Timelike Compton Scattering from JLAB to RHIC and LHC energies

TL;DR

This paper reviews recent advances in Timelike Compton Scattering (TCS), highlighting its potential to probe nucleon structure through GPDs, and discusses upcoming experimental opportunities at JLab, RHIC, and LHC.

Contribution

It provides a comprehensive overview of TCS, emphasizing the theoretical relations to DVCS and the prospects for experimental measurements at various colliders.

Findings

Analyticity and factorization relate NLO corrections of TCS to DVCS.

Upcoming high-energy TCS data expected from JLab 12 GeV.

Ultraperipheral collisions at RHIC and LHC can access small skewness GPDs.

Abstract

Timelike Compton scattering (TCS) i.e. the exclusive photoproduction of a lepton pair with large invariant mass nicely complements the already successful experimental study of deeply virtual Compton scattering (DVCS). The same Generalized Parton Distributions enter both amplitudes, which offer a promissing way to access the quark and gluon nucleon structure. We review recent progress in this domain, emphasizing the fact that analyticity and factorization properties dictate the relation of the NLO corrections to TCS to those of DVCS. We also stress that data on TCS at high energy should be available soon thanks to the proposed experimental program at JLab at 12 GeV, and that, before the future high energy electron ion colliders become reality, the study of ultraperipheral collisions at the RHIC and LHC may open a window on quark and gluon GPDs at very small skewness. .