First Exclusive Measurement of Deeply Virtual Compton Scattering off ⁴He: Toward the 3D Tomography of Nuclei

Authors

M. Hattawy
N. A. Baltzell
R. Dupré
K. Hafidi
S. Stepanyan
S. Bültmann, Old Dominion UniversityFollow
R. De Vita
A. El Alaoui
L. El Fassi
H. Egiyan
B. Torayev, Old Dominion University
D. Adikaram, Old Dominion University
M. J. Amaryan, Old Dominion UniversityFollow
G. Charles, Old Dominion University
M. Khachatryan, Old Dominion University
A. Klein, Old Dominion University
S. E. Kuhn, Old Dominion UniversityFollow
M. Mayer, Old Dominion University
Y. Prok, Old Dominion University
L. B. Weinstein, Old Dominion UniversityFollow
Z. W. Zhao, Old Dominion University

Document Type

Article

Publication Date

11-2017

DOI

10.1103/PhysRevLett.119.202004

Publication Title

Physical Review Letters

Volume

119

Issue

20

Pages

202004 (7 pp.)

Abstract

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized ⁴He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling ⁴He nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only ⁴He Compton form factor, H_A. This first measurement of coherent deeply virtual Compton scattering on the ⁴He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

Original Publication Citation

Hattawy, M., Baltzell, N. A., Dupre, R., Hafidi, K., Stepanyan, S., Bultmann, S., . . . Collaboration, C. (2017). First exclusive measurement of deeply virtual compton scattering off ⁴He: Toward the 3D tomography of nuclei. Physical Review Letters, 119(20), 202004. doi:10.1103/PhysRevLett.119.202004

ORCID

0000-0002-5680-1814 (Bueltmann), 0000-0002-1792-1872 (Torayev), 0000-0003-2243-6836 (Kuhn), 0000-0001-5416-2900 (Weinstein)

Repository Citation

Hattawy, M.; Baltzell, N. A.; Dupré, R.; Hafidi, K.; Stepanyan, S.; Bültmann, S.; Vita, R. De; Alaoui, A. El; Fassi, L. El; Egiyan, H.; Torayev, B.; Adikaram, D.; Amaryan, M. J.; Charles, G.; Khachatryan, M.; Klein, A.; Kuhn, S. E.; Mayer, M.; Prok, Y.; Weinstein, L. B.; and Zhao, Z. W., "First Exclusive Measurement of Deeply Virtual Compton Scattering off ⁴He: Toward the 3D Tomography of Nuclei" (2017). Physics Faculty Publications. 112.
https://digitalcommons.odu.edu/physics_fac_pubs/112