Dark Matter interpretation of low energy IceCube MESE excess

Abstract

The 2-years MESE IceCube events show a slightly excess in the energy range 10-100 TeV with a maximum local statistical significance of 2.3$\sigma$, once a hard astrophysical power-law is assumed. A spectral index smaller than 2.2 is indeed suggested by multi-messenger studies related to $p$-$p$ sources and by the recent IceCube analysis regarding 6-years up-going muon neutrinos. In the present paper, we propose a two-components scenario where the extraterrestrial neutrinos are explained in terms of an astrophysical power-law and a Dark Matter signal. We consider both decaying and annihilating Dark Matter candidates with different final states (quarks and leptons) and different halo density profiles. We perform a likelihood-ratio analysis that provides a statistical significance up to 3.9$\sigma$ for a Dark Matter interpretation of the IceCube low energy excess.

Comments: 20 pages, 7 figures. v2: version published in JCAP