General parametrization of Majorana neutrino mass models

Abstract

We discuss a general formula which allows to automatically reproduce experimental data for Majorana neutrino mass models, while keeping the complete set of the remaining model parameters free for general scans, as necessary in order to provide reliable predictions for observables outside the neutrino sector. We provide a proof of this master parametrization and show how to apply it for several well-known neutrino mass models from the literature. We also discuss a list of special cases, in which the Yukawa couplings have to fulfill some particular additional conditions. * Electronic address: isabel.cordero@uv.es † Electronic address: mahirsch@ific.uv.es ‡ Electronic address: avelino.vicente@ific.uv.es

Minimal 3-loop neutrino mass models and charged lepton flavor violation

“…With M aux being complex symmetric, we can use a suitably modified [54,55] Casas-Ibarra parametrization [56] to express the matrix g as…”

“…The Yukawa matrix Y in the AKS model does not have any specific symmetry. Therefore, this model represents the general class of models in which the Yukawa matrices can be described by using a generalization of the Casas-Ibarra parametrization [56] (see also [54,55]).…”

( g−2 ) anomalies and neutrino mass

“…The master parametrization [44,45] allows us to fit any Majorana neutrino mass model to experimental data. For the case of the BNT model, the general formulas in Ref.…”

Generalizing the Scotogenic model

“…Finally, we must accommodate the neutrino squared mass differences and the leptonic mixing angles measured in neutrino oscillation experiments by properly fixing the Yukawa couplings of the model. In the two variants of the general Scotogenic model considered the Yukawa couplings become 3 × 3 matrices, and then they can be obtained by means of a Casas-Ibarra parametrization [87], adapted to the Scotogenic model as explained in [88][89][90][91]. This allows us to write the Yukawa matrices in full generality as…”

“…For a general discussion on the parametrization of Yukawa couplings in Majorana neutrino mass models we refer to[90,91]. Even though we have focused on the (3, 1) and (1, 3) Scotogenic models, in which the Yukawa couplings are matrices, we note that the master parametrization introduced in these references can be used in variants of the general Scotogenic model with both nN , nη > 1, which can be regarded as hybrid scenarios, see appendix F of[91].…”