Probing Generalized Parton Distributions through the photoproduction of a $\gamma \pi$ pair

Abstract

We study in the framework of collinear QCD factorization the photoproduction of a $\gamma \pi$ pair with a large invariant mass and a small transverse momentum, as a new way to access generalized parton distributions. In the kinematics of JLab 12-GeV, we demonstrate the feasibility of this measurement and show the extreme sensitivity of the unpolarized cross section to the axial quark GPDs.

Comments: 7 pages, 4 figures, to appear in the proceedings of Diffraction and Low-x 2018, 26 August - 1 September 2018, Reggio Calabria, Italy