Neutrinos, B-L Symmetry and the Dark Dimension

TL;DR

This paper explores a model where a gauged B-L symmetry in a 5D dark dimension scenario naturally explains neutrino masses, predicts sterile neutrinos, and links neutrino mass scales to dark energy.

Contribution

It introduces a novel 5D B-L gauge symmetry framework with Higgsing, connecting neutrino masses to the dark energy scale and predicting sterile neutrinos in the keV range.

Findings

Massive B-L gauge field at ~100 GeV with tiny coupling

Neutrino masses linked to KK scale and dark energy

Predicted tower of sterile neutrinos in keV range

Abstract

We consider realizations of a gauged B-L symmetry in the context of the Dark Dimension scenario, where the SM lives on a codimension one brane in 5d spacetime. The B-L can naturally be a bulk gauge symmetery leading to a global symmetry on the SM brane, and have its gauge anomaly canceled by charged bulk modes. This naturally leads to the existence of 3 right-handed neutrinos propagating in the dark dimension. Allowing for Higgsing of B-L by a bulk scalar at the Higgs scale, results in a massive gauge field with $m_{B-L}\sim 100$ GeV and weak coupling $g_{B-L}\sim 10^{-10}$ which is allowed by current bounds. The model also predicts a natural matching $m_\nu\sim m_{KK}\sim\Lambda^{1/4}$, thereby providing a theoretical explanation for the observed coincidence between neutrino masses and the Dark Energy scale. It also predicts a tower of sterile right-handed neutrinos in the $keV$ mass range.