Neutrino masses from Planck-scale lepton number breaking

TL;DR

This paper proposes that neutrino masses around 0.1 eV can naturally arise from Planck-scale lepton number breaking, possibly due to gravitational effects, without adding new mass scales to the Standard Model extension.

Contribution

It introduces a model where Planck-scale lepton number breaking explains neutrino masses without new mass scales.

Findings

Neutrino masses of order 0.1 eV can be generated naturally.

Lepton number breaking at the Planck scale is sufficient.

Implications for neutrino physics and beyond are briefly discussed.

Abstract

We consider an extension of the Standard Model by right-handed neutrinos and we argue that, under plausible assumptions, a neutrino mass of ${\cal O}(0.1)\,{\rm eV}$ is naturally generated by the breaking of the lepton number at the Planck scale, possibly by gravitational effects, without the necessity of introducing new mass scales in the model. Some implications of this framework are also briefly discussed.