Finding the Higgs boson in decays to Z gamma using the matrix element method at Next-to-Leading Order

TL;DR

This paper demonstrates how the Matrix Element Method at Next-to-Leading Order can significantly improve the discrimination of Higgs boson decays to Z gamma from background, enhancing analysis sensitivity.

Contribution

It introduces the application of MEM@NLO for Higgs to Z gamma decay analysis, showing improved signal-to-background discrimination over traditional invariant mass methods.

Findings

Increased S/sqrt(B) ratio by about 50% using MEM@NLO.

Equivalent to doubling the data sample size in terms statistical power.

Method can be integrated into experimental analyses for better Higgs signal detection.

Abstract

We illustrate how the Matrix Element Method at Next-to-Leading Order (MEM@NLO) can be used to discriminate between events arising from the production of a Higgs boson, which subsequently decays to a final state consisting of ell^+ell^-gamma, 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/sqrt(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.