O(alpha_s^2) corrections to fermionic Higgs decays in the MSSM

TL;DR

This paper calculates second-order quantum chromodynamics corrections to Higgs decay processes in the MSSM, significantly refining theoretical predictions for Higgs decay widths.

Contribution

It provides the first computation of O(alpha_s^2) corrections to fermionic Higgs decays in the MSSM using an effective Lagrangian approach.

Findings

Corrections are sizable at large tan_beta and low CP-odd Higgs mass.

Theoretical uncertainties are reduced to below a few percent.

Results improve precision of Higgs decay width predictions.

Abstract

We compute the two-loop corrections of O(alpha_s^2) to the Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is performed using the effective Lagrangian approach under the approximation of neglecting the Higgs boson mass with respect to the top quark, gluino and all squark flavour masses. As an application we derive the O(alpha_s^2) corrections to the partial decay width of the lightest Higgs boson to a bottom quark pair. We find that the two-loop corrections are sizable for large values of tan_beta and low CP-odd Higgs boson mass. With our calculation of the O(alpha_s^2) corrections the remaining theoretical uncertainties reduce below a few percent.