The Inverse Seesaw in Conformal Electro-Weak Symmetry Breaking and Phenomenological Consequences

TL;DR

This paper explores an inverse seesaw model within conformal electroweak symmetry breaking, linking neutrino masses, dark matter, and collider phenomenology without explicit fermion mass terms, and predicts testable experimental signatures.

Contribution

It introduces a conformal inverse seesaw framework where all fermion masses arise from scalar vevs, leading to novel neutrino mass and dark matter phenomenology with testable predictions.

Findings

TeV-scale pseudo-Dirac sterile neutrinos are favored.

KeV-scale warm dark matter can be generated via freeze-in.

Lepton flavor violation may be observable in current experiments.

Abstract

We study the inverse seesaw mechanism for neutrino masses and phenomenological consequences in the context of conformal electro-weak symmetry breaking. The main difference to the usual case is that all explicit fermion mass terms including Majorana masses for neutrinos are forbidden. All fermion mass terms arise therefore from vacuum expectation values of suitable scalars times some Yukawa couplings. This leads to interesting consequences for model building, neutrino mass phenomenology and the Dark Matter abundance. In the context of the inverse seesaw we find a favoured scenario with heavy pseudo-Dirac sterile neutrinos at the TeV scale, which in the conformal framework conspire with the electro-weak scale to generate keV scale warm Dark Matter. The mass scale relations provide naturally the correct relic abundance due to a freeze-in mechanism. We demonstrate also how conformal symmetry decouples the right-handed neutrino mass scale and effective lepton number violation. We find that lepton flavour violating processes can be well within the reach of modern experiments. Furthermore, interesting decay signatures are expected at the LHC.