Charged Higgs-Boson Decays into Quarks

We consider the full genuine next-to-leading order SUSY-QCD corrections to the charged Higgs decays into quarks supplemented by the NNLO corrections to the effective top and bottom Yukawa couplings. The NNLO corrections to the effective top Yukawa coupling are a new ingredient of our analysis. We arrive at an approximate NNLO prediction for MSSM charged Higgs decays after including the N$^4$LO QCD corrections for large charged Higgs masses. The residual uncertainties are in the percent range or below, depending on the particular MSSM scenario.