Deeply virtual Compton scattering cross section at high Bjorken $x_B$

TL;DR

This paper presents high-precision measurements of the DVCS cross section at high Bjorken x, enabling the first extraction of all four helicity-conserving Compton Form Factors and providing new insights into the nucleon's internal structure.

Contribution

It introduces the first experimental extraction of all four helicity-conserving CFFs at high x_B, using exact analytic expressions and high-precision data.

Findings

Demonstrates sensitivity to poorly known CFFs

Provides detailed x_B dependence of CFFs

Validates analytic expressions for DVCS cross section

Abstract

We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable $x_B$. DVCS is sensitive to the Generalized Parton Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of $x_B$, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.