O(\alpha_s^2) corrections to the running top-Yukawa coupling and the mass of the lightest Higgs boson in the MSSM

TL;DR

This paper introduces a method for calculating the top-Yukawa coupling in supersymmetric models with heavy spectra, incorporating two-loop corrections and resummation techniques, leading to more precise Higgs mass predictions.

Contribution

It develops a novel approach combining running and decoupling procedures with two-loop SUSY-QCD corrections for improved Higgs mass predictions in MSSM.

Findings

Reduced renormalization scale dependence in Higgs mass predictions

Increased Higgs mass estimate due to resummation of large logs

Method effectively incorporates higher-order corrections

Abstract

In this paper we propose a method to compute the running top-Yukawa coupling in supersymmetric models with heavy mass spectrum based on the "running" and "decoupling" procedure. In order to enable this approach we compute the two-loop SUSY-QCD radiative corrections required in the decoupling process. The method has the advantage that large logarithmic corrections are automatically resummed through the Renormalization Group Equations. As phenomenological application we study the effects of this approach on the prediction of the lightest Higgs boson mass at three-loop accuracy. We observe a significant reduction of the renormalization scale dependence as compared to the direct method, that is based on the conversion relation between the running and pole mass for the top quark. The effect of resummation of large logarithmic contributions consists in an increased prediction for the Higgs boson mass, an observation in agreement with the previous analyses.