The lepton flavor violating signal of the extra gauge boson Z′ in photon-photon collision at the ILC

Abstract

The hitherto unconstrained lepton flavor mixings, induced by the new gauge boson Z′, which are the prediction of many new physics models, such as topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models, may lead to the lepton flavor violating productions of τ $$ \bar \mu $$ , τ $$ \bar e $$ and µ $$ \bar e $$ in photon-photon collision at the proposed International Linear Collider (ILC). Through a comparative analysis of these processes, we find that the better channel to probe the new physics models is the production of τ $$ \bar \mu $$ or τ $$ \bar e $$ which occurs at a much higher rate than µ $$ \bar e $$ production due to the large mixing angle and the large flavor changing coupling, and may reach the detectable level of the ILC for a large part of the parameter space. Since the rates predicted by the Standard Model are far below the detectable level, these processes may serve as a sensitive probe for such new physics models.