1. Beam Charge Asymmetries for Deeply Virtual Compton Scattering on the Proton at CLAS12
- Author
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Voutier, E., Burkert, V., Niccolai, S., Paremuzyan, R., Afanasev, A., Alvarado-Galeano, J. -S., Atoui, M., Barion, L., Battaglieri, M., Bernauer, J., Bianconi, A., Bondi, M., Briscoe, W., Camsonne, A., Capobianco, R., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Cole, P., Contalbrigo, M., Costantini, G., Defurne, M., Deur, A., De Vita, R., Diehl, S., Dupré, R., Elouadrhiri, L., Fernando, I., Filippi, A., Forest, T., Girod, F. -X., Gosta, G., Grames, J., Gueye, P., Habet, S., Hattawy, M., Higinbotham, D., Hobart, A., Hyde, C., Joo, K., Kim, A., Klimenko, V., Kubarovsky, V., Leali, M., Lenisa, P., Marchand, D., Marsicano, L., Mascagna, V., Matamoros, D., McCaughan, M., McKinnon, B., Migliorati, S., Mitra, H. S., Movsisyan, A., Muñoz-Camacho, C., Osipenko, M., Ouillon, M., Pappalardo, L., Pasquini, B., Pasyuk, E., Pilleux, N., Poelker, M., Raue, B., Ripani, M., Santos, R., Schmidt, A., Singh, R., Sokhan, D., Spreafico, M., Stoler, P., Strakovsky, I., Taiuti, M., Venturelli, L., Wang, P. -K., Wei, X., Zhao, Z., Collaboration, the CLAS, and Group, the Jefferson Lab Positron Working
- Subjects
Nuclear Experiment ,High Energy Physics - Experiment - Abstract
The parameterization of the nucleon structure through Generalized Parton Distributions (GPDs) shed a new light on the nucleon internal dynamics. For its direct interpretation, Deeply Virtual Compton Scattering (DVCS) is the golden channel for GPDs investigation. The DVCS process interferes with the Bethe-Heitler (BH) mechanism to constitute the leading order amplitude of the $eN \to eN\gamma$ process. The study of the $ep\gamma$ reaction with polarized positron and electron beams gives a complete set of unique observables to unravel the different contributions to the $ep \gamma$ cross section. This separates the different reaction amplitudes, providing a direct access to their real and imaginary parts which procures crucial constraints on the model dependences and associated systematic uncertainties on GPDs extraction. The real part of the BH-DVCS interference amplitude is particularly sensitive to the $D$-term which parameterizes the Gravitational Form Factors of the nucleon. The separation of the imaginary parts of the interference and DVCS amplitudes provides insights on possible higher-twist effects. We propose to measure the unpolarized and polarized Beam Charge Asymmetries (BCAs) of the $\vec{e}^{\pm}p \to e^{\pm}p \gamma$ process on an unpolarized hydrogen target with {\tt CLAS12}, using polarized positron and electron beams at 10.6 GeV. The azimuthal and $t$-dependences of the unpolarized and polarized BCAs will be measured over a large $(x_B,Q^2)$ phase space using a 100 day run with a luminosity of 0.66$\times 10^{35}$cm$^{-2}\cdot$s$^{-1}$., Comment: Proposal to the Jefferson Lab Program Advisory Committee (PAC51)
- Published
- 2023