Gauged Horizontal U(1): the power of anomaly cancellation

por E Nardi (SISSA-TRIESTE)

jueves 4 nov. 1999 11:30 → 12:30 Europe/Madrid

Sala de Juntas del IFIC (Edf. Institutos de Investigacion)

If a horizontal U(1) symmetry H is responsible for the generation of the standard model (SM) mass hierarchies, cancellation of the mixed SM-H anomalies (in the supersymmetric case) results in a set of striking prediction: the up quark is massless, providing a simple solution to the strong CP problem, and the $\mu$ term is necessarily somewhat below the SUSY scale, thus solving in a natural way the SUSY $\mu$ problem. Contrary to common belief, we show that phenomenologically viable models can be constructed without appealing to the Green-Schwartz anomaly cancellation mechanism. Few remarks on the naturalness of light sterile neutrinos in this same framework will be discussed as well.