Lepton flavor violating Higgs boson decay H --> mu tau at muon colliders

Abstract

We consider an effective nondiagonal coupling $H\bar{\mu }\tau$ and present the analysis of the Higgs boson mediated lepton-flavor violating (LFV) reaction ${\mu }^{-}{\mu }^{+}-->\mu \tau$. For a Higgs boson mass around 115 GeV and convenient values of the strength of the coupling $H\bar{\mu }\tau$, which are within the bounds obtained from the experimental limits on the LFV decays $\tau -->\eta \mu$ and $\tau -->\mu \gamma$, we found that there would be up to a few hundreds of $\mu \tau$ events per year at a muon collider running with an integrated luminosity of $1f{b}^{-1}$. We paid special attention on the background for this LFV reaction, which arises from the standard model process ${\mu }^{-}{\mu }^{+}-->\mu \tau {\bar{\nu }}_{\mu }{\nu }_{\tau }$, and discuss how it can be separated from the main signal.

10 pages, 6 figures