Deciphering compressed electroweakino excesses with MadAnalysis5

Abstract We present version 1.11 of "Image missing" , which extends the software package in several major ways to improve the handling of efficiency tables, the computation of observables in different reference frames and the calculation of statistical limits and/or significance. We detail how these improvements, whose development was motivated by the desire to implement two Run 2 LHC analyses targeting signatures with soft leptons and missing energy and exhibiting mild excesses (ATLAS-SUSY-2018-16 and ATLAS-SUSY-2019-09), have been implemented by both direct extensions of the code and integrations with third-party software. We then document the implementation and validation of these analyses, demonstrating their utility along with the improved statistics capabilities of "Image missing" through an investigation of the Next-to-Minimal Supersymmetric Standard Model in the context of a larger set of overlapping excesses in channels with soft leptons/jets and missing transverse energy.