Lepton fiavor violating decays are a unique probe of new physics. They might be related to the mechanism of neutrino mass generation, to the spontaneous breaking of supersymmetry, or to new interactions at high energies, above and below the GUT scale. Their detection would give an unmistakable signal of physics beyond the Standard Model and its minimal extensions, and could be the first manifestation of supersymmetric effects. And it would certainly mark the beginning of a new era in particle physics.
Among them, μ → eΥ and τ → μΥ offer excellent experimental perspectives. The limits on these decays are already impressive and significant improvements are expected in the next few years. Thus, their role in constraining and perhaps discovering new physics will be reinforced by future experiments.
Recently, motivated by these experimental efforts, by the study of neutrino mass models, and by the data from ν oscillation experiments, μ → eΥ and τ → μΥ have received particular attention. Different aspects regarding these processes were investigated in papers [1, 2, 3, 4]. This thesis is based on those works.
In the first chapter, the motivation and the general framework are introduced. A critical review of some assumptions commonly employed in the computation of lepton fiavor violating decays is presented in chapter two. We investigate, in the third chapter, the implications, within a particular SO(10) model, μ → eΥ and τ → μΥ for the determination of the viable parameter space, and we confront the perspectives for their detection against accelerator experiments in the search for supersymmetry. Finally, in chapter four we address the relevance of the gaugino spectrum on the computation of BR(μ → eΥ).
