As described in the “Brief introduction to the Higgs Boson”, the H → WW decay branching ratio for the Higgs boson with a mass of 125 GeV is predicted to be 0.214 in the SM, and corresponds to the second-largest branching fraction after the dominant H → bb decay mode. The predicted Higgs-boson production cross sections via the dominant gluon–gluon fusion (ggF) and vector-boson fusion (VBF) times H → WW branching fraction are 10.4 pb and 0.81 pb for ggF and VBF, respectively. Reducing the numerous backgrounds contributing to this channel and accurately estimating the remainder is a major challenge in this analysis. The dominant background stems from non-resonant WW diboson production, while tt, single-top-quark and W+jets (with the jet misidentified as a lepton) events, as well as non-resonant WZ and ZZ processes contribute to the overall background.

In order to identify these events, one needs to apply the standard object-selection criteria (defined in “Reconstructed physics objects”) with a stricter lepton calorimeter and tracking isolation (< 0.1) requirements and tight lepton identification criteria, and an event-selection criteria defined as:

At the end, one is able to compare data and MC prediction for the distribution of e.g. the dilepton transverse mass, as seen below. A small excess in data is observed, and which corresponds to the production of the SM Higgs boson.

Navigation

Go to the previous example, the next example or jump back to the summary page for the analysis examples or the general summary page.