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1. Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

Author: Accardi, A., Achenbach, P., Adhikari, D., Afanasev, A., Akondi, C.S., Akopov, N., Albaladejo, M., Albataineh, H., Albrecht, M., Almeida-Zamora, B., Amaryan, M., Androić, D., Armstrong, W., Armstrong, D.S., Arratia, M., Arrington, J., Asaturyan, A., Austregesilo, A., Avagyan, H., Averett, T., Ayerbe Gayoso, C., Bacchetta, A., Balantekin, A.B., Baltzell, N., Barion, L., Barry, P.C., Bashir, A., Battaglieri, M., Bellini, V., Belov, I., Benhar, O., Benkel, B., Benmokhtar, F., Bentz, W., Bertone, V., Bhatt, H., Bianconi, A., Bibrzycki, L., Bijker, R., Binosi, D., Biswas, D., Boër, M., Boeglin, W., Bogacz, S.A., Boglione, M., Bondí, M., Boos, E.E., Bosted, P., Bozzi, G., Brash, E.J., Briceño, R.A., Brindza, P.D., Briscoe, W.J., Brodsky, S.J., Brooks, W.K., Burkert, V.D., Camsonne, A., Cao, T., Cardman, L.S., Carman, D.S., Carpinelli, M., Cates, G.D., Caylor, J., Celentano, A., Celiberto, F.G., Cerutti, M., Chang, Lei, Chatagnon, P., Chen, C., Chen, J-P, Chetry, T., Christopher, A., Chudakov, E., Cisbani, E., Cloët, I.C., Cobos-Martinez, J.J., Cohen, E.O., Colangelo, P., Cole, P.L., Constantinou, M., Contalbrigo, M., Costantini, G., Cosyn, W., Cotton, C., Dusa, S. Covrig, Cui, Z.-F., D'Angelo, A., Döring, M., Dalton, M.M., Danilkin, I., Davydov, M., Day, D., De Fazio, F., De Napoli, M., De Vita, R., Dean, D.J., Defurne, M., Deur, M., Devkota, B., Dhital, S., Di Nezza, P., Diefenthaler, M., Diehl, S., Dilks, C., Ding, M., Djalali, C., Dobbs, S., Dupré, R., Dutta, D., Edwards, R.G., Egiyan, H., Ehinger, L., Eichmann, G., Elaasar, M., Elouadrhiri, L., El Alaoui, A., El Fassi, L., Emmert, A., Engelhardt, M., Ent, R., Ernst, D.J., Eugenio, P., Evans, G., Fanelli, C., Fegan, S., Fernández-Ramírez, C., Fernandez, L.A., Fernando, I.P., Filippi, A., Fischer, C.S., Fogler, C., Fomin, N., Frankfurt, L., Frederico, T., Freese, A., Fu, Y., Gamberg, L., Gan, L., Gao, F., Garcia-Tecocoatzi, H., Gaskell, D., Gasparian, A., Gates, K., Gavalian, G., Ghoshal, P.K., Giachino, A., Giacosa, F., Giannuzzi, F., Gilfoyle, G.-P., Girod, F-X, Glazier, D.I., Gleason, C., Godfrey, S., Goity, J.L., Golubenko, A.A., Gonzàlez-Solís, S., Gothe, R.W., Gotra, Y., Griffioen, K., Grocholski, O., Grube, B., Guèye, P., Guo, F.-K., Guo, Y., Guo, L., Hague, T.J., Hammoud, N., Hansen, J.-O., Hattawy, M., Hauenstein, F., Hayward, T., Heddle, D., Heinrich, N., Hen, O., Higinbotham, D.W., Higuera-Angulo, I.M., Hiller Blin, A.N., Hobart, A., Holmberg, D.E., Horn, T., Hoyer, P., Huber, G.M., Hurck, P., Hutauruk, P.T.P., Ilieva, Y., Illari, I., Ireland, D.G., Isupov, E.L., Italiano, A., Jaegle, I., Jarvis, N.S., Jenkins, DJ, Jeschonnek, S., Ji, C-R., Jo, H.S., Jones, M., Jones, R.T., Jones, D.C., Joo, K., Junaid, M., Kageya, T., Kalantarians, N., Karki, A., Karyan, G., Katramatou, A.T., Kay, S.J.D., Kazimi, R., Keith, C.D., Keppel, C., Kerbizi, A., Khachatryan, V., Khanal, A., Khandaker, M., Kim, A., Kinney, E.R., Kohl, M., Kotzinian, A., Kriesten, B.T., Kubarovsky, V., Kubis, B., Kuhn, S.E., Kumar, V., Kutz, T., Leali, M., Lebed, R.F., Lenisa, P., Leskovec, L., Li, S., Li, X., Liao, J., Lin, H.-W., Liu, L., Liuti, S., Liyanage, N., Lu, Y., MacGregor, I.J.D., Mack, D.J., Maiani, L., Mamo, K.A., Mandaglio, G., Mariani, C., Markowitz, P., Marukyan, H., Mascagna, V., Mathieu, V., Maxwell, J., Mazouz, M., McCaughan, M., McKeown, R.D., McKinnon, B., Meekins, D., Melnitchouk, W., Meyer, C.A., Meziani, Z.-E., Mezrag, C., Michaels, R., Miller, G.A., Mineeva, T., Miramontes, A.S., Mirazita, M., Mizutani, K., Mkrtchyan, H., Mkrtchyan, A., Moffit, B., Mohanmurthy, P., Mokeev, V.I., Monaghan, P., Montaña, G., Montgomery, R., Moretti, A., Chàvez, J.M. Morgado, Mosel, U., Movsisyan, A., Musico, P., Nadeeshani, S.A., Nakamura, S.X., Nazeer, J., Nefediev, A.V., Neupane, K., Nguyen, D., Niccolai, S., Niculescu, I., Niculescu, G., Nocera, E.R., Nycz, M., Olness, F.I., Ortega, P.G., Osipenko, M., Pace, E., Pandey, B., Pandey, P., Papandreou, Z., Papavassiliou, J., Pappalardo, L.L., Paredes-Torres, G., Paremuzyan, R., Park, S., Parsamyan, B., Paschke, K.D., Pasquini, B., Passemar, E., Pasyuk, E., Patel, T., Paudel, C., Paul, S.J., Peng, J-C., Pentchev, L., Perrino, R., Perry, R.J., Peters, K., Petratos, G.G., Piasetzky, E., Pilloni, A., Pire, B., Pitonyak, D., Pitt, M.L., Polosa, A.D., Pospelov, M., Postuma, A.C., Poudel, J., Preet, L., Prelovsek, S., Price, J.W., Prokudin, A., Puckett, A.J.R., Pybus, J.R., Qin, S.-X., Qiu, J.-W., Radici, M., Rashidi, H., Rathnayake, A.D., Raue, B.A., Reed, T., Reimer, P.E., Reinhold, J., Richard, J.-M., Rinaldi, M., Ringer, F., Ripani, M., Ritman, J., Rittenhouse West, J., Rivero-Acosta, A., Roberts, C.D., Rodas, A., Rodini, S., Rodríguez-Quintero, J., Rogers, T.C., Rojo, J., Rossi, P., Rossi, G.C., Salmè, G., Santiesteban, S.N., Santopinto, E., Sargsian, M., Sato, N., Schadmand, S., Schmidt, A., Schmidt, S.M., Schnell, G., Schumacher, R.A., Schweitzer, P., Scimemi, I., Scott, K.C., Seay, D.A., Segovia, J., Semenov-Tian-Shansky, K., Seryi, A., Sharda, A.S., Shepherd, M.R., Shirokov, E.V., Shrestha, S., Shrestha, U., Signori, A., Slifer, K.J., Smith, W.A., Somov, A., Souder, P., Sparveris, N., Spizzo, F., Spreafico, M., Stepanyan, S., Stevens, J.R., Strakovsky, I.I., Strauch, S., Strikman, M., Su, S., Sumner, B.C.L., Sun, E., Suresh, M., Sutera, C., Swanson, E.S., Szczepaniak, A.P., Sznajder, P., Szumila-Vance, H., Szymanowski, L., Tadepalli, A.-S., Tadevosyan, V., Tamang, B., Tarasov, V.V., Thiel, A., Tong, X.-B., Tyson, R., Ungaro, M., Urciuoli, G.M., Usman, A., Valcarce, A., Vallarino, S., Vaquera-Araujo, C.A., Venturelli, L., Vera, F., Vladimirov, A., Vossen, A., Wagner, J., Wei, X., Weinstein, L.B., Weiss, C., Williams, R., Winney, D., Wojtsekhowski, B., Wood, M.H., Xiao, T., Xu, S.-S., Ye, Z., Yero, C., Yurov, M., Zachariou, N., Zhang, Z., Zhao, Z.W., Zhao, Y., Zheng, X., Zhou, X., Ziegler, V., Zihlmann, B., de Paula, W., de Téramond, G.F., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), National Center for Nuclear Research [Warsaw] (NCBJ), and National Center for Nuclear Research (NCBJ)
Subjects: nucl-th, Nuclear Theory, hep-ex, FOS: Physical sciences, hep-ph, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Nuclear Physics - Theory, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, Particle Physics - Experiment, Particle Physics - Phenomenology
Abstract: This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena.
Published: 2023

2. Measurement of Spin-Density Matrix Elements in $ρ(770)$ Production with a Linearly Polarized Photon Beam at $E_γ= 8.2\,-\,8.8\,\text{GeV}$

Author: Adhikari, S., Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Byer, D., Chudakov, E., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Edo, M., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hague, T. J., Hakobyan, H., Hernandez, J., Hoffman, N. D., Hornidge, D., Hou, G., Huber, G. M., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Ma, R., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Ng, L., Nissen, E., Orešić, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, S., Somov, A., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhao, Z., Zhou, X., Zhou, J., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized $8.5\,\text{GeV}$ photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson $ρ$(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of $s$-channel helicity conservation at small squared four-momentum transfer $t$ and are able to extract the $t$-dependence of natural and unnatural-parity exchange contributions to the production process in detail. We confirm the dominance of natural-parity exchange over the full $t$ range. We also find that helicity amplitudes in which the helicity of the incident photon and the photoproduced $ρ(770)$ differ by two units are negligible for $-t, 15 pages, 11 figures
Published: 2023
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3. Measurement of the J/$ψ$ photoproduction cross section over the full near-threshold kinematic region

