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arXiv · 1710.10868

$γγ\to γγ$ scattering in ultrarelativistic UPC

Antoni Szczurek·Mariola Klusek-Gawenda
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Abstract

We discuss diphoton semi(exclusive) production in ultraperipheral lead-lead collisions at energy of $\sqrt{s_{NN}}$ = 5.5 TeV (LHC) and in proton-proton collisions at $\sqrt{s_{pp}}$ = 7 TeV (LHC) and $\sqrt{s_{pp}}$ = 100 TeV (FCC). The nuclear calculations are based on equivalent photon approximation in the impact parameter space. The cross sections for elementary $γγ\to γγ$ 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 get relatively high cross sections in heavy ion collisions. This opens a possibility to study the light-by-light (quasi)elastic scattering at the LHC. 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 $W_{γγ} \approx$ 15 - 20 GeV. Our Standard Model predictions are compared to a recent ATLAS experimental result. We present differential distributions for PbPb$\to$PbPb$γγ$ and pp$\to$pp$γγ$ reaction.

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Antoni Szczurek, Mariola Klusek-Gawenda. 2017-11-14. $γγ\to γγ$ scattering in ultrarelativistic UPC. https://arxiv.org/abs/1710.10868

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