Improved SUSY QCD corrections to Higgs boson decays into quarks and squarks

TL;DR

This paper refines the calculation of supersymmetric QCD corrections to Higgs decays into quarks and squarks, addressing large correction issues and improving the reliability of decay width predictions in the MSSM.

Contribution

It introduces a method to stabilize SUSY QCD corrections by choosing appropriate Higgs couplings based on running parameters, enhancing decay width calculations.

Findings

Corrected decay widths remain positive and reliable for large 

The approach reduces large correction uncertainties in Higgs decay predictions

Numerical results demonstrate improved accuracy for  decays in MSSM

Abstract

We improve the calculation of the supersymmetric $O(\alpha_s)$ QCD corrections to the decays of Higgs bosons into quarks and squarks in the Minimal Supersymmetric Standard Model. In the on-shell renormalization scheme these corrections can be very large, which makes the perturbative expansion unreliable. This is especially serious for decays into bottom quarks and squarks for large $\tan\beta$. Their corrected widths can even become negative. We show that this problem can be solved by a careful choice of the tree-level Higgs boson couplings to quarks and squarks, in terms of the QCD and SUSY QCD running quark masses, running trilinear couplings $A_q$, and on-shell left-right mixing angles of squarks. We also present numerical results for the corrected partial decay widths for the large $\tan\beta$ case.