Matched predictions for the bb¯ H cross section at the 13 TeV LHC

Abstract

We present up-to-date matched predictions for the bb¯ H inclusive cross section at the LHC at s=13 TeV. Using a previously developed method, our predictions consistently combine the complete NLO contributions that are present in the 4-flavor scheme calculation, including finite b-quark mass effects as well as top-loop induced YbYt interference contributions, with the resummation of collinear logarithms of mb/mH as present in the 5-flavor scheme calculation up to NNLO. We provide a detailed estimate of the perturbative uncertainties of the matched result by examining its dependence on the factorization and renormalization scales, the scale of the Yukawa coupling, and also the low b-quark matching scale in the PDFs. We motivate the use of a central renormalization scale of mH/2, which is halfway between the values typically chosen in the 4-flavor and 5-flavor scheme calculations. We evaluate the parametric uncertainties due to the PDFs and the b-quark mass, and in particular discuss how to systematically disentangle the parametric mb dependence and the unphysical b-quark matching scale dependence. Our best prediction for the bb¯ H production cross section in the Standard Model at 13 TeV and for mH = 125 GeV is σ(bb¯H)=0.52pb[1±9.6%(perturbative)−3.6%+2.9%(parametric)]. We also provide predictions for a range of Higgs masses mH ∈ [50, 750] GeV. Our method to compute the matched prediction and to evaluate its uncertainty can be readily applied to other heavy-quark-initiated processes at the LHC.