Oscillating neutrinos and mu --> e, gamma
Abstract
Description
If neutrino masses and mixings are suitable to explain the atmospheric and solar neutrino fluxes, this amounts to contributions to FCNC processes, in particular mu --> e, gamma. If the theory is supersymmetric and the origin of the masses is a see-saw mechanism, we show that the prediction for BR(mu --> e, gamma) is in general larger than the experimental upper bound, especially if the largest Yukawa coupling is O(1) and the solar data are explained by a large angle MSW effect, which recent analyses suggest as the preferred scenario. Our analysis is bottom-up and completely general, i.e. it is based just on observable low-energy data. The work generalizes previous results of the literature, identifying the dominant contributions. Application of the results to scenarios with approximate top-neutrino unification, like SO(10) models, rules out most of them unless the leptonic Yukawa matrices satisfy very precise requirements. Other possible ways-out, like gauge mediated SUSY breaking, are also discussed.
42 pages, LaTeX, 13 PS figures. References added and minor details corrected
42 pages, LaTeX, 13 PS figures. References added and minor details corrected