Systematic Study of One-Loop Dirac Neutrino Masses and Viable Dark Matter Candidates

TL;DR

This paper systematically explores how small Dirac neutrino masses can be generated through dimension six operators at tree and one-loop levels, identifying models with potential dark matter candidates and analyzing their constraints.

Contribution

It provides a comprehensive classification of all tree and one-loop diagrams for Dirac neutrino mass generation and links these models to viable dark matter candidates.

Findings

All possible finite neutrino mass diagrams identified.

Dark matter candidates can be messenger particles in loops.

Constraints on model parameters for dark matter viability analyzed.

Abstract

We study the generation of small neutrino masses from the dimension six effective operator at tree level and one-loop level, the neutrinos are assumed to be Dirac particles. We find out all possible tree and one-loop diagrams which lead to finite neutrino masses. The relevant mediator fields and the predictions for neutrino masses are presented. The lower order contributions to neutrino masses can be forbidden by introducing soft breaking abelian symmetry or finite non-abelian symmetry. The messengers inside the loop can be dark matter particles. The possible dark matter candidates and the corresponding constraints on the parameter $\alpha$ are analyzed for each model.