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Title: Measurement of two-photon exchange effect by comparing elastic e ± p cross sections

Here, the electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer ($$Q^{2}$$). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron/positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm long liquid hydrogen (LH$$_2$$) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented.
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Publication Date:
Report Number(s):
JLAB-PHY-17-2549; DOE/OR/23177-4209; arXiv:1603.00315
Journal ID: ISSN 2469-9985; PRVCAN
Grant/Contract Number:
AC05-060R23177; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); Instituto Nazionale di Fisica Nucleare (INFN); United Kingdom Science and Technology Facilities Council; National Research Foundation of Korea (NRF); USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Contributing Orgs:
The CLAS Collaboration
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
OSTI Identifier:
1389768
Alternate Identifier(s):
OSTI ID: 1361116; OSTI ID: 1390836; OSTI ID: 1440868

Rimal, D., Adikaram, D., Raue, B. A., Weinstein, L. B., Arrington, J., Brooks, W. K., Ungaro, M., Adhikari, K. P., Afanasev, A. V., Akbar, Z., Pereira, S. Anefalos, Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chetry, T., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Fradi, A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Hafidi, K., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Markov, N., McKinnon, B., Mestayer, M. D., Mirazita, M., Mokeev, V., Movsisyan, A., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Puckett, A. J. R., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Seder, E., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, Ivana, Stepanyan, S., Strauch, S., Sytnik, V., Taiuti, M., Torayev, B., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., and Zonta, I.. Measurement of two-photon exchange effect by comparing elastic e±p cross sections. United States: N. p., Web. doi:10.1103/PhysRevC.95.065201.
Rimal, D., Adikaram, D., Raue, B. A., Weinstein, L. B., Arrington, J., Brooks, W. K., Ungaro, M., Adhikari, K. P., Afanasev, A. V., Akbar, Z., Pereira, S. Anefalos, Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chetry, T., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Fradi, A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Hafidi, K., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Markov, N., McKinnon, B., Mestayer, M. D., Mirazita, M., Mokeev, V., Movsisyan, A., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Puckett, A. J. R., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Seder, E., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, Ivana, Stepanyan, S., Strauch, S., Sytnik, V., Taiuti, M., Torayev, B., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., & Zonta, I.. Measurement of two-photon exchange effect by comparing elastic e±p cross sections. United States. doi:10.1103/PhysRevC.95.065201.
Rimal, D., Adikaram, D., Raue, B. A., Weinstein, L. B., Arrington, J., Brooks, W. K., Ungaro, M., Adhikari, K. P., Afanasev, A. V., Akbar, Z., Pereira, S. Anefalos, Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chetry, T., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Forest, T. A., Fradi, A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Hafidi, K., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Kuleshov, S. V., Lanza, L., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Markov, N., McKinnon, B., Mestayer, M. D., Mirazita, M., Mokeev, V., Movsisyan, A., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Puckett, A. J. R., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Seder, E., Sharabian, Y. G., Skorodumina, Iu., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, Ivana, Stepanyan, S., Strauch, S., Sytnik, V., Taiuti, M., Torayev, B., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., and Zonta, I.. 2017. "Measurement of two-photon exchange effect by comparing elastic e±p cross sections". United States. doi:10.1103/PhysRevC.95.065201. https://www.osti.gov/servlets/purl/1389768.
@article{osti_1389768,
title = {Measurement of two-photon exchange effect by comparing elastic e±p cross sections},
author = {Rimal, D. and Adikaram, D. and Raue, B. A. and Weinstein, L. B. and Arrington, J. and Brooks, W. K. and Ungaro, M. and Adhikari, K. P. and Afanasev, A. V. and Akbar, Z. and Pereira, S. Anefalos and Badui, R. A. and Ball, J. and Baltzell, N. A. and Battaglieri, M. and Batourine, V. and Bedlinskiy, I. and Biselli, A. S. and Boiarinov, S. and Briscoe, W. J. and Bültmann, S. and Burkert, V. D. and Carman, D. S. and Celentano, A. and Chetry, T. and Ciullo, G. and Clark, L. and Colaneri, L. and Cole, P. L. and Compton, N. and Contalbrigo, M. and Cortes, O. and Crede, V. and D'Angelo, A. and Dashyan, N. and De Vita, R. and Deur, A. and Djalali, C. and Dupre, R. and Egiyan, H. and Alaoui, A. El and Fassi, L. El and Eugenio, P. and Fanchini, E. and Fedotov, G. and Fersch, R. and Filippi, A. and Fleming, J. A. and Forest, T. A. and Fradi, A. and Gevorgyan, N. and Ghandilyan, Y. and Gilfoyle, G. P. and Giovanetti, K. L. and Girod, F. X. and Gleason, C. and Gohn, W. and Golovatch, E. and Gothe, R. W. and Griffioen, K. A. and Guo, L. and Hafidi, K. and Hanretty, C. and Harrison, N. and Hattawy, M. and Heddle, D. and Hicks, K. and Holtrop, M. and Hughes, S. M. and Ilieva, Y. and Ireland, D. G. and Ishkhanov, B. S. and Isupov, E. L. and Jenkins, D. and Jiang, H. and Joosten, S. and Keller, D. and Khachatryan, G. and Khandaker, M. and Kim, W. and Klein, A. and Klein, F. J. and Kubarovsky, V. and Kuhn, S. E. and Kuleshov, S. V. and Lanza, L. and Lenisa, P. and Livingston, K. and Lu, H. Y. and MacGregor, I. J. D. and Markov, N. and McKinnon, B. and Mestayer, M. D. and Mirazita, M. and Mokeev, V. and Movsisyan, A. and Munevar, E. and Camacho, C. Munoz and Nadel-Turonski, P. and Ni, A. and Niccolai, S. and Niculescu, G. and Niculescu, I. and Osipenko, M. and Ostrovidov, A. I. and Paolone, M. and Paremuzyan, R. and Park, K. and Pasyuk, E. and Phelps, W. and Pisano, S. and Pogorelko, O. and Price, J. W. and Prok, Y. and Protopopescu, D. and Puckett, A. J. R. and Rizzo, A. and Rosner, G. and Rossi, P. and Roy, P. and Sabatié, F. and Salgado, C. and Schumacher, R. A. and Seder, E. and Sharabian, Y. G. and Skorodumina, Iu. and Smith, G. D. and Sokhan, D. and Sparveris, N. and Stankovic, Ivana and Stepanyan, S. and Strauch, S. and Sytnik, V. and Taiuti, M. and Torayev, B. and Voskanyan, H. and Voutier, E. and Walford, N. K. and Watts, D. P. and Wei, X. and Wood, M. H. and Zachariou, N. and Zana, L. and Zhang, J. and Zhao, Z. W. and Zonta, I.},
abstractNote = {Here, the electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer ($Q^{2}$). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron/positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm long liquid hydrogen (LH$_2$) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented.},
doi = {10.1103/PhysRevC.95.065201},
journal = {Physical Review C},
number = 6,
volume = 95,
place = {United States},
year = {2017},
month = {6}
}