. C., Armstrong, W. R., Atac, H., Avakian, H., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossù, F., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Capobianco, R. A., Carman, D. S., Carvajal, J. C., Chatagnon, P., Chesnokov, V., Ciullo, G., Cole, P. L., Clary, B. A., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Gavalian, G., Gilfoyle, G. P., Glazier, D.I., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Illari, I., Ireland, D.G., Jenkins, D., Jo, H. S., Keller, D., Khanal, A., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Klimenko, V., Kripko, A., Kubarovsky, V., Lagerquist, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I.J.D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Munoz Camacho, C., Nadel-Turonski, P., Neupane, K., Niccolai, S., O'Connell, T., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Ritman, J., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Ziegler, V.
Subjects: High Energy Physics::Experiment, ddc:530, Nuclear Experiment
Abstract: The first results on the σLT′ structure function in exclusive π0p electroproduction at invariant masses of the final state of 1.5GeV
Published: 2022

2. Exclusive π0p electroproduction off protons in the resonance region at photon virtualities 0.4 GeV2≤Q2≤1 GeV2 EXCLUSIVE π0p ELECTROPRODUCTION off ⋯ N. MARKOV et al

Author: Markov, N., Joo, K., Burkert, V. D., Mokeev, V. I., Smith, L. C., Ungaro, M., Adhikari, S., Amaryan, M. J., Angelini, G., Atac, H., Avakian, H., Ayerbe Gayoso, C., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Cole, P. L., Contalbrigo, M., Crede, V., Ciullo, G., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Evans, C., Filippi, A., Ghandilyan, Y., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., H. S., Jo, Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Livingston, K., Macgregor, I. J. D., Marchand, D., Mascagna, V., Mckinnon, B., Mineeva, T., Mirazita, M., Nadel-Turonski, P., Nanda, S., Niccolai, S., Niculescu, G., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tan, J. A., Tyler, N., Venturelli, L., Voskanyan, H., Voutier, E., Wang, R., Wei, X., Wood, M. H., and Zachariou, N.
Published: 2020

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

Author: Markov, N., Joo, K., Burkert, V. D., Mokeev, V. I., Smith, L. C., Ungaro, M., Adhikari, S., Amaryan, M. J., Angelini, G., Atac, H., Avakian, H., Ayerbe Gayoso, C., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Biselli, A. S., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Cole, P. L., Contalbrigo, M., Crede, V., Ciullo, G., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Evans, C., Filippi, A., Ghandilyan, Y., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Livingston, K., MacGregor, I. J. D., Marchand, D., Mascagna, V., McKinnon, B., Mineeva, T., Mirazita, M., Nadel-Turonski, P., Nanda, S., Niccolai, S., Niculescu, G., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rowley, J., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tan, J. A., Tyler, N., Venturelli, L., Voskanyan, H., Voutier, E., Wang, R., Wei, X., Wood, M. H., and Zachariou, N.
Subjects: QC
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+εσL,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

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

Author: Ho, D. H., Schumacher, R. A., D'Angelo, A., Deur, A., Fleming, J., Hanretty, C., Kageya, T., Klein, F. J., Klempt, E., Lowry, M. M., Lu, H., Nikonov, V. A., Peng, P., Sandorfi, A. M., Sarantsev, A. V., Strakovsky, I. I., Walford, N. K., Wei, X., Workman, R. L., Adhikari, K. P., Adhikari, S., Adikaram, D., Akbar, Z., Ball, J., Barion, L., Bashkanov, M., Bass, C. D., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Boiarinov, S., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Chatagnon, P., Chetry, T., Ciullo, G., Clary, B. A., Cole, P., Collins, P., Contalbrigo, M., Crede, V., De Vita, R., Defurne, M., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fegan, S., Fersch, R., Filippi, A., Fradi, A., Ghandilyan, Y., Giovanetti, K. L., Girod, F. X., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Kubarovsky, V., Laine, V., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I.J.D., Marchand, D., Markov, N., Mayer, M., McKinnon, B., Meyer, C. A., Mirazita, M., Mokeev, V., Montgomery, R.A., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., O'Connell, T., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Rehfuss, M., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Sabatié, F., Salgado, C., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sober, D. I., Sokhan, D., Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Wang, R., Watts, D. P., Weinstein, L. B., Whisnant, C. S., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., and Zonta, I.
Subjects: Nuclear and High Energy Physics, Nuclear Theory, Socio-culturale, Nuclear Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract: We report the first measurements of the E beam-target helicity asymmetry for the →γ→n→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

5. Center of mass motion of short-range correlated nucleon pairs studied via the A(e,e'pp) reaction

Author: Cohen, E O, Hen, O, Piasetzky, E, Weinstein, L B, Duer, M, Schmidt, A, Korover, I, Hakobyan, H, Adhikari, S, Akbar, Z, Amaryan, M J, Avakian, H, Ball, J, Barion, L, Battaglieri, M, Beck, A, Bedlinskiy, I, Biselli, A S, Boiarinov, S, Briscoe, W, Burkert, V D, Cao, F, Carman, D S, Celentano, A, Charles, G, Chatagnon, Pierre, Chetry, T, Ciullo, G, Clary, Brandon A, Contalbrigo, M, Crede, V, Cruz Torres, R, D'Angelo, A, Dashyan, N, De Vita, R, De Sanctis, E, Defurne, M, Deur, A, Diehl, S, Djalali, C, Dupre, R, Egiyan, H, Ehrhart, Mathieu, El Alaoui, A, Fassi, L El, Eugenio, P, Fedotov, G, Fersch, R, Filippi, A, Ghandilyan, Y, Giovanetti, K L, Girod, F X, Golovatch, E, Gothe, R W, Griffioen, K A, Hafidi, K, Harrison, N, Hauenstein, F, Heddle, D, Hicks, K, Holtrop, M, Ireland, D.G., Ishkhanov, B S, Isupov, E L, Jenkins, D, Jo, H S, Johnston, S, Kabir, M L, Keller, D, Khachatryan, G, Khachatryan, M, Khandaker, M, Kim, A, Kim, W, Klein, A, Klein, F J, Kubarovsky, V, Kuhn, S E, Lanza, L, Lenisa, P, Livingston, K., MacGregor, I.J.D., Marchand, D, McKinnon, B., Mey-Tal Beck, S, Meyer, C A, Mirazita, M, Mokeev, V, Montgomery, R.A., Movsisyan, A, Munoz Camacho, C, Mustapha, B, Nadel-Turonski, P, Niccolai, S, Niculescu, G, Osipenko, M, Ostrovidov, A I, Paolone, M, Paremuzyan, R, Pasyuk, E, Pogorelko, O, Price, J W, Prok, Y, Protopopescu, D., Ripani, M, Riser, D, Rizzo, A, Rosner, G., Rossi, P, Sabatié, F, Schmookler, B A, Schumacher, R A, Sharabian, Y G, Sokhan, D., Sparveris, N, Stepanyan, S, Strauch, S, Taiuti, M, Tan, J A, Ungaro, M, Voskanyan, H, Voutier, E, Wang, R, Watts, D P, Wei, X, Wood, M H, Zachariou, N, Zhang, J, Zheng, X, and Zhao, Z W
Subjects: Nuclear Theory, Nuclear Experiment
Abstract: Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.
Published: 2018

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

7. 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: Roy, P., Akbar, Z., Park, S., Crede, V., Anisovich, A. V., Denisenko, I., Klempt, E., Nikonov, V. A., Sarantsev, A. V., Adhikari, K. P., Adhikari, S., Anefalos Pereira, S., Ball, J., Balossino, I., Bashkanov, M., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brock, J., Brooks, W. K., Burkert, V. D., Carlin, C., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clary, B. A., Cole, P. L., Contalbrigo, M., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Djalali, C., Dugger, M., Dupre, R., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Filippi, A., Fradi, A., Gavalian, G., Gevorgyan, N., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Hattawy, M., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Joosten, S., Keith, C. D., Keller, D., Khachatryan, G., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., 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., Meekins, D. G., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mokeev, V., Montgomery, R.A., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, E., Phelps, W., Pierce, J. J., Pogorelko, O., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Riser, D., Ritchie, B. G., Rizzo, A., Rosner, G., Sabatié, 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., Tan, J. A., Torayev, B., Ungaro, M., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.
Subjects: Nuclear and High Energy Physics, Nuclear Theory, Socio-culturale, High Energy Physics::Experiment, Nuclear Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract: The photoproduction of ω mesons off the proton has been studied in the reaction γp → p ω using the CEBAF\ud Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National\ud Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the\ud decay ω → π+π−π0, using a transversely polarized target with energies ranging from just above the reaction\ud threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30–40%\ud in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which\ud agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional\ud ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina\ud framework. Significant contributions from s-channel resonance production were found in addition to t-channel\ud exchange processes.
Published: 2018

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

Author: Kunkel, M. C., Amaryan, M. J., Strakovsky, I. I., Ritman, J., Goldstein, G. R., Adhikari, K. P., Adhikari, S., Avakian, H., Ball, J., Balossino, I., Barion, L., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bultmann, S., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Degtyarenko, P. V., Defurne, M., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Gavalian, G., Ghandilyan, Y., Ghosh, S., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hyde, C. E., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F., Kubarovsky, V., Kuhn, S. E., Laget, J. M., Lanza, L., Lenisa, P., Lersch, D., Livingston, K., Macgregor, I. J. D., Markov, N., Mbianda Njencheu, G., Mckinnon, B., Mineeva, T., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Park, K., Pasyuk, E., Payette, D., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Roy, A., Sabatie, F., Salgado, C., Schadmand, S., Schumacher, R. A., Sharabian, Y. G., Skorodumina, I., Stepanyan, S., Sokhan, D., Sober, D. I., Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D. P., Weinstein, L., Wei, X., Weygand, D. P., Zachariou, N., Zhang, J., and Zhao, Z. W.
Published: 2018

9. Measurement of the helicity asymmetry E in ω → π+π−π0 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., Anefalos Pereira, S., 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., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Garcon, M., Gevorgyan, N., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, 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., Munoz Camacho, C., 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., Sabatié, 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
Abstract: The double-polarization observable E was studied for the reaction γp → pω using the CEBAF Large\ud Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the\ud longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay\ud mode of the meson, ω → π+π−π0, using a circularly polarized tagged-photon beam with energies ranging\ud from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found\ud dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold\ud N(1720) 3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections\ud and a large variety of polarization observables, further contributions from other nucleon resonances were found\ud to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small\ud across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold\ud to dominate all other contributions above W ≈ 2 GeV.
Published: 2017

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

Author: Fersch, R. G., Guler, N., Bosted, P., Deur, A., Griffioen, K., Keith, C., Kuhn, S. E., Minehart, R., Prok, Y., Adhikari, K. P., Adhikari, S., Akbar, Z., Amaryan, M. J., Anefalos Pereira, S., Asryan, G., Avakian, H., Ball, J., Balossino, I., Baltzell, N. A., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Brooks, W. K., Bültmann, S., Burkert, V. D., Thanh Cao, Frank, Carman, D. S., Careccia, S., Celentano, A., Chandavar, S., Charles, G., Chetry, T., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Djalali, C., Dodge, G. E., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fanchini, E., Fedotov, G., Filippi, A., Fleming, J. A., Forest, T. A., Garçon, M., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Golovatch, E., Gothe, R. W., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Lagerquist, V. G., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., McKinnon, B., Meyer, C. A., Mirazita, M., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pierce, J., Pisano, S., Pogorelko, O., Price, J. W., Protopopescu, D., Raue, B. A., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Ye, Torayev, B., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Zachariou, N., and Zhang, J.
Subjects: High Energy Physics::Experiment, Nuclear Experiment
Abstract: We present the results of our final analysis of the full data set of \ud g\ud p\ud 1\ud (\ud Q\ud 2\ud )\ud , the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000–2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets (\ud 15\ud NH\ud 3\ud dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries \ud A\ud p\ud 1\ud and \ud A\ud p\ud 2\ud and spin structure functions \ud g\ud p\ud 1\ud and \ud g\ud p\ud 2\ud over a wide kinematic range (0.05 \ud GeV\ud 2\ud
Published: 2017

11. Search for a dark photon in electroproduced e+e- pairs with the Heavy Photon Search experiment at JLab

Author: Adrian, P, Baltzell, N, Battaglieri, M, Bondí, M, Boyarinov, S, Bueltmann, S, Burkert, V, 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, Graf, N, Graham, M, Griffioen, K, 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, Munoz Camacho, C, 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, 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, Wojtsekhowski, B, Yale, B, 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., Munoz Camacho, C., 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., Yale, B., Adrian, P, Baltzell, N, Battaglieri, M, Bondí, M, Boyarinov, S, Bueltmann, S, Burkert, V, 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, Graf, N, Graham, M, Griffioen, K, 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, Munoz Camacho, C, 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, 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, Wojtsekhowski, B, Yale, B, 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., Munoz Camacho, C., 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.
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 a prompt, electroproduced dark photon with a mass between 19 and 81 MeV/c2. A search for a resonance in the e+e- invariant mass distribution, using 1.7 days (1170 nb-1) of data, 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 6×10-6. Future runs with higher luminosity will explore new territory.
Published: 2018

