Revealing transversity GPDs through the photoproduction of a photon and   a $\rho$ meson
  Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We discuss the production of a photon and a meson, where the wide angle Compton scattering on a meson subprocess factorizes from generalized parton distribution. We calculate at dominant twist and leading order in $\alpha_s$, the production cross-section of a transversely polarized $\rho$ meson which is sensitive to chiral-odd GPDs, and show that it may be measurable in near future JLab experiments. 
R. Boussarie, B. Pire, L. Szymanowski, S. Wallon
hep-ph hep-ex nucl-ex nucl-th