Speaker: Raj Gandhi, HRI, India and Fermi National Accelerator Laboratory
Abstract: Given present day constraints, dark matter (DM) may not comprise of thermal weakly interacting massive particles (WIMPS). Drawing closely upon the fact that neutral current neutrino nucleon interactions are indistinguishable from DM-nucleon interactions at low energies, we study the consequences of extending this feature to high energies for a small, non-thermal but highly energetic population of DM particle χ, created via the decay of a significantly more massive and long-lived non-thermal relic φ, which forms the bulk of DM. If χ interacts with nucleons, it is possible that its cross-section, like the neutrino-nucleus coherent cross-section, may rise sharply with energy leading to deep inelastic scattering, similar to neutral current neutrino-nucleon interactions at high energies. Thus, its direct detection may be possible via cascades in very large neutrino detectors. IceCube (IC) has recently reported three ultra-high energy PeV cascade events clustered around 1-2 PeV. We apply this notion to these events and discuss the features which may help discriminate this scenario from one in which only astrophysical neutrinos constitute the IC event sample.