Neutrino mass genesis in Scoto-Inverse Seesaw with Modular $A_4$

TL;DR

This paper introduces a novel hybrid scotogenic inverse seesaw model with modular $A_4$ symmetry, generating neutrino masses at one-loop and providing a dark matter candidate, with testable predictions for various experiments.

Contribution

It presents a new model combining scotogenic inverse seesaw with modular $A_4$ symmetry, leading to distinctive flavor structures and phenomenological predictions.

Findings

Majorana mass generated at one-loop level

Dark matter candidate with limited interactions

Testable predictions for $0 uetaeta$, cLFV, and direct detection

Abstract

We propose a hybrid scotogenic inverse seesaw framework in which the Majorana mass term is generated at the one-loop level through the inclusion of a singlet fermion. This singlet Majorana fermion also serves as a viable thermal relic dark matter candidate due to its limited interactions with other fields. To construct the model, we adopt an $A_4$ flavour symmetry in a modular framework, where the odd modular weight of the fields ensures their stability, and the specific modular weights of the couplings yield distinctive modular forms, leading to various phenomenological consequences. The explicit flavour structure of the mass matrices produces characteristic correlation patterns among the parameters. Furthermore, we examine several testable implications of the model, including neutrinoless double beta decay ($0\nu\beta\beta$), charged lepton flavour violation (cLFV), and direct detection prospects for the dark matter candidate. These features make our model highly testable in upcoming experiments.