Leptogenesis with a GeV-Scale Quasi-Dirac Neutrino
Abstract
We discuss leptogenesis in a model with a GeV-scale quasi-Dirac neutral lepton, comprising mainly sterile states, which is accessible to future experiments. In particular, we show that Higgs-decay leptogenesis can naturally arise from the type-I seesaw mechanism with spontaneously broken global lepton number together with a discrete Z2 symmetry, yielding two quasi-degenerate right-handed neutrinos (RHNs) which, to excellent approximation, form a single Dirac neutrino, with a tiny mass splitting as required for resonant enhancement generated by higher-dimensional lepton-number-violating operators. Incorporating finite-temperature effects, we show that the observed baryon asymmetry can be successfully generated through thermal Higgs decays for 0.1-10 GeV mass quasi-Dirac neutrinos, with the CP asymmetry arising from the interplay between the vacuum and thermal contributions to the mass splitting. In the parameter region of successful leptogenesis, the quasi-Dirac neutrino is accessible to future heavy neutral lepton searches at SHiP, MATHUSLA and FCC-ee. In addition, the same symmetry-breaking sector gives rise to unstable domain walls whose annihilation can generate a stochastic gravitational-wave background, providing a complementary probe of the framework.
Related
- Singlet-doublet dark matter induced radiative neutrino mass and TeV scale leptogenesis
- Primordial Black Hole Assisted Dirac Leptogenesis
- Inelastic Dark Matter at LZ from Radiative Dirac Neutrino Mass Paradigm
- Quasi-steady flavor configuration of multi-energy neutrino ensembles
- Decay-Assisted Leptogenesis during Preheating
BibTeX
@misc{king2026leptogenesis,
title = {{Leptogenesis with a GeV-Scale Quasi-Dirac Neutrino}},
author = {Stephen F. King and Soumen Kumar Manna and Rishav Roshan and Arunansu Sil},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.20729},
eprint = {2610.20729},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.20729},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Leptogenesis with a GeV-Scale Quasi-Dirac Neutrino
AU - Stephen F. King
AU - Soumen Kumar Manna
AU - Rishav Roshan
AU - Arunansu Sil
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.20729
UR - https://arxiv.org/abs/2610.20729
AB - We discuss leptogenesis in a model with a GeV-scale quasi-Dirac neutral lepton, comprising mainly sterile states, which is accessible to future experiments. In particular, we show that Higgs-decay leptogenesis can naturally arise from the type-I seesaw mechanism with spontaneously broken global lepton number together with a discrete Z_2 symmetry, yielding two quasi-degenerate right-handed neutrinos (RHNs) which, to excellent approximation, form a single Dirac neutrino, with a tiny mass splitting as required for resonant enhancement generated by higher-dimensional lepton-number-violating operators. Incorporating finite-temperature effects, we show that the observed baryon asymmetry can be successfully generated through thermal Higgs decays for 0.1-10 GeV mass quasi-Dirac neutrinos, with the CP asymmetry arising from the interplay between the vacuum and thermal contributions to the mass splitting. In the parameter region of successful leptogenesis, the quasi-Dirac neutrino is accessible to future heavy neutral lepton searches at SHiP, MATHUSLA and FCC-ee. In addition, the same symmetry-breaking sector gives rise to unstable domain walls whose annihilation can generate a stochastic gravitational-wave background, providing a complementary probe of the framework.
ER -