Evidence of $W\gamma\gamma$ production in $pp$ collisions at $\sqrt{s}=8$ TeV and limits on anomalous quartic gauge couplings with the ATLAS detector

Understand

This Letter reports evidence of triple gauge boson production $pp\to W(\ell\nu)\gamma\gamma + X$, which is accessible for the first time with the 8 TeV LHC data set.

• The fiducial cross section for this process is measured in a data sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$, collected by the ATLAS detector in 2012.
• Events are selected using the $W$ boson decay to $e\nu$ or $\mu\nu$ as well as requiring two isolated photons.
• The measured cross section is used to set limits on anomalous quartic gauge couplings in the high diphoton mass region.