Diphoton spectrum in the mass range 120-140 GeV at the LHC

TL;DR

This paper presents a detailed NNLO QCD calculation of diphoton production at the LHC, crucial for Higgs boson searches in the gamma gamma decay channel, using a flexible Monte Carlo implementation.

Contribution

The paper introduces a fully-differential NNLO QCD calculation for diphoton production using the q_T subtraction formalism, implemented in a Monte Carlo program for arbitrary kinematic cuts.

Findings

NNLO corrections significantly impact diphoton background estimates.

The calculation improves the precision of Higgs to gamma gamma analyses.

The Monte Carlo tool allows detailed phenomenological studies.

Abstract

We consider direct diphoton production in hadron collisions. We compute the next-to-next-to-leading order (NNLO) QCD radiative corrections at the fully-differential level. Our calculation uses the q_T subtraction formalism and it is implemented in a parton level Monte Carlo program, which allows the user to apply arbitrary kinematical cuts on the final-state photons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We present selected numerical results related to Higgs boson searches at the LHC, and we show how the NNLO corrections to diphoton production are relevant to understand the main background of the decay channel H -> gamma gamma.