CP violating anomalous couplings in $W\gamma$ and $Z\gamma$ production at the LHC

Abstract

The ATLAS and CMS collaborations have recently published new limits on CP conserving anomalous couplings from the $W\gamma$ and $Z\gamma$ production processes. We study the corresponding limits that can be placed on the CP violating anomalous couplings ${\kappa }_{t}ild{e}_{\gamma }$ and $h_{\gamma ,Z}^1$ at the LHC. We find that the process $pp-->W\gamma$ at 14 TeV can place the 95% CL limit $|{\kappa }_{t}ild{e}_{\gamma }|<0.05$ with 10 fb^{-1} which is comparable to the existing LHC bound on the CP conserving anomalous couplings ${\kappa }_{\gamma }$. Similarly, the process $pp-->Z\gamma$ can place the 95% CL limits $|h_{\gamma }^1|<20$ and $|h_Z^1|<40$ respectively. None of these limits is derived from a truly CP-odd observable so that it is not possible to separate the effects of the CP violating anomalous couplings from the rest.

Comments: 16 LaTex pages, 4 figures, 5 tables, accepted version for publication in Physical Review D