Study of WW gamma and WZ gamma production in pp collisions at root s=8 TeV and search for anomalous quartic gauge couplings with the ATLAS experiment

Abstract

This paper presents a study of

W W γ

and

W Z γ

triboson production using events from proton-proton collisions at a centre-of-mass energy of

s

= 8

TeV

recorded with the ATLAS detector at the LHC and corresponding to an integrated luminosity of 20.2 fb

- 1

. The

W W γ

production cross-section is determined using a final state containing an electron, a muon, a photon, and neutrinos (

e ν μ ν γ

). Upper limits on the production cross-section of the

e ν μ ν γ

final state and the

W W γ

and

W Z γ

final states containing an electron or a muon, two jets, a photon, and a neutrino (

e ν j j γ

or

μ ν j j γ

) are also derived. The results are compared to the cross-sections predicted by the Standard Model at next-to-leading order in the strong-coupling constant. In addition, upper limits on the production cross-sections are derived in a fiducial region optimised for a search for new physics beyond the Standard Model. The results are interpreted in the context of anomalous quartic gauge couplings using an effective field theory. Confidence intervals at 95% confidence level are derived for the 14 coupling coefficients to which

W W γ

and

W Z γ

production are sensitive.