Light-by-light scattering in ultraperipheral collisions of heavy ions with future FoCal and ALICE 3 detectors

Abstract

I present possible future studies of light-by-light scattering using FoCal@ALICE and ALICE 3 detectors. Different mechanisms are discussed. The PbPb → PbPb γγ cross section is calculated within the equivalent photon approximation in the impact parameter space. Several differential distributions are presented and discussed.

We predict the cross section in the (mb-b) range for typical ALICE 3 cuts, a few orders of magnitude larger than for the current ATLAS or CMS experiments. We also consider the two-π⁰ background, which can, in principle, be eliminated in the new kinematical range for the ALICE 3 measurements by imposing dedicated cuts on diphoton transverse momentum and/or so-called vector asymmetry.