Lepton-number-violating decays of heavy flavors induced by doubly-charged Higgs boson

TL;DR

This paper investigates lepton-number-violating decays of heavy particles induced by a doubly-charged Higgs boson within the Higgs triplet model, finding suppressed tau decays but potentially observable top quark decays at the LHC.

Contribution

It provides the first detailed analysis of LNV heavy flavor decays mediated by doubly-charged Higgs bosons, highlighting their potential observability and constraints on the Higgs triplet model.

Findings

LNV tau decays are highly suppressed below experimental limits.

Top quark LNV decays could have branching ratios around 10^{-7} to 10^{-8}.

Observation of these decays would signal lepton-number violation and constrain the model parameters.

Abstract

We study lepton-number-violating (LNV) decays of heavy flavors ($\tau$ lepton and top quark) induced by doubly-charged Higgs boson in the Higgs triplet model. It is found that the branching fractions of LNV $\tau^- \to \ell^{+}M_1^-M_2^-$ decays are highly suppressed compared with the current experimental limits. On the other hand, for LNV top quark decays, the most optimistic branching ratios for $t \to b\ell^{+}\ell^{+}W^{-}$ turn out to be at the level of $\sim 10^{-7} - 10^{-8}$. The observation of these rare top quark decays would be a clear signal of LNV processes, and their non-observation would allow us to constraint the parameters of the Higgs triplet model.