Precise Predictions for Event Shapes in Hadronic Higgs Decays

Abstract

We present NNLO QCD predictions for a wide range of event-shape observables in hadronic Higgs decays, taking into account the two dominant decay modes $H\to gg$ and $H\to b\bar{b}$. Specifically, we consider the six classical event shapes thrust, heavy jet mass, $C$-parameter, total and wide jet broadening, and the three-jet resolution $y_{23}$ in the Durham algorithm. We also present results for the soft-drop variant of thrust. Decays of the Higgs boson to two gluons are treated in the heavy-top limit, whereas decays to a bottom-quark pair are mediated by a non-vanishing Yukawa coupling, despite considering kinematically massless quarks. Our results highlight the importance of NNLO QCD corrections in the calculation of event-shape observables and provide means to quantify the intrinsic difference between the two Higgs decay modes.