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

Author: Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Hen, Or, Cruz Torres, Reynier, Beck, Sharon, Beck, Arie, Schmookler, Barak Abraham, Cohen, E. O., Piasetzky, E., Weinstein, L. B., Duer, M., Schmidt, A., Korover, I., Hakobyan, H., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chatagnon, Pierre, Chetry, T., Ciullo, G., Clary, Brandon A., Contalbrigo, M., Crede, V., D’Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, Mathieu, El Alaoui, A., Fassi, L. El, Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Ghandilyan, Y., Giovanetti, K. L., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Hafidi, K., Harrison, N., Hauenstein, F., Heddle, D., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., McKinnon, B., Meyer, C. A., Mirazita, M., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Mustapha, B., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Pasyuk, E., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Schumacher, R. A., Sharabian, Y. G., Sokhan, D., Sparveris, N., Stepanyan, S., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Wang, R., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., Zheng, X., Zhao, Z. W., Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Hen, Or, Cruz Torres, Reynier, Beck, Sharon, Beck, Arie, Schmookler, Barak Abraham, Cohen, E. O., Piasetzky, E., Weinstein, L. B., Duer, M., Schmidt, A., Korover, I., Hakobyan, H., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chatagnon, Pierre, Chetry, T., Ciullo, G., Clary, Brandon A., Contalbrigo, M., Crede, V., D’Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, Mathieu, El Alaoui, A., Fassi, L. El, Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Ghandilyan, Y., Giovanetti, K. L., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Hafidi, K., Harrison, N., Hauenstein, F., Heddle, D., Hicks, K., Holtrop, M., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., McKinnon, B., Meyer, C. A., Mirazita, M., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Mustapha, B., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Pasyuk, E., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Schumacher, R. A., Sharabian, Y. G., Sokhan, D., Sparveris, N., Stepanyan, S., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Wang, R., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., Zheng, X., and Zhao, Z. W.
Abstract: Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k[subscript F]). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k[subscript F], and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e′ pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states., National Science Foundation (U.S.)
Published: 2018

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

Author: Mattione, P. T., Carman, D. S., Strakovsky, I. I., Workman, R. L., Kudryavtsev, A. E., Svarc, A., Tarasov, V. E., Adhikari, K. P., Adhikari, S., Adikaram, D., Akbar, Z., Anefalos Pereira, S., Ball, J., Baltzell, N. A., Bashkanov, M., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Burkert, V. D., Cao, T., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Fradi, A., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Hollis, G., Holtrop, M., Hughes, S. M., 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, A., Klein, F. J., Kubarovsky, V., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I. J. D., Markov, N., McKinnon, B., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Murdoch, G., 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, W., Pisano, S., Pogorelko, O., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Stepanyan, S., Strauch, S., Taiuti, M., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.
Subjects: High Energy Physics::Experiment
Abstract: The quasifree \ud γ\ud d\ud →\ud π\ud −\ud p\ud (\ud p\ud )\ud differential cross section has been measured with CLAS at photon beam energies \ud E\ud γ\ud from 0.445 to 2.510 GeV (corresponding to \ud W\ud from 1.311 to 2.366 GeV) for pion center-of-mass angles \ud cos\ud θ\ud c\ud .\ud m\ud .\ud π\ud from \ud −\ud 0.72\ud to 0.92. A correction for final state interactions has been applied to these data to extract the \ud γ\ud n\ud →\ud π\ud −\ud p\ud differential cross sections. These cross sections are quoted in 8428 \ud (\ud E\ud γ\ud ,\ud cos\ud θ\ud c\ud .\ud m\ud .\ud π\ud )\ud bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of \ud N\ud ∗\ud resonances and extract their properties. Selected photon decay amplitudes \ud N\ud ∗\ud →\ud γ\ud n\ud at the resonance poles are determined for the first time and are reported here.
Published: 2017

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

Author: Isupov, E. L., Burkert, V. D., Carman, D. S., Gothe, R. W., Hicks, K., Ishkhanov, B. S., Mokeev, V. I., Adhikari, K. P., Adhikari, S., Adikaram, D., Akbar, Z., Amaryan, M. J., Anefalos Pereira, S., Avakian, H., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Brooks, W. K., Bültmann, S., Cao, T., 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 Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dupre, R., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Garçon, M., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Gleason, C., Golovatch, E., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Jenkins, D., Jiang, H., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuleshov, S. V., Kunkel, M., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Markov, N., McKinnon, B., Mineeva, T., Mirazita, M., Montgomery, R. A., Movsisyan, A., Munevar, E., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Riser, D., Ritchie, B. G., Rizzo, A., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Ye, Torayev, B., Trivedi, A., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Wei, X., Wood, M. H., Zachariou, N., and Zhang, J.
Abstract: This paper reports new exclusive cross sections for ep → ep\ud π+π−p' using the CLAS detector at Jefferson\ud Laboratory. These results are presented for the first time at photon virtualities 2.0 GeV2 < Q2 < 5.0 GeV2 in\ud the center-of-mass energy range 1.4 GeV
Published: 2017

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

Author: Bosted, P. E., Kim, A., Adhikari, K. P., Adikaram, D., Akbar, Z., Amaryan, M. J., Anefalos Pereira, S., Avakian, H., Badui, R. A., Ball, J., Balossino, I., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bültmann, S., Burkert, V. D., Cao, T., Carman, D. S., Celentano, A., Chandavar, S., 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 Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fanchini, E., Fedotov, G., Fegan, S., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Fradi, A., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Hakobyan, H., Guo, L., Hafidi, K., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Hollis, G., Holtrop, M., Hughes, S. M., Ireland, D. G., Isupov, E. L., Jenkins, D., Jiang, H., Jo, H. S., Joo, K., Keller, D., Khachatryan, G., Khandaker, M., Kim, W., Klei, A., Klein, F. J., Koirala, S., Kubarovsky, V., Kuhn, S. E., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Markov, N., Mayer, M., McCracken, M. E., McKinnon, B., Mineeva, T., Mirazita, M., Mokeev, V. I., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., 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., Schumacher, R. A., Seder, E., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Ye, Torayev, B., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Zachariou, N., Zhang, J., Zhao, Z. W., and Zonta, I.
Subjects: Nuclear and High Energy Physics, Economica, Socio-culturale, High Energy Physics::Experiment, RESONANCE, Nuclear Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract: Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive \ud π\ud 0\ud electroproduction reaction \ud γ\ud ∗\ud p\ud →\ud p\ud π\ud 0\ud , expanding an analysis of the \ud γ\ud ∗\ud p\ud →\ud n\ud π\ud +\ud reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are \ud 1.1\ud
Published: 2017

16. Measurement of target and double-spin asymmetries for the e p → eπ+(n) reaction in the nucleon resonance region at low Q2

Author: Zheng, X., Adhikari, K. P., Bosted, P., Deur, A., Drozdov, V., El Fassi, L., Kang, Hyekoo, Kovacs, K., Kuhn, S., Long, E., Phillips, S. K., Ripani, M., Slifer, K., Smith, L. C., Adikaram, D., Akbar, Z., Amaryan, M. J., Anefalos Pereira, S., Asryan, G., Avakian, H., Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Chen, J.-P., Chetry, T., Choi, Seonho, Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Djalali, C., Dodge, G. E., Dupre, R., Egiyan, H., El Alaoui, A., Elouadrhiri, L., Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Golovach, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Guo, L., Hanretty, C., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Jo, H. S., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I.J.D., Markov, N., McKinnon, B., Mirazita, M., Mokeev, V., Movsisyan, A., Munevar, E., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Net, L. A., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Peng, P., Pisano, S., Pogorelko, O., Price, J. W., Puckett, A. J. R., Raue, B. A., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Ye, Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Zachariou, N., Zhang, J., and Zonta, I.
Subjects: Nuclear and High Energy Physics, Economica, Socio-culturale, High Energy Physics::Experiment, Nuclear Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract: We report measurements of target- and double-spin asymmetries for the exclusive channel ep → eπ+(n) in\ud the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These\ud asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally\ud polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous\ud CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35 (GeV/c)\ud 2. The Q2 access was made\ud possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low\ud as 6◦. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis\ud prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results\ud on the target asymmetry, help to constrain the polarization-dependent components of these models.
Published: 2016

17. Beam asymmetry Sigma for pi(+) and pi(0) photoproduction on the proton for photon energies from 1.102 to 1.862 GeV

Author: Dugger, M, Ritchie B, G, Collins, P, Pasyuk, E, Briscoe W, J, Strakovsky I, I, Workman R, L, Azimov, Y, Adhikari K, P, Adikaram, D, Aghasyan, M, Amaryan M, J, Anderson M, D, Pereira S, A, Avakian, H, Ball, J, Baltzell N, A, Battaglieri, M, Batourine, V, Bedlinskiy, I, Biselli A, S, Boiarinov, S, Burkert V, D, Carman D, S, Celentano, A, Chandavar, S, 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, El Alaoui, A, El Fassi, L, Eugenio, P, Fedotov, G, Fegan, S, Fleming J, A, Gevorgyan, N, Gilfoyle G, P, Giovanetti K, L, Girod F, X, Goetz J, T, Gohn, W, Golovatch, E, Gothe R, W, Griffioen K, A, Guidal, M, Guo, L, Hafidi, K, Hakobyan, H, Hanretty, C, Harrison, N, Heddle, D, Hicks, K, Ho, D, Holtrop, M, Ilieva, Y, Ireland D, G, Ishkhanov B, S, Isupov E, L, Jo H, S, Joo, K, Keller, D, Khandaker, M, Kim, W, Klein, A, Klein F, J, Koirala, S, Kubarovsky, A, Kubarovsky, V, Kuleshov S, V, Lewis, S, Livingston, K, Lu H, Y, MacGregor I. J, D, Martinez, D, Mayer, M, Mckinnon, B, Mineeva, T, Mirazita, M, Mokeev, V, Montgomery R, A, Moutarde, H, Munevar, E, Camacho C, M, Nadel Turonski, P, Nepali C, S, Niccolai, S, Niculescu, G, Niculescu, I, Osipenko, M, Ostrovidov A, I, Pappalardo L, L, Paremuzyan, R, Park, K, Park, S, Phelps, E, Phillips J, J, Pisano, S, Pogorelko, O, Pozdniakov, S, Price J, W, Procureur, S, Prok, Y, Protopopescu, D, Raue B, A, Rimal, D, Ripani, M, Rosner, G, Rossi, P, Sabatie, F, Saini M, S, Salgado, C, Schott, D, Schumacher R, A, Seder, E, Seraydaryan, H, Sharabian Y, G, Smith G, D, Sober D, I, Sokhan, D, Stepanyan S, S, Stoler, P, Strauch, S, Null, T, Null, M, Tang, W, Tian, Y, Tkachenko, S, Torayev, B, Voskanyan, H, Voutier, E, Walford N, K, Watts D, P, Weygand D, P, Zachariou, N, L, Zhang, J, Zhao Z, W, and Zonta, I
Subjects: POSITIVE PION-PHOTOPRODUCTION, RESONANCE REGION, POLARIZED PHOTONS, CROSS-SECTION, PI-0 MESONS, CLAS, PARAMETERS, SYSTEM, PI0, Settore FIS/04 - Fisica Nucleare e Subnucleare
Published: 2013

