Ultrahigh energy neutrinos from hidden-sector topological defects - art. no. 083512

We study topological defects (TD) in hidden (mirror) matter as possible sou rces of ultrahigh energy neutrinos. The hidden or mirror and ordinary matte r are assumed to interact very weakly through gravity or superheavy particl es. An inflationary scenario is outlined in which superheavy defects are fo rmed in hidden or mirror matter (and not in ordinary matter), and at the sa me time the density of mirror matter produced at the end of inflation is mu ch smaller than that of ordinary matter. Superheavy particles produced by h idden-setter TD and the products of their decays are all sterile in our wor ld. Only mirror neutrinos are not, due to oscillation into ordinary neutrin os. We show that oscillations of ultrahigh energy neutrinos can occur on a time scale less than the present age of the Universe. A model of mass-degen erate visible and mirror neutrinos with maximal mixing is constructed. Cons traints on UHE neutrino fluxes are obtained. The estimated fluxes can be 3 orders of magnitude higher than those from ordinary matter.