Search for the Standard Model Higgs boson in the vector boson fusion-mediated diphoton decay channel using multivariate analysis techniques

A search for the Standard Model Higgs boson in the diphoton decay channel is presented using multivariate analysis techniques, with a focus on the vector boson fusion (VBF) production mechanism. Data events are separated into signal (VBF H → γγ) and background-like categories using a gradient boosted decision tree, with the optimized analysis applied to the full 2011−2012 dataset, corresponding to 4.8 fb−1 of √ s = 7 TeV pp collisions, and 21 fb−1 of √ s = 8 TeV collisions. The best fit invariant mass for events categorized as VBF H → γγ is found to be mH = 123.5 GeV, with a local significance of 2.9σ. The best fit signal strength for the W, Z-mediated H → γγ decay (VBF + associated production) is found to be µVBF+VH × B/BSM = 1.72+0.85 −0.77 (stat)+0.48 −0.29 (syst)+0.25 −0.29 (theory) at mH = 126.8 GeV, which agrees with Standard Model predictions within 2σ.