Relic neutrinos, monopoles, and cosmic rays above {approx}10{sup 20} eV
- Department of Physics and Astronomy, Vanderbilt University, Nashville Tennessee 37235 (United States)
The observation of cosmic ray events above the Greisen-Kuzmin-Zatsepin (GZK) cut-off of 5x10{sup 19} eV offers an enormous opportunity for the discovery of new physics. We explore two possible origins for these super-GZK events. The first example uses Standard Model (SM) physics augmented only by < or approx. eV neutrino masses as suggested by solar, atmospheric, and terrestrial neutrino detection, and by the cosmological need for a hot dark matter component. In this example, cosmic ray neutrinos from distant, highest energy sources annihilate relatively nearby on the relic neutrino background to produce 'Z-bursts', highly collimated, highly boosted ({gamma}{sub Z}{approx}10{sup 11}) hadronic jets. The SM and hot Big Bang cosmology give the probability for each neutrino flavor at its resonant energy to annihilate within the halo of our galactic supercluster as likely within an order of magnitude of 1%. The kinematics are completely determined by the neutrino masses and the properties of the Z boson. The burst energy is E{sub R}=4 (eV/m{sub {nu}})x10{sup 21} eV, and the burst content includes, on average, thirty photons and 2.7 nucleons with super-GZK energies. The second example goes beyond SM physics to invoke relativistic magnetic monopoles as the cosmic ray primaries. Motivations for this hypothesis are twofold: (i) conventional primaries are problematic, while monopoles are naturally accelerated to E{approx}10{sup 20} eV by galactic magnetic fields; (ii) the observed highest energy cosmic ray flux is just a few orders of magnitude below the Parker flux limit for monopoles. By matching the cosmic monopole production mechanism to the observed highest energy cosmic ray flux we estimate the monopole mass to be < or approx. 10{sup 10} GeV. Several tests of the neutrino annihilation and monopole hypotheses are indicated.
- OSTI ID:
- 21199246
- Journal Information:
- AIP Conference Proceedings, Vol. 433, Issue 1; Conference: Workshop on observing giant cosmic ray air showers from >10{sup 20} eV particles from space, College Park, MD (United States), 13-15 Nov 1997; Other Information: DOI: 10.1063/1.56143; (c) 1998 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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