Spectator-Tagged Deeply Virtual Compton Scattering on Light Nuclei

• Published in: arXiv.org
• Main Authors: Armstrong, Whitney, Arrington, John, Cloët, Ian, Freese, Adam, Hafidi, Kawtar, Hattawy, Mohammad, Riordan, Seamus, Johnston, Sereres, Potteveld, David, Reimer, Paul, Ye, Zhihong, Ball, Jacques, Defurne, Maxime, Garcon, Michel, Moutarde, Herve, Procureur, Sebastien, Sabatie, Franck, Cosyn, Wim, Mazouz, Malek, Accardi, Alberto, Bettane, Julien, Gabriel, Charles, Dupre, Raphael, Guidal, Michel, Marchand, Dominique, Munoz, Carlos, Niccolai, Silvia, Voutier, Eric, Adhikari, Krishna, Dunne, James, Dutta, Dipangkar, Lamiaa El Fassi, Kabir, Md Latiful, Li, Ye, Guzey, Vadim, Baltzell, Nathan, Francois-Xavier Girod, Kubarovsky, Valery, Park, Kijun, Stepanyan, Stepan, Duran, Burcu, Joosten, Sylvester, Zein-Eddine Meziani, Paolone, Michael, Rehfuss, Melanie, Sparveris, Nikos, Cao, Frank, Joo, Kyungseon, Kim, Andrei, Markov, N, Scopetta, Sergio, McKinnon, Bryan, Brooks, William, El-Alaoui, Ahmed, Liuti, Simonetta, Jenkins, David
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 02.08.2017
• Subjects: Deuterium; Elastic scattering; Gluons; Marking; Nuclei (nuclear physics); Quarks
• ISSN: 2331-8422

The three-dimensional picture of quarks and gluons in the proton is set to be revealed through Deeply virtual Compton scattering while a critically important puzzle in the one-dimensional picture remains, namely, the origins of the EMC effect. Incoherent nuclear DVCS, i.e. DVCS on a nucleon inside a nucleus, can reveal the 3D partonic structure of the bound nucleon and shed a new light on the EMC effect. However, the Fermi motion of the struck nucleon, off-shell effects and final-state interactions (FSIs) complicate this parton level interpretation. We propose here a measurement of incoherent DVCS with a tagging of the recoiling spectator system (nucleus A-1) to systematically control nuclear effects. Through spectator-tagged DVCS, a fully detected final state presents a unique opportunity to systematically study these nuclear effects and cleanly observe possible modification of the nucleon's quark distributions. We propose to measure the DVCS beam-spin asymmetries (BSAs) on \(^4\)He and deuterium targets. The reaction \(^4\)He\((e,e^{\prime}\gamma\,p\,^3\)H\()\) with a fully detected final state has the rare ability to simultaneously quantify FSIs, measure initial nucleon momentum, and provide a sensitive probe to other nuclear effects at the parton level. The DVCS BSA on a (quasi-free) neutron will be measured by tagging a spectator proton with a deuteron target. Similarly, a bound neutron measurement detects a spectator \(^3\)He off a \(^4\)He target. These two observables will allow for a self-contained measurement of the neutron off-forward EMC Effect.