SMEFiT: a flexible toolbox for global interpretations of particle physics data with effective field theories

Abstract

The Standard Model Effective Field Theory (SMEFT) provides a robust framework to interpret experimental measurements in the context of new physics scenarios while minimising assumptions on the nature of the underlying UV-complete theory. We present the Python open source SMEFiT framework, designed to carry out parameter inference in the SMEFT within a global analysis of particle physics data. SMEFiT is suitable for inference problems involving a large number of EFT degrees of freedom, without restrictions on their functional dependence in the fitted observables, can include UV-inspired restrictions in the parameter space, and implements arbitrary rotations between operator bases. Posterior distributions are determined from two complementary approaches, Nested Sampling and Monte Carlo optimisation. SMEFiT is released together with documentation, tutorials, and post-analysis reporting tools, and can be used to carry out state-of-the-art EFT fits of Higgs, top quark, and electroweak production data. To illustrate its functionalities, we reproduce the results of the recent ATLAS EFT interpretation of Higgs and electroweak data from Run II and demonstrate how equivalent results are obtained in two different operator bases.

Searches for new physics with boosted top quarks in the MadAnalysis 5 and Rivet frameworks

“…In our analysis, we aim to leverage the detector-simulation capabilities of the MadAnalysis 5 and Rivet frameworks (including our implementation of HEPTopTagger) to realistically explore the effects of effective operators on the reconstruction performance of boosted top quarks. Among the full set of potentially impactful SMEFT operators [39], only eight of them are not too strongly constrained by other means [40][41][42][43][44][45], so that an investigation of pair-production and decay of boosted top quarks could offer new handles on them. They read, in the notation of Ref.…”

“…Global SMEFT interpretations of measurements at the LHC in the top sector have recently been achieved by several groups [40][41][42][43][44][45]. These studies demonstrated in particular that dozens of SMEFT operators could be constrained (and therefore determined) simultaneously, correlating sometimes information originating from different sectors.…”