Electroweak Precision Fit and New Physics in light of $W$ Boson Mass

TL;DR

The paper analyzes the recent W boson mass measurement showing significant deviation from the Standard Model, performs a global electroweak fit, and explores implications for new physics models like the two-Higgs doublet model.

Contribution

It provides updated oblique parameters based on the new W mass and demonstrates how these results can be explained within the two-Higgs doublet model framework.

Findings

New oblique parameters indicate need for non-degenerate multiplets beyond the SM.

The W mass anomaly can be accommodated in the two-Higgs doublet model.

Searching for non-SM Higgs bosons offers a way to test the anomaly.

Abstract

The $W$ boson mass is one of the most important electroweak precision observables for testing the Standard Model or its extensions. The very recent measured $W$ boson mass at CDF shows about $7\sigma$ deviations from the SM prediction, which may challenge the internal consistency of the SM. By performing the global electroweak fit with the new $W$-boson, we present the new values of the oblique parameters: $S = 0.06 \pm 0.10$, $T= 0.11 \pm 0.12$, $U=0.13 \pm 0.09$, or $S=0.14 \pm 0.08$, $T= 0.26 \pm 0.06$ with $U =0$ and the corresponding correlation matrices, which strongly indicates the need for the non-degenerate multiplets beyond the SM. As a proof-of-concept, we show that the new results can be accommodated in the two-Higgs doublet model, where the charged Higgs boson has to be either heavier or lighter than both two heavy neutral Higgs bosons. Therefore, searching for these non-SM Higgs bosons will provide a complementary way to test the new physics for the $W$ boson mass anomaly.