Light-by-light scattering in ultra-peripheral Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV with the ATLAS detector at the LHC

This note reports evidence for light-by-light scattering, using 480 $\mu$b$^{-1}$ of Pb+Pb collision data at $\sqrt{s_{NN}}=5.02$ TeV recorded by the ATLAS experiment at the LHC. After background subtraction and analysis corrections, the cross section of $\gamma\gamma\rightarrow\gamma\gamma$ process for photon transverse momentum, $E_\textrm{T}>3$ GeV, photon pseudorapidity, $|\eta|<2.4$, diphoton invariant mass greater than $6$ GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, has been measured to be $70 \pm 20~\textrm{(stat.)} \pm 17~\textrm{(syst.)}$ nb, which is in agreement with the SM prediction of $49 \pm 10$ nb.