Lepton-number-violating decays of singly-charged Higgs bosons in the minimal type-(I+II) seesaw model at the TeV scale

TL;DR

This paper studies lepton-number-violating decays of charged Higgs bosons in a minimal seesaw model at the TeV scale, revealing how neutrino parameters and heavy neutrino contributions influence decay probabilities and CP violation effects.

Contribution

It provides a detailed analysis of how light and heavy neutrino parameters affect charged Higgs decay branching ratios in the minimal type-(I+II) seesaw model at TeV energies.

Findings

Decay branching ratios depend on light and heavy neutrino parameters.

Interference effects between light and heavy neutrinos can significantly alter decay probabilities.

Majorana CP phases can influence the magnitude of decay branching ratios.

Abstract

The lepton-number-violating decays of singly-charged Higgs bosons H^\pm are investigated in the minimal type-(I+II) seesaw model with one SU(2)_L Higgs triplet \Delta and one heavy Majorana neutrino N_1 at the TeV scale. We find that the branching ratios {\cal B}(H^+ \to l^+_\alpha{\bar \nu}) (for \alpha = e, \mu, \tau) depend not only on the mass and mixing parameters of three light neutrinos \nu_i (for i = 1, 2, 3) but also on those of N_1. Assuming the mass of N_1 to lie in the range of 200 GeV to 1 TeV, we figure out the generous interference bands for the contributions of \nu_i and N_1 to {\cal B}(H^+ \to l^+_\alpha{\bar \nu}). We illustrate some salient features of such interference effects by considering three typical mass patterns of \nu_i, and show that the relevant Majorana CP-violating phases can affect the magnitudes of {\cal B}(H^+ \to l^+_\alpha{\bar \nu}) in this parameter region.