A Monte Carlo global analysis of the Standard Model Effective Field Theory: the top quark sector

TL;DR

This paper introduces SMEFiT, a Monte Carlo-based framework for global SMEFT analysis, demonstrating its application to top quark data from the LHC to derive constraints on new physics effects.

Contribution

The paper presents a novel Monte Carlo replica method for SMEFT global analysis, enabling comprehensive uncertainty estimation and probability distribution construction.

Findings

Derived bounds on 34 SMEFT parameters from LHC top quark data.

Showed the potential of LHC measurements to constrain beyond Standard Model physics.

Compared new constraints with previous results, highlighting improvements.

Abstract

We present a novel framework for carrying out global analyses of the Standard Model Effective Field Theory (SMEFT) at dimension-six: SMEFiT. This approach is based on the Monte Carlo replica method for deriving a faithful estimate of the experimental and theoretical uncertainties and enables one to construct the probability distribution in the space of the SMEFT degrees of freedom. As a proof of concept of the SMEFiT methodology, we present a first study of the constraints on the SMEFT provided by top quark production measurements from the LHC. Our analysis includes more than 30 independent measurements from 10 different processes at 8 and 13 TeV such as inclusive top-quark pair and single-top production and the associated production of top quarks with weak vector bosons and the Higgs boson. State-of-the-art theoretical calculations are adopted both for the Standard Model and for the SMEFT contributions, where in the latter case NLO QCD corrections are included for the majority of processes. We derive bounds for the 34 degrees of freedom relevant for the interpretation of the LHC top quark data and compare these bounds with previously reported constraints. Our study illustrates the significant potential of LHC precision measurements to constrain physics beyond the Standard Model in a model-independent way, and paves the way towards a global analysis of the SMEFT.