# Probing axial quark generalized parton distributions through exclusive photoproduction of a γπ ± pair with a large invariant mass

Duplančić, G. (0000 0004 0635 7705, Theoretical Physics Division, Rudjer Bošković Institute, HR-10002, Zagreb, Croatia) ; Passek-Kumerički, K. (0000 0004 0635 7705, Theoretical Physics Division, Rudjer Bošković Institute, HR-10002, Zagreb, Croatia) ; Pire, B. (0000 0001 2165 9021, Centre de Physique Théorique, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128, Palaiseau, France) ; Szymanowski, L. (0000 0001 0941 0848, National Center for Nuclear Research (NCBJ), Warsaw, Poland) ; Wallon, S. (Laboratoire de Physique Théorique, UMR 8627, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France) (0000 0001 2308 1657, Sorbonne Université, Faculté de Physique, 4 place Jussieu, 75252, Paris Cedex 05, France)

29 November 2018

Abstract: Exclusive photoproduction of a γπ ± pair in the kinematics where the pair has a large invariant mass and the final nucleon has a small transverse momentum is described in the collinear factorization framework. The scattering amplitude is calculated at leading order in α s and the differential cross sections for the process are estimated in the kinematics of the JLab 12-GeV experiments. The order of magnitude of the predicted cross-sections seems sufficient for a dedicated experiment to be performed. The process turns out to be very sensitive to the axial generalized parton distribution combination H ˜ u − H ˜ d ${\tilde{H}}_u-{\tilde{H}}_d$ .

Published in: JHEP 1811 (2018) 179