Updated Global SMEFT Fit to Higgs, Diboson and Electroweak Data

TL;DR

This paper presents an updated global SMEFT fit incorporating recent LHC Run 2 Higgs and diboson data, improving constraints on operator coefficients and exploring implications for beyond Standard Model theories.

Contribution

It provides the first comprehensive SMEFT fit using the latest LHC data in both Warsaw and SILH bases, including all coefficients and their correlations.

Findings

LHC Run 2 data significantly tighten constraints on SMEFT operators.

Correlations between operator coefficients are quantitatively analyzed.

Implications for BSM models like MSSM are discussed.

Abstract

The ATLAS and CMS collaborations have recently released significant new data on Higgs and diboson production in LHC Run 2. Measurements of Higgs properties have improved in many channels, while kinematic information for $h \to \gamma\gamma$ and $h \to ZZ$ can now be more accurately incorporated in fits using the STXS method, and $W^+ W^-$ diboson production at high $p_T$ gives new sensitivity to deviations from the Standard Model. We have performed an updated global fit to precision electroweak data, $W^+W^-$ measurements at LEP, and Higgs and diboson data from Runs 1 and 2 of the LHC in the framework of the Standard Model Effective Field Theory (SMEFT), allowing all coefficients to vary across the combined dataset, and present the results in both the Warsaw and SILH operator bases. We exhibit the improvement in the constraints on operator coefficients provided by the LHC Run 2 data, and discuss the correlations between them. We also explore the constraints our fit results impose on several models of physics beyond the Standard Model, including models that contribute to the operator coefficients at the tree level and stops in the MSSM that contribute via loops.