Speaker
Description
In this talk, I will discuss the exclusive photoproduction of a photon-meson pair with large $p_T$ as a channel to probe GPDs. Like other $2 \to 3$ exclusive processes, this channel allows us to better study the $x$-dependence of GPDs, unlike other $2 \to 2$ processes such as DVCS which give "moment-type" information. Moreover, it also gives the possibility to access chiral-odd GPDs at the leading twist, which is completely unknown experimentally. The computation of the amplitude is performed at leading order and leading twist. The various mesons we consider are charged pions, and rho mesons of any charge and polarisation. I will also discuss the possibility of measuring such processes at various experiments, namely JLab, COMPASS, future EIC and LHC in ultra-peripheral collisions. In particular, in collider experiments, the dependence of GPDs at small skewness ($<10^{-3}$) can be extracted. I will discuss our recent progress in computing $\pi^0 \gamma$ photoproduction, where gluonic GPD contributions enter, as well as the extension of the calculation to next-to-leading order.
