A complete O(alpha_S^2) calculation of the signal-background interference for the Higgs diphoton decay channel

TL;DR

This paper provides a comprehensive calculation of the interference effects between Higgs diphoton decay signals and background processes at the LHC, including new subprocess contributions, affecting the diphoton mass peak measurement.

Contribution

It presents the complete ${ m O}( ext{alpha}_S^2)$ calculation of signal-background interference, incorporating $qg$ and $qar{q}$ channels, which were previously neglected.

Findings

Interference effects are significantly influenced by $qg$ and $qar{q}$ channels.

Corrections from these channels can be up to 35% of the dominant $gg$ contribution.

The results impact the interpretation of the diphoton invariant mass peak.

Abstract

We present the full ${\cal O}(\as^2)$ computation of the interference effects between the Higgs diphoton signal and the continuum background at the LHC. While the main contribution to the interference originates on the $gg$ partonic subprocess, we find that the corrections from the $qg$ and $q\bar{q}$ channels amount up to 35% of it. We discuss the effect of these new subprocesses in the shift of the diphoton invariant mass peak recently reported by S. Martin in Ref.\cite{Martin:2012xc}.