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 $\kappa_tilde_\gamma$ and $h^1_{\gamma, Z}$ at the LHC. We find that the process $pp --> W\gamma$ at 14 TeV can place the 95% CL limit $|\kappa_tilde_\gamma| <~ 0.05$ 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 $|h^1_\gamma| <~ 20$ and $|h^1_Z| <~ 40$ 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.