The Low‐Scale Seesaw Solution to the MW$M_W$ and (g−2)μ$(g-2)_\umu$ Anomalies

Abstract

The recent CDF‐II measurement of the W‐boson mass shows a strong tension with the corresponding Standard Model prediction. Once active neutrino masses are explained in the context of the Low‐Scale Seesaw mechanisms, this tension can be resolved. We investigate the possibility of explaining the longstanding muon anomalous magnetic moment anomaly within the same frameworks. We present a simplified extension of the Standard Model, accounting only for the second lepton generation, that describes a massive active neutrino and provides a combined solution to these anomalies. The model is renormalisable and introduces in the spectrum, beyond the sterile species of the Low‐Scale Seesaw mechanism, only one pair of exotic vector‐like leptons, doublets under the electroweak symmetry. We moreover discuss the extension of this model to the realistic three‐family case.