Speaker
Description
Higgs production in association with quarks (QQH) offers an interesting setting to study heavy-quark mass effects and the interplay between factorisation schemes in precision QCD. We present a strategy to combine the massive- (4FS in bbH) and massless schemes (5FS in bbH) consistently at the fully differential level for fixed-order QQH predictions in a general-mass variable-flavour-number scheme (GM-VFNS).
We discuss a method to isolate power corrections in the 4FS in a gauge-invariant and fully differential manner, providing the complementary ingredient to the 5FS calculation needed for a complete description of mass effects in Higgs observables. The logarithmic contributions of the massive scheme are captured through space-like Operator Matrix Elements (OMEs), while a slicing in the heavy-quark mass isolates the constant terms and validates the matching. Subtracting these from the 4FS result leaves the genuine power corrections, which are then added to the 5FS differential predictions.
We show fixed-order results for Higgs observables at second and third order in the strong coupling constant. We conclude by discussing an alternative GM-VFNS scheme based on the ACOT formalism, which provides a different organisation of mass contributions in QQH predictions.