Particle theory

Abstract:

We interpret the KARMEN time anomaly as being due to the production of a (dominantly bino) neutralino with mass 33.9 MeV, which is the lightest supersymmetric particle but decays into 3 leptons through the violation of R-parity. For independent gaugino masses M_1 and M_2 we find regions in the (M_1, M_2, mu, tan beta) parameter space where such a light neutralino is consistent with all experiments. Future tests of this hypothesis are outlined.

Abstract:

We describe a simple lattice model of higher-curvature quantum gravity in two dimensions and study the phase structure of the theory as a function of the curvature coupling. It is shown that the ensemble of flat graphs is entropically unstable to the formation of baby universes. In these simplified models the growth in graphs exhibits a branched polymer behaviour in the phase directly before the flattening transition.