18. Differential photoproduction cross sections of the Sigma(0)(1385), Lambda(1405), and Lambda(1520)

Author: Moriya, K, Schumacher R, A, Adhikari K, P, Adikaram, D, Aghasyan, M, Anderson, M, Pereira, S, Anefalos Ball, J, Baltzell N, A, Battaglieri, M, Batourine, V, Bedlinskiy, I, Bellis, M, Biselli A, S, Bono, J, Boiarinov, S, Briscoe W, J, Burkert V, D, Carman D, S, Celentano, A, Chandavar, S, Charles, G, Cole, P, Collins, P, Crede, V, D'Angelo, A, Dashyan, N, De Sanctis, E, De Vita, R, Deur, A, Dey, B, Djalali, C, Doughty, D, Dupre, R, Egiyan, H, El Fassi, L, Eugenio, P, Fedotov, G, Fegan, S, Fersch, R, Fleming J, A, Gevorgyan, N, Gilfoyle G, P, Giovanetti K, L, Girod, F, Null, X, Goetz J, T, Gohn, W, Golovatch, E, Gothe R, W, Griffioen K, A, Guidal, M, Hafidi, K, Hakobyan, H, Hanretty, C, Harrison, N, Heddle, D, Hicks, K, Ho, D, Holtrop, M, Hyde C, E, Ilieva, Y, Ireland D, G, Ishkhanov B, S, Isupov E, L, Jo, H, Null, S, Keller, D, Khandaker, M, Khetarpal, P, Kim, A, Kim, W, Klein, A, Klein, F, Null, J, Koirala, S, Kubarovsky, A, Kubarovsky, V, Kuleshov, S, Null, V, Kvaltine, N, Null, D, Livingston, K, Lu, H, Null, Y, Macgregor, I, Markov, N, Mayer, M, Mccracken, M, Mckinnon, B, Mestayer M, D, Meyer C, A, Mirazita, M, Mineeva, T, Mokeev, V, Montgomery R, A, Munevar, E, Camacho, C, Munoz Nadel Turonski, P, Nasseripour, R, Nepali C, S, Niccolai, S, Niculescu, G, Niculescu, I, Osipenko, M, Ostrovidov, A, Null, I, Pappalardo, L, Null, L, Paremuzyan, R, Park, K, Park, S, Pasyuk, E, Phelps, E, Phillips, J, Pisano, S, Pivnyuk, N, Pogorelko, O, Pozdniakov, S, Price, J, Null, W, Procureur, S, Protopopescu, D, Rimal, D, Ripani, M, Ritchie B, G, Rosner, G, Rossi, P, Sabatie, F, Saini M, S, Salgado, C, Schott, D, Seder, E, Seraydaryan, H, Sharabian Y, G, Smith E, S, Smith, G, Sober, D, Stepanyan S, S, Stepanyan, S, Stoler, P, Strakovsky I, I, Strauch, S, Taiuti, M, Tang, W, Taylor, S, Taylor C, E, Tian Ye Tkachenko, S, Torayev, B, Ungaro, M, Vernarsky, B, Vlassov A, V, Voskanyan, H, Voutier, E, Walford N, K, Watts D, P, Weygand D, P, Williams, M, Zachariou, N, Zana, L, Zhang, J, Zhao Z, W, and Zonta, I
Subjects: STATES, SCATTERING, HYPERON, MASSES, Settore FIS/04 - Fisica Nucleare e Subnucleare
Published: 2013

19. Cross sections for the γp→K+Λ and γp→K+Σ0 reactions measured at CLAS

Author: Tang, W., Hicks, K., Keller, D., Kim, S. H., Kim, H. C., Adhikari, K. P., Aghasyan, M., Amaryan, M. J., Anderson, M. D., Anefalos Pereira, S., Baltzell, N. A., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Bono, J., Boiarinov, S., Briscoe, W. J., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Cole, P. L., Collins, P., 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., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fedotov, G., Fegan, S., Fleming, J. A., Gabrielyan, M. Y., Gevorgyan, N., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Heddle, D., Ho, D., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jo, H. S., Joo, K., Khandaker, M., Khetarpal, P., Kim, A., Kim, W., Klein, F. J., Koirala, S., Kubarovsky, A., Kubarovsky, V., Kuleshov, S. V., Livingston, K., Lu, H. Y., MacGregor, I.J.D., Mao, Y., Markov, N., Martinez, D., Mayer, M., McKinnon, B., Meyer, C. A., Mokeev, V., Moutarde, H., Munevar, E., Munoz Camacho, C., Nadel-Turonski, P., Nepali, C. S., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Pappalardo, L. L., Paremuzyan, R., Park, K., Park, S., Pasyuk, E., Phelps, E., Phillips, J. J., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Puckett, A. J. R., Raue, B. A., Ripani, M., Rimal, D., Ritchie, B. G., Rosner, G., Rossi, P., Sabatié, F., Saini, M. S., Salgado, C., Schott, D., Schumacher, R. A., Seraydaryan, H., Sharabian, Y. G., Smith, G.D., Sober, D. I., Sokhan, Daria, Stepanyan, S. S., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taylor, C. E., Tian, Ye, Tkachenko, S., Torayev, B., Ungaro, M., Vernarsky, B., Vlassov, A. V., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Weinstein, L. B., Weygand, D. P., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., and Zonta, I.
Subjects: SYSTEM, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract: The first high-statistics cross sections for the reactions γp→K*+Λ and γp→K*+Σ0 were measured using the CLAS detector at photon energies between threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. Differential cross sections are presented over the full range of the center-of-mass angles, and then fitted to Legendre polynomials to extract the total cross section. Results for the K*+Λ final state are compared with two different calculations in an isobar and a Regge model, respectively. Theoretical calculations significantly underestimate the K*+Λ total cross sections between 2.1 and 2.6 GeV, but are in better agreement with present data at higher photon energies.
Published: 2013

20. Measurement of the generalized form factors near threshold via gamma* p -> n pi(+) at high Q(2)

Author: Park, K., Gothe, R. W., Adhikari, K. P., Adikaram, D., Anghinolfi, M., Baghdasaryan, H., Ball, J., Battaglieri, M., Batourine, V., Bedlinskiy, I., Bennett, R. P., Biselli, A. S., Bookwalter, C., Boiarinov, S., Branford, D., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Cole, P. L., Contalbrigo, Marco, Crede, V., D'Angelo, A., Daniel, A., Dashyan, N., Vita, R. D., Sanctis, E. D., Deur, A., Djalali, C., Doughty, D., Dupre, R., Alaoui, A. E., Fassi, L. E., Eugenio, P., Fedotov, G., Fradi, A., Gabrielyan, M. Y., Gevorgyan, N., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Goetz, J. T., Gohn, W., Golovatch, E., Graham, L., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Heddle, D., Hicks, K., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., H. S., Jo, Joo, K., Kalantarians, N., Khandaker, M., Khetarpal, P., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, A., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Kvaltine, N. D., Livingston, K., H. Y., Lu, I. J. D., Markov, N., Mayer, M., Mckinnon, B., Mestayer, M. D., Meyer, C. A., Mineeva, T., Mirazita, M., Mokeev, V., Moutarde, H., Munevar, E., Nadel Turonski, P., Nasseripour, R., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, Luciano Libero, Paremuzyan, R., Park, S., Pereira, S. A., Phelps, E., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Prok, Y., Ricco, G., Rimal, D., Ripani, M., Ritchie, B. G., Rosner, G., Rossi, P., Sabatie, F., Saini, M. S., Salgado, C., Schott, D., Schumacher, R. A., Seraydaryan, H., Sharabian, Y. G., Smith, E. S., Smith, G. D., Sober, D. I., Sokhan, D., Stepanyan, S. S., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tang, W., Taylor, C. E., Tian, Y., Tkachenko, S., Trivedi, A., Ungaro, M., Vernarsky, B., Vlassov, A. V., Voutier, E., Watts, D. P., Weygand, D. P., Wood, M. H., Zachariou, N., Zhao, B., and Zhao, Z. W.
Subjects: QUANTUM CHROMODYNAMICS, PI-0, PION ELECTROPRODUCTION, NUCLEONS, PROTON, PHOTOPRODUCTION, Settore FIS/04 - Fisica Nucleare e Subnucleare
Published: 2012

21. Experimental study of the P-11(1440) and D-13(1520) resonances from the CLAS data on ep -> e 'pi(+)pi(-)p

Author: Mokeev, V. I., Burkert, V. D., Elouadrhiri, L., Fedotov, G. V., Golovatch, E. N., Gothe, R. W., Ishkhanov, B. S., Isupov, E. L., Adhikari, K. P., Aghasyan, M., Anghinolfi, M., Avakian, H., Baghdasaryan, H., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Bookwalter, C., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Celentano, A., Charles, G., Cole, P. L., Contalbrigo, Marco, Crede, V., D'Angelo, A., Daniel, A., Dashyan, N., Vita, R. D., Sanctis, E. D., Deur, A., Djalali, C., Doughty, D., Dupre, R., Alaoui, A. E., Eugenio, P., Fegan, S., Fradi, A., Giovanetti, K. L., Girod, F. X., Gohn, W., Graham, L., Griffioen, K. A., Guegan, B., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Hicks, K., Ho, D., Holtrop, M., Ilieva, Y., Ireland, D. G., H. S., Jo, Joo, K., Keller, D., Khandaker, M., Khetarpal, P., Kim, A., Kim, W., Klein, A., Klein, F. J., Koirala, S., Kubarovsky, A., Kubarovsky, V., Kuleshov, S. V., Kvaltine, N. D., Livingston, K., H. Y., Lu, I. J. D., Mao, Y., Markov, N., Martinez, D., Mayer, M., Mckinnon, B., Meyer, C. A., Mineeva, T., Mirazita, M., Moutarde, H., Munevar, E., Nadel Turonski, P., Nepali, C. S., Ostrovidov, A. I., Pappalardo, Luciano Libero, Paremuzyan, R., Park, K., Park, S., Pasyuk, E., Pereira, S. A., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Protopopescu, D., Raue, B. A., Ricco, G., Rimal, D., Ripani, M., Rosner, G., Rossi, P., Sabatie, F., Saini, M. S., Salgado, C., Schott, D., Schumacher, R. A., Seder, E., Seraydaryan, H., Sharabian, Y. G., Smith, G. D., Smith, L. C., Sober, D. I., Sokhan, D., Stepanyan, S., Stepanyan, S. S., Stoler, P., Strakovsky, I. I., Strauch, S., Tang, W., Taylor, C. E., Tian, Y., Tkachenko, S., Trivedi, A., Ungaro, M., Vineyard, M. F., Voskanyan, H., Voutier, E., Walford, N. K., Wood, M. H., Zachariou, N., Zhao, Z. W., and Zonta, I.
Subjects: NUCLEON FORM-FACTORS, BARYON RESONANCES, MESON PRODUCTION, PI-N SCATTERING, QUARK-MODEL, DECAYS, ELECTROPRODUCTION, REGION, Settore FIS/04 - Fisica Nucleare e Subnucleare
Published: 2012

22. Electromagnetic decay of the Sigma(0)(1385) to Lambda gamma

Author: Keller, D., Hicks, K., Adhikari, K. P., Adikaram, D., Aghasyan, M., Amarian, M., Baghdasaryan, H., Ball, J., Battaglieri, M., Batourine, V., Bedlinskiy, I., Bennett, R. P., Biselli, A. S., Branford, D., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Careccia, S. L., Carman, D. S., Casey, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Daniel, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Dey, B., Dickson, R., Djalali, C., Doughty, D., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fegan, S., Forest, T. A., Gabrielyan, M. Y., Gavalian, G., Gevorgyan, N., Giovanetti, K. L., Girod, F. X., Gohn, W., Golovatch, E., Gothe, R. W., Graham, L., Guidal, M., Guegan, B., Hafidi, K., Hakobyan, H., Hanretty, C., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jawalkar, S. S., Jenkins, D., Jo, H. S., Joo, K., Khandaker, M., Khetarpal, P., Kim, A., Kim, W., Klein, A., Klein, F. J., Konczykowski, P., Kubarovsky, V., Kuleshov, S. V., Kuznetsov, V., Lu, H. Y., MacGregor, I. J. D., Markov, N., McAndrew, J., McKinnon, B., Meyer, C. A., Micherdzinska, A. M., Mirazita, M., Mokeev, V., Moreno, B., Moriya, K., Morrison, B., Moutarde, H., Munevar, E., Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paremuzyan, R., Park, K., Park, S., Pasyuk, E., Pereira, S. Anefalos, Pappalardo, L. L., Pisano, S., Pogorelko, O., Pozdniakov, S., Price, J. W., Procureur, S., Protopopescu, D., Raue, B. A., Ripani, M., Ritchie, B. G., Rosner, G., Rossi, P., Sabatie, F., Saini, M. S., Salgado, C., Schott, D., Schumacher, R. A., Seder, E., Seraydaryan, H., Sharabian, Y. G., Smith, E. S., Smith, G. D., Sober, D. I., Stepanyan, S. S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tang, W., Taylor, C. E., Vernarsky, B., Vineyard, M. F., Voutier, E., Weinstein, L. B., Watts, D. P., Wood, M. H., Zachariou, N., Zana, L., Zhao, B., and Zhao, Z. W.
Subjects: BARYONS, STRANGENESS, Electric and Magnetyic Moments, Leptonic, and radiative decays, Electromagnetic decays, Settore FIS/04 - Fisica Nucleare e Subnucleare, DECUPLET, semileptonic, Hyperons, HYPERONS, QUARK-MODEL, RADIATIVE DECAYS
Published: 2011

23. First Measurement of Hard Exclusive π^{-}Δ^{++} Electroproduction Beam-Spin Asymmetries off the Proton.

Author: Diehl S, Trotta N, Joo K, Achenbach P, Akbar Z, Armstrong WR, Atac H, Avakian H, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bossù F, Brinkmann KT, Briscoe WJ, Bulumulla D, Burkert V, Capobianco R, Carman DS, Carvajal JC, Celentano A, Charles G, Chatagnon P, Chesnokov V, Ciullo G, Cole PL, Contalbrigo M, Costantini G, Crede V, D'Angelo A, Dashyan N, De Vita R, Deur A, Djalali C, Dupre R, Ehrhart M, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Filippi A, Gavalian G, Glazier DI, Golubenko AA, Gosta G, Gothe RW, Gotra Y, Griffioen K, Hafidi K, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Hobart A, Holtrop M, Illari I, Ireland DG, Isupov EL, Jo HS, Johnston R, Keller D, Khachatryan M, Khanal A, Kim A, Kim W, Klimenko V, Kripko A, Kubarovsky V, Kuhn SE, Lagerquist V, Lanza L, Leali M, Lee S, Lenisa P, Li X, MacGregor IJD, Marchand D, Mascagna V, Matousek G, McKinnon B, McLauchlin C, Meziani ZE, Migliorati S, Milner RG, Mineeva T, Mirazita M, Mokeev V, Moran P, Munoz Camacho C, Naidoo P, Neupane K, Niccolai S, Niculescu G, Osipenko M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Paul SJ, Phelps W, Pilleux N, Pokhrel M, Poudel J, Price JW, Prok Y, Radic A, Raue BA, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Sabatié F, Salgado C, Schadmand S, Schmidt A, Sharabian YG, Shrestha U, Sokhan D, Sparveris N, Spreafico M, Stepanyan S, Strakovsky I, Strauch S, Turisini M, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei X, Williams R, Wishart R, Wood MH, Yurov M, Zachariou N, Zhao ZW, and Zurek M
Abstract: The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2 GeV/10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5 GeV^{2} up to 7 GeV^{2}. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ^{++} transition generalized parton distributions. A comparison to existing results for hard exclusive π^{+}n and π^{0}p electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.
Published: 2023
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24. First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region.

