QCD and SUSY-QCD corrections to the Three-Body Decay of the Charged Higgs Boson

TL;DR

This paper calculates QCD and SUSY-QCD corrections to the three-body decay of the charged Higgs in the MSSM, showing significant effects that impact Higgs search strategies.

Contribution

It provides the first detailed analysis of both standard and supersymmetric QCD corrections to this decay mode within the MSSM, highlighting their importance.

Findings

QCD corrections increase decay width by about 12%.

SUSY-QCD corrections can be comparable or larger than standard QCD corrections.

Large stop mixing enhances SUSY-QCD effects.

Abstract

The ${\cal O}(\alpha_s)$ QCD corrections to the three-body decay width of the charged Higgs $\Gamma$($H^+\to W^+b\bar{b}$) are discussed in the MSSM model. Our calculations indicate that the standard QCD corrections to the three-body decay mode raise the width by about 12% and the supersymmetric QCD corrections(due to $\tilde{g}, \tilde{t}, \tilde{b}$ exchanges) can be comparable to or even larger than the standard QCD corrctions in some regions of the supersymmetric parameter space. This is mainly due to the effect of large left-right mixing of stop($\tilde{t}$). It could significantly affect the phenomenology of the $H^+$ search.