Axion-like Dark Matter from the Type-II Seesaw Mechanism

TL;DR

This paper introduces a novel mechanism for axion-like particle mass generation during the electroweak phase transition, linking it to the type-II seesaw mechanism and addressing neutrino oscillations and recent W-boson mass anomalies.

Contribution

It proposes a new ALP mass generation mechanism at the electroweak scale within the type-II seesaw framework, connecting dark matter, neutrino physics, and collider anomalies.

Findings

ALP mass is generated at the electroweak scale with a cutoff on oscillation temperature.

ALPs couple to active neutrinos, affecting neutrino oscillations in dense environments.

The model explains the W-boson mass anomaly observed by CDF.

Abstract

Although axion-like particles (ALPs) are popular dark matter candidates, their mass generation mechanisms as well as cosmic thermal evolutions are still unclear. In this letter, we propose a new mass generation mechanism of ALP during the electroweak phase transition in the presence of the type-II seesaw mechanism. As ALP gets mass uniquely at the electroweak scale, there is a cutoff scale on the ALP oscillation temperature irrelevant to the specific mass of ALP, which is a distinctive feature of this scenario. The ALP couples to the active neutrinos, leaving the matter effect of neutrino oscillations in a dense ALP environment as a smoking gun. As a by-product, the recent $W$-boson mass anomaly observed by the CDF collaboration is also quoted by the TeV-scale type-II seesaw. We explain three kinds of new physics phenomena are with one stroke.