Author: Adhikari, S., Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Byer, D., Chudakov, E., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hague, T. J., Hakobyan, H., Hernandez, J., Hoffman, N. D., Hornidge, D., Hou, G., Huber, G. M., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Mack, D., Mahmood, A., Martel, P. P., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Ng, L., Nissen, E., Orei, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, S., Somov, A., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhao, Z., Zhou, X., Zhou, J., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: We report the total and differential cross sections for $J/ψ$ photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2~GeV up to 11.44~GeV and over the full kinematic range of momentum transfer squared, $t$. Such coverage facilitates the extrapolation of the differential cross sections to the forward ($t = 0$) point beyond the physical region. The forward cross section is used by many theoretical models and plays an important role in understanding $J/ψ$ photoproduction and its relation to the $J/ψ-$proton interaction. These measurements of $J/ψ$ photoproduction near threshold are also crucial inputs to theoretical models that are used to study important aspects of the gluon structure of the proton, such as the gluon Generalized Parton Distribution (GPD) of the proton, the mass radius of the proton, and the trace anomaly contribution to the proton mass. We observe possible structures in the total cross section energy dependence and find evidence for contributions beyond gluon exchange in the differential cross section close to threshold, both of which are consistent with contributions from open-charm intermediate states., 15 pages 18 figures
Published: 2023
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4. Search for photoproduction of axionlike particles at GlueX

Author: GlueX Collaboration, Adhikari, S., Akondi, C. S., Albrecht, M., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Chudakov, E., Cole, S., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hagen, M., Hakobyan, H., Hamdi, A., Hernandez, J., Hoffman, N. D., Hou, G., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Luckas, K., Lyubovitskij, V., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Yoon, S., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, X., and Zihlmann, B.
Subjects: Astrophysics::High Energy Astrophysical Phenomena, фотоны, FOS: Physical sciences, глюоны, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), ddc:530, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, протон-протонные столкновения, аксионоподобные частицы
Abstract: We present a search for axion-like particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\to\gamma\gamma$ and $a\to\pi^+\pi^-\pi^0$ decays, and a data sample corresponding to an integrated luminosity of 168 pb$^{-1}$ collected with the GlueX detector. The search for $a\to\gamma\gamma$ decays is performed in the mass range of $180 < m_a < 480$ MeV, while the search for $a\to\pi^+\pi^-\pi^0$ decays explores the $600 < m_a < 720$ MeV region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered., Comment: 8 pages, 4 figures, 2 tables; updated to published version
Published: 2022
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5. Studying Short-Range Correlations with Real Photon Beams at GlueX

Author: Hen, O., Patsyuk, M., Piasetzky, E., Schmidt, A., Somov, A., Szumila-Vance, H., Weinstein, L. B., Dutta, D., Gao, H., Amaryan, M., Ashkenazi, A., Beck, A., Berdnikov, V., Black, T., Briscoe, W. J., Britton, T., Brooks, W., Cruz-Torres, R., Dalton, M. M., Denniston, A., Deur, A., Egiyan, H., Fanelli, C., Fegan, S., Furletov, S., Gan, L., Guo, L., Hauenstein, F., Haykobyan, H., Higinbotham, D. W., Ireland, D. G., Johansson, G., Kamel, M., Korover, I., Kuleshov, S., Lawrence, D., Livingston, K., Mack, D., Marukyan, H., McCaughan, M., Mckinnon, B., Meytal-Beck, S., Nerline, F., Nguyen, D., Papadopoulou, A., Pauli, P., Pedroni, R., Pentchev, L., Pybus, J. R., Ratliff, S., Romanov, D., Romera, C., Salgado, C., Schmookler, B., Segarra, E. P., Seroka, E., Sharp, P., Somov, S., Strakovsky, I. I., Taylor, S., Thiel, A., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The past few years has seen tremendous progress in our understanding of short-range correlated (SRC) pairing of nucleons within nuclei, much of it coming from electron scattering experiments leading to the break-up of an SRC pair. The interpretation of these experiments rests on assumptions about the mechanism of the reaction. These assumptions can be directly tested by studying SRC pairs using alternate probes, such as real photons. We propose a 30-day experiment using the Hall D photon beam, nuclear targets, and the GlueX detector in its standard configuration to study short-range correlations with photon-induced reactions. Several different reaction channels are possible, and we project sensitivity in most channels to equal or exceed the 6 GeV-era SRC experiments from Halls A and B. The proposed experiment will therefore decisively test the phenomena of np dominance, the short-distance NN interaction, and reaction theory, while also providing new insight into bound nucleon structure and the onset of color transparency., Comment: 38 pages, 26 figures, proposal for Jefferson Lab Experiment E12-19-003, submitted to Jefferson Lab PAC 47 (2019)
Published: 2020
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6. Measurement of beam asymmetry for $��^-��^{++}$ photoproduction on the proton at $E_��$=8.5 GeV

Author: GlueX Collaboration, Adhikari, S., Akondi, C. S., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Luckas, K., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schumacher, R. A., Schwiening, J., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, Q., Zhou, X., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report a measurement of the $��^-$ photoproduction beam asymmetry for the reaction $\vec�� p \rightarrow ��^- ��^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $��$ is measured as a function of four-momentum transfer $t$ to the $��^{++}$ and compared to phenomenological models. We find that $��$ varies as a function of $t$: negative at smaller values and positive at higher values of $|t|$. The reaction can be described theoretically by $t$-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy., 7 pages, 5 figures
Published: 2020
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7. Measurement of the Photon Beam Asymmetry in $\vec�� p\to K^+��^0$ at $E_�� = 8.5$ GeV

Author: The GlueX Collaboration, Adhikari, S., Ali, A., Amaryan, M., Austregesilo, A., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Nerling, F., Ng, L., Ni, H., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhou, Q., Zhou, X., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report measurements of the photon beam asymmetry $��$ for the reaction $\vec�� p\to K^+��^0$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $��$ was measured as a function of the Mandelstam variable $t$, and a single value of $��$ was extracted for events produced in the $u$-channel. These are the first exclusive measurements of the photon beam asymmetry $��$ for the reaction in this energy range. For the $t$-channel, the measured beam asymmetry is close to unity over the $t$-range studied, $-t=(0.1-1.4)~$(GeV/$c$)$^{2}$, with an average value of $��= 1.00\pm 0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the $K^{*}$(892) Regge trajectory. A value of $��= 0.41 \pm 0.09$ is obtained for the $u$-channel integrated up to $-u=2.0$~(GeV/$c$)$^{2}$.
Published: 2020
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8. Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons

Author: Airapetian, A., Akopov, N., Bryzgalov, V., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Akopov, Z., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Frullani, S., Gavrilov, G., Gharibyan, V., Aschenauer, E. C., Giordano, F., Gliske, S., Hasch, D., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Augustyniak, W., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lorenzon, W., Avakian, R., Ma, B.-Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Mussgiller, A., Avetissian, A., Naryshkin, Y., Nass, A., Nazaryan, G., Nowak, W.-D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Belostotski, S., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T.-A., Statera, M., Blok, H. P., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Borissov, A., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, Christian, Wang, S., Yaschenko, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, and Student Lab and Education
Subjects: Proton, charged-lepton interactions with hadrons, media_common.quotation_subject, Particle interactions, HELICITY, Hadron, Nuclear Theory, Socio-culturale, FOS: Physical sciences, Strong interaction, Polarization in interactions &amp, 01 natural sciences, 7. Clean energy, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Pion, Strong interaction, Particle interactions, Deep inelastic scattering, Photon & charged-lepton interactions with hadrons, Polarization in interactions & scattering, Quantum chromodynamics, 0103 physical sciences, DISTRIBUTIONS, ddc:530, SDG 7 - Affordable and Clean Energy, valence, 010306 general physics, Nuclear Experiment, media_common, Physics, 010308 nuclear & particles physics, Scattering, polarized quark distributions, scattering, nucleon, electroproduction, Deep inelastic scattering, Helicity, Photon &amp, High Energy Physics - Phenomenology, Physics and Astronomy, helicity distributions, High Energy Physics::Experiment, Nucleon, Quantum chromodynamics, azimuthal dependence
Abstract: A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks. We gratefully acknowledge the DESY management for its support, the staff at DESY and the collaborating institutions for their significant effort. This work was supported by the State Committee of Science of the Republic of Armenia, Grant No. 18T-1C180; the FWO-Flanders and IWT, Belgium; the Natural Sciences and Engineering Research Council of Canada; the National Natural Science Foundation of China; the Alexander von Humboldt Stiftung, the German Bundesministerium fur Bildung und Forschung (BMBF), and the Deutsche Forschungsgemeinschaft (DFG); the Italian Istituto Nazionale di Fisica Nucleare (INFN); the MEXT, JSPS, and G-COE of Japan; the Dutch Foundation for Fundamenteel Onderzoek der Materie (FOM); the Russian Academy of Science and the Russian Federal Agency for Science and Innovations; the Basque Foundation for Science (IKERBASQUE), the Basque Government, Grant No. IT956-16, and MINECO (Juan de la Cierva), Spain; the U.K. Engineering and Physical Sciences Research Council, the Science and Technology Facilities Council, and the Scottish Universities Physics Alliance; as well as the U.S. Department of Energy (DOE) and the National Science Foundation (NSF).
Published: 2019
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9. First measurement of near-threshold J/$��$ exclusive photoproduction off the proton

Author: The GlueX Collaboration, Ali, A., Amaryan, M., Anassontzis, E. G., Austregesilo, A., Baalouch, M., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gauzshtein, V., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Han, S., Hardin, J., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Kuznetsov, I., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Werthmueller, D., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., and Zihlmann, B.
Subjects: FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report on the measurement of the $��p \rightarrow J/��p$ cross section from $E_��= 11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section $d��/dt$ has an exponential slope of $1.67 \pm 0.39$ GeV$^{-2}$ at $10.7$ GeV average energy. The LHCb pentaquark candidates $P_c^+$ can be produced in the $s$-channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions $\mathcal{B}(P_c^+ \rightarrow J/��p)$ and cross sections $��(��p \to P_c^+)\times\mathcal{B}(P_c^+ \to J/��p) $., 12 pages, 7 figures
Published: 2019
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10. Beam Asymmetry $\mathbf��$ for the Photoproduction of $\mathbf��$ and $\mathbf{��^{\prime}}$ Mesons at $\mathbf{E_��=8.8}$GeV

Author: The GlueX Collaboration, Adhikari, S., Ali, A., Amaryan, M., Austregesilo, A., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Mattione, P., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Staib, M., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report on the measurement of the beam asymmetry $��$ for the reactions $\vec��p\rightarrow p��$ and $\vec��p \rightarrow p��^{\prime}$ from the GlueX experiment, using an 8.2--8.8 GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Lab. These measurements are made as a function of momentum transfer $-t$, with significantly higher statistical precision than our earlier $��$ measurements, and are the first measurements of $��^{\prime}$ in this energy range. We compare the results to theoretical predictions based on $t$--channel quasi-particle exchange. We also compare the ratio of $��_��$ to $��_{��^{\prime}}$ to these models, as this ratio is predicted to be sensitive to the amount of $s\bar{s}$ exchange in the production. We find that photoproduction of both $��$ and $��^{\prime}$ is dominated by natural parity exchange with little dependence on $-t$., 18 pages, 7 figures
Published: 2019
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11. Measurement of the beam asymmetry Σ for π0 and η photoproduction on the proton at Eγ=9 GeV

