Abstract
Resonant annihilation of ultrahigh energy cosmic neutrinos () on the cosmic neutrino background () into bosons—the -burst mechanism—and its associated absorption and emission phenomenology provide a unique, albeit indirect, probe of the in its present state. In this paper, we examine the implications of gravitational clustering of the in nearby galaxy clusters for the -burst phenomenology. In particular, we study the emission features of the -decay products originating from the Virgo cluster, and the potential of future cosmic ray experiments to observe clustering-enhanced -burst rates. We find that a detector with an exposure equivalent to three years of observations at the Extreme Universe Space Observatory (EUSO) will very likely measure these enhanced rates together with the associated flux, provided that the latter saturates current observational limits and the neutrino masses are quasidegenerate, . In the case of fluxes below the electromagnetic cascade limit, or a hierarchical neutrino mass spectrum, an experimental sensitivity exceeding that of EUSO by at least 2 orders of magnitude is required to detect the clustering enhancements with any certainty.
1 More- Received 30 May 2005
DOI:https://doi.org/10.1103/PhysRevD.72.043008
©2005 American Physical Society