Loop quantum gravity corrections to neutrino and photon propagation

by Jorge Alfaro (Santiago, Chile)

Thursday 25 Jul 2002, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

Within loop quantum gravity we construct a coarse-grained approximation for the Einstein-Maxwell theory and massive spin-1/2 fields that yields effective equations in flat spacetime comprising Planck scale corrections. The resulting energy dispersion relations entail Planck scale corrections to those in flat spacetime. The electric/magnetic asymmetry in the regularization procedure yields nonlinearities only in the magnetic sector which are briefly discussed. Observations of cosmological Gamma Ray Bursts and accompaning Neutrino Bursts ({\bar p}\approx 10⁵ GeV) might eventually lead to the needed accuracy to study some of these quantum gravity effects. Additionally we consider the modified dispersion relations in the context of the observed GZK limit anomaly and related processes. This is accomplished through a kinematical analysis of the modified threshold conditions for the decay reactions involved. Especially interesting is the possibility of a helicity dependent violation of the limit, whose primary effect would be the observation of favoured helicity states for highly energetic particles.