Author: Christiaens G, Defurne M, Sokhan D, Achenbach P, Akbar Z, Amaryan MJ, Atac H, Avakian H, Gayoso CA, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biselli AS, Bondi M, Booth WA, Bossù F, Boiarinov S, Brinkmann KT, Briscoe WJ, Bueltmann S, Bulumulla D, Burkert VD, Cao T, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chesnokov V, Chetry T, Ciullo G, Clash G, Cole PL, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, Ehrhart M, Alaoui AE, Fassi LE, Elouadrhiri L, Fegan S, Filippi A, Gates K, Gavalian G, Ghandilyan Y, Gilfoyle GP, Girod FX, Glazier DI, Golubenko AA, Gosta G, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Hafidi K, Hakobyan H, Hattawy M, Hauenstein F, Hayward TB, Heddle D, Hobart A, Holmberg DE, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Keller D, Khachatryan M, Khanal A, Kim W, Kripko A, Kubarovsky V, Kuhn SE, Lagerquist V, Lanza L, Kabir ML, Leali M, Lee S, Lenisa P, Li X, Livingston K, MacGregor IJD, Marchand D, Mascagna V, Matousek G, McKinnon B, McLauchlin C, Meziani ZE, Migliorati S, Milner RG, Mineeva T, Mirazita M, Mokeev V, Molina E, Camacho CM, Nadel-Turonski P, Naidoo P, Neupane K, Niccolai S, Nicol M, Niculescu G, Osipenko M, Ouillon M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Paul SJ, Phelps W, Pilleux N, Pokhrel M, Poudel J, Price JW, Prok Y, Radic A, Ramasubramanian N, Raue BA, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Sabatié F, Salgado C, Schadmand S, Schmidt A, Scott MBC, Sharabian YG, Shirokov EV, Shrestha U, Simmerling P, Sparveris N, Spreafico M, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Trotta N, Turisini M, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei X, Williams R, Wishart R, Wood MH, Zachariou N, Zhang J, Zhao ZW, Ziegler V, and Zurek M
Abstract: Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q^{2} and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies.
Published: 2023
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25. First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions.

Author: Chetry T, El Fassi L, Brooks WK, Dupré R, El Alaoui A, Hafidi K, Achenbach P, Adhikari KP, Akbar Z, Armstrong WR, Arratia M, Atac H, Avakian H, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biselli AS, Bondi M, Booth WA, Bossù F, Boiarinov S, Brinkmann KT, Briscoe WJ, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chesnokov V, Ciullo G, Cole PL, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Djalali C, Egiyan H, Elouadrhiri L, Eugenio P, Fegan S, Filippi A, Gavalian G, Ghandilyan Y, Gilfoyle GP, Glazier DI, Golubenko AA, Gosta G, Gothe RW, Griffioen KA, Guidal M, Guo L, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Hobart A, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jenkins D, Jo HS, Kabir ML, Khanal A, Khandaker M, Kim A, Kim W, Klein FJ, Kripko A, Kubarovsky V, Lagerquist V, Lanza L, Leali M, Lee S, Lenisa P, Li X, Livingston K, MacGregor IJD, Marchand D, Mascagna V, McKinnon B, McLauchlin C, Meziani ZE, Migliorati S, Mineeva T, Mirazita M, Mokeev V, Munoz Camacho C, Nadel-Turonski P, Neupane K, Niccolai S, Nicol M, Niculescu G, Osipenko M, Ostrovidov AI, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Paul SJ, Phelps W, Pilleux N, Pokhrel M, Poudel J, Price JW, Prok Y, Raue BA, Reed T, Richards J, Ripani M, Ritman J, Rosner G, Sabatié F, Salgado C, Schadmand S, Schmidt A, Schumacher RA, Sharabian YG, Shirokov EV, Shrestha U, Simmerling P, Sokhan D, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Trotta N, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Voutier E, Wei X, Weinstein LB, Williams R, Wishart R, Wood MH, Yurov M, Zachariou N, Zhao ZW, and Zurek M
Abstract: We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high z and an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high z. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons.
Published: 2023
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26. Observation of Correlations between Spin and Transverse Momenta in Back-to-Back Dihadron Production at CLAS12.

Author: Avakian H, Hayward TB, Kotzinian A, Armstrong WR, Atac H, Ayerbe Gayoso C, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biondo L, Biselli AS, Bondi M, Boiarinov S, Bossù F, Brinkman KT, Briscoe WJ, Brooks WK, Bueltmann S, Bulumulla D, Burkert VD, Capobianco R, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chesnokov V, Chetry T, Ciullo G, Cole PL, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Filippi A, Forest T, Gates K, Gavalian G, Ghandilyan Y, Glazier DI, Golubenko AA, Gosta G, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Hakobyan H, Hattawy M, Hauenstein F, Heddle D, Hobart A, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Johnston R, Joo K, Kabir ML, Keller D, Khachatryan M, Khanal A, Kim A, Kim W, Klimenko V, Kripko A, Kubarovsky V, Kuhn SE, Lagerquist V, Lanza L, Leali M, Lee S, Lenisa P, Li X, MacGregor IJD, Marchand D, Mascagna V, McKinnon B, Migliorati S, Mineeva T, Mirazita M, Mokeev V, Montgomery RA, Munoz Camacho C, Nadel-Turonski P, Naidoo P, Neupane K, Nguyen D, Niccolai S, Nicol M, Niculescu G, Osipenko M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Paul SJ, Phelps W, Pilleux N, Pogorelko O, Pokhrel M, Poudel J, Price JW, Prok Y, Raue BA, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Sabatié F, Salgado C, Schmidt A, Sharabian YG, Shirokov EV, Shrestha U, Simmerling P, Sokhan D, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Trotta N, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts DP, Wei X, Wishart R, Wood MH, Zachariou N, Zhao ZW, and Zurek M
Abstract: We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e^{'}pπ^{+}X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.
Published: 2023
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27. Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei.

Author: Paul SJ, Morán S, Arratia M, El Alaoui A, Hakobyan H, Brooks W, Amaryan MJ, Armstrong WR, Atac H, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biondo L, Biselli AS, Bondi M, Bossù F, Boiarinov S, Brinkmann KT, Briscoe WJ, Bulumulla D, Burkert VD, Capobianco R, Carman DS, Celentano A, Chesnokov V, Chetry T, Ciullo G, Cole PL, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, El Fassi L, Eugenio P, Fegan S, Filippi A, Gavalian G, Ghandilyan Y, Gilfoyle GP, Golubenko AA, Gosta G, Gothe RW, Griffioen KA, Guidal M, Hattawy M, Hayward TB, Heddle D, Hobart A, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Johnston R, Joo K, Joosten S, Keller D, Khanal A, Khandaker M, Kim W, Kripko A, Kubarovsky V, Lagerquist V, Lanza L, Leali M, Lee S, Lenisa P, Li X, Livingston K, MacGregor IJD, Marchand D, Mascagna V, McKinnon B, Meziani ZE, Migliorati S, Milner RG, Mineeva T, Mirazita M, Mokeev VI, Moran P, Munoz Camacho C, Neupane K, Nguyen D, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Phelps W, Pilleux N, Pocanic D, Pogorelko O, Pokhrel M, Poudel J, Price JW, Prok Y, Raue BA, Reed T, Ripani M, Rosner G, Sabatié F, Salgado C, Schmidt A, Schumacher RA, Sharabian YG, Shirokov EV, Shrestha U, Simmerling P, Sokhan D, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Voutier E, Wei X, Wishart R, Wood MH, Zachariou N, Zhao ZW, Ziegler V, and Zurek M
Abstract: We present the first measurement of dihadron 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.
Published: 2022
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28. Multidimensional, High Precision Measurements of Beam Single Spin Asymmetries in Semi-inclusive π^{+} Electroproduction off Protons in the Valence Region.

Author: Diehl S, Kim A, Angelini G, Joo K, Adhikari S, Amaryan M, Arratia M, Atac H, Avakian H, Ayerbe Gayoso C, Baltzell NA, Barion L, Bastami S, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bondi M, Bossù F, Boiarinov S, Brinkmann KT, Briscoe WJ, Brooks W, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chetry T, Ciullo G, Clark L, Clary BA, Cole PL, Contalbrigo M, Costantini G, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Dilks C, Djalali C, Dugger M, Dupre R, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Filippi A, Forest T, Gavalian G, Gilfoyle GP, Girod FX, Glazier DI, Golubenko AA, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Hafidi K, Hakobyan H, Hattawy M, Hauenstein F, Hayward TB, Heddle D, Hicks K, Hobart A, Holtrop M, Hyde CE, Ireland DG, Isupov EL, Jo HS, Johnston R, Joosten S, Keller D, Khachatryan M, Khanal A, Kim W, Kripko A, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lee S, Lenisa P, Livingston K, Lu Z, MacGregor IJD, Marchand D, Markov N, Marsicano L, Mascagna V, McKinnon B, Meziani ZE, Milner RG, Mineeva T, Mirazita M, Mokeev V, Moran P, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Naidoo P, Nanda S, Neupane K, Niccolai S, Niculescu G, O'Connell TR, Osipenko M, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Phelps W, Pogorelko O, Prok Y, Prokudin A, Raue BA, Ripani M, Ritman J, Rizzo A, Roberts CD, Rossi P, Rowley J, Sabatié F, Salgado C, Schmidt A, Segarra EP, Sharabian YG, Shrestha U, Simmerling P, Sokhan D, Soto O, Sparveris N, Stepanyan S, Stoler P, Strakovsky II, Strauch S, Tezgin K, Thornton A, Tyler N, Tyson R, Ungaro M, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts DP, Wei K, Wei X, Xu SS, Yale B, Zachariou N, and Zhang J
Abstract: High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single π^{+} SIDIS data over a large kinematic range in Bjorken x, fractional energy, and transverse momentum of the hadron as well as photon virtualities Q^{2} ranging from 1-7 GeV^{2}. In particular, the structure function ratio F_{LU}^{sinϕ}/F_{UU} has been determined, where F_{LU}^{sinϕ} is a twist-3 quantity that can reveal novel aspects of emergent hadron mass and quark-gluon correlations within the nucleon. The data's impact on the evolving understanding of the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing transverse momentum dependent parton distribution functions.
Published: 2022
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29. Improved Λp Elastic Scattering Cross Sections between 0.9 and 2.0 GeV/c as a Main Ingredient of the Neutron Star Equation of State.

Author: Rowley J, Compton N, Djalali C, Hicks K, Price J, Zachariou N, Adhikari KP, Armstrong WR, Atac H, Baashen L, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biondo L, Biselli AS, Bondi M, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chesnokov V, Chetry T, Ciullo G, Clark L, Cole PL, Contalbrigo M, Costantini G, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dupré R, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Eugenio P, Fedotov G, Fegan S, Fersch R, Filippi A, Fradi A, Gavalian G, Girod FX, Glazier DI, Golubenko A, Gothe RW, Griffioen K, Guo L, Hafidi K, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Hobart A, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jenkins D, Jo HS, Joo K, Keller D, Khanal A, Khandaker M, Kim A, Korover I, Kripko A, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Markov N, Marsicano L, Mascagna V, McCracken ME, McKinnon B, McLauchlin C, Meziani ZE, Migliorati S, Mineeva T, Mirazita M, Mokeev V, Munevar E, Munoz Camacho C, Nadel-Turonski P, Neupane K, Niccolai S, Niculescu G, O'Connell TR, Osipenko M, Ostrovidov AI, Pandey P, Paolone M, Pappalardo LL, Pasyuk E, Pogorelko O, Prok Y, Reed T, Ripani M, Ritman J, Rizzo A, Rosner G, Sabatie F, Salgado C, Schmidt A, Schumacher RA, Sharabian YG, Shrestha U, Sokhan D, Soto O, Sparveris N, Strakovsky II, Strauch S, Tyson R, Ungaro M, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts DP, Wei K, Wei X, Wishart R, Wood MH, Yale B, Yurov M, Zhang J, and Zhao ZW
Abstract: Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0 GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.
Published: 2021
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30. First Measurement of Timelike Compton Scattering.

