18 research outputs found
Light-by-light scattering in ultraperipheral collisions of heavy ions with future FoCal and ALICE 3 detectors
We discuss possible future studies of photon-photon (light-by-light)
scattering using a planned FoCal and ALICE 3 detectors. We include different
mechanisms of scattering, such as double-hadronic
photon fluctuations, -channel neutral pion exchange or resonance
excitations () and deexcitation ().
The broad range of (pseudo)rapidities and lower cuts on transverse momenta open
a necessity to consider not only dominant box contributions but also other
subleading contributions. Here we include low mass resonant ,
, contributions. The resonance contributions give intermediate
photon transverse momenta. However, these contributions can be eliminated by
imposing windows on di-photon invariant mass. We study and quantify individual
box contributions (leptonic, quarkish). The electron/positron boxes dominate at
low GeV di-photon invariant masses. The
PbPbPbPb cross section is calculated within equivalent
photon approximation in the impact parameter space. Several differential
distributions are presented and discussed. We consider four different kinematic
regions. 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- background which can, in principle, be
eliminated at the new kinematical range for the ALICE 3 measurements by
imposing dedicated cuts on di-photon transverse momentum and\or so-called
vector asymmetry.Comment: 20 pages, 19 Figures, 3 Tables; misprint corrected, 1 figure adde