Studying $WW\gamma$ and $WZ\gamma$ production in proton-proton collisions at $\sqrt{s} = 8$ TeV with the ATLAS experiment

TL;DR

This study investigates the production of $WW\gamma$ and $WZ\gamma$ events in proton-proton collisions at 8 TeV using the ATLAS detector, testing quartic gauge couplings and searching for new physics through cross-section measurements and limits.

Contribution

It provides the first measurement of $WW\\gamma$ production cross-section at 8 TeV and sets limits on anomalous quartic gauge couplings using effective field theory.

Findings

Measured $WW\\gamma$ production cross-section in fiducial regions.

Set upper limits on $WW\\gamma$ and $WZ\\gamma$ production cross-sections.

Derived constraints on anomalous quartic gauge couplings.

Abstract

Quartic gauge couplings are tested by this study of the production of $WW\gamma$ and $WZ\gamma$ events in 20.2 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of $\sqrt{s} = 8$ TeV recorded with the ATLAS detector at the LHC. The final state of $WW\gamma$ events containing an electron, a muon and a photon is analysed as well as the final states of $WW\gamma$ and $WZ\gamma$ production containing an electron or a muon, two jets and a photon. For all final states two different fiducial regions are defined: one yielding the best sensitivity to the production cross-section of the process and one optimised for the detection of new physical phenomena. In the former region, the $WW\gamma$ production cross-section is computed and in both regions, upper limits on the $WW\gamma$ and $WZ\gamma$ production cross-section are derived. The results obtained in the second phase space are combined for the interpretation in the context of anomalous quartic gauge couplings using an effective field theory.