The Di-Photon Background to a Light Higgs Boson at the LHC
  Recent years have seen a significant advance in our ability to calculate two-loop matrix elements. In this talk we describe an application of this breakthrough to improve our understanding of the background to the search for a light Higgs boson at the LHC. In particular, we focus on the QCD corrections to the gluon fusion subprocess gg to gamma gamma, which forms an important component of the background in the di-photon channel. We find that the K factor for this subprocess is significantly smaller than estimated previously. 
Zvi Bern, Lance Dixon and Carl Schmidt