Gravitational Interactions and Neutrino Masses

Understand

We describe a scenario where the smallness of neutrino masses is related to a global symmetry that is only violated by quantum gravitational effects.

• The coupling of neutrinos to gauge singlet right-handed fermions is attributed to symmetry preserving gravitational operators suppressed by the Planck mass, in this framework.
• The proposed scenario leads to axion particles that decay into neutrinos, which could be probed through cosmological measurements and may help explain the Hubble parameter tension.
• Depending on the details of the implementation, the scenario could provide axion dark matter candidates.