@article{2eac2207f66d4479a7da47426aaeb337,
title = "First Exclusive Measurement of Deeply Virtual Compton Scattering off He 4: Toward the 3D Tomography of Nuclei",
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 He4 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 He4 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 He4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.",
author = "{CLAS Collaboration} and M. Hattawy and Baltzell, {N. A.} and R. Dupr{\'e} and K. Hafidi and S. Stepanyan and S. B{\"u}ltmann and {De Vita}, R. and {El Alaoui}, A. and {El Fassi}, L. and H. Egiyan and Girod, {F. X.} and M. Guidal and D. Jenkins and S. Liuti and Y. Perrin and B. Torayev and E. Voutier and Adhikari, {K. P.} and S. Adhikari and D. Adikaram and Z. Akbar and Amaryan, {M. J.} and {Anefalos Pereira}, S. and Armstrong, {Whitney R.} and H. Avakian and J. Ball and M. Bashkanov and M. Battaglieri and V. Batourine and I. Bedlinskiy and Biselli, {A. S.} and S. Boiarinov and Briscoe, {W. J.} and Brooks, {W. K.} and Burkert, {V. D.} and {Thanh Cao}, Frank and Carman, {D. S.} and A. Celentano and G. Charles and T. Chetry and G. Ciullo and L. Clark and L. Colaneri and Cole, {P. L.} and M. Contalbrigo and O. Cortes and V. Crede and A. D'Angelo and N. Dashyan and Barry Ritchie",
note = "Funding Information: The authors thank the staff of the Accelerator and Physics Divisions at the Thomas Jefferson National Accelerator Facility who made this experiment possible. This work was supported in part by the Chilean Comisi{\'o}n Nacional de Investigaci{\'o}n Cient{\'i}fica y Tecnol{\'o}gica (CONICYT), the Italian Instituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique, the French Commissariat {\`a} l{\textquoteright}Energie Atomique, the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, the United Kingdom Science and Technology Facilities Council (STFC), the Scottish Universities Physics Alliance (SUPA), the National Research Foundation of Korea, and the Office of Research and Economic Development at Mississippi State University. M. Hattawy also acknowledges the support of the Consulat G{\'e}n{\'e}ral de France {\`a} J{\'e}rusalem. The Southeastern Universities Research Association operates the Thomas Jefferson National Accelerator Facility for the United States Department of Energy under Contract No. DE-AC05-06OR23177. Publisher Copyright: {\textcopyright} 2017 American Physical Society.",
year = "2017",
month = nov,
day = "15",
doi = "10.1103/PhysRevLett.119.202004",
language = "English (US)",
volume = "119",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "20",
}