Changing patterns in electroweak precision with new color-charged states: Oblique corrections and the $W$ boson mass

TL;DR

This paper proposes simple models with color-charged scalar multiplets that can generate oblique corrections, accommodating the recent CDF measurement of the W boson mass and addressing tensions with the Standard Model.

Contribution

It introduces models with weak multiplets of scalars charged under color and hypercharge that produce positive S and T parameters, explaining the W mass discrepancy.

Findings

Models can produce non-negative S and T consistent with CDF W mass

Parameter space exists supporting the CDF measurement of m_W

Oblique corrections computed for proposed scalar multiplets

Abstract

The recent measurement by the CDF Collaboration of the $W$ boson mass is in significant tension with the Standard Model expectation, showing a discrepancy of seven standard deviations. A larger value of $m_W$ affects the global electroweak fit, particularly the best-fit values of the Peskin-Takeuchi parameters $S$, $T$ (and perhaps $U$) that measure oblique corrections from new physics. To meet this challenge, we propose some simple models capable of generating non-negative $S$ and $T$, the latter of which faces the greatest upward pressure from the CDF measurement in scenarios with $U=0$. Our models feature weak multiplets of scalars charged under $\mathrm{SU}(3)_{\text{c}} \times \mathrm{U}(1)_Y$, which cannot attain nonzero vacuum expectation values but nevertheless produce e.g. $T \neq 0$ given some other mechanism to split the electrically charged and neutral scalars. We compute the oblique corrections in these models and identify ample parameter space supporting the CDF value of $m_W$.