Neutral Higgs Bosons in the Higgs Triplet Model with nontrivial mixing

TL;DR

This paper analyzes the neutral Higgs sector in the Higgs Triplet Model with mixing, exploring how it can explain observed Higgs signals and predicting distinctive decay patterns that could be tested at the LHC.

Contribution

It provides a detailed study of Higgs mixing effects in the triplet model and identifies conditions for enhanced gamma gamma decay rates, offering potential experimental signatures.

Findings

Enhanced gamma gamma decay possible only for mixed heavier Higgs

Branching ratios into WW*, ZZ*, bb, tau tau are similar or reduced compared to SM

Distinctive correlations between Z gamma and gamma gamma decay modes

Abstract

We revisit the neutral Higgs sector of the Higgs Triplet Model, with non-negligible mixing in the CP-even Higgs sector. We examine the possibility that one of the Higgs boson state is the particle observed at the LHC at 125 GeV, and the other is either the small LEP excess at 98 GeV; or the CMS excess at 136 GeV; or that the neutral Higgs bosons are (almost) degenerate and have both mass 125 GeV. We show that, under general considerations, an (unmixed) neutral Higgs boson cannot have an enhanced decay branching ratio into gamma gamma with respect to the Standard Model one. An enhancement is however possible for the mixed case, but only for the heavier of the two neutral Higgs bosons, and not for mass-degenerate Higgs bosons. At the same time the branching ratios into WW^*,ZZ^*, bb and tau tau are similar to the Standard Model, or reduced. We correlate the branching ratios of both Higgs states into Z gamma to those into gamma gamma for the three scenarios. The mixed neutral sector of the Higgs triplet model exhibits some features which could distinguish it from other scenarios at the LHC.