MSSM Higgs Couplings to Bottom Quarks: Two-Loop Corrections

TL;DR

This paper calculates two-loop SUSY-QCD corrections to bottom Yukawa couplings in the MSSM, reducing theoretical uncertainties and improving predictions for Higgs decays at future colliders.

Contribution

It provides the first detailed two-loop SUSY-QCD corrections to effective bottom Yukawa couplings, including resummation of non-decoupling effects, enhancing precision in MSSM Higgs predictions.

Findings

Reduced scale dependence of Yukawa couplings from 10% to percent level

Improved accuracy of MSSM Higgs branching ratio predictions

Enhanced theoretical precision for future collider experiments

Abstract

We present the two-loop SUSY-QCD corrections to the effective bottom Yukawa couplings within the minimal supersymmetric extension of the Standard Model. The effective Yukawa couplings include the resummation of the non-decoupling corrections Delta m_b for large values of tg(beta). We have derived the two-loop SUSY-QCD corrections to the leading SUSY-QCD and top-induced SUSY-electroweak contributions to Delta m_b. The scale dependence of the resummed Yukawa couplings is reduced from O(10%) to the per-cent level. These results reduce the theoretical uncertainties of the MSSM Higgs branching ratios to the accuracy which can be achieved at a future linear e+e- collider.