Author: Chatagnon P, Niccolai S, Stepanyan S, Amaryan MJ, Angelini G, Armstrong WR, Atac H, Ayerbe Gayoso C, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biondo L, Biselli AS, Bondi M, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Caudron M, Celentano A, Chetry T, Ciullo G, Clark L, Cole PL, Contalbrigo M, Costantini G, Crede V, D'Angelo A, Dashyan N, Defurne M, De Vita R, Deur A, Diehl S, Djalali C, Dupré R, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Fersch R, Filippi A, Gavalian G, Ghandilyan Y, Gilfoyle GP, Girod FX, Glazier DI, Golubenko AA, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Guo L, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Hobart A, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Joo K, Kabir ML, Keller D, Khachatryan G, Khanal A, Kim A, Kim W, Kripko A, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lee S, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Marsicano L, Mascagna V, McKinnon B, McLauchlin C, Migliorati S, Mirazita M, Mokeev V, Montgomery RA, Munoz Camacho C, Nadel-Turonski P, Naidoo P, Neupane K, O'Connell TR, Osipenko M, Ouillon M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Phelps W, Pogorelko O, Poudel J, Price JW, Prok Y, Raue BA, Reed T, Ripani M, Rizzo A, Rossi P, Rowley J, Sabatié F, Schmidt A, Segarra EP, Sharabian YG, Shirokov EV, Shrestha U, Sokhan D, Soto O, Sparveris N, Strakovsky II, Strauch S, Tyler N, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts DP, Wei K, Wei X, Wishart R, Yale B, Zachariou N, Zhang J, and Zhao ZW
Abstract: We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25
Published: 2021
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31. Observation of Beam Spin Asymmetries in the Process ep→e^{'}π^{+}π^{-}X with CLAS12.

Author: Hayward TB, Dilks C, Vossen A, Avakian H, Adhikari S, Angelini G, Arratia M, Atac H, Ayerbe Gayoso C, Baltzell NA, Barion L, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bondì M, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chetry T, Ciullo G, Clary BA, Cole PL, Contalbrigo M, Costantini G, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Djalali C, Dupre R, Dugger M, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Filippi A, Forest TA, Gavalian G, Gilfoyle GP, Girod FX, Glazier DI, Golubenko AA, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Hafidi K, Hakobyan H, Hattawy M, Hauenstein F, Hicks K, Hobart A, Holtrop M, Ireland DG, Isupov EL, Jo HS, Joo K, Joosten S, Keller D, Khachatryan M, Khanal A, Kim A, Kim W, Kripko A, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lee S, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Markov N, Marsicano L, Mascagna V, McKinnon B, Meziani ZE, Mirazita M, Mokeev V, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Naidoo P, Nanda S, Neupane K, Niccolai S, Niculescu G, O'Connell TR, Osipenko M, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Phelps W, Pogorelko O, Prok Y, Raue BA, Ripani M, Ritman J, Rizzo A, Rossi P, Rowley J, Sabatié F, Salgado C, Schmidt A, Segarra EP, Sharabian YG, Shrestha U, Sokhan D, Soto O, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Thornton A, Tyler N, Tyson R, Ungaro M, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei K, Wei X, Wood MH, Yale B, Zachariou N, and Zhang J
Abstract: The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. 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 opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function G_{1}^{⊥}. A clear sign change is observed around the ρ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark.
Published: 2021
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32. Photoproduction of the f_{2}(1270) Meson Using the CLAS Detector.

Author: Carver M, Celentano A, Hicks K, Marsicano L, Mathieu V, Pilloni A, Adhikari KP, Adhikari S, Amaryan MJ, Angelini G, Atac H, Baltzell NA, Barion L, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bondi M, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Chatagnon P, Chetry T, Ciullo G, Clark L, Clary BA, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Djalali C, Dugger M, Dupre R, Egiyan H, Ehrhart M, Alaoui AE, Fassi LE, Eugenio P, Fedotov G, Fegan S, Filippi A, Gavalian G, Gevorgyan N, Gilfoyle GP, Girod FX, Gothe RW, Griffioen KA, Hafidi K, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Holtrop M, Huang Q, Hyde CE, Ilieva Y, Ireland DG, Isupov EL, Jenkins D, Jo HS, Joo K, Joosten S, Keller D, Khanal A, Khandaker M, Kim A, Kim CW, Klein FJ, Kripko A, Kubarovsky V, Lanza L, Leali M, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Mascagna V, McCracken ME, McKinnon B, Meziani ZE, Mokeev V, Movsisyan A, Munevar E, Camacho CM, Nadel-Turonski P, Neupane K, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Phelps W, Pogorelko O, Prok Y, Protopopescu D, Ripani M, Ritchie BG, Ritman J, Rizzo A, Rosner G, Rowley J, Sabatié F, Salgado C, Schmidt A, Schumacher RA, Sharabian YG, Shrestha U, Sokhan D, Soto O, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Tyler N, Tyson R, Ungaro M, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei K, Wei X, Yale B, Zachariou N, Zhang J, and Zhao ZW
Abstract: The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(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→π^{0}π^{0}p, 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 f_{2}(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.
Published: 2021
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33. Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs.

Author: Mirazita M, Avakian H, Courtoy A, Pisano S, Adhikari S, Amaryan MJ, Angelini G, Atac H, Baltzell NA, Barion L, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chetry T, Ciullo G, Clary B, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, Ehrhart M, Alaoui AE, Fassi LE, Eugenio P, Fegan S, Fersch R, Filippi A, Forest TA, Ghandilyan Y, Gavalian G, Gilfoyle GP, Giovanetti KL, Girod FX, Glazier DI, Golovatch E, Gothe RW, Griffioen KA, Guidal M, Guo L, Hafidi K, Hakobyan H, Hattawy M, Hayward TB, Heddle D, Hicks K, Hobart A, Holtrop M, Huang Q, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jenkins D, Jo HS, Joo K, Keller D, Khanal A, Khandaker M, Kim CW, Kim W, Klein FJ, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Markov N, Marsicano L, Mascagna V, McKinnon B, Milner RG, Mineeva T, Mokeev V, Mullen C, Camacho CM, Neupane K, Niculescu G, O'Connell T, Osipenko M, Paolone M, Pappalardo LL, Paremuzyan R, Park K, Pasyuk E, Phelps W, Pocanic D, Pogorelko O, Poudel J, Prok Y, Raue BA, Ripani M, Ritman J, Rizzo A, Rossi P, Sabatié F, Salgado C, Schmidt A, Schumacher RA, Sharabian YG, Shrestha U, Soto O, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Tyler N, Ungaro M, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts D, Wei K, Wei X, Wood MH, Yale B, Zachariou N, Zhang J, and Zhao ZW
Abstract: A first measurement of the longitudinal beam spin asymmetry A_{LU} in the semi-inclusive electroproduction of pairs of charged pions is reported. A_{LU} is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A_{LU}^{sinϕ_{R}} moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.
Published: 2021
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34. Extraction of Beam-Spin Asymmetries from the Hard Exclusive π^{+} Channel off Protons in a Wide Range of Kinematics.

Author: Diehl S, Joo K, Kim A, Avakian H, Kroll P, Park K, Riser D, Semenov-Tian-Shansky K, Tezgin K, Adhikari KP, Adhikari S, Amaryan MJ, Angelini G, Asryan G, Atac H, Barion L, Battaglieri M, Bedlinskiy I, Benmokhtar F, Bianconi A, Biselli AS, Bossù F, Boiarinov S, Briscoe WJ, Brooks WK, Bulumulla D, Burkert VD, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chetry T, Ciullo G, Clark L, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Dilks C, Djalali C, Dupre R, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Eugenio P, Filippi A, Forest TA, Ghandilyan Y, Gilfoyle GP, Giovanetti KL, Girod FX, Glazier DI, Golovatch E, Gothe RW, Griffioen KA, Guidal M, Guo L, Hakobyan H, Harrison N, Hattawy M, Hayward TB, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jenkins D, Jo HS, Joosten S, Keller D, Khachatryan M, Khanal A, Khandaker M, Kim CW, Kim W, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Markov N, Marsicano L, Mascagna V, McKinnon B, Meziani ZE, Mineeva T, Mirazita M, Mokeev V, Munoz Camacho C, Nadel-Turonski P, Niculescu G, Osipenko M, Paolone M, Pappalardo LL, Pasyuk E, Phelps W, Pogorelko O, Price JW, Prok Y, Raue BA, Ripani M, Rizzo A, Rossi P, Rowley J, Sabatié F, Salgado C, Schmidt A, Schumacher RA, Sharabian YG, Shrestha U, Soto O, Sparveris N, Stepanyan S, Stoler P, Strakovsky II, Strauch S, Tan JA, Tyler N, Ungaro M, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei X, Wood MH, Zachariou N, Zhang J, and Zhao ZW
Abstract: We have measured beam-spin asymmetries to extract the sinϕ moment A_{LU}^{sinϕ} from the hard exclusive e[over →]p→e^{'}nπ^{+} reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The A_{LU}^{sinϕ} moment has been measured up to 6.6 GeV^{2} in -t, 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 A_{LU}^{sinϕ} 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
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35. Exploring the Structure of the Bound Proton with Deeply Virtual Compton Scattering.

Author: Hattawy M, Baltzell NA, Dupré R, Bültmann S, De Vita R, El Alaoui A, El Fassi L, Egiyan H, Girod FX, Guidal M, Hafidi K, Jenkins D, Liuti S, Perrin Y, Stepanyan S, Torayev B, Voutier E, Adhikari S, Angelini G, Ayerbe Gayoso C, Barion L, Battaglieri M, Bedlinskiy I, Biselli AS, Bossù F, Brooks W, Cao F, Carman DS, Celentano A, Chatagnon P, Chetry T, Ciullo G, Clark L, Cole PL, 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 TA, Fradi A, Garçon M, Gavalian G, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Golovatch E, Gothe RW, Griffioen KA, Harrison N, Hauenstein F, Hayward TB, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Johnston S, Keller D, Khachatryan G, Khachatryan M, Khanal A, Khandaker M, Kim CW, Kim W, Klein FJ, Kubarovsky V, Kuhn SE, Lanza L, L Kabir M, Lenisa P, Livingston K, MacGregor IJD, Marchand D, Markov N, Mayer M, McKinnon B, Meziani ZE, Mineeva T, Mirazita M, Montgomery RA, Munoz Camacho C, Nadel-Turonski P, Niccolai S, Ostrovidov AI, Pappalardo LL, 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 RA, Sharabian YG, Skorodumina I, Sokhan D, Soto O, Sparveris N, Strauch S, Taiuti M, Tan JA, Tyler N, Ungaro M, Voskanyan H, Wang R, Watts DP, Wei X, Weinstein LB, Wood MH, Zachariou N, Zhang J, and Zhao ZW
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 Letter, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering 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 (ϕ) 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: 2019
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36. First Measurements of the Double-Polarization Observables F, P, and H in ω Photoproduction off Transversely Polarized Protons in the N^{*} Resonance Region.

Author: Roy P, Park S, Crede V, Anisovich AV, Klempt E, Nikonov VA, Sarantsev AV, Wei NC, Huang F, Nakayama K, Adhikari KP, Adhikari S, Angelini G, Avakian H, Barion L, Battaglieri M, Bedlinskiy I, Biselli AS, Boiarinov S, Briscoe WJ, Brock J, Brooks WK, Burkert VD, Cao F, Carlin C, Carman DS, Celentano A, Chatagnon P, Chetry T, Ciullo G, Cole PL, Contalbrigo M, Cortes O, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Deur A, Diehl S, Djalali C, Dugger M, Dupre R, Duran B, Egiyan H, Ehrhart M, El Alaoui A, El Fassi L, Eugenio P, Fegan S, Filippi A, Fradi A, Gilfoyle GP, Girod FX, Golovatch E, Gothe RW, Griffioen KA, Guidal M, Guo L, Hafidi K, Hanretty C, Harrison N, Hattawy M, Hayward TB, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jenkins D, Jo HS, Johnston S, Joosten S, Kabir ML, Keith CD, Keller D, Khachatryan G, Khachatryan M, Khanal A, Khandaker M, Kim A, Kim W, Klein FJ, Kubarovsky V, Kuleshov SV, Kunkel MC, Lanza L, Lenisa P, Livingston K, MacGregor IJD, Marchand D, McKinnon B, Meekins DG, Meyer CA, Mineeva T, Mokeev V, Montgomery RA, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Payette D, Phelps W, Pierce J, Pogorelko O, Prok Y, Protopopescu D, Raue BA, Ripani M, Riser D, Ritchie BG, Rizzo A, Rosner G, Sabatié F, Salgado C, Schumacher RA, Seely ML, Sharabian YG, Shrestha U, Skorodumina I, Sokhan D, Soto O, Sparveris N, Strakovsky II, Strauch S, Taiuti M, Tan JA, Torayev B, Tyler N, Ungaro M, Voskanyan H, Voutier E, Walford NK, Wang R, Watts DP, Wei X, Wood MH, Zachariou N, Zhang J, and Zhao ZW
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
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37. Center of Mass Motion of Short-Range Correlated Nucleon Pairs studied via the A(e,e^{'}pp) Reaction.