Author: Al Ghoul, H., Anassontzis, E. G., Austregesilo, A., Barbosa, F., Barnes, A., Beattie, T. D., Bennett, D. W., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Brooks, W. K., Cannon, B. E., Chernyshov, O., Chudakov, E., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Egiyan, H., Eugenio, P., Fanelli, C., Foda, A. M., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gerasimov, A., Gevorgyan, N., Goetzen, K., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kamel, M., Klein, F. J., Kliemt, R., Kourkoumeli, C., Kuleshov, S., Kuznetsov, I., Lara, M., Larin, I., Lawrence, D., Levine, W. I., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Mattione, P. T., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Mendez, R., Meyer, Curtis, Miskimen, R., Mitchell, R. E., Mokaya, F., Moriya, K., Nerling, F., Nigmatkulov, G., Ochoa, N., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pedroni, R., Pennington, M. R., Pentchev, L, Peters, K. J., Pooser, E., Pratt, B., Qiang, Y., Reinhold, J., Ritchie, B. G., Robison, L, Romanov, D., Salgado, C., Schumacher, R. A., Schwarz, C., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Sparks, N., Staib, M. J., Stevens, J. R., Strakovsky, I. I., Subedi, A., Tarasov, V., Taylor, S., Teymurazyan, A., Tolstukhin, I., Tomaradze, A., Toro, A., Tsaris, A., Vasileiadis, G., Vega, I, Walford, N. K., Werthmuller, D., Whitlatch, T., Williams, M., Wolin, E., Xiao, T., Zarling, J., Zhang, Z., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment, 20202 Nuclear Physics, 20203 Particle Physics
Abstract: We report measurements of the photon beam asymmetry Σ for the reactions ⃗γp→pπ0 and ⃗γp→pη from the GlueX experiment using a 9 GeV linearly polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous π0 measurements and are the first η measurements in this energy regime. The results are compared with theoretical predictions based on t-channel, quasiparticle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.
Published: 2017
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12. Measurement of the beam asymmetry $��$ for $��^0$ and $��$ photoproduction on the proton at $E_��= 9$ GeV

Author: GlueX Collaboration, Ghoul, H. Al, Anassontzis, E. G., Austregesilo, A., Barbosa, F., Barnes, A., Beattie, T. D., Bennett, D. W., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Brooks, W. K., Cannon, B. E., Chernyshov, O., Chudakov, E., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Egiyan, H., Eugenio, P., Fanelli, C., Foda, A. M., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gerasimov, A., Gevorgyan, N., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hardin, J., Henderson, A., Huber, G. M., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kamel, M., Klein, F. J., Kliemt, R., Kourkoumeli, C., Kuleshov, S., Kuznetsov, I., Lara, M., Larin, I., Lawrence, D., Levine, W. I., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Mattione, P. T., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Mendez, R., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Moriya, K., Nerling, F., Nigmatkulov, G., Ochoa, N., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pedroni, R., Pennington, M. R., Pentchev, L., Peters, K. J., Pooser, E., Pratt, B., Qiang, Y., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Salgado, C., Schumacher, R. A., Schwarz, C., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Sparks, N., Staib, M. J., Stevens, J. R., Strakovsky, I. I., Subedi, A., Tarasov, V., Taylor, S., Teymurazyan, A., Tolstukhin, I., Tomaradze, A., Toro, A., Tsaris, A., Vasileiadis, G., Vega, I., Walford, N. K., Werthmuller, D., Whitlatch, T., Williams, M., Wolin, E., Xiao, T., Zarling, J., Zhang, Z., Zihlmann, B., Mathieu, V., and Nys, J.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report measurements of the photon beam asymmetry $��$ for the reactions $\vec��p\to p��^0$ and $\vec��p\to p��$ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $��^0$ measurements and are the first $��$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models., 6 pages, 6 figures, Published in Physical Review C: Rapid Communication
Published: 2017
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13. Measurements of the Separated Longitudinal Structure Function F_L from Hydrogen and Deuterium Targets at Low Q^2

Author: Tvaskis, V., Tvaskis, A., Niculescu, I., Abbott, D., Adams, G. S., Afanasev, A., Ahmidouch, A., Angelescu, T., Arrington, J., Asaturyan, R., Avery, S., Baker, O. K., Benmouna, N., Berman, B. L., Biselli, A., Blok, H. P., Boeglin, W. U., Bosted, P. E., Brash, E., Breuer, H., Chang, G., Chant, N., Christy, M. E., Connell, S. H., Dalton, M. M., Danagoulian, S., Day, D., Dodario, T., Dunne, J. A., Dutta, D., Khayari, N. El, Ent, R., Fenker, H. C., Frolov, V. V., Gaskell, D., Garrow, K., Gilman, R., Gueye, P., Hafidi, K., Hinton, W., Holt, R. J., Horn, T., Huber, G. M., Jackson, H., Jiang, X., Jones, M. K., Joo, K., Kelly, J. J., Keppel, C. E., Kuhn, J., Kinney, E., Klein, A., Kubarovsky, V., Liang, M., Liang, Y., Lolos, G., Lung, A., Mack, D., Malace, S., Markowitz, P., Mbianda, G., McGrath, E., Mckee, D., McKee, P., Meekins, D. G., Mkrtchyan, H., Moziak, B., Napolitano, J., Navasardyan, T., Niculescu, G., Nozar, M., Ostapenko, T., Papandreou, Z., Potterveld, D., Reimer, P. E., Reinhold, J., Roche, J., Rock, S. E., Schulte, E., Segbefia, E., Smith, C., Smith, G. R., Stoler, P., Tadevosyan, V., Tang, L., Telfeyan, J., Todor, L., Ungaro, M., Uzzle, A., Vidakovic, S., Villano, A., Vulcan, W. F., Wang, M., Warren, G., Wesselmann, F., Wojtsekhowski, B., Wood, S. A., Xu, C., Yan, C., Yuan, L., Zheng, X., Zihlmann, B., and Zhu, H.
Subjects: High Energy Physics - Experiment (hep-ex), Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract: Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the quark dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available for the longitudinal structure function in particular. Here we present separated structure functions for hydrogen and deuterium at low four--momentum transfer squared, Q^2< 1 GeV^2, and compare these with parton distribution parameterizations and a k_T factorization approach. While differences are found, the parameterizations generally agree with the data even at the very low Q^2 scale of the data. The deuterium data show a smaller longitudinal structure function, and smaller ratio of longitudinal to transverse cross section R, than the proton. This suggests either an unexpected difference in R for the proton and neutron or a suppression of the gluonic distribution in nuclei., 11 pages, 7 figures, 2 data tables
Published: 2016

14. Spin density matrix elements in exclusive rho (0) electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy

Author: Airapetian, A., Akopov, N., Akopov, Z., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetissian, E., Belostotski, S., Bianchi, N., Blok, H. P., Böttcher, H., Bonomo, C., Borissov, A., Brüll, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., Demey, M., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dreschler, J., Düren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Funel, A., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Grebeniouk, O., Gregor, I. M., Guler, H., Hadjidakis, C., Hartig, M., Hasch, D., Hasegawa, T., Hesselink, W. H. A., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Keri, T., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikás, L., Lehmann, I., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, S., Lu, X.-R., Ma, B.-Q., Maiheu, B., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Mexner, V., Miller, C. A., Miyachi, Y., Muccifora, V., Murray, M., Mussgiller, A., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W.-D., Osborne, A., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rock, S. E., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shearer, C., Shibata, T.-A., Shutov, V., Stancari, M., Statera, M., Steffens, J. E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Streit, J., Tait, P., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Van Haarlem, Y., Van Hulse, C., Varanda, M., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Y., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., (Astro)-Particles Physics, Photo Conversion Materials, Network Institute, Student Lab and Education, and Artificial Intelligence (section level)
Subjects: HERMES experiment, Particle physics, Hydrogen, Physics and Astronomy (miscellaneous), FOS: Physical sciences, chemistry.chemical_element, Kinematics, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, SDG 14 - Life Below Water, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous), Physics, 010308 nuclear & particles physics, Polarization (waves), Helicity, Amplitude, Deuterium, chemistry, High Energy Physics::Experiment, Condensed Matter::Strongly Correlated Electrons, Beam energy
Abstract: Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive rho^0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1 GeV^2 < Q^2 < 7 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t < 0.4 GeV^2. Within the given experimental uncertainties, a hierarchy of relative sizes of helicity amplitudes is observed. Kinematic dependences of all SDMEs on Q^2 and t are presented, as well as the longitudinal-to-transverse rho^0 electroproduction cross section ratio as a function of Q^2. A small but statistically significant deviation from the hypothesis of s-channel helicity conservation is observed. An indication is seen of a contribution of unnatural-parity-exchange amplitudes; these amplitudes are naturally generated with a quark-exchange mechanism., 41 pages, 20 figures, 16 table; revised version corrects small typos, text clarified on 6 pages, two references added and new data added to figure 20
Published: 2009

15. Bose–Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon

Author: Airapetian, A., Akopov, N., Blok, H. P., Statera, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Borissov, A., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Akopov, Z., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Aschenauer, E. C., Fantoni, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garay Garcia, Jasone, Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Augustyniak, W., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Avakian, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Avetissian, A., Lehmann, I., Lenisa, P., Ruiz, A. López, Lorenzon, W., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Mao, Y., Marianski, B., Avetisyan, E., Martinez de la Ossa, Alberto, Marukyan, H., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Belostotski, S., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, Anush, Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Bianchi, N., Rubin, J., Ryckbosch, D., Salomatin, Y., Schäfer, A., Schnell, Gunar, Seitz, B., Shibata, T. -A., Shutov, V., Stahl, M., and Stancari, M.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, ddc:530, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract: Bose-Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $^1$H, $^2$H, $^3$He, $^4$He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose-Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose-Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass $W$ of the photon-nucleon system is found when the results are compared to those of previous experiments.
Published: 2015

16. Transverse-target-spin asymmetry in exclusive $��$-meson electroproduction

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avetissian, A., Belostotski, S., Blok, H. P., Borissov, A., Bryzgalov, V., Capitani, G. P., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Elbakian, G., Ellinghaus, F., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Gharibyan, V., Giordano, F., Gliske, S., Hasch, D., Hoek, M., Holler, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miyachi, Y., Movsisyan, A., Muccifora, V., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Seitz, B., Shibata, T. -A., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Yen, S., Zihlmann, B., and Zupranski, P.
Subjects: High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract: Hard exclusive electroproduction of $��$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $��$ transition form factor., DESY Report 15-149
Published: 2015
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17. Pentaquark $��^+$ search at HERMES

