The majoron coupling to charged leptons

TL;DR

This paper derives general analytical formulas for the one-loop coupling of the majoron to charged leptons in Majorana neutrino mass models with spontaneous lepton number violation, applicable across various models with hierarchical energy scales.

Contribution

It provides a unified analytical framework for calculating majoron-charged lepton couplings, including new results for models not previously analyzed.

Findings

Derived general formulas for majoron-charged lepton couplings.

Validated formulas against existing models, confirming accuracy.

Produced novel coupling results for previously unexplored models.

Abstract

The particle spectrum of all Majorana neutrino mass models with spontaneous violation of global lepton number include a Goldstone boson, the so-called majoron. The presence of this massless pseudoscalar changes the phenomenology dramatically. In this work we derive general analytical expressions for the 1-loop coupling of the majoron to charged leptons. These can be applied to any model featuring a majoron that have a clear hierarchy of energy scales, required for an expansion in powers of the low-energy scale to be valid. We show how to use our general results by applying them to some example models, finding full agreement with previous results in several popular scenarios and deriving novel ones in other setups.