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arXiv · 1509.05564

Asymmetric dark matter and effective number of neutrinos

Teruyuki Kitabayashi·Yoshihiro Kurosawa
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Abstract

We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos $N_{\rm eff}$ at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter $\chi$ couples more strongly to the neutrinos $\nu$ than to the photons $\gamma$ and electrons $e^-$, $\Gamma_{\chi\gamma, \chi e} \ll \Gamma_{\chi\nu}$, or $\Gamma_{\chi\gamma, \chi e} \gg \Gamma_{\chi\nu}$, the lower mass limit on the asymmetric dark matter is about $18$ MeV for $N_{\rm eff}\simeq 3.0$.

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Teruyuki Kitabayashi, Yoshihiro Kurosawa. 2015-09-18. Asymmetric dark matter and effective number of neutrinos. https://doi.org/10.1103/physrevd.93.033002

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