Finite quark-mass effects in the NNLOPS POWHEG+MiNLO Higgs generator
Keith Hamilton, Paolo Nason, Giulia Zanderighi
TL;DR
The paper tackles the need for high-precision Higgs predictions in gluon-fusion by incorporating finite top- and bottom-quark masses into the NNLOPS POWHEG+MiNLO generator. It extends the existing large-$m_t$ effective-theory framework by implementing mass corrections at the HJ generator level, explores two MiNLO strategies for bottom-m mass logarithms (MEMB and RMB), and includes exact mass dependence at NLO in the HNNLO stage via approxim=2 for NNLO. A numerical study at 8 TeV with $m_H\approx125$ GeV shows that bottom-mass scheme choices and matrix-element implementation details influence cross sections, but the bottom-mass uncertainties remain within standard scale uncertainties. The work provides practical guidance for including finite-mass effects in NNLOPS Higgs simulations and assesses theoretical uncertainties related to bottom-quark logarithms in this context.
Abstract
We include finite top- and bottom-mass effects in the next-to-next-to-leading order parton shower (NNLOPS) event generator for inclusive Higgs boson production in gluon fusion based upon the POWHEG+MiNLO approach. Since fixed-order results for quark-mass effects only reach NLO accuracy, we add them to the NNLOPS generator at that accuracy. We explore uncertainties related to the unknown all-order logarithmic structure of bottom-mass effects by comparing the assumption of full exponentiation to no exponentiation at all. Phenomenological results showing the effects of finite quark-masses in the NNLOPS simulation are presented. These suggest that the aforementioned uncertainty is well contained within the envelope of plain renormalization and factorization scale uncertainties.