A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg -> H -> gamma gamma, with the continuum QCD background, gg -> gamma gamma induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg -> gamma gamma scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.
@article{arxiv.hep-ph/0302233,
title = {Resonance-continuum interference in the di-photon Higgs signal at the LHC},
author = {Lance Dixon and M. Stewart Siu},
journal= {arXiv preprint arXiv:hep-ph/0302233},
year = {2010}
}