Singlet-Doublet Fermion Origin of Dark Matter, Neutrino Mass and W-Mass Anomaly

TL;DR

This paper proposes a singlet-doublet Majorana fermion model to explain the W boson mass anomaly, dark matter, and neutrino masses, highlighting the necessity of multiple fermion generations for consistency.

Contribution

It introduces a multi-generation SD fermion model that simultaneously addresses the W-mass anomaly, dark matter, and neutrino mass generation, which was not achieved in single-generation models.

Findings

Two generations of SD fermions can explain the W-mass anomaly.

The model accommodates dark matter phenomenology.

Light neutrino masses are generated radiatively with an added scalar.

Abstract

Motivated by the recently reported anomaly in W boson mass by the CDF collaboration with $7\sigma$ statistical significance, we consider a singlet-doublet (SD) Majorana fermion dark matter (DM) model where the required correction to W boson mass arises from radiative corrections induced by SD fermions. While a single generation of SD fermions, odd under an unbroken $Z_2$ symmetry, can not explain the W boson mass anomaly while being consistent with DM phenomenology, two generations of SD fermions can do so with the heavier generation playing the dominant role in W-mass correction and lighter generation playing the role in DM phenomenology. Additionally, such multiple generations of SD fermions can also generate light neutrino masses radiatively if a $Z_2$-odd singlet scalar is included.