Author: Cohen EO, Hen O, Piasetzky E, Weinstein LB, Duer M, Schmidt A, Korover I, Hakobyan H, Adhikari S, Akbar Z, Amaryan MJ, Avakian H, Ball J, Barion L, Battaglieri M, Beck A, Bedlinskiy I, Biselli AS, Boiarinov S, Briscoe W, Burkert VD, Cao F, Carman DS, Celentano A, Charles G, Chatagnon P, Chetry T, Ciullo G, Clary BA, Contalbrigo M, Crede V, Cruz Torres R, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Defurne M, Deur A, Diehl S, Djalali C, Duer M, Dupre R, Egiyan H, Ehrhart M, El Alaoui A, Fassi LE, Eugenio P, Fedotov G, Fersch R, Filippi A, Ghandilyan Y, Giovanetti KL, Girod FX, Golovatch E, Gothe RW, Griffioen KA, Hafidi K, Harrison N, Hauenstein F, Heddle D, Hicks K, Holtrop M, Ireland DG, Ishkhanov BS, Isupov EL, Jenkins D, Jo HS, Johnston S, Kabir ML, Keller D, Khachatryan G, Khachatryan M, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Korover I, Kubarovsky V, Kuhn SE, Lanza L, Lenisa P, Livingston K, MacGregor IJD, Marchand D, McKinnon B, Mey-Tal Beck S, Meyer CA, Mirazita M, Mokeev V, Montgomery RA, Movsisyan A, Munoz Camacho C, Mustapha B, Nadel-Turonski P, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Paolone M, Paremuzyan R, Pasyuk E, Pogorelko O, Price JW, Prok Y, Protopopescu D, Ripani M, Riser D, Rizzo A, Rosner G, Rossi P, Sabatié F, Schmookler BA, Schumacher RA, Sharabian YG, Sokhan D, Sparveris N, Stepanyan S, Strauch S, Taiuti M, Tan JA, Ungaro M, Voskanyan H, Voutier E, Wang R, Watts DP, Wei X, Wood MH, Zachariou N, Zhang J, Zheng X, and Zhao ZW
Abstract: Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.
Published: 2018
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38. Measurement of the Q^{2} Dependence of the Deuteron Spin Structure Function g_{1} and its Moments at Low Q^{2} with CLAS.

Author: Adhikari KP, Deur A, El Fassi L, Kang H, Kuhn SE, Ripani M, Slifer K, Zheng X, Adhikari S, Akbar Z, Amaryan MJ, Avakian H, Ball J, Balossino I, Barion L, Battaglieri M, Bedlinskiy I, Biselli AS, Bosted P, Briscoe WJ, Brock J, Bültmann S, Burkert VD, Thanh Cao F, Carlin C, Carman DS, Celentano A, Charles G, Chen JP, Chetry T, Choi S, Ciullo G, Clark L, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Defurne M, Djalali C, Dodge GE, Drozdov V, Dupre R, Egiyan H, El Alaoui A, Elouadrhiri L, Eugenio P, Fedotov G, Filippi A, Ghandilyan Y, Gilfoyle GP, Golovatch E, Gothe RW, Griffioen KA, Guidal M, Guler N, Guo L, Hafidi K, Hakobyan H, Hanretty C, Harrison N, Hattawy M, Heddle D, Hicks K, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Isupov EL, Jenkins D, Jo HS, Johnston SC, Joo K, Joosten S, Kabir ML, Keith CD, Keller D, Khachatryan G, Khachatryan M, Khandaker M, Kim W, Klein A, Klein FJ, Konczykowski P, Kovacs K, Kubarovsky V, Lanza L, Lenisa P, Livingston K, Long E, MacGregor IJD, Markov N, Mayer M, McKinnon B, Meekins DG, Meyer CA, Mineeva T, Mirazita M, Mokeev V, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Niculescu G, Niccolai S, Osipenko M, Ostrovidov AI, Paolone M, Pappalardo L, Paremuzyan R, Park K, Pasyuk E, Payette D, Phelps W, Phillips SK, Pierce J, Pogorelko O, Poudel J, Price JW, Prok Y, Protopopescu D, Raue BA, Rizzo A, Rosner G, Rossi P, Sabatié F, Salgado C, Schumacher RA, Sharabian YG, Shigeyuki T, Simonyan A, Skorodumina I, Smith GD, Sparveris N, Sokhan D, Stepanyan S, Strakovsky II, Strauch S, Sulkosky V, Taiuti M, Tan JA, Ungaro M, Voutier E, Wei X, Weinstein LB, Zhang J, and Zhao ZW
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 (χPT). 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_{1}^{d} and the spin polarizability γ_{0}^{d} 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 χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.
Published: 2018
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39. First Exclusive Measurement of Deeply Virtual Compton Scattering off ^{4}He: Toward the 3D Tomography of Nuclei.

Author: Hattawy M, Baltzell NA, Dupré R, Hafidi K, Stepanyan S, Bültmann S, De Vita R, El Alaoui A, El Fassi L, Egiyan H, Girod FX, Guidal M, Jenkins D, Liuti S, Perrin Y, Torayev B, Voutier E, Adhikari KP, Adhikari S, Adikaram D, Akbar Z, Amaryan MJ, Anefalos Pereira S, Armstrong WR, Avakian H, Ball J, Bashkanov M, Battaglieri M, Batourine V, Bedlinskiy I, Biselli AS, Boiarinov S, Briscoe WJ, Brooks WK, Burkert VD, Thanh Cao F, Carman DS, Celentano A, Charles G, Chetry T, Ciullo G, Clark L, Colaneri L, Cole PL, 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 JA, Forest TA, Fradi A, Garçon M, Gevorgyan N, Ghandilyan Y, Gilfoyle GP, Giovanetti KL, Gleason C, Gohn W, Golovatch E, Gothe RW, Griffioen KA, Guo L, Hakobyan H, Hanretty C, Harrison N, Heddle D, Hicks K, Holtrop M, Hughes SM, Ireland DG, Ishkhanov BS, Isupov EL, Jiang H, Joo K, Joosten S, Keller D, Khachatryan G, Khachatryan M, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Kubarovsky V, Kuhn SE, Kuleshov SV, Lanza L, Lenisa P, Livingston K, Lu HY, MacGregor IJD, Markov N, Mayer M, McCracken ME, McKinnon B, Meyer CA, Meziani ZE, Mineeva T, Mirazita M, Mokeev V, Montgomery RA, Moutarde H, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Net LA, Niccolai S, Niculescu G, Niculescu I, Osipenko M, Ostrovidov AI, Paolone M, Paremuzyan R, Park K, Pasyuk E, Phelps E, Phelps W, Pisano S, Pogorelko O, Price JW, Prok Y, Protopopescu D, Ripani M, Ritchie BG, Rizzo A, Rosner G, Rossi P, Sabatié F, Salgado C, Schumacher RA, Seder E, Sharabian YG, Simonyan A, Skorodumina I, Smith GD, Sokhan D, Sparveris N, Strauch S, Taiuti M, Ungaro M, Voskanyan H, Walford NK, Watts DP, Wei X, Weinstein LB, Wood MH, Zachariou N, Zana L, Zhang J, and Zhao ZW
Abstract: We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized ^{4}He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling ^{4}He nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only ^{4}He Compton form factor, 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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40. Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region.

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

Author: Adikaram D, Rimal D, Weinstein LB, Raue B, Khetarpal P, Bennett RP, Arrington J, Brooks WK, Adhikari KP, Afanasev AV, Amaryan MJ, Anderson MD, Anefalos Pereira S, Avakian H, Ball J, Battaglieri M, Bedlinskiy I, Biselli AS, Bono J, Boiarinov S, Briscoe WJ, Burkert VD, Carman DS, Careccia S, Celentano A, Chandavar S, Charles G, Colaneri L, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Deur A, Djalali C, Dodge GE, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Filippi A, Fleming JA, Fradi A, Garillon B, Gilfoyle GP, Giovanetti KL, Girod FX, Goetz JT, Gohn W, Golovatch E, Gothe RW, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Harrison N, Hattawy M, Hicks K, Holtrop M, Hughes SM, Hyde CE, Ilieva Y, Ireland DG, Ishkhanov BS, Jenkins D, Jiang H, Jo HS, Joo K, Joosten S, Kalantarians N, Keller D, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Koirala S, Kubarovsky V, Kuhn SE, Livingston K, Lu HY, MacGregor IJ, Markov N, Mattione P, Mayer M, McKinnon B, Mestayer MD, Meyer CA, Mirazita M, Mokeev V, Montgomery RA, Moody CI, Moutarde H, Movsisyan A, Camacho CM, Nadel-Turonski P, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Park K, Pasyuk E, Peña C, Pisano S, Pogorelko O, Price JW, Procureur S, Prok Y, Protopopescu D, Puckett AJ, Ripani M, Rizzo A, Rosner G, Rossi P, Roy P, Sabatié F, Salgado C, Schott D, Schumacher RA, Seder E, Sharabian YG, Simonyan A, Skorodumina I, Smith ES, Smith GD, Sober DI, Sokhan D, Sparveris N, Stepanyan S, Stoler P, Strauch S, Sytnik V, Taiuti M, Tian Y, Trivedi A, Ungaro M, Voskanyan H, Voutier E, Walford NK, Watts DP, Wei X, Wood MH, Zachariou N, Zana L, Zhang J, Zhao ZW, and Zonta I
Abstract: There is a significant discrepancy between the values of the proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of G(E)(p) from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ϵ) and momentum transfer (Q(2)) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ϵ at Q(2)=1.45 GeV(2). This measurement is consistent with the size of the form factor discrepancy at Q(2)≈1.75 GeV(2) and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2-3 GeV(2).
Published: 2015
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42. Measurement of exclusive π(0) electroproduction structure functions and their relationship to transverse generalized parton distributions.

Author: Bedlinskiy I, Kubarovsky V, Niccolai S, Stoler P, Adhikari KP, Aghasyan M, Amaryan MJ, Anghinolfi M, Avakian H, Baghdasaryan H, Ball J, Baltzell NA, Battaglieri M, Bennett RP, Biselli AS, Bookwalter C, Boiarinov S, Briscoe WJ, Brooks WK, Burkert VD, Carman DS, 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, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Fleming JA, Forest TA, Fradi A, Garçon M, Gevorgyan N, Giovanetti KL, Girod FX, Gohn W, Gothe RW, Graham L, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jo HS, Joo K, Keller D, Khandaker M, Khetarpal P, Kim A, Kim W, Klein FJ, Koirala S, Kubarovsky A, Kuhn SE, Kuleshov SV, Kvaltine ND, Livingston K, Lu HY, MacGregor IJ, Mao Y, Markov N, Martinez D, Mayer M, McKinnon B, Meyer CA, Mineeva T, Mirazita M, Mokeev V, Moutarde H, Munevar E, Munoz Camacho C, Nadel-Turonski P, Niculescu G, Niculescu I, Osipenko M, Ostrovidov AI, Pappalardo LL, Paremuzyan R, Park K, Park S, Pasyuk E, Anefalos Pereira S, Phelps E, Pisano S, Pogorelko O, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Puckett AJ, Raue BA, Ricco G, Rimal D, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salgado C, Saylor N, Schott D, Schumacher RA, Seder E, Seraydaryan H, Sharabian YG, Smith GD, Sober DI, Sokhan D, Stepanyan SS, Stepanyan S, Strauch S, Taiuti M, Tang W, Taylor CE, Tian Y, Tkachenko S, Ungaro M, Vineyard MF, Vlassov A, Voskanyan H, Voutier E, Walford NK, Watts DP, Weinstein LB, Weygand DP, Wood MH, Zachariou N, Zhang J, Zhao ZW, and Zonta I
Abstract: Exclusive π(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 ϕ(π), 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 σ(T)+ϵσ(L), σ(TT), and σ(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 generalized parton distributions (GPDs). Inclusion of only longitudinal GPDs very strongly underestimates σ(T)+ϵσ(L) and fails to account for σ(TT) and σ(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 nonflip processes. The results confirm that exclusive π(0) electroproduction offers direct experimental access to the transversity GPDs.
Published: 2012
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43. Measurement of the neutron F2 structure function via spectator tagging with CLAS.

