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arXiv · 2512.14271

Cosmological Bounds on Scotogenic Model with Asymmetric Mediator

Kento Asai·Seishi Enomoto·Takuya Hirose·Masato Yamanaka
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Abstract

We study cosmological constraints on the asymmetric mediator scenario, a variant of the scotogenic model that addresses the origins of neutrino masses, dark matter (DM), and the baryon asymmetry. An SU(2)$_L$ doublet scalar $\eta$ mediates between the visible and dark sectors, while a singlet scalar $\sigma$ serves as the DM candidate. We evaluate the DM relic abundance by solving the Boltzmann equations including $\eta$ decay and scattering processes prior to the freeze-out of the $\eta$ asymmetry, and show Big Bang nucleosynthesis constraints from late-time $\eta$ decays. Combining the DM abundance and BBN bounds, we find the favored parameter space of this model, for instance, the mediator masses of $m_\eta \lesssim \mathcal{O}(10)$ TeV.

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Kento Asai, Seishi Enomoto, Takuya Hirose, Masato Yamanaka. 2025-12-16. Cosmological Bounds on Scotogenic Model with Asymmetric Mediator. https://arxiv.org/abs/2512.14271

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