Resonant production of gamma rays in jolted cold neutron stars

Acoustic shock waves passing through colliding cold neutron stars can cause repetitive superconducting phase transitions in which the proton condensate relaxes to its equilibrium value via coherent oscillations. As a result, a resonant non-thermal production of gamma rays in the MeV energy range with power up to 10^(52) erg/s can take place during the short period of time before the nuclear matter is heated by the shock waves.Comment: 9 pages, 2 figures include

Supersymmetric Q-balls: theory and cosmology

MSSM predicts the existence of Q-balls, some of which can be entirely stable. Both stable and unstable Q-balls can play an important role in cosmology. In particular, Affleck-Dine baryogenesis can result in a copious production of stable baryonic Q-balls, which can presently exist as a form of dark matter.Comment: talk presented at PASCOS-98; transparencies available at http://wwwinfo.cern.ch/~kusenko/PASCOS98.ps; 4 pages, latex, sprocl, psfi

Ultrahigh-energy nuclei, photons, and magnetic fields

Combined recent data from cosmic-ray detectors and gamma-ray detectors have produced some surprising insights regarding the sources of ultrahigh-energy cosmic rays (UHECRs), magnetic fields inside and outside the Milky Way, and the universal photon backgrounds. The energy-dependent composition of UHECRs implies a non-negligible contribution of sources located in the Milky Way, such as past gamma-ray bursts that took place in our Galaxy. Extended halos of distant sources seen in the Fermi data imply that intergalactic magnetic fields have average strengths of the order of a femtogauss. Such relatively low magnetic fields imply that the protons from distant blazars generate a detectable flux of secondary gamma rays in their interactions with the photon background. A comparison with the data shows an excellent agreement of the secondary photons with the spectra of distant blazars observed by atmospheric Cherenkov telescopes.Comment: 6 pages, 3 figures, talk presented at "Cosmic Ray International Seminar (CRIS 2010)", Catania, September, 13-17, 201

Future determination of the neutrino-nucleon cross section at extreme energies

Future detectors of cosmic rays, such as EUSO and OWL, can test the Standard Model predictions for the neutrino interactions at energies well beyond the reach of any terrestrial experiment. The relative rates of horizontal and upgoing air showers, combined with the angular distribution of upgoing air showers will allow one to measure the neutrino-nucleon cross section at center-of-mass energy 10^5 GeV or higher.Comment: Talk presented at Workshop on electromagnetic probes of fundamental physics, October 16-21, 2001, Erice, Ital

Dark matter from Affleck-Dine baryogenesis

Fragmentation of the Affleck-Dine condensate into Q-balls could fill the Universe with dark matter either in the form of stable baryonic balls, or LSP produced from the decay of unstable Q-balls. The dark matter and the ordinary matter in the Universe may share the same origin.Comment: 4 pages, aipproc macro included; to appear in "Particle Physics and the Early Universe (COSMO-98)", ed. by David O. Caldwell, American Institute of Physic