Author: Baillie N, Tkachenko S, Zhang J, Bosted P, Bültmann S, Christy ME, Fenker H, Griffioen KA, Keppel CE, Kuhn SE, Melnitchouk W, Tvaskis V, Adhikari KP, Adikaram D, Aghasyan M, Amaryan MJ, Anghinolfi M, Arrington J, Avakian H, Baghdasaryan H, Battaglieri M, Biselli AS, Branford D, Briscoe WJ, Brooks WK, Burkert VD, Carman DS, Celentano A, Chandavar S, Charles G, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Daniel A, Dashyan N, De Vita R, De Sanctis E, Deur A, Dey B, Djalali C, Dodge G, Domingo J, Doughty D, Dupre R, Dutta D, Ent R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Fradi A, Gabrielyan MY, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Girod FX, Gohn W, Golovatch E, Gothe RW, Graham L, Guegan B, Guidal M, Guler N, Guo L, Hafidi K, Heddle D, Hicks K, Holtrop M, Hungerford E, Hyde CE, Ilieva Y, Ireland DG, Ispiryan M, Isupov EL, Jawalkar SS, Jo HS, Kalantarians N, Khandaker M, Khetarpal P, Kim A, Kim W, King PM, Klein A, Klein FJ, Klimenko A, Kubarovsky V, Kuleshov SV, Kvaltine ND, Livingston K, Lu HY, MacGregor IJ, Mao Y, Markov N, McKinnon B, Mineeva T, Morrison B, Moutarde H, Munevar E, Nadel-Turonski P, Ni A, Niccolai S, Niculescu I, Niculescu G, Osipenko M, Ostrovidov AI, Pappalardo L, Park K, Park S, Pasyuk E, Anefalos Pereira S, Pisano S, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Raue BA, Ricco G, Rimal D, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salgado C, Schott D, Schumacher RA, Seder E, Sharabian YG, Sober DI, Sokhan D, Stepanyan S, Stepanyan SS, Stoler P, Strauch S, Taiuti M, Tang W, Ungaro M, Vineyard MF, Voutier E, Watts DP, Weinstein LB, Weygand DP, Wood MH, Zana L, and Zhao B
Abstract: We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲100 MeV/c and their angles to ≳100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65
Published: 2012
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44. Measurement of single- and double-spin asymmetries in deep inelastic pion electroproduction with a longitudinally polarized target.

Author: Avakian H, Bosted P, Burkert VD, Elouadrhiri L, Adhikari KP, Aghasyan M, Amaryan M, Anghinolfi M, Baghdasaryan H, Ball J, Battaglieri M, Bedlinskiy I, Biselli AS, Branford D, Briscoe WJ, Brooks W, Carman DS, Casey L, Cole PL, Collins P, Crabb D, Crede V, D'Angelo A, Daniel A, Dashyan N, De Vita R, De Sanctis E, Deur A, Dey B, Dhamija S, Dickson R, Djalali C, Dodge G, Doughty D, Dupre R, El Alaoui A, Eugenio P, Fegan S, Fersch R, Forest TA, Fradi A, Gabrielyan MY, Gavalian G, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Girod FX, Gohn W, Gothe RW, Griffioen KA, Guidal M, Guler N, Guo L, Hafidi K, Hakobyan H, Hanretty C, Hassall N, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jawalkar SS, Jo HS, Joo K, Keller D, Khandaker M, Khetarpal P, Kim W, Klein A, Klein FJ, Konczykowski P, Kubarovsky V, Kuhn SE, Kuleshov SV, Kuznetsov V, Livingston K, Lu HY, Markov N, Mayer M, Martinez D, McAndrew J, McCracken ME, McKinnon B, Meyer CA, Mineeva T, Mirazita M, Mokeev V, Moreno B, Moriya K, Morrison B, Moutarde H, Munevar E, Nadel-Turonski P, Nasseripour R, Niccolai S, Niculescu G, Niculescu I, Niroula MR, Osipenko M, Ostrovidov AI, Paremuzyan R, Park K, Park S, Pasyuk E, Pereira SA, Perrin Y, Pisano S, Pogorelko O, Price JW, Procureur S, Prok Y, Protopopescu D, Raue BA, Ricco G, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salamanca J, Salgado C, Schumacher RA, Seder E, Seraydaryan H, Sharabian YG, Sober DI, Sokhan D, Stepanyan SS, Stepanyan S, Stoler P, Strauch S, Suleiman R, Taiuti M, Tedeschi DJ, Tkachenko S, Ungaro M, Vernarsky B, Vineyard MF, Voutier E, Watts DP, Weinstein LB, Weygand DP, Wood MH, Zhang J, Zhao B, and Zhao ZW
Abstract: We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes ϕ have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin2ϕ single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.
Published: 2010
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45. Absorption of the ω and ϕ mesons in nuclei.

Author: Wood MH, Nasseripour R, Paolone M, Djalali C, Weygand DP, Adhikari KP, Anghinolfi M, Ball J, Battaglieri M, Batourine V, Bedlinskiy I, Bellis M, Berman BL, Biselli AS, Branford D, Briscoe WJ, Brooks WK, Burkert VD, Careccia SL, Carman DS, Cole PL, Collins P, Crede V, D'Angelo A, Daniel A, De Vita R, De Sanctis E, Deur A, Dey B, Dhamija S, Dickson R, Doughty D, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Eugenio P, Fegan S, Gabrielyan MY, Garçon M, Gilfoyle GP, Giovanetti KL, Girod FX, Goetz JT, Gohn W, Gothe RW, Graham L, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Hassall N, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Ishkhanov BS, Jawalkar SS, Jo HS, Joo K, Keller D, Khandaker M, Khetarpal P, Kim A, Kim W, Klein A, Klein FJ, Konczykowski P, Kubarovsky V, Kuleshov SV, Kuznetsov V, Livingston K, Martinez D, Mayer M, McAndrew J, McCracken ME, McKinnon B, Meyer CA, Mineeva T, Mirazita M, Mokeev V, Moreno B, Moriya K, Morrison B, Munevar E, Nadel-Turonski P, Ni A, Niccolai S, Niculescu G, Niculescu I, Niroula MR, Osipenko M, Ostrovidov AI, Paremuzyan R, Park K, Park S, Pasyuk E, Anefalos Pereira S, Pisano S, Pogorelko O, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Raue BA, Ricco G, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salamanca J, Salgado C, Schott D, Schumacher RA, Seder E, Seraydaryan H, Sharabian YG, Smith GD, Sober DI, Sokhan D, Stepanyan S, Stepanyan SS, Stoler P, Strakovsky II, Strauch S, Taiuti M, Tang W, Taylor CE, Tedeschi DJ, Tkachenko S, Ungaro M, Vernarsky B, Vineyard MF, Voutier E, Watts DP, Weinstein LB, Zhang J, Zhao B, and Zhao ZW
Abstract: Because of their long lifetimes, the ω and ϕ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e+e- channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the ω meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.
Published: 2010
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46. Measurement of the differential cross section for the reaction gamman-->pi- p from deuterium.

Author: Chen W, Mibe T, Dutta D, Gao H, Laget JM, Mirazita M, Rossi P, Stepanyan S, Strakovsky II, Amaryan MJ, Anghinolfi M, Bagdasaryan H, Battaglieri M, Bellis M, Berman BL, Biselli AS, Bookwalter C, Branford D, Briscoe WJ, Brooks WK, Burkert VD, Careccia SL, Carman DS, Casey L, Cole PL, Collins P, Crede V, Daniel A, Dashyan N, De Vita R, De Sanctis E, Deur A, Dhamija S, Dickson R, Djalali C, Dodge GE, Doughty D, Egiyan H, Eugenio P, Fedotov G, Fradi A, Garçon M, Gilfoyle GP, Giovanetti KL, Girod FX, Gohn W, Gothe RW, Griffioen KA, Guidal M, Hakobyan H, Hanretty C, Hassall N, Heddle D, Hicks K, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jo HS, Johnstone JR, Joo K, Keller D, Khandaker M, Khetarpal P, Kim W, Klein A, Klein FJ, Kramer LH, Kubarovsky V, Kuhn SE, Kuleshov SV, Kuznetsov V, Livingston K, Lu HY, Markov N, McCracken ME, McKinnon B, Meyer CA, Mineeva T, Mokeev V, Moreno B, Moriya K, Nadel-Turonski P, Nasseripour R, Niccolai S, Niculescu I, Niroula MR, Osipenko M, Ostrovidov AI, Park K, Park S, Pereira SA, Pogorelko O, Pozdniakov S, Price JW, Procureur S, Protopopescu D, Raue BA, Ricco G, Ripani M, Ritchie BG, Rosner G, Sabatié F, Saini MS, Salamanca J, Salgado C, Schumacher RA, Sharabian YG, Sober DI, Sokhan D, Stepanyan SS, Strauch S, Taiuti M, Tedeschi DJ, Tkachenko S, Ungaro M, Vineyard MF, Watts DP, Weinstein LB, Weygand DP, Wood MH, Yegneswaran A, Zhang J, and Zhao B
Abstract: We report a measurement of the differential cross section for the gamman-->pi- p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (thetac.m.) between 50 degrees and 115 degrees. We confirm a previous indication of a broad enhancement around a c.m. energy ([sqrt]s) of 2.1 GeV at thetac.m.=90 degrees in the scaled differential cross section s7dsigma/dt and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for thetac.m. from 70 degrees to 105 degrees.
Published: 2009
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47. Precise measurement of the neutron magnetic form factor G(M)n in the few-GeV2 region.

Author: Lachniet J, Afanasev A, Arenhövel H, Brooks WK, Gilfoyle GP, Higinbotham D, Jeschonnek S, Quinn B, Vineyard MF, Adams G, Adhikari KP, Amaryan MJ, Anghinolfi M, Asavapibhop B, Asryan G, Avakian H, Bagdasaryan H, Baillie N, Ball JP, Baltzell NA, Barrow S, Batourine V, Battaglieri M, Beard K, Bedlinskiy I, Bektasoglu M, Bellis M, Benmouna N, Berman BL, Biselli AS, Bonner BE, Bookwalter C, Bouchigny S, Boiarinov S, Bradford R, Branford D, Briscoe WJ, Bültmann S, Burkert VD, Calarco JR, Careccia SL, Carman DS, Casey L, Cheng L, Cole PL, Coleman A, Collins P, Cords D, Corvisiero P, Crabb D, Crede V, Cummings JP, Dale D, Daniel A, Dashyan N, De Masi R, De Vita R, De Sanctis E, Degtyarenko PV, Denizli H, Dennis L, Deur A, Dhamija S, Dharmawardane KV, Dhuga KS, Dickson R, Djalali C, Dodge GE, Doughty D, Dragovitsch P, Dugger M, Dytman S, Dzyubak OP, Egiyan H, Egiyan KS, El Fassi L, Elouadrhiri L, Empl A, Eugenio P, Fatemi R, Fedotov G, Fersch R, Feuerbach RJ, Forest TA, Fradi A, Gabrielyan MY, Garçon M, Gavalian G, Gevorgyan N, Giovanetti KL, Girod FX, Goetz JT, Gohn W, Golovatch E, Gothe RW, Graham L, Griffioen KA, Guidal M, Guillo M, Guler N, Guo L, Gyurjyan V, Hadjidakis C, Hafidi K, Hakobyan H, Hanretty C, Hardie J, Hassall N, Heddle D, Hersman FW, Hicks K, Hleiqawi I, Holtrop M, Hu J, Huertas M, Hyde-Wright CE, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Ito MM, Jenkins D, Jo HS, Johnstone JR, Joo K, Juengst HG, Kageya T, Kalantarians N, Keller D, Kellie JD, Khandaker M, Khetarpal P, Kim KY, Kim K, Kim W, Klein A, Klein FJ, Klusman M, Konczykowski P, Kossov M, Kramer LH, Kubarovsky V, Kuhn J, Kuhn SE, Kuleshov SV, Kuznetsov V, Laget JM, Langheinrich J, Lawrence D, Lima AC, Livingston K, Lowry M, Lu HY, Lukashin K, Maccormick M, Malace S, Manak JJ, Markov N, Mattione P, McAleer S, McCracken ME, McKinnon B, McNabb JW, Mecking BA, Mestayer MD, Meyer CA, Mibe T, Mikhailov K, Mineeva T, Minehart R, Mirazita M, Miskimen R, Mokeev V, Moreno B, Moriya K, Morrow SA, Moteabbed M, Mueller J, Munevar E, Mutchler GS, Nadel-Turonski P, Nasseripour R, Niccolai S, Niculescu G, Niculescu I, Niczyporuk BB, Niroula MR, Niyazov RA, Nozar M, O'Rielly GV, Osipenko M, Ostrovidov AI, Park K, Park S, Pasyuk E, Paterson C, Pereira SA, Philips SA, Pierce J, Pivnyuk N, Pocanic D, Pogorelko O, Polli E, Popa I, Pozdniakov S, Preedom BM, Price JW, Prok Y, Protopopescu D, Qin LM, Raue BA, Riccardi G, Ricco G, Ripani M, Ritchie BG, Rosner G, Rossi P, Rowntree D, Rubin PD, Sabatié F, Saini MS, Salamanca J, Salgado C, Sandorfi A, Santoro JP, Sapunenko V, Schott D, Schumacher RA, Serov VS, Sharabian YG, Sharov D, Shaw J, Shvedunov NV, Skabelin AV, Smith ES, Smith LC, Sober DI, Sokhan D, Starostin A, Stavinsky A, Stepanyan S, Stepanyan SS, Stokes BE, Stoler P, Stopani KA, Strakovsky II, Strauch S, Suleiman R, Taiuti M, Taylor S, Tedeschi DJ, Thompson R, Tkabladze A, Tkachenko S, Ungaro M, Vlassov AV, Watts DP, Wei X, Weinstein LB, Weygand DP, Williams M, Wolin E, Wood MH, Yegneswaran A, Yun J, Yurov M, Zana L, Zhang J, Zhao B, and Zhao ZW
Abstract: The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.
Published: 2009
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48. Measurement of direct f0(980) photoproduction on the proton.

