High Energy Cosmic Rays from Neutrinos

We discuss recent models in which neutrinos, which are assumed to have mass in the eV range, originate the highest energy cosmic rays by interaction with the enhanced density in the galactic halo of the relic cosmic neutrino background. We make an analytical calculation of the required neutrino fluxes to show that the parameter space for these models is constrained by horizontal air shower searches and by the total number of background neutrinos, so that only models which have fairly unnatural halo sizes and enhanced densities are allowed.Comment: 14 pages, 3 ps figures. To appear in Phys. Rev.

Relic Neutrino Absorption Spectroscopy

Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10^{21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m_{nu} >~ 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.Comment: 19 pages, 26 figures, REVTeX

Standing on the Shoulders of Goffman: Advancing a Relational Research Agenda on Stigma

Drawing from Goffman’s (1963) original observations on stigma and the consequences of interactions between the stigmatized and supportive or stigmatizing audiences, we conduct a 20-year review of the diverse literature on stigma to revisit the collective nature of stigmatization processes. We find that studies on stigma’s origins, responses, processes, and outcomes have diverged from Goffman’s relational view of stigma as they have overlooked important relational mechanisms explaining the processes of (de)stigmatization. We draw from those conclusions to justify the need to study stigma as a collective phenomenon. We develop a relational perspective on stigma based on understanding how attributes are stigmatized (or not) by audiences in their interactions. We argue that to advance stigma research, it is necessary to build on Goffman’s theory to include the stigmatizers (i.e., the normal) and supporters (i.e., the wise), how they create, sustain, or remove stigma, and how they relate to the stigmatized (i.e., the targets). Accordingly, we provide a research agenda on stigma as a collective phenomenon that theorizes a relational perspective, proposes a typology of how audiences relate to stigmatization, and identifies patterns of relations between audiences. We thus offer a missing piece to existing accounts of stigma by focusing on the key role of audiences (i.e., stigmatizers or supporters of the stigmatized) rather than on the targets of stigma (i.e., the own)