Composite Dirac Neutrinos

TL;DR

This paper proposes a natural mechanism for light Dirac neutrinos where right-handed neutrinos are composite, involving hidden flavor symmetries that can survive confinement and manifest as an exact B-L symmetry, with implications for dark matter.

Contribution

It introduces a novel composite model for Dirac neutrinos that incorporates hidden flavor symmetries and predicts sterile states as potential warm dark matter candidates.

Findings

Neutrinos are naturally light due to compositeness.

The model predicts the existence of sterile states.

Some sterile states can serve as warm dark matter candidates.

Abstract

We present a mechanism that naturally produces light Dirac neutrinos. The basic idea is that the right-handed neutrinos are composite. Any realistic composite model must involve `hidden flavor' chiral symmetries. In general some of these symmetries may survive confinement, and in particular, one of them manifests itself at low energy as an exact $B-L$ symmetry. Dirac neutrinos are therefore produced. The neutrinos are naturally light due to compositeness. In general, sterile states are present in the model, some of them can naturally be warm dark matter candidates.