W-boson mass anomaly as a manifestation of spontaneously broken additional SU(2) global symmetry on a new fundamental scale

Abstract

Recently the CDF Collaboration has announced a new precise measurement of the $W$-boson mass $M_W$ that deviates from the Standard Model (SM) prediction by $7\sigma$. The discrepancy in $M_W$ is about $\Delta_W\simeq70$ MeV and probably caused by a beyond the SM physics. Within a certain scenario of extension of the SM, we obtain the relation $\Delta_W\simeq\frac{3\alpha}{8\pi}M_W\simeq70$ MeV, where $\alpha$ is the electromagnetic fine structure constant. The main conjecture is the appearance of longitudinal components of the $W$-bosons as the Goldstone bosons of a spontaneously broken additional $SU(2)$ global symmetry at distances much smaller than the electroweak symmetry breaking scale. We argue that within this scenario, the masses of charged Higgs scalars can get an electromagnetic radiative contribution which enhances the observed value of $M_{W^\pm}$ with respect to the usual SM prediction. Our relation for $\Delta_W$ follows from the known one-loop result for the corresponding effective Coleman-Weinberg potential in combination with the Weinberg sum rules.