Probing $WWγ$ coupling through $e^- γ\rightarrow ν_e W^-$ at ILC

Abstract

The anomalous $WWγ$ coupling is probed through $eγ\rightarrow νW$ at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Cross section measurements can probe $δκ_γ$ to about $\pm 0.004$ for a luminosity of 100 fb$^{-1}$ at $500$ GeV center-of-mass energy with unpolarized electron beam. The limits derivable on $λ_γ$ from the total cross section are comparatively more relaxed. Exploiting the energy-angle double distribution of the secondary muons, kinematic regions sensitive to these couplings are identified. The derivable limit on $λ_γ< 0$ could be improved to a few per-mil, focusing on such regions. More importantly, the angular distributions at fixed energy values, and energy distribution at fixed angles present very interesting possibility of distinguishing the case of $λ_γ<0$ and $λ_γ\ge 0$.