Impact of flavour coupling on SO(10)-inspired leptogenesis

2025/07/08 by Pasquale Di Bari, X. Hu, Di Bari, Pasquale +1 · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle physics theoretical and experimental studies

paper · pdf · doi:10.48550/arxiv.2507.06144

openalex publication_date 2025/07/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We discuss the impact of flavour coupling on the predictions of low energy neutrino parameters from SO(10)-inspired leptogenesis (SO10INLEP). The right-handed (RH) neutrino mass spectrum is strongly hierarchical and successful leptogenesis relies on generating the asymmetry from next-to-lightest RH neutrino decays (N₂-leptogenesis) and circumventing the lightest RH neutrino washout. These two conditions yield distinctive predictions such as a lower bound on the lightest neutrino mass m₁ \gtrsim 1 \rm meV. We first review the status of SO10INLEP, noticing how cosmological observations are now testing a particular neutrino mass window, m₁ ≃ (10--30) \rm meV, where only the first octant is allowed and a large range of values for the Dirac phase is excluded. Including flavour coupling, we find that the lower bound relaxes to m₁ \gtrsim 0.65 \rm meV. Moreover, new muon-dominated solutions appear slightly relaxing the upper bound on the atmospheric mixing angle. We also study the impact on strong thermal SO10INLEP (ST-SO10INLEP) scenario where, in addition to successful leptogenesis, one can washout a large pre-existing asymmetry. Contrarily to naive expectations, for which flavour coupling could jeopardise the scenario, allowing a large pre-existing asymmetry to survive unconditionally, we show, and explain analytically, that ST-SO10INLEP is still viable within almost the same allowed region of parameters. There is even a slight relaxation of the m₁ viable window from (9--30)meV to (4--40)meV for a 10^-3 pre-existing asymmetry. The new results from atmospheric neutrinos, mildly favouring normal ordering and first octant, are now in nice agreement with the predictions of ST-SO10INLEP. Intriguingly, the predicted 0νββ signal is starting to be within the reach of KamLAND-Zen.

Citations

• Thermal leptogenesis in minimal unified models
• Electroweak Triplet Scalar Contribution to SO(10) Leptogenesis
• Constraints on Neutrino Physics from DESI DR2 BAO and DR1 Full Shape
• GLOBAL ANALYSIS OF NEUTRINO OSCILLATIONS
• Leptogenesis in SO(10) with Minimal Yukawa sector
• Living at the Edge: A Critical Look at the Cosmological Neutrino Mass Bound
• Neutrino mass bounds from DESI 2024 are relaxed by Planck PR4 and cosmological supernovae
• Direct neutrino-mass measurement based on 259 days of KATRIN data
• Direct neutrino-mass measurement based on 259 days of KATRIN data
• One-anchor structural construction of Standard Model observables, a dark-matter tower, and Newton's constant from E₈ x E₈ Coxeter geometry on a Schoen Calabi-Yau threefold
• The SO(10)-inspired leptogenesis timely opportunity
• Planck 2018 results
• Observation of Gravitational Waves from a Binary Black Hole Merger
• Complex Spinors and Unified Theories
• Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations
• The Family Group in Grand Unified Theories

Cited by

• One Phase to Rule Them All: Spontaneous CP Violation and Leptogenesis in SO(10)

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