Neutrino Yukawa couplings and FCNC processes in B decays in SUSY-GUT

Flavor changing neutral current and lepton flavor violating processes are studied in the SU(5) SUSY-GUT with right-handed neutrino supermultiplets. Using input parameters motivated by neutrino oscillation, it is shown that the time-dependent CP asymmetry of b → s γ can be as large as 20%. We also show that the Bs–B̄s mixing can be significantly different from the standard model prediction. Effects of the physics beyond the standard model (SM) may appear in the flavor physics in quarks and leptons. One of indications is already given by the atmospheric and the solar neutrino anomalies which are interpreted as evidences of neutrino oscillation [1]. A natural way to explain small neutrino masses is the see-saw mechanism with very heavy right-handed neutrinos. This scenario suggests the existence of new sources of flavor mixings in the lepton sector at much higher energy scale than the electroweak scale. In this work [2] we consider flavor changing neutral current (FCNC) and lepton flavor violation (LFV) processes in the model of a SU(5) supersymmetric (SUSY) grand unified theory (GUT) which incorporates the see-saw ∗ Talk given in International Seminar Quarks-2000, May 14–21, 2000, Pushkin, Russia and XXXth International Conference on High Energy Physics, July 27–August 2, 2000, Osaka, Japan.