Lepton-flavor-violating Higgs decay $h \to \mu\tau$ and muon anomalous magnetic moment in a general two Higgs doublet model

TL;DR

This paper explores how a general two Higgs doublet model can explain the CMS observed excess in lepton-flavor-violating Higgs decay and address the muon g-2 anomaly, predicting observable rare tau decays.

Contribution

It demonstrates that flavor-changing neutral currents in a general 2HDM can simultaneously explain the CMS $h o $ excess and the muon g-2 discrepancy, linking these phenomena.

Findings

The model can account for the CMS excess in $h o $ decay.

It provides a resolution to the muon g-2 anomaly.

Predicts sizable $\tau \to \mu \gamma$ decay rate within future experimental reach.

Abstract

A two Higgs doublet model (2HDM) is one of the minimal extensions of the Standard Model (SM), and it is well-known that the general setup predicts the flavor-violating phenomena, mediated by neutral Higgs interactions. Recently the CMS collaboration has reported an excess of the lepton-flavor-violating Higgs decay in $h \rightarrow \mu \tau$ channel with a significance of 2.5 $ \sigma$. We investigate the CMS excess in a general 2HDM with tree-level Flavor Changing Neutral Currents (FCNCs), and discuss its impact on the other physical observations. Especially, we see that the FCNCs relevant to the excess can enhance the neutral Higgs contributions to the muon anomalous magnetic moment, and can resolve the discrepancy between the measured value and the SM prediction. We also find that the couplings to be consistent with the muon g-2 anomaly as well as the CMS excess in $h\rightarrow \mu\tau$ predict the sizable rate of $ \tau \rightarrow \mu \gamma$, which is within the reach of future B factory.