W-mass Anomaly in the Simplest Linear Seesaw Mechanism

TL;DR

This paper demonstrates that the simplest linear seesaw model can explain the W-mass anomaly reported by CDF-II, while remaining consistent with various experimental constraints.

Contribution

It introduces a minimal linear seesaw framework with a leptophilic scalar doublet that accounts for the W-mass anomaly and satisfies existing experimental bounds.

Findings

The model can accommodate the new W mass measurement.

A new charged scalar below a few TeV is required.

The model remains consistent with electroweak and neutrino data.

Abstract

The simplest linear seesaw mechanism can accommodate the new CDF-II $W$ mass measurement. In addition to Standard Model particles, the model includes quasi-Dirac leptons, and a second, leptophilic, scalar doublet seeding small neutrino masses. Our proposal is consistent with electroweak precision tests, neutrino physics, rare decays and collider restrictions, requiring a new charged scalar below a few TeV, split in mass from the new degenerate scalar and pseudoscalar neutral Higgs bosons.