Particle theory

Abstract:

M theory is considered in its low-energy limit on a G2 manifold with nonvanishing flux. Using the Killing spinor equations for linear flux, an explicit set of first-order bosonic equations for supersymmetric solutions is found. These solutions describe a warped product of a domain wall in four-dimensional space-time and a deformed G2 manifold. It is shown how these domain walls arise from the perspective of the associated four-dimensional N = 1 effective supergravity theories. We also discuss the inclusion of membrane and M5-brane sources. © 2005 The American Physical Society.

Abstract:

As ultra-high energy cosmic ray protons propagate through the universe, they undergo photo-meson interactions with the cosmic microwave background, generating the 'cosmogenic' neutrino flux. If, however, a substantial fraction of the cosmic ray primaries are heavy nuclei rather than protons, they would preferentially lose energy through photo-disintegration so the corresponding neutrino flux may be substantially depleted. We investigate this issue using a Monte Carlo simulation of cosmic ray propagation through intragalactic radiation fields and assess the impact of the altered neutrino fluxes on next-generation neutrino telescopes. © 2004 Elsevier B.V. All rights reserved.