Majorana Neutrino Masses in the RGEs for Lepton Flavour Violation

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.

Comments: 12 pages, plus 18 pages appendices and one figure