Author: The HERMES Collaboration, Akopov, N., Akopov, Z., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Blok, H. P., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Di Nezza, P., Elbakian, G., Etzelm��ller, E., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Garc��a, J. Garay, Garibaldi, F., Gavrilov, G., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Ruiz, A. L��pez, Lorenzon, W., Lu, X., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Nappi, E., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Stancari, M., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Zihlmann, B., and Zupranski, P.
Subjects: High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract: The earlier search at HERMES for narrow baryon states excited in quasi-real photoproduction, decaying through the channel $pK_S^0\rightarrow p��^+��^-$, has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2$��$ for data taken with a deuterium target. The number of events above background is $68_{-31}^{+98}\text{(stat)}\pm13\text{(sys)}$. No such structure is observed in the hydrogen data set.
Published: 2014
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18. Transverse polarization of $��$ hyperons from quasireal photoproduction on nuclei

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Ruiz, A. L��pez, Lorenzon, W., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Sch��fer, A., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yu, W., Zagrebelnyy, V., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: High Energy Physics - Experiment (hep-ex), High Energy Physics::Phenomenology, Nuclear Theory, Physics::Atomic and Molecular Clusters, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The transverse polarization of $��$ hyperons was measured in inclusive quasireal photoproduction for various target nuclei ranging from hydrogen to xenon. The data were obtained by the HERMES experiment at HERA using the 27.6 GeV lepton beam and nuclear gas targets internal to the lepton storage ring. The polarization observed is positive for light target nuclei and is compatible with zero for krypton and xenon., final version to be published in Phys. Rev. D (in press)
Published: 2014
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19. A study of decays to strange final states with GlueX in Hall D using components of the BaBar DIRC

Author: The GlueX Collaboration, Dugger, M., Ritchie, B., Senderovich, I., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Vasileiadis, G., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., McGinley, W., Meyer, C. A., Schumacher, R., Staib, M., Klein, F., Sober, D., Sparks, N., Walford, N., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Boeglin, W., Guo, L., Pooser, E., Reinhold, J., Ghoul, H. Al, Crede, V., Eugenio, P., Ostrovidov, A., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Lara, M., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Chernyshov, O., Dolgolenko, A., Gerasimov, A., Goryachev, V., Larin, I., Matveev, V., Tarasov, V., Barbosa, F., Chudakov, E., Dalton, M., Deur, A., Dudek, J., Egiyan, H., Furletov, S., Ito, M., Mack, D., Lawrence, D., McCaughan, M., Pennington, M., Pentchev, L., Qiang, Y., Smith, E., Somov, A., Taylor, S., Whitlatch, T., Zihlmann, B., Miskimen, R., Guegan, B., Hardin, J., Stevens, J., Williams, M., Berdnikov, V., Nigmatkulov, G., Ponosov, A., Romanov, D., Somov, S., Tolstukhin, I., Salgado, C., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dobbs, S., Seth, K., Ting, X., Tomaradze, A., Beattie, T., Huber, G., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Brooks, W., Hakobyan, H., Kuleshov, S., Soto, O., Toro, A., Vega, I., Gevorgyan, N., and Kakoyan, V.
Subjects: High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, FOS: Physical sciences, High Energy Physics::Experiment, Instrumentation and Detectors (physics.ins-det), High Energy Physics - Experiment
Abstract: We propose to enhance the kaon identification capabilities of the GlueX detector by constructing an FDIRC (Focusing Detection of Internally Reflected Cherenkov) detector utilizing the decommissioned BaBar DIRC components. The GlueX FDIRC would significantly enhance the GlueX physics program by allowing one to search for and study hybrid mesons decaying into kaon final states. Such systematic studies of kaon final states are essential for inferring the quark flavor content of hybrid and conventional mesons. The GlueX FDIRC would reuse one-third of the synthetic fused silica bars that were utilized in the BaBar DIRC. A new focussing photon camera, read out with large area photodetectors, would be developed. We propose operating the enhanced GlueX detector in Hall D for a total of 220 days at an average intensity of 5x10^7 {\gamma}/s, a program that was conditionally approved by PAC39, Comment: 25 pages, 29 figures
Published: 2014
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20. Spin density matrix elements in exclusive $��$ electroproduction on $^1$H and $^2$H targets at 27.5 GeV beam energy

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelm��ller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Lorenzon, W., Ma, B. -Q., Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Sch��fer, A., Schnell, G., Sch��ler, K. P., Seitz, B., Shibata, T. -A., Stahl, M., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment
Abstract: Exclusive electroproduction of $��$ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q$^2$>1.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t'< 0.2 GeV$^2$. Results on the angular distribution of the $��$ meson, including its decay products, are presented. The data were accumulated with the HERMES forward spectrometer during the 1996-2007 running period using the 27.6 GeV longitudinally polarized electron or positron beam of HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio reveals that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are presented in projections of Q$^2$ or -t'. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse $��$ production by longitudinal and transverse virtual photons, $��^{*}_{L} \to ��_{T}$ and $��^{*}_{T} \to ��_{T}$, is determined for the first time. A hierarchy of helicity amplitudes is established, which mainly means that the unnatural-parity-exchange amplitude describing the $��^*_T \to ��_T$ transition dominates over the two natural-parity-exchange amplitudes describing the $��^*_L \to ��_L$ and $��^*_T \to ��_T$ transitions, with the latter two being of similar magnitude. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions, which are of unnatural parity., "Erratum version", e.g., includes the corrected version of Figure 6, to be published in "Erratum to: Spin density matrix elements in exclusive omega electroproduction on 1H and 2H targets at 27.5 GeV beam energy". Three SDMEs were mislabeled in the figure of the previously published version [EPJC74(2014)3110]. The labels have been fixed, while none of the results or conclusions changed
Published: 2014
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21. Separated Response Functions in Exclusive, Forward $��^{\pm}$ Electroproduction on Deuterium

Author: Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., Zihlmann, B., and Collaboration, The Jefferson Lab Fpi
Subjects: FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $��^-$ and $��^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45 GeV$^2$ at W=2.22 GeV. There was significant coverage in $��$ and $��$, which allowed separation of $��_{L,T,LT,TT}$. Results: $��_L$ shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, $��_T$ is much flatter versus t. The longitudinal/transverse ratios evolve with $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight enhancement for $��^-$ production compared to $��^+$. The $��^-/��^+$ ratio for transverse photons exhibits only a small $Q^2$-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The $��_{TT}/��_T$ ratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel helicity conservation. The $��^-/��^+$ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics., 25 pages, 16 figures, 6 tables
Published: 2014
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22. An initial study of mesons and baryons containing strange quarks with GlueX

Author: The GlueX Collaboration, AlekSejevs, A., Barkanova, S., Dugger, M., Ritchie, B., Senderovich, I., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., McGinley, W., Meyer, C. A., Schumacher, R., Staib, M., Collins, P., Klein, F., Sober, D., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Boeglin, W., Guo, L., Khetarpal, P., Pooser, E., Reinhold, J., Ghoul, H. Al, Capstick, S., Crede, V., Eugenio, P., Ostrovidov, A., Sparks, N., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Lara, M., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Szczepaniak, A., Miskimen, R., Mushkarenkov, A., Guegan, B., Hardin, J., Stevens, J., Williams, M., Ponosov, A., Somov, S., Salgado, C., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dobbs, S., Seth, K. K., Tomaradze, A., Dudek, J., Close, F., Swanson, E., Denisov, S., Huber, G., Kolybaba, D., Krueger, S., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Tahani, M., Brooks, W., Hakobyan, H., Kuleshov, S., Soto, O., Toro, A., Vega, I., White, R., Barbosa, F., Chudakov, E., Egiyan, H., Ito, M., Lawrence, D., McCaughan, M., Pennington, M., Pentchev, L., Qiang, Y., Smith, E. S., Somov, A., Taylor, S., Whitlatch, T., Wolin, E., and Zihlmann, B.
Subjects: High Energy Physics::Phenomenology, Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in $��p$ collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic $J^{PC}$, corresponding to $q\bar{q}$ states ($q=u,$ $d,$ or $s$) coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and $\pm1$, and both isoscalar members, $|s\bar{s}\ >$ and $|u\bar{u}\ > + |d\bar{d}\ >$, for each predicted hybrid combination of $J^{PC}$, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. Detailed studies of the performance of the \gx detector have indicated that identification of particular final states with kaons is possible using the baseline detector configuration. The efficiency of kaon detection coupled with the relatively lower production cross section for particles containing hidden strangeness will require a high intensity run in order for analyses of such states to be feasible. We propose to collect a total of 200 days of physics analysis data at an average intensity of $5\times 10^7$ tagged photons on target per second. This data sample will provide an order of magnitude statistical improvement over the initial GlueX running, which will allow us to begin a program of studying mesons and baryons containing strange quarks. In addition, the increased intensity will permit us to study reactions that may have been statistically limited in the initial phases of GlueX. Overall, this will lead to a significant increase in the potential for \gx to make key experimental advances in our knowledge of hybrid mesons and excited $��$ baryons., 22 pages, 8 figures
Published: 2013

23. Beam-helicity asymmetry in associated electroproduction of real photons $ep \to e��N$ in the $��$-resonance region

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Blok, H. P., B��ttcher, H., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., D��ren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelm��ller, E., Fabbri, R., Frullani, S., Gapienko, G., Gapienko, V., Garc��a, J. Garay, Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapik��s, L., Lehmann, I., Lenisa, P., Lorenzon, W., Lu, X. -G., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sch��fer, A., Schnell, G., Seitz, B., Shibata, T. -A., Stahl, M., Statera, M., Steffens, E., Steijger, J. J. M., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zagrebelnyy, V., Zihlmann, B., and Zupranski, P.
Subjects: High Energy Physics - Experiment (hep-ex), Physics::Accelerator Physics, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex)
Abstract: The beam-helicity asymmetry in associated electroproduction of real photons, $ep\to e��N$, in the $��$(1232)-resonance region is measured using the longitudinally polarized HERA positron beam and an unpolarized hydrogen target. Azimuthal Fourier amplitudes of this asymmetry are extracted separately for two channels, $ep\to e��^0 p$ and $ep\to e��^+ n$, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero., 17 pages, 4 figures, (minor changes wit respect to previous arXiv version)
Published: 2013
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24. Beam-helicity asymmetry arising from deeply virtual compton scattering measured with kinematically complete event reconstruction

