First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region

Area of Science:

• Nuclear physics
• Particle physics
• Hadron structure

Background:

• Deeply Virtual Compton Scattering (DVCS) is a key process for probing generalized parton distributions.
• Generalized parton distributions offer insights into the three-dimensional structure of the nucleon.
• Existing experimental data on DVCS has limited coverage in certain kinematic regions.

Purpose of the Study:

• To perform the first measurement of the DVCS beam-spin asymmetry.
• To extend the kinematic coverage (Q^2 and Bjorken-x) for DVCS measurements.
• To provide precise new data for constraining theoretical models of nucleon structure.

Main Methods:

• Utilized the CLAS12 spectrometer at Jefferson Lab.
• Employed a 10.2 and 10.6 GeV longitudinally polarized electron beam.
• Scattered the electron beam off unpolarized protons.

Main Results:

• Reported the first measurement of the DVCS beam-spin asymmetry.
• Extended the Q^2 and Bjorken-x phase space significantly beyond previous experiments.
• Acquired 1600 new data points with high statistical precision.

Conclusions:

• The new data provide unprecedented constraints for phenomenological studies of generalized parton distributions.
• This measurement advances our understanding of the 3D structure of the proton.
• The results pave the way for future precision studies of nucleon structure.