A new B-L model without right-handed neutrinos

TL;DR

This paper introduces a novel B-L gauge symmetry extension of the Standard Model that explains dark matter and neutrino masses without right-handed neutrinos, using anomaly cancellation by chiral fermions and a new scalar sector.

Contribution

It presents a new B-L model with fractional charges, stable dark matter candidate, and a modified type-II seesaw mechanism for neutrino masses, expanding beyond traditional models.

Findings

Identifies parameter space consistent with dark matter density

Proposes detection strategies via collider and dark matter experiments

Demonstrates anomaly cancellation with fractional charge fermions

Abstract

We propose and study a novel extension of the Standard Model based on the B-L gauge symmetry that can account for dark matter and neutrino masses. In this model, right-handed neutrinos are absent and the gauge anomalies are canceled instead by four chiral fermions with fractional B-L charges. After the breaking of $U(1)_{B-L}$, these fermions arrange themselves into two Dirac particles, the lightest of which is automatically stable and plays the role of the dark matter. We determine the regions of the parameter space consistent with the observed dark matter density and show that they can be partially probed via direct and indirect dark matter detection or collider searches at the LHC. Neutrino masses, on the other hand, can be explained by a variant of the type-II seesaw mechanism involving one of the two scalar fields responsible for the dark matter mass.