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Gregor, I. M., Guler, H., Hartig, M., Hasch, D., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Krauss, B., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, P., Ruiz, A. López, Lorenzon, W., Lu, S., Lu, X., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfré, L., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Osborne, A., Pappalardo, L. L., Perez-Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shearer, C., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steijger, J. J. M., Stewart, J., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Zagrebelnyy, V., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: Nuclear and High Energy Physics, Particle physics, Photon, Proton, media_common.quotation_subject, HERA, Lepton-Nucleon Scattering, FOS: Physical sciences, 01 natural sciences, Asymmetry, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Recoil, 0103 physical sciences, ddc:530, NUCLEON, 010306 general physics, Nuclear Experiment, media_common, Physics, 010308 nuclear & particles physics, Scattering, Compton scattering, Helicity, EP, Physics and Astronomy, SPIN, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract: The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized Hera positron beam scattering off an unpolarized hydrogen target is measured at Hermes. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe-Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting ofep→epγevents with detection of all particles in the final state including the recoiling proton. The installation of a recoil detector, while reducing the acceptance of the experiment, allows the elimination of background fromep→eN πγevents, which was estimated to contribute an average of about 12% to the signal in previous Hermes publications. The removal of this background from the present data sample is shown to increase the magnitude of the leading asymmetry amplitude by 0.054 ± 0.016 to −0.328 ± 0.027 (stat.) ± 0.045 (syst.).
Published: 2012

25. A study of meson and baryon decays to strange final states with GlueX in Hall D (A proposal to the 39th Jefferson Lab Program Advisory Committee)

Author: The GlueX Collaboration, Dugger, M., Ritchie, B., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., Meyer, C. A., Schumacher, R., Collins, P., Klein, F., Sober, D., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Senderovich, I., Boeglin, W., Guo, L., Khetarpal, P., Pooser, E., Reinhold, J., Ghoul, H. Al, Capstick, S., Crede, V., Eugenio, P., Ostrovidov, A., Sparks, N., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Szczepaniak, A., Miskimen, R., Williams, M., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dudek, J., Close, F., Swanson, E., Denisov, S., Huber, G., Katsaganis, S., Kolybaba, D., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Tahani, M., Brooks, W., Kuleshov, S., Toro, A., Barbosa, F., Chudakov, E., Egiyan, H., Ito, M., Lawrence, D., Pentchev, L., Qiang, Y., Smith, E. S., Somov, A., Taylor, S., Whitlatch, T., Wolin, E., and Zihlmann, B.
Subjects: High Energy Physics - Experiment (hep-ex), Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract: The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in gamma p collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic JPC, corresponding to q q-bar (q=u, d, or s) states coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and +-1, and both isoscalar members, |s s-bar> and |u u-bar> + |d d-bar>, for each predicted hybrid combination of JPC, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. We propose the development of a kaon identification system, supplementing the existing GlueX forward time-of-flight detector, in order to cleanly select meson and baryon decay channels that include kaons. Once this detector has been installed and commissioned, we plan to collect a total of 200 days of physics analysis data at an average intensity of 5 x 10^7 tagged photons on target per second. This data sample will provide an order of magnitude statistical improvement over the initial GlueX data set and, with the developed kaon identification system, a significant increase in the potential for GlueX to make key experimental advances in our knowledge of hybrid mesons and Cascade baryons., 20 pages, 9 figures (submitted to the 39th Jefferson Lab PAC)
Published: 2012
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26. Inclusive measurements of inelastic electron and positron scattering from unpolarized hydrogen and deuterium targets

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, P., Linden-Levy, L. A., Ruiz, A. Lopez, Lorenzon, W., Lu, X. -G., Lu, X. -R., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Taroian, S., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., and (Astro)-Particles Physics
Subjects: HERMES experiment, Nuclear and High Energy Physics, Particle physics, Lepton-Nucleon Scattering, HERA, MUON SCATTERING, FOS: Physical sciences, 25.30.Dh, Electron, RATIO F2(N)/F2(P), CURRENT CROSS-SECTIONS, 01 natural sciences, 25.30.Hm, High Energy Physics - Experiment, Nuclear physics, Cross section (physics), High Energy Physics - Experiment (hep-ex), Positron, LOW-X, 0103 physical sciences, LOW Q(2), ddc:530, 13.60.-r, 13.40.Gp, QCD ANALYSIS, 010306 general physics, Absorption (electromagnetic radiation), PROTON COLLISIONS, Nuclear Experiment, STRUCTURE-FUNCTION F-2, E(+)P SCATTERING, Quantum chromodynamics, Physics, 010308 nuclear & particles physics, Scattering, Deuterium, Physics and Astronomy, High Energy Physics::Experiment
Abstract: Results of inclusive measurements of inelastic electron and positron scattering from unpolarized protons and deuterons at the HERMES experiment are presented. The structure functions $F_2^p$ and $F_2^d$ are determined using a parameterization of existing data for the longitudinal-to-transverse virtual-photon absorption cross-section ratio. The HERMES results provide data in the ranges $0.006\leq x\leq 0.9$ and 0.1 GeV$^2\leq Q^2\leq$ 20 GeV$^2$, covering the transition region between the perturbative and the non-perturbative regimes of QCD in a so-far largely unexplored kinematic region. They are in agreement with existing world data in the region of overlap. The measured cross sections are used, in combination with data from other experiments, to perform fits to the photon-nucleon cross section using the functional form of the ALLM model. The deuteron-to-proton cross-section ratio is also determined., Comment: 38 pages, 11 Figures, 9 Tables; Fig. 9 modified, Ref. [46] added, minor textual additions on pages 12 and 17
Published: 2011

27. Measurement of azimuthal asymmetries associated with deeply virtual Compton scattering on a longitudinally polarized deuterium target

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Jgoun, A., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Krauss, B., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, P., Linden-Levy, L. A., Ruiz, A. Lopez, Lorenzon, W., Lu, X. -G., Lu, X. -R., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Movsisyan, A., Muccifora, V., Murray, M., Mueller, D., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., and (Astro)-Particles Physics
Subjects: Nuclear and High Energy Physics, EVOLUTION KERNELS, 010308 nuclear & particles physics, GENERALIZED PARTON DISTRIBUTIONS, IMPACT PARAMETER SPACE, ELECTRON STORAGE-RING, HERA, SPIN, NUCLEON, QCD, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, ddc:530, High Energy Physics::Experiment, SDG 7 - Affordable and Clean Energy, 010306 general physics
Abstract: Azimuthal asymmetries in exclusive electroproduction of a real photon from a longitudinally polarized deuterium target are measured with respect to target polarization alone and with respect to target polarization combined with beam helicity and/or beam charge. The asymmetries appear in the distribution of the real photons in the azimuthal angle $\phi$ around the virtual photon direction, relative to the lepton scattering plane. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe-Heitler process. The results for the beam-charge and beam-helicity asymmetries from a tensor polarized deuterium target with vanishing vector polarization are shown to be compatible with those from an unpolarized deuterium target, which is expected for incoherent scattering dominant at larger momentum transfer. Furthermore, the results for the single target-spin asymmetry and for the double-spin asymmetry are found to be compatible with the corresponding asymmetries previously measured on a hydrogen target. For coherent scattering on the deuteron at small momentum transfer to the target, these findings imply that the tensor contribution to the cross section is small. Furthermore, the tensor asymmetry is found to be compatible with zero., Comment: 33 pages, 7 figures, 7 tables; minor textual changes on pages 5 and 27, additional Table 2 added on page 10
Published: 2010

28. Leading-order determination of the gluon polarization from high-p T hadron electroproduction

Author: Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Ball, B., Belostotski, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, Marco, Ferretti, Paola, Deconinck, W., Leo, R. D., Nardo, L. D., Sanctis, E. D., Diefenthaler, M., Nezza, P. D., Duren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, Francesca, Gliske, S., Guler, H., Guzey, V., Haan, S., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., H. S., Jo, Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, Paolo, Ruiz, A. L., Lorenzon, W., X. G., Lu, X. R., Lu, B. Q., Ma, Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. M., Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schafer, A., Schnell, G., Schuler, K. P., Shanidze, R., Shibata, T. A., Shutov, V., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Haarlem, Y. V., Hulse, C. V., Varanda, M., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yu, W., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, Nuclear Theory, Lepton-Nucleon Scattering, Hadron, Monte Carlo method, FOS: Physical sciences, neutron spin structure, transverse momentum, 01 natural sciences, High Energy Physics - Experiment, NO, High Energy Physics - Experiment (hep-ex), deep inelastic scattering, 0103 physical sciences, ddc:530, Nuclear Experiment, 010306 general physics, s Hermes experiment, Lepton-Nucleon Scattering, deep inelastic scattering, neutron spin structure, dependent structure functions, electron storage ring, parton distribution,s Hermes experiment, transverse momentum, proton scattering, EP scattering, Physics, electron storage ring, dependent structure functions, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, EP scattering, HERA, Polarization (waves), parton distribution, Gluon, Deuterium, proton scattering, Transverse momentum, High Energy Physics::Experiment, Nucleon
Abstract: Longitudinal double-spin asymmetries of charged hadrons with high transverse momentum $p_T$ have been measured in electroproduction using the \hermes\ detector at \hera. Processes involving gluons in the nucleon have been enhanced relative to others by selecting hadrons with $p_T$ typically above 1 GeV. In this kinematic domain the gluon polarization has been extracted in leading order making use of the model embedded in the Monte Carlo Generator \Pythia\ 6.2. The gluon polarization obtained from single inclusive hadrons in the $p_T$ range 1 GeV $< p_T
Published: 2010

29. Exclusive leptoproduction of real photons on a longitudinally polarised hydrogen target

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Ball, B., Belostotski, S., Bianchi, N., Blok, H. P., Boettcher, H., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijne, V. G., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, P., Linden-Levy, L. A., Lopez~Ruiz, A., Lorenzon, W., Lu, X. -G., Lu, X. -R., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: Nuclear and High Energy Physics, Particle physics, Photon, media_common.quotation_subject, Lepton-Nucleon Scattering, Virtual particle, FOS: Physical sciences, Parton, forward parton distributions, 01 natural sciences, Asymmetry, NO, High Energy Physics - Experiment, REGION, High Energy Physics - Experiment (hep-ex), ASYMMETRIES, FORWARD PARTON DISTRIBUTIONS, 0103 physical sciences, virtual compton scattering, ddc:530, 010306 general physics, NUCLEON, media_common, asymmetries, VIRTUAL COMPTON-SCATTERING, Physics, region, 010308 nuclear & particles physics, Compton scattering, nucleon, electroproduction, ELECTROPRODUCTION, 3. Good health, Azimuth, Amplitude, Physics and Astronomy, virtual compton scattering, forward parton distributions, electroproduction, asymmetries, nucleon, region, High Energy Physics::Experiment, Beam (structure)
Abstract: Polarisation asymmetries are measured for the hard exclusive leptoproduction of real photons from a longitudinally polarised hydrogen target. These asymmetries arise from the deeply virtual Compton scattering and Bethe-Heitler processes. From the data are extracted two asymmetries in the azimuthal distribution of produced real photons about the direction of the exchanged virtual photon: A_UL with respect to the target polarisation and A_LL with respect to the product of the beam and target polarisations. Results for both asymmetries are compared to the predictions from a generalised parton distribution model. The sin(phi) and cos(0*phi) amplitudes observed respectively for the A_UL and A_LL asymmetries are compatible with the sizeable predictions from the model. Unexpectedly, a sin(2*phi) modulation in the A_UL asymmetry with a magnitude similar to that of the sin(phi) modulation is observed., 18 pages, 2 figures, 5 tables
Published: 2010

30. Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe-Heitler process in measurements on a hydrogen target

Author: Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Bacchetta, A., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, Marco, Ferretti, Paola, Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gharibyan, V., Giordano, Francesca, Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., H. S., Jo, Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, Paolo, Linden Levy, L. A., Lopez Ruiz, A., Lorenzon, W., X. G., Lu, X. R., Lu, B. Q., Ma, Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., Martinez de la Ossa, A., Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Seitz, B., Shibata, T. A., Shutov, V., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., and Biophotonics and Medical Imaging
Subjects: Nuclear and High Energy Physics, Particle physics, Photon, Proton, 12.39.-x Phenomenological quark models, FOS: Physical sciences, Parton, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Cross section (physics), Lepton-nucleon scattering, 0103 physical sciences, time reversal and other discrete symmetries, ddc:530, 010306 general physics, 11.30.Er Charge conjugation, Physics, Luminosity (scattering theory), 010308 nuclear & particles physics, Compton scattering, Helicity, 13.60.Fz Elastic and Compton scattering, parity, 11.30.Er Charge conjugation, parity, time reversal and other discrete symmetries, 13.60.Hb Total and inclusive cross sections (including deep-inelastic processes), Beam (structure)
Abstract: Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996--2005 with the HERMES spectrometer are analyzed to yield asymmetries with respect to the combined dependence of the cross section on beam helicity and charge, thereby revealing previously unseparated contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process. The integrated luminosity is sufficient to show correlated dependences on two kinematic variables, and provides the most precise determination of the dependence on only the beam charge., 21 pages, 5 Figures, and 5 Tables
Published: 2009

31. Single-spin azimuthal asymmetry in exclusive electroproduction of pi+ mesons on transversely polarized protons

Author: Airapetian, A, Akopov, N, Akopov, Z, Aschenauer, EC, Augustyniak, W, Avetissian, A, Avetisyan, E, Ball, B, Belostotski, S, Bianchi, N, Blok, HP, Bottcher, H, Bonomo, C, Borissov, A, Bryzgalov, V, Burns, J, Capiluppi, M, Capitani, GP, Cisbani, E, Ciullo, G, Contalbrigo, M, Dalpiaz, PF, Deconinck, W, De Leo, R, De Nardo, Lara, De Sanctis, E, Diefenthaler, M, Di Nezza, P, Dreschler, J, Duren, M, Ehrenfried, M, Elbakian, G, Ellinghaus, F, Fabbri, R, Fantoni, A, Felawka, L, Frullani, S, Gabbert, Dominik, Gapienko, V, Garibaldi, F, Gharibyan, V, Giordano, F, Gliske, S, Hadjidakis, C, Hartig, M, Hasch, D, Hill, G, Hillenbrand, A, Hoek, M, Holler, Y, Hristova, I, Imazu, Y, Ivanilov, A, Jackson, HE, Jo, HS, Joosten, S, Kaiser, R, Keri, T, Kinney, E, Kisselev, A, Kobayashi, N, Korotkov, V, Kravchenko, P, Lagamba, L, Lamb, R, Lapikas, L, Lehmann, I, Lenisa, P, Linden-Levy, LA, Lopez Ruiz, Alejandro, Lorenzon, W, Lu, XG, Lu, XR, Ma, BQ, Mahon, D, Makins, NCR, Manaenkov, SI, Manfre, L, Mao, Y, Marianski, B, de la Ossa, BM, Marukyan, H, Miller, CA, Miyachi, Y, Movsisyan, A, Muccifora, V, Murray, M, Mussgiller, A, Nappi, E, Naryshkin, Y, Nass, A, Nowak, WD, Pappalardo, LL, Perez-Benito, R, Reimer, PE, Reolon, AR, Riedl, C, Rith, K, Rosner, G, Rostomyan, A, Rubin, J, Ryckbosch, Dirk, Salomatin, Y, Sanftl, F, Schafer, A, Schnell, Gunar, Schuler, KP, Seitz, B, Shibata, TA, Shutov, V, Stancari, M, Statera, M, Steijger, JJM, Stenzel, H, Stewart, J, Taroian, S, Terkulov, A, Trzcinski, A, Tytgat, Michael, Vandenbroucke, A, van der Nat, PB, Van Haarlem, Y, Van Hulse, Charlotte, Varanda, M, Veretennikov, D, Vikhrov, V, Vilardi, I, Vogel, C, Wang, S, Yaschenko, S, Ye, H, Ye, Z, Yen, S, Yu, W, Zeiler, D, Zihlmann, B, and Zupranski, P
Subjects: 14.40.Aq, RING, IMPACT PARAMETER SPACE, FOS: Physical sciences, HYDROGEN, 13.60.-rm, 13.60.Le, 13.85.Lg, 14.20.Dh, PHYSICS EVENT GENERATION, LIMIT, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), TARGET, Physics and Astronomy, GENERALIZED PARTON DISTRIBUTIONS, SCATTERING, ddc:530, High Energy Physics::Experiment, NUCLEON, Nuclear Experiment, TO-LEADING ORDER
Abstract: Exclusive electroproduction of pi+ mesons was studied by scattering 27.6 GeV positrons or electrons off a transversely polarized hydrogen target. The single-spin azimuthal asymmetry with respect to target polarization was measured as a function of the Mandelstam variable t, the Bjorken scaling variable x_B, and the virtuality Q^2 of the exchanged photon. The extracted Fourier components of the asymmetry were found to be consistent with zero, except one that was found to be large and that involves interference of contributions from longitudinal and transverse virtual photons., 7 pages, 2 figures
Published: 2009

32. Investigation of the Exclusive ^{3}He(e,e'pn)p Reaction

Author: Middleton, D. G., Annand, J. R. M., Antelo, M. Ases, Ayerbe, C., Barneo, P., Baumann, D., Bermuth, J., Bernauer, J., Blok, H. P., Bosnar, D., B��hm, R., Ding, M., Distler, M. O., Friedrich, J., Llongo, J. Garc��a, Glazier, D. I., Golak, J., Gl��ckle, W., Grabmayr, P., Hehl, T., Heim, J., Hesselink, W. H. A., Jans, E., Kamada, H., Ma��as, G. Jover, Kohl, M., Lapik��s, L., MacGregor, I. J. D., Martin, I., McGeorge, J. C., Merkel, H., Merle, P., Monstad, K., Moschini, F., M��ller, U., Nogga, A., Benito, R. P��rez, Pospischil, Th., Potokar, M., Rosner, G., Seimetz, M., Skibi��ski, R., de Vries, H., Walcher, Th., Watts, D. P., Weinriefer, M., Weiss, M., Wita��a, H., and Zihlmann, B.
Subjects: Nuclear Theory, FOS: Physical sciences, Physics::Accelerator Physics, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Cross sections for the ^{3}He(e,e'pn)p reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming much smaller at higher recoil momentum., 5, pages, 3 figures
Published: 2009

33. Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor

Author: Huber, G. M., Blok, H. P., Horn, T., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Kiang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
Subjects: FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime., 18 pages, 11 figures
Published: 2008

34. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'��^+$)$n$ reaction

Author: Blok, H. P., Horn, T., Huber, G. M., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract: Cross sections for the reaction ${^1}$H($e,e'��^+$)$n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the CEBAF high-intensity, continous electron beam in order to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from $Q^2$=0.60 to 2.45 GeV$^2$ at an invariant mass of the virtual photon-nucleon system of $W$=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions $��_L$, $��_T$, $��_{LT}$, and $��_{TT}$. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable $t$ at the different values of $Q^2$ are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction ${^1}$H($e,e'��^+$)$n$., 26 pages, 23 figures
Published: 2008
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35. Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H, 3,4He, and carbon

Author: Dohrmann, F., Ahmidouch, A., Armstrong, C. S., Arrington, J., Asaturyan, R., Avery, S., Bailey, K., Bitao, H., Breuer, H., Brown, D. S., Carlini, R., Cha, J., Chant, N., Christy, E., Cochran, A., Cole, L., Crowder, J., Danagoulian, S., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Gan, L., Garrow, K., Geesaman, D. F., Gueye, P., Hafidi, K., Hinton, W., Juengst, H., Keppel, C., Liang, Y., Liu, J. H., Lung, A., Mack, D., Markowitz, P., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mtingwa, S. K., Mueller, B., Niculescu, G., Niculescu, I., Potterveld, D., Raue, B. A., Reimer, P. E., Reinhold, J., Roche, J., Sarsour, M., Sato, Y., Segel, R. E., Semenov, A., Stepanyan, S., Tadevosyan, V., Tajima, S., Tang, L., Uzzle, A., Wood, S., Yamaguchi, H., Yan, C., Yuan, L., Zeidman, B., Zeier, M., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He, 4He, and Carbon targets has been measured at Jefferson Laboratory. The quasifree angular distributions of Lambda and Sigma hyperons were determined at Q^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured at the same kinematics for reference., 34 pages, 9 figures v2:minor grammatical changes, correcting typos
Published: 2007

36. Determination of the pion charge form factor for Q^2=0.60-1.60 GeV^2

Author: collaboration, The Fpi-1, Tadevosyan, V., Blok, H. P., Huber, G. M., Abbott, D., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Bochna, C., Brash, E. J., Breuer, H., Chant, N., Dunne, J., Eden, T., Ent, R., Gaskell, D., Gilman, R., Gustafsson, K., Hinton, W., Jackson, H., Jones, M. K., Keppel, C., Kim, P. H., Kim, W., Klein, A., Koltenuk, D., Liang, M., Lolos, G. J., Lung, A., Mack, D. J., McKee, D., Meekins, D., Mitchell, J., Mkrtchyan, H., Mueller, B., Niculescu, G. Niculescu I., Pitz, D., Potterveld, D., Qin, L. M., Reinhold, J., Shin, I. K., Stepanyan, S., Tang, L. G., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Volmer, J., Vulcan, W., Wood, S., Yan, C., Zhao, W. -X., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: The data analysis for the reaction H(e,e' pi^+)n, which was used to determine values for the charged pion form factor Fpi for values of Q^2=0.6-1.6 GeV^2, has been repeated with careful inspection of all steps and special attention to systematic uncertainties. Also the method used to extract Fpi from the measured longitudinal cross section was critically reconsidered. Final values for the separated longitudinal and transverse cross sections and the extracted values of Fpi are presented., Comment: 11 pages, 6 figures
Published: 2006
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37. Nuclear transparency from quasielastic 12C(e,e'p)

