Exotic Charges, Multicomponent Dark Matter and Light Sterile Neutrinos

TL;DR

This paper proposes a model where a new U(1)' gauge symmetry enforces a specific neutrino mass structure, introduces exotic fermions that form multicomponent dark matter, and predicts dark matter annihilation mainly into neutrinos.

Contribution

It introduces a novel U(1)' symmetry-based framework that links sterile neutrino masses, exotic fermions, and multicomponent dark matter with unique annihilation signatures.

Findings

Dark matter predominantly annihilates into neutrinos.

Exotic fermions carry unusual charges for anomaly cancellation.

New neutrino portal opens via active-sterile mixing.

Abstract

Generating small sterile neutrino masses via the same seesaw mechanism that suppresses active neutrino masses requires a specific structure in the neutral fermion mass matrix. We present a model where this structure is enforced by a new U(1)' gauge symmetry, spontaneously broken at the TeV scale. In order not to spoil the neutrino structure, the additional fermions necessary for anomaly cancellations need to carry exotic charges, and turn out to form multicomponent cold dark matter. The active-sterile mixing then connects the new particles and the Standard Model---opening a new portal in addition to the usual Higgs- and kinetic-mixing portals---which leads to dark matter annihilation almost exclusively into neutrinos.