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arXiv · 2011.02487

Intimate Relationship Between Sterile Neutrino Dark Matter and $\Delta N_{\rm eff}$

Kevin J. Kelly·Manibrata Sen·Yue Zhang
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Abstract

The self-interacting neutrino hypothesis is well motivated for addressing the tension between the origin of sterile neutrino dark matter and indirect detection constraints. It can also result in a number of testable signals from the laboratories to the cosmos. We explore a model of neutrino self-interaction mediated by a Majoron-like scalar with sub-MeV mass, and show that explaining the relic density of sterile neutrino dark matter implies a lower bound on the amount of extra radiation in early universe, in particular $\Delta N_{\rm eff}>0.12$ at the CMB epoch. This lower bound will be further strengthened with an improved $X$-ray search at the Athena observatory. Such an intimate relationship will be unambiguously tested by the upcoming CMB-S4 project.

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Kevin J. Kelly, Manibrata Sen, Yue Zhang. 2020-11-04. Intimate Relationship Between Sterile Neutrino Dark Matter and $\Delta N_{\rm eff}$. https://doi.org/10.1103/physrevlett.127.041101

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