Author: Rohe, D., Benhar, O., Armstrong, C. S., Asaturyan, R., Baker, O. K., Bueltmann, S., Carasco, C., Day, D., Ent, R., Fenker, H. C., Garrow, K., Gasparian, A., Gueye, P., Hauger, M., Honegger, A., Jourdan, J., Keppel, C. E., Kubon, G., Lindgren, R., Lung, A., Mack, D. J., Mitchell, J. H., Mkrtchyan, H., Mocelj, D., Normand, K., Petitjean, T., Rondon, O., Segbefia, E., Sick, I., Stepanyan, S., Tang, L., Tiefenbacher, F., Vulcan, W. F., Warren, G., Wood, S. A., Yuan, L., Zeier, M., Zhu, H., and Zihlmann, B.
Subjects: Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We studied the reaction 12C(e,e'p) in quasielastic kinematics at momentum transfers between 0.6 and 1.8 (GeV/c)^2 covering the single-particle region. From this the nuclear transparency factors are extracted using two methods. The results are compared to theoretical predictions obtained using a generalization of Glauber theory described in this paper. Furthermore, the momentum distribution in the region of the 1s-state up to momenta of 300 MeV/c is obtained from the data and compared to the Correlated Basis Function theory and the Independent-Particle Shell model., accepted by Phys. Rev. C
Published: 2005

38. Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering

Author: Airapetian, A., Akopov, N., Avetissian, E., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Bailey, P., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Oganessyan, K., Ohsuga, H., Pickert, N., Potashov, S., Potterveld, D. H., Baturin, V., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Baumgarten, C., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Beckmann, M., Schwind, A., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Shutov, V., Simani, M. C., Sinram, K., Belostotski, S., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stosslein, U., Tait, P., Tanaka, H., Taroian, S., Bernreuther, S., Tchuiko, B., Terkulov, A., Tkabladze, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P., van der Steenhoven, G., Vetterli, M. C., Vikhrov, V., Bianchi, N., Vincter, M. G., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Ybeles Smit, G., Yen, S., Zihlmann, B., Blok, H. P., Zohrabian, H., Zupranski, P., HERMES Collaboration, Blumlein, J., Akopov, Z., Bottcher, H., Borissov, A., Borysenko, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G. P., Chiang, H. C., Ciullo, G., Amarian, M., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Ammosov, V. V., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Andrus, A., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Aschenauer, E. C., Grebeniouk, O., Greeniaus, L. G., Gregor, I. M., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W. H. A., Augustyniak, W., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Kaiser, R., Avakian, R., Kinney, E., Kisselev, A., Konigsmann, K., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Lagamba, L., Lapikas, Louk, Avetissian, A., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T., Linden-Levy, L. A., Lipka, K., Lorenzon, W., Lu, J., Maiheu, B., Makins, N. C. R., (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Quark, internal [polarized target], Nuclear and High Energy Physics, Particle physics, Strange quark, sea [quark], High Energy Physics::Lattice, deep inelastic scattering [positron deuteron], Hadron, Nuclear Theory, dependence [flavor], Down quark, FOS: Physical sciences, HERMES, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), density [helicity], 27.5 GeV, Pion, 0103 physical sciences, ddc:530, SDG 14 - Life Below Water, deep inelastic scattering [positron p], 010306 general physics, electroproduction [pi], Physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, moment, Baryon, DESY HERA Stor, electroproduction [K], Up quark, valence [quark], polarization [cross section], High Energy Physics::Experiment, polarized beam [positron], asymmetry [spin], experimental results
Abstract: Polarized deep-inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double-spin asymmetries of cross sections. Inclusive and semi-inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a reanalysis of previously published data. Inclusive and semi-inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti-up, anti-down, and strange sea quarks were computed from these asymmetries in a "leading order" QCD analysis. The polarization of the up-quark is positive and that of the down-quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data. © 2005 The American Physical Society.
Published: 2005

39. Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Author: Airapetian, A., Akopov, N., Bacchetta, A., Mikloukho, O., Miller, C. A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Bailey, P., Oganessyan, K., Ohsuga, H., Osborne, A., Pickert, N., Potterveld, D. H., Raithel, M., Reggiani, D., Reimer, P. E., Reischl, A., Reolon, A. R., Balin, D., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Savin, Igor A., Beckmann, M., Schafer, A., Schill, C., Schnell, G., Schuler, K. P., Seele, J., Seidl, R., Seitz, B., Shanidze, R., Shearer, C., Shibata, T. A., Belostotski, S., Shutov, V., Sinram, K., Sommer, W., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Bianchi, N., Tait, P., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Blok, H. P., van Haarlem, Y., Vetterli, M. C., Vikhrov, V., Vincter, M. G., Vogel, C., Volmer, J., Wang, S., Wendland, J., Wilbert, J., Ybeles Smit, G., Bottcher, H., Ye, Y., Ye, Z., Yen, S., Zihlmann, B., Zupranski, P., HERMES Collaboration, Borissov, A., Borysenko, A., Akopov, Z., Bouwhuis, M., Brull, A., Bryzgalov, V., Capitani, G. P., Cappiluppi, M., Chen, T., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., De Leo, R., Amarian, M., Demey, M., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Andrus, A., Elschenbroich, U., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Frullani, S., Gapienko, G., Gapienko, V., Garibaldi, F., Garrow, K., Aschenauer, E. C., Gavrilov, G., Gharibyan, V., Grebeniouk, O., Gregor, I. M., Hadjidakis, C., Hafidi, K., Hartig, M., Hasch, D., Henoch, M., Hesselink, W. H. A., Augustyniak, W., Hillenbrand, A., Hoek, M., Holler, Y., Hommez, B., Hristova, I., Iarygin, G., Ilyichev, A., Ivanilov, A., Izotov, A., Jackson, H. E., Avakian, R., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Kobayashi, T., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V. G., Avetissian, A., Lagamba, L., Lapikas, Louk, Laziev, A., Lenisa, P., Liebing, P., Linden-Levy, L. A., Lorenzon, W., Lu, H., Lu, J., Lu, S., Avetissian, E., Ma, B. Q., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Masoli, F., Mexner, V., Meyners, N., Michler, T., (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Particle physics, transverse [polarization], Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, HERMES, 13.60.–r, Inelastic scattering, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 27.5 GeV, Pion, 13.88.+e, ddc:550, Vector meson, SDG 14 - Life Below Water, deep inelastic scattering [positron p], 14.20.Dh, 14.65.–q, Nuclear Experiment, Physics, Scattering, polarized target [hydrogen], High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, +pi+positron+anything%22">positron p --> pi positron anything, angular dependence, DESY HERA Stor, Distribution function, High Energy Physics::Experiment, transverse momentum [quark], Nucleon, electroproduction [pi+], asymmetry [spin], electroproduction [pi-], Lepton, experimental results
Abstract: Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion ($\ensuremath{\phi}$) and the target spin axis (${\ensuremath{\phi}}_{S}$) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component $\mathbf{⟨}\mathrm{sin} (\ensuremath{\phi}+{\ensuremath{\phi}}_{S}){\mathbf{⟩}}_{UT}^{\ensuremath{\pi}}$ is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component $\mathbf{⟨}\mathrm{sin} (\ensuremath{\phi}\ensuremath{-}{\ensuremath{\phi}}_{S}{\mathbf{⟩}}_{UT}^{\ensuremath{\pi}}$ arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.
Published: 2005

40. Measurement of R = sigma_L / sigma_T and the Separated Longitudinal and Transverse Structure Functions in the Nucleon Resonance Region

Author: Collaboration, The Jefferson Lab Hall C E94-110, Liang, Y., Tvaskis, V., Christy, M. E., Ahmidouch, A., Armstrong, C. S., Arrington, J., Asaturyan, R., Avery, S., Baker, O. K., Beck, D. H., Blok, H. P., Bochna, C. W., Boeglin, W., Bosted, P., Bouwhuis, M., Breuer, H., Brown, D. S., Bruell, A., Carlini, R. D., Cha, J., Chant, N. S., Cochran, A., Cole, L., Danagoulian, S., Day, D. B., Dunne, J., Dutta, D., Ent, R., Fenker, H. C., Fox, B., Gan, L., Gao, H., Garrow, K., Gaskell, D., Gasparian, A., Geesaman, D. F., Gilman, R., Gu`eye, P. L. J., Harvey, M., Holt, R. J., Jiang, X., Jones, M., Keppel, C. E., Kinney, E., Lorenzon, W., Lung, A., Mack, D. J., Markowitz, P., Martin, J. W., McIlhany, K., McKee, D., Meekins, D., Miller, M. A., Milner, R. G., Mitchell, J. H., Mkrtchyan, H., Mueller, B. A., Nathan, A., Niculescu, G., Niculescu, I., O'Neill, T. G., Papavassiliou, V., Pate, S. F., Piercey, R. B., Potterveld, D., Ransome, R. D., Reinhold, J., Rollinde, E., Rondon, O., Roos, P., Sarty, A. J., Sawafta, R., Schulte, E. C., Segbefia, E., Smith, C., Stepanyan, S., Strauch, S., Tadevosyan, V., Tang, L., Tieulent, R., Uzzle, A., Vulcan, W. F., Wood, S. A., Xiong, F., Yuan, L., Zeier, M., Zihlmann, B., and Ziskin, V.
Subjects: FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2 < Q^2 < 5.5 GeV^2. The data have been used to accurately perform 167 Rosenbluth-type longitudinal / transverse separations. The precision R = sigma_L / sigma_T data are presented here, along with the first separate values of the inelastic structure functions F_1 and F_L in this regime. The resonance longitudinal component is found to be significant, both in magnitude and in the existence of defined mass peaks. Additionally, quark-hadron duality is here observed above Q^2 = 1 GeV^2 in the separated structure functions independently., 5 pages, 4 figures
Published: 2004
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41. Measurement of single-spin azimuthal asymmetries in semi-inclusive electroproduction of pions and kaons on a longitudinally polarised deuterium target

