Finding the Higgs boson in decays to Zγ using the matrix element method at next-to-leading order

We illustrate how the matrix element method at next-to-leading order can be used to discriminate between events arising from the production of a Higgs boson, which subsequently decays to a final state consisting of ℓ⁺ℓ^-γ, and the background production of the same final state. We illustrate how the method could be used in an experimental analysis by devising cuts on the signal (P_S) and background (P _B) weights that are computed event by event in this approach. We find that we can increase the S/√B ratio by around 50% compared to an invariant mass fit on its own. Considering only statistical uncertainty, this is equivalent to recording a factor of around two times more integrated luminosity.