BSM Matter providing Neutrino Masses and Gauge Unification

TL;DR

This paper explores TeV-scale particles in non-trivial weak-isospin multiplets that generate neutrino masses through novel mechanisms, some testable at the LHC, and investigates their implications for gauge unification and grand unified theories.

Contribution

It introduces new neutrino-mass mechanisms involving TeV-scale particles, including tree-level and loop models, and studies their embedding into SU(5) for gauge unification.

Findings

Two tree-level dim 9 mechanisms are testable at the LHC.

Genuine loop models without competing contributions are identified.

The one-loop scalar triplet model supports gauge coupling unification.

Abstract

I present several scenarios developed in Zagreb, in which TeV-scale particles belonging to non-trivial weak-isospin multiplets give rise to neutrino-mass mechanisms different from conventional type I, II and III seesaw models. Two dim 9 tree-level mechanisms, presented first, provide an appealing testability of their exotic TeV-scale particles at the LHC. These models are not genuine, since their particles also provide competing dim 5 loop contributions. The loop-models presented next are genuine, without competing tree-level contributions. Among them, the three-loop model involves high-order weak multiplets leading to Landau poles. The one-loop model with scalar triplet as the largest multiplet, in addition to good UV properties, provides the particle set promising for gauge coupling unification. Therefore, it served us as a starting point for a study of SU(5) embedding of additional particles leading to viable unification scenarios. To distinguish among them begs for additional principle which reigns over particle completion and eventual dark matter considerations.