Hybrid Resonant Type-I and Type-II Leptogenesis in SO(10) with Quasi-Degenerate Triplet and Right-Handed Neutrino Masses $M_T \simeq M_{N_3}$

Fuente: arXiv
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Main Author: Ghosh, Gayatri
Format: Preprint
Published: 2025
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author Ghosh, Gayatri
author_facet Ghosh, Gayatri
contents The origin of the baryon asymmetry of the Universe remains one of the central open problems in particle physics and cosmology. We identify a regime of \emph{hybrid resonant leptogenesis} in renormalizable SO(10) grand unified theories, where a quasi-degeneracy between the scalar triplet and the heaviest right-handed neutrino, \( M_T \simeq M_{N_3}, \) naturally arises from their common origin in unified scalar multiplets and leads to an enhanced interference between type-I and type-II decay amplitudes. This interference gives rise to a physical CP-violating phase, \( ϕ_{\rm HR} = \arg(μf Y_ν^\dagger), \) which cannot be removed by field redefinitions and induces a resonant enhancement of the baryon asymmetry without requiring extreme Yukawa hierarchies or fine-tuned mass splittings. We show that the observed asymmetry, \( Y_B \simeq 8.7 \times 10^{-11}, \) can be reproduced for mass scales around \(10^{11}\,\mathrm{GeV}\), moderate washout effects, and $\mathcal{O}(1)$ CP-violating phases. The mechanism leads to correlated low-energy signatures in lepton-flavour violation and electric dipole moments, providing potential experimental tests.
format Preprint
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institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid Resonant Type-I and Type-II Leptogenesis in SO(10) with Quasi-Degenerate Triplet and Right-Handed Neutrino Masses $M_T \simeq M_{N_3}$
Ghosh, Gayatri
High Energy Physics - Phenomenology
The origin of the baryon asymmetry of the Universe remains one of the central open problems in particle physics and cosmology. We identify a regime of \emph{hybrid resonant leptogenesis} in renormalizable SO(10) grand unified theories, where a quasi-degeneracy between the scalar triplet and the heaviest right-handed neutrino, \( M_T \simeq M_{N_3}, \) naturally arises from their common origin in unified scalar multiplets and leads to an enhanced interference between type-I and type-II decay amplitudes. This interference gives rise to a physical CP-violating phase, \( ϕ_{\rm HR} = \arg(μf Y_ν^\dagger), \) which cannot be removed by field redefinitions and induces a resonant enhancement of the baryon asymmetry without requiring extreme Yukawa hierarchies or fine-tuned mass splittings. We show that the observed asymmetry, \( Y_B \simeq 8.7 \times 10^{-11}, \) can be reproduced for mass scales around \(10^{11}\,\mathrm{GeV}\), moderate washout effects, and $\mathcal{O}(1)$ CP-violating phases. The mechanism leads to correlated low-energy signatures in lepton-flavour violation and electric dipole moments, providing potential experimental tests.
title Hybrid Resonant Type-I and Type-II Leptogenesis in SO(10) with Quasi-Degenerate Triplet and Right-Handed Neutrino Masses $M_T \simeq M_{N_3}$
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2512.15654