Imprints of massive inverse seesaw model neutrinos in lepton flavor violating Higgs boson decays

TL;DR

This paper investigates lepton flavor violating Higgs decays within the inverse seesaw model, calculating branching ratios and ensuring consistency with neutrino data and radiative decay constraints, revealing potential observable signals beyond the Standard Model.

Contribution

It provides a comprehensive one-loop analysis of LFV Higgs decays in the inverse seesaw model, considering full parameter space and experimental constraints, which was not previously detailed.

Findings

Predicted LFV Higgs decay rates can be within experimental reach.

Correlated predictions for radiative decays are consistent with current bounds.

Maximum allowed LFV Higgs decay rates are identified within the model constraints.

Abstract

In this paper we consider a Higgs boson with mass and other properties compatible with those of the recently discovered Higgs particle at the LHC, and explore the possibility of new Higgs leptonic decays, beyond the standard model, with the singular feature of being lepton flavor violating (LFV). We study these LFV Higgs decays, $H \to l_k\bar l_m$, within the context of the inverse seesaw model (ISS) and consider the most generic case where three additional pairs of massive right-handed singlet neutrinos are added to the standard model particle content. We require in addition that the input parameters of this ISS model are compatible with the present neutrino data and other constraints, like perturbativity of the neutrino Yukawa couplings. We present a full one-loop computation of the BR($H \to l_k\bar l_m$) rates for the three possible channels, $l_k\bar l_m=\mu \bar \tau,\, e \bar \tau,\, e \bar \mu$, and analyze in full detail the predictions as functions of the various relevant ISS parameters. We study in parallel the correlated one-loop predictions for the radiative decays, $l_m \to l_k \gamma$, within this same ISS context, and require full compatibility of our predictions with the present experimental bounds for the three radiative decays, $\mu \to e \gamma$, $\tau \to \mu \gamma$, and $\tau \to e \gamma$. After exploring the ISS parameter space we conclude on the maximum allowed LFV Higgs decay rates within the ISS.