Testing models with non-minimal Higgs sector through the decay t->q+WZ

TL;DR

This paper investigates how charged Higgs bosons in extended Higgs models influence the rare top quark decay t->q+WZ, revealing potential observable branching ratios that could signal new physics beyond the Standard Model.

Contribution

It introduces a detailed analysis of charged Higgs effects on t->q+WZ decays within models with doublets and triplets, highlighting conditions for significant branching ratios.

Findings

Branching ratio for t->b+WZ can reach 0.0178 in certain models.

t->(d,s)+WZ decays can also have similar branching ratios.

Models respecting custodial symmetry and suppressing FCNCs predict observable decay rates.

Abstract

We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model that respect the custodial SU(2) symmetry and avoids flavour changing neutral currents by imposing discrete symmetries, the decay mode t->b+WZ, can reach a branching ratio of order 0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching ratio in models where flavour changing neutral currents are suppressed by flavour symmetries.