Neutrino mass and the Standard Model

TL;DR

This paper discusses how the minimal Standard Model can accommodate neutrino masses and mixing through a nonrenormalizable interaction that violates B-L symmetry, independent of grand unification theories.

Contribution

It highlights that neutrino masses can arise in the Standard Model without additional particles, via a nonrenormalizable interaction that breaks B-L symmetry.

Findings

Neutrino masses are compatible with the Standard Model without extra fields.

The interaction responsible is nonrenormalizable and breaks B-L symmetry.

The origin of this interaction may be linked to grand unification or other theories.

Abstract

It is pointed out (not for the first time) that the minimal Standard Model, without additional gauge-singlet right-handed neutrinos or isotriplet Higgs fields, allows for nonvanishing neutrino masses and mixing. The required interaction term is nonrenormalizable and violates the global B-L symmetry. The ultimate explanation of this interaction term may or may not rely on grand unification.