A combined astrophysical and dark matter interpretation of the IceCube HESE and throughgoing muon events

摘要

We perform a combined likelihood analysis for the IceCube 6-year high-energy starting events (HESE) above 60 TeV and 8-year throughgoing muon events above 10 TeV using a two-component neutrino ?ux model. The two-component ?ux can be motivated either from purely astrophysical sources or due to a beyond Standard Model contribution, such as decaying heavy dark matter. As for the astrophysical neutrinos, we consider two different source ?avor compositions corresponding to the standard pion decay and muon-damped pion decay sources. We ?nd that the latter is slightly preferred over the former as the high-energy component, while the low-energy component does not show any such preference. We also take into account the multi-messenger gamma-ray constraints and ?nd that our two-component ?t is compatible with these constraints, whereas the single-component power-law best?t to the HESE data is ruled out. The astrophysical plus dark matter interpretation of the two-component ?ux is found to be mildly preferred by the current data and the gamma-ray constraints over the purely astrophysical explanation.