Particle theory

Abstract:

We develop a new and efficient method to systematically analyse four dimensional effective supergravities which descend from flux compactifications. The issue of finding vacua of such systems, both supersymmetric and non-supersymmetric, is mapped into a problem in computational algebraic geometry. Using recent developments in computer algebra, the problem can then be rapidly dealt with in a completely algorithmic fashion. Two main results are (1) a procedure for calculating constraints which the flux parameters must satisfy in these models if any given type of vacuum is to exist; (2) a stepwise process for finding all of the isolated vacua of such systems and their physical properties. We illustrate our discussion with several concrete examples, some of which have eluded conventional methods so far. © SISSA 2006.

Abstract:

The sources of the observed ultrahigh energy cosmic rays must also generate ultrahigh energy neutrinos. Deep inelastic scattering of these neutrinos with nucleons on Earth probe center-of-mass energies s∼100TeV, well beyond those attainable at terrestrial colliders. By comparing the rates for two classes of observable events, any departure from the benchmark (unscreened perturbative QCD) neutrino-nucleon cross section can be constrained. Using the projected sensitivity of the Pierre Auger Observatory to quasihorizontal showers and Earth-skimming tau neutrinos, we show that a "super-Auger" detector can thus provide an unique probe of strong interaction dynamics. © 2006 The American Physical Society.