Lepton-pair production in ultraperipheral collisions at AFTER@LHC

TL;DR

This paper explores the use of lepton-pair production in ultraperipheral collisions at a fixed-target experiment with LHC beams to study hadron structure, test theoretical models, and investigate various production mechanisms.

Contribution

It introduces the potential of ultraperipheral collisions at a fixed-target setup for probing hadron structure and testing photon approximation models with new experimental observables.

Findings

Lepton-pair production can serve as a luminosity monitor.

Azimuthal asymmetry measurements probe the hadron's internal structure.

Potential to study eta(c) production and Pomeron-Odderon fusion.

Abstract

We investigate the potentialities offered by the study of lepton-pair production in ultraperipheral collisions at a fixed-target experiment using the proton and ion LHC beams. In these collisions, exclusive or semi-exclusive lepton-pair production can be used as luminosity monitor as well as a check of the equivalent-photon approximation, via the measurement of the Bethe-Heitler cross section. It can also serve as a probe of the inner hadron structure via the measurement of the lepton-pair azimuthal asymmetry which is sensitive to the timelike virtual Compton scattering. We also briefly discuss the possibility offered by the study of eta(c) production. Finally, we outline the possibilities for lepton-pair production by Pomeron-Odderon fusion in exclusive pp and pA collisions.