Author: Battaglieri M, De Vita R, Szczepaniak AP, Adhikari KP, Aghasyan M, Amaryan MJ, Ambrozewicz P, Anghinolfi M, Asryan G, Avakian H, Bagdasaryan H, Baillie N, Ball JP, Baltzell NA, Batourine V, Bedlinskiy I, Bellis M, Benmouna N, Berman BL, Bibrzycki L, Biselli AS, Bookwalter C, Bouchigny S, Boiarinov S, Bradford R, Branford D, Briscoe WJ, Brooks WK, Bültmann S, Burkert VD, Calarco JR, Careccia SL, Carman DS, Casey L, Chen S, Cheng L, Clinton E, Cole PL, Collins P, Crabb D, Crannell H, Crede V, Cummings JP, Dale D, Daniel A, Dashyan N, De Masi R, De Sanctis E, Degtyarenko PV, Deur A, Dhamija S, Dharmawardane KV, Dickson R, Djalali C, Dodge GE, Donnelly J, Doughty D, Dugger M, Dzyubak OP, Egiyan H, Egiyan KS, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fersch R, Forest TA, Fradi A, Gabrielyan MY, Gan L, Garçon M, Gasparian A, Gavalian G, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Girod FX, Glamazdin O, Goett J, Goetz JT, Gohn W, Golovatch E, Gordon CI, Gothe RW, Graham L, Griffioen KA, Guidal M, Guler N, Guo L, Gyurjyan V, Hadjidakis C, Hafidi K, Hakobyan H, Hakobyan RS, Hanretty C, Hardie J, Hassall N, Heddle D, Hersman FW, Hicks K, Hleiqawi I, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Ito MM, Jenkins D, Jo HS, Johnstone JR, Joo K, Juengst HG, Kageya T, Kalantarians N, Keller D, Kellie JD, Khandaker M, Khetarpal P, Kim W, Klein A, Klein FJ, Klimenko AV, Konczykowski P, Kossov M, Krahn Z, Kramer LH, Kubarovsky V, Kuhn J, Kuhn SE, Kuleshov SV, Kuznetsov V, Lachniet J, Laget JM, Langheinrich J, Lawrence D, Lee T, Lesniak L, Li J, Livingston K, Lowry M, Lu HY, Maccormick M, Malace S, Markov N, Mattione P, McCracken ME, McKinnon B, Mecking BA, Melone JJ, Mestayer MD, Meyer CA, Mibe T, Mikhailov K, Mineeva T, Minehart R, Mirazita M, Miskimen R, Mochalov V, Mokeev V, Moreno B, Moriya K, Morrow SA, Moteabbed M, Munevar E, Mutchler GS, Nadel-Turonski P, Nakagawa I, Nasseripour R, Niccolai S, Niculescu G, Niculescu I, Niczyporuk BB, Niroula MR, Niyazov RA, Nozar M, Osipenko M, Ostrovidov AI, Park K, Park S, Pasyuk E, Paris M, Paterson C, Pereira SA, Pierce J, Pivnyuk N, Pocanic D, Pogorelko O, Pozdniakov S, Price JW, Prok Y, Protopopescu D, Raue BA, Riccardi G, Ricco G, Ripani M, Ritchie BG, Rosner G, Rossi P, Sabatié F, Saini MS, Salamanca J, Salgado C, Sandorfi A, Santoro JP, Sapunenko V, Schott D, Schumacher RA, Serov VS, Sharabian YG, Sharov D, Shvedunov NV, Smith ES, Smith LC, Sober DI, Sokhan D, Starostin A, Stavinsky A, Stepanyan S, Stepanyan SS, Stokes BE, Stoler P, Stopani KA, Strakovsky II, Strauch S, Taiuti M, Tedeschi DJ, Teymurazyan A, Tkabladze A, Tkachenko S, Todor L, Tur C, Ungaro M, Vineyard MF, Vlassov AV, Watts DP, Wei X, Weinstein LB, Weygand DP, Williams M, Wolin E, Wood MH, Yegneswaran A, Yurov M, Zana L, Zhang J, Zhao B, and Zhao ZW
Abstract: We report on the results of the first measurement of exclusive f_{0}(980) meson photoproduction on protons for E_{gamma}=3.0-3.8 GeV and -t=0.4-1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the pi;{+}pi;{-} channel by performing a partial wave analysis of the reaction gammap-->ppi;{+}pi;{-}. Clear evidence of the f_{0}(980) meson was found in the interference between P and S waves at M_{pi;{+}pi;{-}} approximately 1 GeV. The S-wave differential cross section integrated in the mass range of the f_{0}(980) was found to be a factor of about 50 smaller than the cross section for the rho meson. This is the first time the f_{0}(980) meson has been measured in a photoproduction experiment.
Published: 2009
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49. Search for the photoexcitation of exotic mesons in the pi+pi+pi- system.

Author: Nozar M, Salgado C, Weygand DP, Guo L, Adams G, Li J, Eugenio P, Amaryan MJ, Anghinolfi M, Asryan G, Avakian H, Bagdasaryan H, Baillie N, Ball JP, Baltzell NA, Barrow S, Battaglieri M, Bedlinskiy I, Bektasoglu M, Bellis M, Benmouna N, Berman BL, Biselli AS, Blaszczyk L, Bonner BE, Bouchigny S, Boiarinov S, Bradford R, Branford D, Briscoe WJ, Brooks WK, Bültmann S, Burkert VD, Butuceanu C, Calarco JR, Careccia SL, Carman DS, Carnahan B, Casey L, Cazes A, Chen S, Cheng L, Cole PL, Collins P, Coltharp P, Cords D, Corvisiero P, Crabb D, Crannell H, Crede V, Cummings JP, Dale D, Dashyan N, De Masi R, De Vita R, De Sanctis E, Degtyarenko PV, Denizli H, Dennis L, Deur A, Dharmawardane KV, Dhuga KS, Dickson R, Djalali C, Dodge GE, Doughty D, Dugger M, Dytman S, Dzyubak OP, Egiyan H, Egiyan KS, El Fassi L, Elouadrhiri L, Fatemi R, Fedotov G, Feuerbach RJ, Forest TA, Fradi A, Funsten H, Garçon M, Gavalian G, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Girod FX, Goetz JT, Gothe RW, Griffioen KA, Guidal M, Guillo M, Guler N, Gyurjyan V, Hadjidakis C, Hafidi K, Hakobyan H, Hanretty C, Hardie J, Hassall N, Heddle D, Hersman FW, Hicks K, Hleiqawi I, Holtrop M, Hyde-Wright CE, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Ito MM, Jenkins D, Jo HS, Johnstone JR, Joo K, Juengst HG, Kalantarians N, Kellie JD, Khandaker M, Kim W, Klein A, Klein FJ, Kossov M, Krahn Z, Kramer LH, Kubarovsky V, Kuhn J, Kuhn SE, Kuleshov SV, Kuznetsov V, Lachniet J, Laget JM, Langheinrich J, Lawrence D, Livingston K, Lu HY, Maccormick M, Markov N, Mattione P, McAleer S, McKinnon B, McNabb JW, Mecking BA, Mehrabyan S, Mestayer MD, Meyer CA, Mibe T, Mikhailov K, Mirazita M, Miskimen R, Mokeev V, Moreno B, Moriya K, Morrow SA, Moteabbed M, Mueller J, Munevar E, Mutchler GS, Nadel-Turonski P, Nasseripour R, Niccolai S, Niculescu G, Niculescu I, Niczyporuk BB, Niroula MR, Niyazov RA, O'Rielly GV, Osipenko M, Ostrovidov AI, Park K, Pasyuk E, Paterson C, Anefalos Pereira S, Philips SA, Pierce J, Pivnyuk N, Pocanic D, Pogorelko O, Polli E, Popa I, Pozdniakov S, Preedom BM, Price JW, Prok Y, Protopopescu D, Qin LM, Raue BA, Riccardi G, Ricco G, Ripani M, Ritchie BG, Ronchetti F, Rosner G, Rossi P, Rubin PD, Sabatié F, Salamanca J, Santoro JP, Sapunenko V, Schumacher RA, Serov VS, Sharabian YG, Sharov D, Shvedunov NV, 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 M, Tedeschi DJ, Thoma U, Tkabladze A, Tkachenko S, Todor L, Ungaro M, Vineyard MF, Vlassov AV, Watts DP, Weinstein LB, Williams M, Wolin E, Wood MH, Yegneswaran A, Zana L, Zhang J, Zhao B, and Zhao ZW
Abstract: A search for exotic mesons in the pi;{+}pi;{+}pi;{-} system photoproduced by the charge exchange reaction gammap-->pi;{+}pi;{+}pi;{-}(n) was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83 000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the photoproduction of an exotic J;{PC}=1;{-+} resonant state in the 1 to 2 GeV mass range. Our partial wave analysis shows production of the a_{2}(1320) and the pi_{2}(1670) mesons, but no evidence for the a_{1}(1260), nor the pi_{1}(1600) exotic state at the expected levels. An upper limit of 13.5 nb is determined for the exotic pi_{1}(1600) cross section, less than 2% of the a_{2}(1320) production.
Published: 2009
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50. Measurement of deeply virtual compton scattering beam-spin asymmetries.

Author: Girod FX, Niyazov RA, Avakian H, Ball J, Bedlinskiy I, Burkert VD, De Masi R, Elouadrhiri L, Garçon M, Guidal M, Jo HS, Joo K, Kubarovsky V, Kuleshov SV, MacCormick M, Niccolai S, Pogorelko O, Sabatié F, Stepanyan S, Stoler P, Ungaro M, Zhao B, Amaryan MJ, Ambrozewicz P, Anghinolfi M, Asryan G, Bagdasaryan H, Baillie N, Ball JP, Baltzell NA, Batourine V, Battaglieri M, Bellis M, Benmouna N, Berman BL, Biselli AS, Blaszczyk L, Bouchigny S, Boiarinov S, Bradford R, Branford D, Briscoe WJ, Brooks WK, Bültmann S, Butuceanu C, Calarco JR, Careccia SL, Carman DS, Casey L, Chen S, Cheng L, Cole PL, Collins P, Coltharp P, Crabb D, Crede V, Dashyan N, De Sanctis E, De Vita R, Degtyarenko PV, Deur A, Dharmawardane KV, Dickson R, Djalali C, Dodge GE, Donnelly J, Doughty D, Dugger M, Dzyubak OP, Egiyan H, Egiyan KS, El Fassi L, Eugenio P, Fedotov G, Feldman G, Funsten H, Gavalian G, Gilfoyle GP, Giovanetti KL, Goetz JT, Gonenc A, Gothe RW, Griffioen KA, Guler N, Guo L, Gyurjyan V, Hafidi K, Hakobyan H, Hanretty C, Hersman FW, Hicks K, Hleiqawi I, Holtrop M, Hyde CE, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Ito MM, Jenkins D, Johnstone JR, Juengst HG, Kalantarians N, Kellie JD, Khandaker M, Kim W, Klein A, Klein FJ, Klimenko AV, Kossov M, Krahn Z, Kramer LH, Kuhn J, Kuhn SE, Lachniet J, Laget JM, Langheinrich J, Lawrence D, Lee T, Livingston K, Lu HY, Markov N, Mattione P, Mazouz M, McKinnon B, Mecking BA, Mestayer MD, Meyer CA, Mibe T, Michel B, Mikhailov K, Mirazita M, Miskimen R, Mokeev V, Moriya K, Morrow SA, Moteabbed M, Munevar E, Mutchler GS, Nadel-Turonski P, Nasseripour R, Niculescu G, Niculescu I, Niczyporuk BB, Niroula MR, Nozar M, Osipenko M, Ostrovidov AI, Park K, Pasyuk E, Paterson C, Anefalos Pereira S, Pierce J, Pivnyuk N, Pocanic D, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Raue BA, Ricco G, Ripani M, Ritchie BG, Rosner G, Rossi P, Salamanca J, Salgado C, Santoro JP, Sapunenko V, Schumacher RA, Serov VS, Sharabian YG, Sharov D, Shvedunov NV, Smith ES, Smith LC, Sober DI, Sokhan D, Stavinsky A, Stepanyan SS, Stokes BE, Strakovsky II, Strauch S, Taiuti M, Tedeschi DJ, Tkabladze A, Tkachenko S, Tur C, Vineyard MF, Vlassov AV, Voutier E, Watts DP, Weinstein LB, Weygand DP, Williams M, Wolin E, Wood MH, Yegneswaran A, Zana L, Zhang J, and Zhao ZW
Abstract: The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (e p-->epgamma) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (x(B) from 0.11 to 0.58, Q2 from 1 to 4.8 GeV2, -t from 0.09 to 1.8 GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A approximately a sinphi/(1+c cosphi). This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.
Published: 2008
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