15–18 Jun 2026
NTHU
Asia/Taipei timezone

Dark-Portal Leptogenesis in a Non-Holomorphic Modular Scoto-Seesaw Model

17 Jun 2026, 17:55
10m
NTHU

NTHU

Poster presentation Parallel Session R124

Speaker

Labh Singh (Central University of Himachal Pradesh)

Description

This work explores the neutrino phenomenology of the scoto-seesaw model under non-holomorphic $A_4$ modular flavor symmetry providing a non-SUSY framework for realization of the modular symmetry. To prevent mixing between the beyond standard model fields associated with the tree and loop-level neutrino mass contributions, we assign even and odd modular weights to these sectors, respectively. The physical allowed ranges of oscillation parameters are used to identify the viable region of modulus parameter $\tau$ in its fundamental domain. With the complex modulus $\tau$ serving as the unique source of CP violation (all other parameters are real) the framework realizes successful low-scale leptogenesis through CP-violating decays of the lightest right-handed neutrino into Standard Model leptons and the Higgs boson. The requisite CP asymmetry arises from one-loop diagrams involving dark-sector states, obviating the need for degenerate mass spectra and thereby circumventing the usual resonant leptogenesis mechanism. The observation of a long-lived charged particle ($\eta^{\pm}$) in collider experiments would offer compelling evidence for the inert scalar sector of the model and provide a crucial experimental hint on the dark-sector assisted generation of neutrino masses and leptogenesis.

Authors

Labh Singh (Central University of Himachal Pradesh) Prof. Salah Nasri (Department of physics, United Arab Emirates University, Al-Ain, UAE) Dr Surender Verma (Department of Physics and Astronomical Science, Central University of Himachal Pradesh, Dharamshala, Himachal Pradesh 176215, India)

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