Majorana Neutrino Masses in the RGEs for Lepton Flavour Violation

TL;DR

This paper investigates how high-scale Majorana neutrino masses influence lepton flavour violation through renormalization group equations, considering extensions like the Two Higgs Doublet Model and their experimental implications.

Contribution

It provides a detailed calculation of lepton flavour violation effects induced by Majorana neutrino masses and extends the analysis to models with additional Higgs fields.

Findings

Log-enhanced lepton flavour violation predicted by the model.

Additional dimension-five operators in Two Higgs Doublet Model affect anomalous dimensions.

Current experiments have sensitivity to these Wilson coefficients.

Abstract

We suppose that the observed neutrino masses can be parametrised by a lepton number violating dimension-five operator, and calculate the mixing of double insertions of this operator into lepton flavour changing dimension-six operators of the standard model effective theory. This allows to predict the log-enhanced, but $m_\nu^2$-suppressed lepton flavour violation that is generic to high-scale Majorana neutrino mass models. We also consider the Two Higgs Doublet Model, where the second Higgs allows the construction of three additional dimension-five operators, and evaluate the corresponding anomalous dimensions. The sensitivity of current searches for lepton flavour violation to these additional Wilson coefficients is then examined.