$h\to \mu \tau$ at Hadron Colliders

Abstract

We study the observability for a lepton flavor-changing decay of a Higgs boson $h\to \mu \tau$ at hadron colliders. Flavor-changing couplings of a Higgs boson exist at tree level in models with multiple Higgs doublets. The $h\mu \tau$ coupling is particularly motivated by the favorable intepretation of ${\nu }_{\mu }-{\nu }_{\tau }$ oscillation. We find that at the Tevatron Run II the unique $\mu \tau$ signature could serve as the Higgs discovery channel, surpassing expectations for Higgs boson searches in the SM and in a large parameter region of the MSSM. The sensitivity will be greatly improved at the LHC, beyond the coverage at a muon collider Higgs factory.

Comments: Version to appear in PRL