A search for WWgamma and WZgamma production and constraints on anomalous quartic gauge couplings in pp collisions at sqrt{s}=8 TeV

A search for WV gamma triple vector boson production is presented based on
events containing a W boson decaying to a muon or an electron and a neutrino, a
second V (W or Z) boson, and a photon. The data correspond to an integrated
luminosity of 19.3 inverse femtobarns collected in 2012 with the CMS detector
at the LHC in pp collisions at sqrt(s) = 8 TeV. An upper limit of 311 fb on the
fiducial cross section for the WV gamma production process is obtained at 95%
confidence level for photons with a transverse energy above 30 GeV and with an
absolute value of pseudorapidity of less than 1.44. This limit is approximately
a factor of 3.4 larger than the standard model predictions that are based on
next-to-leading order QCD calculations. Since no evidence of anomalous WW gamma
gamma or WWZ gamma quartic gauge boson couplings is found, this paper presents
the first experimental limits on the dimension-8 parameter f[T,0] and the
CP-conserving WWZ gamma parameters kappa[0,W] and kappa[C,W]. Limits are also
obtained for the WW gamma gamma parameters a[0,W] and a[C,W].