Can one measure timelike Compton scattering at LHC ?

TL;DR

This paper explores the feasibility of measuring timelike Compton scattering at the LHC through exclusive dilepton photoproduction, highlighting its potential to probe nucleon structure via generalized parton distributions in high-energy collisions.

Contribution

It demonstrates that the timelike deeply virtual Compton scattering mechanism can dominate dilepton production in certain kinematic regions at hadron colliders, offering a new method to study GPDs.

Findings

TCS mechanism dominates in specific kinematic regions.

Interference between TCS and QED subprocesses enables GPD studies.

Feasibility of measuring TCS at LHC is discussed.

Abstract

Exclusive photoproduction of dileptons, gamma N->e+e-N, is and will be measured in ultraperipheral collisions at hadron colliders, such as the Tevatron, RHIC and the LHC . We demonstrate that the timelike deeply virtual Compton scattering (TCS) mechanism gamma q -> e+e- 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. High energy kinematics enables to probe parton distributions at small skewedness. This subprocess interferes at the amplitude level with the pure QED subprocess gamma gamma* -> e+e- where the virtual photon is radiated from the nucleon.