Year: 2026
Type: article
Abstract: Low-scale leptogenesis scenarios, such as the resonant leptogenesis, typically require a highly degenerate mass spectrum of right-handed neutrinos (RHNs). This requirement can be circumvented by extending the seesaw framework with a scalar singlet S that couples to RHNs via the $$S N_I N_J$$ S N I N J terms (with $$I \ne J$$ I ≠ J ), which opens up new decay channels $$N_I \rightarrow N_J S$$ N I → N J S and provides additional sources of CP violation, thereby enabling successful leptogenesis at the TeV scale without the need for mass degeneracy. In this work, for the first time, we point out that the flavon fields, which are introduced in many flavor-symmetry neutrino mass models to be responsible for the generation of RHN masses through the acquisition of non-zero vacuum expectation values, serve as ideal candidates for the S field. Taking as an example a flavor-symmetry neutrino mass model that naturally realizes the experimentally allowed TM1 mixing pattern and has the attractive features that only one flavon field plays the role of S and that it couples to only two RHNs, we demonstrate that the observed neutrino masses and mixing angles can be consistently reproduced, while the observed baryon asymmetry can be achieved within a parameter space compatible with current experimental constraints.
Source: The European Physical Journal C
Authors: Yan Shao, Zhen-hua Zhao
Institution: Liaoning Normal University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Awards: G1953370800, G6221555079
OpenAlex ID: W7155367334
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