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$\to$PbPb$γγ$ cross section is calculated within equivalent photon approximation in the impact parameter space. Several differential distributions are presented and discussed. We predict 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-$π^0$ background which can, in principle, be eliminated at the new kinematical range for the ALICE 3 measurements by imposing dedicated cuts on diphoton transverse momentum and$\slash$or so-called vector asymmetry.