Strength in numbers: optimal and scalable combination of LHC new-physics searches

Authors:
  • JAJack Y. Araz
    Jack Y. Araz
  • ABAndy Buckley
    Andy Buckley
  • BFBenjamin Fuks
    Benjamin Fuks
  • HRHumberto Reyes-Gonzalez
    Humberto Reyes-Gonzalez
  • WWWolfgang Waltenberger
    Wolfgang Waltenberger
  • SWSophie L. Williamson
    Sophie L. Williamson
  • JYJamie Yellen
    Jamie Yellen
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Abstract
To gain a comprehensive view of what the LHC tells us about physics beyond the Standard Model (BSM), it is crucial that different BSM-sensitive analyses can be combined. But in general, search analyses are not statistically orthogonal, so performing comprehensive combinations requires knowledge of the extent to which the same events co-populate multiple analyses' signal regions. We present a novel, stochastic method to determine this degree of overlap and a graph algorithm to efficiently find the combination of signal regions with no mutual overlap that optimises expected upper limits on BSM-model cross-sections. The gain in exclusion power relative to single-analysis limits is demonstrated with models with varying degrees of complexity, ranging from simplified models to a 19-dimensional supersymmetric model.