Light-by-light scattering cross-section measurements at LHC

Abstract

This note represents an attempt to gather the input related to light-by-light scattering ($\gamma\gamma$) cross-section measurements at LHC with the aim of checking the consistency with different standard model predictions. For the first time, we also consider the contribution from the $\eta_b(1S)$ meson production to the diphoton invariant mass distribution, by calculating its inclusive photoproduction cross-section. Using a simplified set of assumptions, we find a result of $115\pm 19\,\,\text{nb}$, consistent with standard model predictions within two standard deviations. Although an improved determination of the integrated fiducial $\textrm{PbPb}\,(\gamma\gamma)\to \textrm{Pb}^{(\ast)}\textrm{+}\textrm{Pb}^{(\ast)}\,\gamma\gamma$ cross-section by approximately 10\% could be potentially achieved relative to current measurements, further improvements are expected with the inclusion of existing or forthcoming LHC nuclear data.