Defining a Minimum Resolution for Unbinned Analyses

Abstract

Collider analyses combine rigorous statistical techniques with state-of-the-art Machine Learning models. However, when the latter are used directly to estimate the likelihood function of the background, hard to quantify systematic effects may bias the estimation of the relevant signal parameters. To address this problem, we present the Minimum Resolution Likelihood (MRL) method, which defines a Fiducial Signal Region that effectively turns the systematic effects into statistical uncertainties. We show with examples that the resulting signal strength estimation has a reduced bias. We consider both toy examples and a realistic application based on the HI-SIGMA technique applied to di-Higgs searches.

arXiv comment22 pages + references and 10 figures. Updated version to be resubmitted to SciPost Physics. The figures and text have been modified to reflect the behavior observed for a larger number of pseudo-experiments in the toy problems. Comments welcome!