Resonant Leptogenesis in a Two-Triplet Type-II Seesaw: A Dynamical Origin of Suppressed Lepton Flavor Violation

TL;DR

This paper explores how resonant leptogenesis in a two-triplet Type-II seesaw model can explain neutrino masses and baryogenesis while naturally suppressing lepton flavor violation, making it testable at collider scales.

Contribution

It demonstrates a coherent link between neutrino mass, baryogenesis, and LFV suppression through resonant effects in a two-triplet framework, with detailed numerical analysis.

Findings

Resonant enhancement enables successful baryogenesis at TeV scale.

Viable solutions require near-resonant mass splittings and moderate-to-strong washout.

Suppressed Yukawa couplings lead to strongly suppressed LFV rates.

Abstract

We investigate resonant leptogenesis in a two-triplet Type-II seesaw framework and demonstrate a coherent and predictive connection between neutrino mass generation, baryogenesis, and charge lepton flavor violation (LFV). In the presence of quasi-degenerate scalar triplets, self-energy effects induce a resonant enhancement of the CP asymmetry, enabling successful baryogenesis at the TeV scale. We construct Yukawa couplings consistent with neutrino oscillation data and perform a comprehensive numerical analysis by solving the Boltzmann equations across a wide parameter space. We find that viable solutions arise only within a restricted region characterized by near-resonant mass splittings and moderate-to-strong washout. In this regime, successful leptogenesis is achieved through resonant enhancement, which compensates for suppressed Yukawa couplings. A key prediction of the framework is that the allowed parameter space dynamically favors small Yukawa couplings, leading to strongly suppressed LFV rates. The near-absence of observable LFV signals therefore emerges as a direct consequence of the dynamics responsible for baryogenesis. Our results highlight a distinctive feature of the two-triplet Type-II scenario: the simultaneous realization of resonant enhancement and LFV suppression within a unified and testable framework.