Neutrino Masses in Superstring Derived Standard--like Models

TL;DR

This paper introduces a novel mechanism within superstring derived models that explains the smallness of left-handed neutrino masses through a generalized see-saw process involving nonrenormalizable terms and symmetry breaking.

Contribution

It presents a new scenario where the see-saw scale and right-handed neutrino masses are suppressed relative to the $U(1)_{Z'}$ breaking scale, differing from traditional GUT models.

Findings

Proposes a generalized see-saw mechanism in superstring models.

Shows suppression of neutrino masses via nonrenormalizable terms.

Highlights differences from traditional GUT see-saw models.

Abstract

We propose a new scenario in a class of superstring derived standard--like models that explains the suppression of the left--handed neutrino masses. Due to nonrenormalizable terms and the breaking of the $U(1)_{Z^\prime}$ symmetry a generalized see--saw mechanism takes place. Contrary to the traditional see--saw mechanism in GUTs, the see--saw scale and the right--handed neutrino mass scale are suppressed relative to the $U(1)_{Z^\prime}$ breaking scale.