On the implications of positive W mass shift

TL;DR

This paper explores the implications of the recent CDF W mass measurement showing tension with the Standard Model, suggesting new physics contributions could reconcile the discrepancy, especially involving non-universal operators and TeV-scale top partners.

Contribution

It performs an electroweak fit within the Standard Model effective field theory considering non-universal operators, highlighting potential new physics explanations for the W mass shift.

Findings

Non-universal new physics operators improve fit to W mass data.

Indications of 2-3 sigma for certain Wilson coefficients.

TeV-scale top partners could explain the W mass shift.

Abstract

We investigate the phenomenological implications of the recent $W$ mass measurement by the CDF collaboration, which exhibits tension with the standard model (SM) electroweak fit. Performing the fit to the electroweak observables within the SM effective field theory, we find that the new physics that contributes either to the determination of the electroweak vacuum expectation value, or to the oblique parameters, can improve the agreement with data. The best description is obtained from a fit where flavor universality is not required in the new physics operators, with 2 to 3 $\sigma$ indications for several nonzero Wilson coefficients. We point out that top partners with order TeV masses could lead to the observed shift in the $W$ mass.