2017/10/31 by Klusek-Gawenda, Mariola, Szczurek, Antoni
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.1710.11466
We study dilepton, proton-antiproton and diphoton production in ultraperipheral lead-lead collisions at √sNN = 5.02 and 5.5 TeV. The nuclear calculations are based on equivalent photon approximation in the impact parameter space. For correct description of the γγ→ pp Belle data we include the proton-exchange, the f2(1270) and f2(1950) s-channel exchanges, as well as the handbag mechanism. For four muon production, we take into account electromagnetic (two-photon) double-scattering production and direct γγ production of four muons in one scattering. The cross sections for elementary γγ→ γγ subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution. We find that the cross section for elastic γγ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to Wγγ ≈ 15 - 20 GeV. Our Standard Model predictions are compared with a recent ATLAS experimental result. We discuss results for PbPb→PbPbμ+μ-μ+μ-, PbPb→PbPbe+e-e+e-, PbPb→PbPbpp and PbPb→PbPbγγ reactions at LHC energy.