Beta-decay implications for the W-boson mass anomaly

TL;DR

This paper explores how beta-decay measurements impact explanations of the W-boson mass anomaly within the Standard Model Effective Field Theory, highlighting potential conflicts with CKM unitarity.

Contribution

It emphasizes the importance of beta-decay observables in resolving the W-boson mass anomaly and assesses the viability of solutions considering these constraints.

Findings

Global analyses predicting the W-boson anomaly imply large CKM unitarity violations.

Including beta-decay constraints narrows down viable solutions.

Beta-decay data can challenge or support new physics explanations for the anomaly.

Abstract

We point out the necessity to consider $\beta$-decay observables in resolutions of the $W$-boson anomaly in the Standard Model Effective Field Theory that go beyond pure oblique corrections. We demonstrate that present global analyses that explain the $W$-boson mass anomaly predict a large, percent-level, violation of first-row CKM unitarity. We investigate what solutions to the $W$-boson mass anomaly survive after including $\beta$-decay constraints.