Tri-hypercharge versus tri-darkcharge

TL;DR

This paper introduces a minimal extension of the Standard Model with family-dependent hypercharges and a dark gauge symmetry, explaining neutrino masses, dark matter stability, and fermion mass hierarchies.

Contribution

It presents a novel, UV-complete model that unifies explanations for neutrino masses, dark matter, and fermion hierarchies within a consistent gauge framework.

Findings

The model naturally realizes a hybrid scotoseesaw mechanism.

It accounts for dark matter stability and relic abundance.

Constraints from experiments are consistent with the model.

Abstract

We propose a minimal, ultraviolet-complete, and renormalizable extension of the Standard Model, in which the three generations of ordinary fermions are distinguished by family-dependent hypercharges, while three right-handed neutrinos are separated by a dark gauge symmetry that is trivial for all Standard Model fields. This setup yields a fully flipped inert doublet model. The model naturally realizes a hybrid scotoseesaw mechanism that accounts for the smallness of neutrino masses and the largeness of lepton mixing. Simultaneously, it explains the stability and relic abundance of dark matter through a residual dark parity and addresses the hierarchies of charged fermion masses and the suppression of quark mixing via higher-dimensional operators involving high-scale scalar singlets and vector-like fermions. We explore the phenomenological implications of the model and derive constraints from electroweak precision tests, collider searches, flavor-changing processes, and observations of dark matter.