Angularity in Higgs boson decays via H→gg at NNLL' accuracy*

Abstract We present improved predictions of a class of event-shape distributions called angularity for a contribution from an effective operator in Higgs hadronic decay that suffers from large perturbative uncertainties. In the framework of the soft-collinear effective theory, logarithmic terms of the distribution are resummed at NNLL' accuracy, for which a two-loop constant of gluon-jet function for angularity is independently determined using a fit to the fixed-order distribution at the NLO corresponding to relative to the Born rate. Our determination has reasonable agreement with the value in a recently released thesis. In the fit, we use an asymptotic form with a fractional power conjectured from recoil corrections at one-loop order, and it improves the accuracy of determining positive values of the angularity parameter a . The resummed distribution is matched to the NLO fixed-order results to make our predictions valid at all angularity values. We also discuss the first and subtracted moments of angularity as a function of a that enable the extraction of information on leading and subleading nonperturbative corrections associated with gluons.