# Revisiting Large Neutrino Magnetic Moments

## TL;DR

This paper explores theoretical models that could explain large neutrino magnetic moments, which are much higher than Standard Model predictions, while remaining consistent with neutrino mass constraints.

## Contribution

It identifies and discusses two viable mechanisms for large transition magnetic moments in Majorana neutrinos, addressing the fine-tuning problem.

## Key findings

- Only two mechanisms can produce large transition magnetic moments for Majorana neutrinos.
- Models where neutrino masses are proportional to magnetic moments are viable.
- Proposes solutions that reconcile large magnetic moments with neutrino mass constraints.

## Abstract

Current experimental sensitivity on neutrino magnetic moments is many orders of magnitude above the Standard Model prediction. A potential measurement of next-generation experiments would therefore strongly request new physics beyond the Standard Model. However, large neutrino magnetic moments generically tend to induce large corrections to the neutrino masses and lead to fine-tuning. We show that in a model where neutrino masses are proportional to neutrino magnetic moments. We revisit, discuss and propose mechanisms that still provide theoretical consistent explanations for a potential measurement of large neutrino magnetic moments. We find only two viable mechanisms to realize large transition magnetic moments for Majorana neutrinos only.