Author: Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Ammosov, V.V., Andrus, A., Aschenauer, E.C., Augustyniak, W., Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bailey, P., Baturin, V., Baumgarten, C., Beckmann, M., Belostotski, S., Bernreuther, S., Bianchi, N., Blok, H.P., Bottcher, H., Borissov, A., Bouwhuis, M., Brack, J., Brull, A., Bryzgalov, V., Capitani, G.P., Chiang, H.C., Ciullo, G., Contalbrigo, M., Court, G.R., Dalpiaz, P.F., De Leo, R., De Nardo, L., De Sanctis, E., Devitsin, E., Di Nezza, P., Duren, M., Ehrenfried, M., Elalaoui-Moulay, A., Elbakian, G., Ellinghaus, F., Eischenbroich, U., Ely, J., Fabbri, R., Fantoni, A., Fechtchenko, A., Felawka, L., Fox, B., Franz, J., Frullani, S., Garber, Y., Gapienko, G., Gapienko, V., Garibaldi, F., Garutti, E., Gaskell, D., Gavrilov, G., Gharibyan, V., Graw, G., Grebeniouk, O., Greeniaus, L.G., Haeberli, W., Hafidi, K., Hartig, M., Hasch, D., Heesbeen, D., Henoch, M., Hertenberger, R., Hesselink, W.H.A., Hillenbrand, A., Holler, Y., Hommez, B., Iarygin, G., Ivanilov, A., Izotov, A., Jackson, H.E., Jgoun, A., Kaiser, R., Kinney, E., Kisselev, A., Konigsmann, K., Kolster, H., Kopytin, M., Korotkov, V., Kozlov, V., Krauss, B., Krivokhijine, V.G., Lagamba, L., Lapikas, L., Laziev, A., Lenisa, P., Liebing, P., Lindemann, T, Lipka, K., Lorenzon, W., Ma, B., Makins, N.C.R., Marukyan, H., Masoli, F., Menden, F., Mexner, V., Meyners, N., Mikloukho, O., Miller, C.A., Miyachi, Y., Muccifora, V., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Nowak, W.D., Oganessyan, K., Ohsuga, H., Orlandi, G., Potashov, S., Potterveld, D.H., Raithel, M., Reggiani, D., Reimer, P.E., Reischl, A., Reolon, A.R., Rith, K., Rosner, G., Rostomyan, A., Ryckbosch, D., Sanjiev, I., Savin, I., Scarlett, C., Schafer, A., Schill, C., Schnell, G., Schuler, K.P., Schwind, A., Seidl, R., Seibert, J., Seitz, B., Shanidze, R., Shibata, T., Shutov, V., Simani, M.C., Sinram, K., Stancari, M., Statera, M., Steffens, E., Steijger, J.J.M., Stewart, J., Stosslein, U., Tanaka, H., Taroian, S., Tchuiko, B., Terkulov, A., Tessarin, S., Thomas, E., Tkabladze, A., Trzcinski, A., Tytgat, A., Urciuoli, G.M., van der Nat, P., van der Steenhoven, G., Van de Vyver, R., Vetterli, M.C., Vikhrov, V., Vincter, M.G., Visser, J., Vogel, C., Vogt, M., Volmer, J., Weiskopf, C., Wendland, J., Wilbert, J., Wise, T., Yen, S., Yoneyama, S., Zihlmann, B., Zohrabian, H., Zupranski, P., Photo Conversion Materials, (Astro)-Particles Physics, and Student Lab and Education
Subjects: Nuclear and High Energy Physics, Particle physics, Meson, Nuclear Theory, Hadron, Virtual particle, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, 0103 physical sciences, 010306 general physics, Nuclear Experiment, QC, Spin-½, 13.60.-r, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deuterium, 13.87.Fh, 14.20.Dh, Condensed Matter::Strongly Correlated Electrons, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, SDG 6 - Clean Water and Sanitation, Lepton
Abstract: Single-spin asymmetries have been measured for semi-inclusive electroproduction of $\pi^+$, $\pi^-$, $\pi^0$ and $K^+$ mesons in deep-inelastic scattering off a longitudinally polarised deuterium target. The asymmetries appear in the distribution of the hadrons in the azimuthal angle $\phi$ around the virtual photon direction, relative to the lepton scattering plane. The corresponding analysing powers in the $\sin \phi$ moment of the cross section are $0.012 \pm 0.002 {(stat.)} \pm 0.002 {(syst.)}$ for $\pi^+$, $0.006 \pm 0.003 {(stat.)} \pm 0.002 {(syst.)}$ for $\pi^-$, $0.021 \pm 0.005 {(stat.)} \pm 0.003 {(syst.)}$ for $\pi^0$ and $0.013 \pm 0.006 {(stat.)} \pm 0.003 {(syst.)}$ for $K^+$. The $\sin 2\phi$ moments are compatible with zero for all particles., Comment: Revised version shortened 9 pages, 3 tables, 7 figures
Published: 2002
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42. x- and xi-scaling of the Nuclear Structure Function at Large x

Author: Arrington, J., Armstrong, C. S., Averett, T., Baker, O. K., de Bever, L., Bochna, C. W., Boeglin, W., Bray, B., Carlini, R. D., Collins, G., Cothran, C., Crabb, D., Day, D., Dunne, J. A., Dutta, D., Ent, R., Filippone, B. W., Honegger, A., Hughes, E. W., Jensen, J., Jourdan, J., Keppel, C. E., Koltenuk, D. M., Lindgren, R., Lung, A., Mack, D. J, McCarthy, J., McKeown, R. D., Meekins, D., Mitchell, J. H., Mkrtchyan, H. G., Niculescu, G., Niculescu, I., Petitjean, T., Rondon, O., Sick, I., Smith, C., Terburg, B., Vulcan, W. F., Wood, S. A., Yan, C., Zhao, J., and Zihlmann, B.
Subjects: FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: Inclusive electron scattering data are presented for ^2H and Fe targets at an incident electron energy of 4.045 GeV for a range of momentum transfers from Q^2 = 1 to 7 (GeV/c)^2. Data were taken at Jefferson Laboratory for low values of energy loss, corresponding to values of Bjorken x greater than or near 1. The structure functions do not show scaling in x in this range, where inelastic scattering is not expected to dominate the cross section. The data do show scaling, however, in the Nachtmann variable \xi. This scaling may be the result of Bloom Gilman duality in the nucleon structure function combined with the Fermi motion of the nucleons in the nucleus. The resulting extension of scaling to larger values of \xi opens up the possibility of accessing nuclear structure functions in the high-x region at lower values of Q^2 than previously believed., Comment: RevTeX, 5 pages with 4 postscript figures, submitted to PRC
Published: 2001
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43. Evidence for a transverse single-spin asymmetry in leptoproduction of π+π−pairs

Author: Hermes, Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Andrus, A., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Barion, Luca, Belostotski, S., Bianchi, N., Blok, H. P., Böttcher, H., Bonomo, C., Borissov, A., Brüll, A., Bryzgalov, V., Burns, J., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, Marco, Ferretti, Paola, Deconinck, W., De Leo, R., Demey, M., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dreschler, J., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Funel, A., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, Francesca, Gliske, S., Guler, H., Hadjidakis, C., Hasch, D., Hasegawa, T., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Iarygin, G., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., Jgoun, A., Joosten, S., Kaiser, R., Keri, T., Kinney, E., Kisselev, A., Kopytin, M., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikás, L., Lehmann, I., Lenisa, Paolo, Linden Levy, L. A., Lorenzon, W., Lu, S., Lu, X., B. Q., Ma, Mahon, D., Maiheu, B., Makins, N. C. R., Mao, Y., Marianski, B., Marukyan, H., Miller, C. A., Miyachi, Y., Muccifora, V., Murray, M., Mussgiller, A., Nagaitsev, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Osborne, A., Pappalardo, Luciano Libero, Perez Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reischl, A., Reolon, A. R., Riedl, C., Rith, K., Rock, S. E., Rosner, G., Rostomyan, A., Rubacek, L., Rubin, J., Ruiz, A. L., Ryckbosch, D., Salomatin, Y., Sanjiev, I., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shearer, C., Shibata, T. A., Shutov, V., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Tait, P., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., van der Nat, P. B., van der Steenhoven, G., Van Haarlem, Y., Van Hulse, C., Varanda, M., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., and Zupranski, P.
Subjects: Quark, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, FOS: Physical sciences, 01 natural sciences, Asymmetry, Molecular physics, NO, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), 14.40.Aq pi K and eta mesons, 0103 physical sciences, Pi, ddc:530, Nuclear Experiment, 010306 general physics, media_common, Physics, 010308 nuclear & particles physics, Scattering, 25.30.-c Lepton-induced reactions, Polarization (waves), 24.70.+s polarization in electron scattering, Azimuth, Transverse plane, Distribution function, High Energy Physics::Experiment
Abstract: A single-spin asymmetry was measured in the azimuthal distribution of pi+pi- pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation between the transverse target polarization and the azimuthal orientation of the plane containing the two pions.The corresponding single-spin asymmetry is expected to be related to the product of the little-known quark transversity distribution function and an unknown naive-T-odd chiral-odd dihadron fragmentation function., Comment: 18 pages, 4 figures, 1 table; minor revisions to content for clarity
Published: 2008

44. Ratios of helicity amplitudes for exclusive ρ 0 electroproduction

Author: The HERMES Collaboration, Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, F., Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., Jo, H. S., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, P., Linden-Levy, L. A., Ruiz, A. Lopez, Lorenzon, W., Lu, X. -G., Lu, X. -R., Ma, B. -Q., Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. Martinez, Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. -D., Pappalardo, L. L., Perez-Benito, R., Pickert, N., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. -A., Shutov, V., Stancari, M., Statera, M., Steffens, E., Steijger, J. J. M., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Yu, W., Zihlmann, B., Zupranski, P., and (Astro)-Particles Physics
Subjects: HERMES experiment, Particle physics, J/PSI MESONS, Hydrogen, Physics and Astronomy (miscellaneous), Positron beam, Astrophysics::High Energy Astrophysical Phenomena, HERA, chemistry.chemical_element, FOS: Physical sciences, Electron, 01 natural sciences, High Energy Physics - Experiment, ELASTIC ELECTROPRODUCTION, High Energy Physics - Experiment (hep-ex), P(0) MESONS, GENERALIZED PARTON DISTRIBUTIONS, 0103 physical sciences, SCATTERING, ddc:530, DIFFRACTIVE ELECTROPRODUCTION, 010306 general physics, Nuclear Experiment, Engineering (miscellaneous), Physics, 010308 nuclear & particles physics, Perturbative QCD, HYDROGEN, VECTOR-MESON PRODUCTION, QCD, Helicity, Amplitude, Physics and Astronomy, chemistry, Deuterium, High Energy Physics::Experiment
Abstract: Exclusive rho^0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV^2 < Q^2 < 7.0 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t' < 0.4 GeV^2. Real and imaginary parts of the ratios of the natural-parity-exchange helicity amplitudes T_{11} (\gamma^*_T --> \rho_T), T_{01} (\gamma^*_T --> \rho_L), T_{10} (\gamma^*_L --> \rho_T), and T_{1-1} (\gamma^*_{-T} -->\rho_T) to T_{00} (\gamma^*_L --> \rho_L) are extracted from the data. For the unnatural-parity-exchange amplitude U_{11}, the ratio |U_{11}/T_{00}| is obtained. The Q^2 and t' dependences of these ratios are presented and compared with perturbative QCD predictions., Comment: 27 pages, 8 tables, 13 figures; minor textual changes on pages 2, 3,9, 10, 11, and some changes to the list of references
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