NNLO QCD corrections to associated $WH$ production and $H \to b \bar b$ decay

TL;DR

This paper calculates NNLO QCD corrections for associated WH production and H to b bbar decay at the LHC, revealing significant impacts on kinematic distributions and demonstrating the effectiveness of a nested soft-collinear subtraction scheme.

Contribution

It presents the first fully differential NNLO QCD calculation for associated WH production and Higgs decay to b bbar, including new decay contributions and advanced subtraction techniques.

Findings

Significant corrections to kinematic distributions involving Higgs decay products.

Impact of W boson transverse momentum cuts on radiative corrections.

Validation of the nested soft-collinear subtraction scheme for NNLO calculations.

Abstract

We present a computation of the next-to-next-to-leading order (NNLO) QCD corrections to the production of a Higgs boson in association with a W boson at the LHC and the subsequent decay of the Higgs boson into a b-bbar pair, treating the b-quarks as massless. We consider various kinematic distributions and find significant corrections to observables that resolve the Higgs decay products. We also find that a cut on the transverse momentum of the W boson, important for experimental analyses, may have a significant impact on kinematic distributions and radiative corrections. We show that some of these effects can be adequately described by simulating QCD radiation in Higgs boson decays to b-quarks using parton showers. We also describe contributions to Higgs decay to a b-bbar pair that first appear at NNLO and that were not considered in previous fully-differential computations. The calculation of NNLO QCD corrections to production and decay sub-processes is carried out within the nested soft-collinear subtraction scheme presented by some of us earlier this year. We demonstrate that this subtraction scheme performs very well, allowing a computation of the coefficient of the second order QCD corrections at the level of a few per mill.