Timelike Compton Scattering in Ultraperipheral Collisions

TL;DR

This paper explores how ultraperipheral collisions can be used to study timelike Compton scattering, providing a new method to investigate the internal structure of nucleons through generalized parton distributions at small skewedness.

Contribution

It demonstrates that the TCS mechanism dominates in certain kinematic regions, enabling novel access to GPDs in the nucleon at small skewedness.

Findings

TCS mechanism dominates in specific kinematic regions.

Ultraperipheral collisions can effectively probe GPDs.

New insights into nucleon structure at small skewedness.

Abstract

Exclusive photoproduction of dileptons, gamma N ->l+l- N, is and will be measured in ultraperipheral collisions at hadron colliders. We demonstrate that the timelike deeply virtual Compton scattering (TCS) mechanism gamma q -> l+l- q, where the lepton pair comes from the subprocess gamma q -> gamma* q, dominates in some accessible kinematical regions, thus opening a new way to study generalized parton distributions (GPD) in the nucleon at small skewedness.