Naturally Large Radiative Lepton Flavor Violating Higgs Decay Mediated by Lepton-flavored Dark Matter

TL;DR

This paper explores a lepton-flavored dark matter model with scalar mediators that can produce large lepton flavor violating Higgs decays, potentially explaining experimental hints of h→τμ, while evading existing bounds.

Contribution

It introduces both left- and right-handed scalar leptons in a lepton-flavored dark matter model, enabling large LFV Higgs decay rates and addressing experimental anomalies.

Findings

Large LFV Higgs decay rates can be achieved in the model.

The model naturally evades bounds from τ→μγ decay.

Differences from previous models in relic density and direct detection are highlighted.

Abstract

In the standard model (SM), lepton flavor violating (LFV) Higgs decay is absent at renormalizable level and thus it is a good probe to new physics. In this article we study a type of new physics that could lead to large LFV Higgs decay, i.e., a lepton-flavored dark matter (DM) model which is specified by a Majorana DM and scalar lepton mediators. Different from other similar models with similar setup, we introduce both left-handed and right-handed scalar leptons. They allow large LFV Higgs decay and thus may explain the tentative Br$(h\ra\tau\mu)\sim1\%$ experimental results from the LHC. In particular, we find that the stringent bound from $\tau\ra\mu\gamma$ can be naturally evaded. One reason, among others, is a large chirality violation in the mediator sector. Aspects of relic density and especially radiative direct detection of the leptonic DM are also investigated, stressing the difference from previous lepton-flavored DM models.