An NNLO subtraction formalism in hadron collisions and its application to Higgs boson production at the LHC

TL;DR

A new formulation of the subtraction method is proposed to numerically compute arbitrary infrared-safe observables for this class of processes and exploits the universal behavior of the associated transverse-momentum distributions in the small-qT region to cancel the infrared divergences.

Abstract

We consider higher-order QCD corrections to the production of colourless high-mass systems (lepton pairs, vector bosons, Higgs bosons,...) in hadron collisions. We propose a new formulation of the subtraction method to numerically compute arbitrary infrared-safe observables for this class of processes. To cancel the infrared divergences, we exploit the universal behaviour of the associated transverse-momentum (q_T) distributions in the small-q_T region. The method is illustrated in general terms up to the next-to-next-to-leading order (NNLO) in QCD perturbation theory. As a first explicit application, we study Higgs boson production through gluon fusion. Our calculation is implemented in a parton level Monte Carlo program that includes the decay of the Higgs boson in two photons. We present selected numerical results at the LHC.

Figures (3)

• Figure 1: Bin-integrated rapidity distribution of the Higgs boson with $M_H=125$ GeV: results at LO (dotted), NLO (dashed) and NNLO (solid).
• Figure 2: Bin-integrated rapidity distribution of the Higgs boson with $M_H=165$ GeV. Final-state jets are required to have transverse momentum smaller than $40$ GeV.
• Figure 3: Distributions in $p_{T{\rm min}}$ and $p_{T{\rm max}}$ for the diphoton signal at the LHC. The cross section is divided by the branching ratio in two photons.