Seesaw in the bulk

TL;DR

This paper introduces a five-dimensional seesaw framework using a propagator method to evaluate neutrino masses, accommodating various boundary conditions and geometries, and naturally explaining inverse seesaw suppression.

Contribution

It presents a novel propagator-based approach for analyzing bulk neutrino effects in higher-dimensional models, including warped geometries, simplifying calculations and providing new insights.

Findings

The propagator method effectively evaluates neutrino masses in complex geometries.

Higher-dimensional seesaw models naturally realize inverse seesaw suppression.

The framework accommodates various boundary conditions for bulk neutrinos.

Abstract

A five-dimensional seesaw framework is analyzed with the lepton-number-violating propagator of bulk right-handed neutrinos. That can bypass summing up the effects of heavy Majorana particles whose masses and wavefunctions are not exactly known. The propagator method makes it easier to evaluate the seesaw-induced neutrino mass for various boundary conditions of bulk neutrinos and in a general background geometry, including the warped extra dimension. It is also found that the higher-dimensional seesaw gives a natural framework for the inverse seesaw suppression of low-energy neutrino masses.