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arXiv · astro-ph/9810076

A New Dark Matter Candidate: Non-thermal Sterile Neutrinos

Xiangdong Shi·George M. Fuller
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Abstract

We propose a new and unique dark matter candidate: $\sim 100$ eV to $\sim 10$ keV sterile neutrinos produced via lepton number-driven resonant MSW (Mikheyev-Smirnov-Wolfenstein) conversion of active neutrinos. The requisite lepton number asymmetries in any of the active neutrino flavors range from 10$^{-3}$ to 10$^{-1}$ of the photon number - well within primordial nucleosynthesis bounds. The unique feature here is that the adiabaticity condition of the resonance strongly favors the production of lower energy sterile neutrinos. The resulting non-thermal (cold) energy spectrum can cause these sterile neutrinos to revert to non-relativistic kinematics at an early epoch, so that free-streaming lengths at or below the dwarf galaxy scale are possible. Therefore, the main problem associated with light neutrino dark matter candidates can be circumvented in our model.

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Xiangdong Shi, George M. Fuller. 1999-04-03. A New Dark Matter Candidate: Non-thermal Sterile Neutrinos. https://doi.org/10.1103/physrevlett.82.2832

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