Heavy Pseudo-Dirac Doublet Dark Matter and Non-Thermal Leptogenesis in Light of the LZ Event

Masahiro Ibe; Jun Miyamoto

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arXiv · 2610.29335

Heavy Pseudo-Dirac Doublet Dark Matter and Non-Thermal Leptogenesis in Light of the LZ Event

Masahiro Ibe·Jun Miyamoto

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Abstract

Motivated by the recent LZ candidate nuclear-recoil event, we study pseudo-Dirac electroweak doublet dark matter in the mass range $10^2$--$10^4\,\mathrm{TeV}$, where bounds from searches for neutrinos produced by dark matter annihilation in the Sun can be evaded. To suppress the excessive thermal relic abundance, we consider freeze-out during inflaton domination followed by entropy production during reheating. We examine whether this cosmological history can also accommodate non-thermal leptogenesis. Our analysis includes dark matter production through the emission of virtual electroweak gauge bosons in right-handed-neutrino decays and through thermalization cascades. Our estimates suggest that the two scenarios can be reconciled if dark matter pair emission in right-handed-neutrino decays is kinematically forbidden and cascade production is sufficiently suppressed. Such a realization, however, requires enhanced CP violation, typically involving fine-tuning in the seesaw mechanism or the right-handed-neutrino mass spectrum.

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Masahiro Ibe, Jun Miyamoto. 2026-10-21. Heavy Pseudo-Dirac Doublet Dark Matter and Non-Thermal Leptogenesis in Light of the LZ Event. https://arxiv.org/abs/2610.29335

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