A Search for WWgamma and WZgamma production in pp Collisions at sqrt(s) = 8 TeV.

A study of the WV$\gamma$ three vector boson production and the anomalous quartic gauge boson couplings is presented, based on events containing a W boson decaying to leptons, a second V (W or Z) boson decaying to two jets, and a photon. The data analyzed corresponds to an integrated luminosity of 19.3~fb$^{-1}$ from pp collisions at $\sqrt{s}$ = 8~TeV collected in 2012 by the CMS detector at the Large Hadron Collider. With the selection criteria used, the number of observed events in data is 322, while the estimated background yield is 341.5~$\pm$~15.8. This is consistent with the standard model next-to-leading order QCD predictions, and corresponds to an upper limit of 241~fb at 95\% confidence level for WV$\gamma$ with photon $\pt >$~10~GeV. No evidence of anomalous WW$\gamma\gamma$ and WWZ$\gamma$ quartic gauge boson couplings is found. The following 95\% confidence level upper limits are obtained for these couplings: \begin{align*} -21 &< a_{0}^{W}/\Lambda^{2} < 20 \unit{TeV}^{-2}, \\ -34 &< a_{C}^{W}/\Lambda^{2} < 32 \unit{TeV}^{-2}, \\ -25 &< f_{T,0}/\Lambda^{4} < 24 \unit{TeV}^{-4}, \\ -12 &< \kappa_{0}^{W}/\Lambda^{2} < 10 \unit{TeV}^{-2} \textrm{, and} \\ -18 &< \kappa_{C}^{W}/\Lambda^{2} < 17 \unit{TeV}^{-2}. \end{align*} These are the first ever limits on the pure dimension 8 WW$\gamma\gamma$ parameter $f_{T,0}$ and CP conserving WWZ$\gamma$ parameters $\kappa_0^W$ and $\kappa_C^W$.