Speaker
Description
The Large Hadron Collider (LHC) has paved the way for an increasingly deeper understanding of hadronic structure. Particularly exciting is the potential to exploit the high center-of-mass energies to investigate gluon saturation in nuclei and nucleons through Ultra Peripheral Collisions (UPC).
We consider the exclusive photoproduction of a photon-pion pair, $\gamma + P \rightarrow \gamma + \pi^0 + P$, as a promising channel to study gluon saturation. Furthermore, it has recently been demonstrated that this process does not admit a collinear factorization in terms of generalised parton distributions (GPDs) at the leading twist. In such a situation, a (generalized) $k_T$-dependent factorization, reliable at small-$x$, is a valid option, since the end-point singularities are naturally regularized by the transverse momenta of the $t$-channel gluons. The numerics from our analysis indicate that this process could be measured in UPCs at the LHC.
