Explaining the AMS positron excess via right-handed neutrinos.

We have witnessed in the past decade the observation of a puzzling cosmic-ray excess at energies larger than 10 GeV. The AMS-02 data published this year have new ingredients such as the bump around 300 GeV followed by a drop at 800 GeV, as well as smaller error bars. Adopting the background used by the AMS-02 Collaboration in their analysis, one can conclude that previous explanations to the new AMS-02 such as one component annihilating and decaying dark matter as well as pulsars seem to fail at reproducing the data. Here, we show that in the right-handed neutrino portal might reside the answer. We discuss a decaying two-component dark matter scenario where the two-body decay products are right-handed neutrinos that have their decay pattern governed by the type-I seesaw mechanism. This setup provides a very good fit to the data; for example, a conservative approach including just statistical uncertainties leads to χ²/DOF~2.3 for mDM1=2150 GeV with t1=3.78×1026 s and mDM2=300 with t2=5.0×1027 s for MN=10 GeV, and, in an optimistic case, including systematic uncertainties, we find χ²/DOF~1.12, for MN=10 GeV, with mDM1=2200 GeV with t1=3.8×1026 s and mDM2=323 GeV with t2=1.68×1027 s. [ABSTRACT FROM AUTHOR]