General Conditions for Lepton Flavour Violation at Tree- and 1-Loop Level
Sep, 2007Citations per year
Abstract: (arXiv)
In this work, we compile the necessary and sufficient conditions a theory has to fulfill in order to ensure general lepton flavour conservation, in the spirit of the Glashow-Weinberg criteria for the absence of flavour-changing neutral currents. At tree-level, interactions involving electrically neutral and doubly charged bosons are investigated. We also investigate flavour changes at 1-loop level. In all cases we find that the essential theoretical requirements can be reduced to a few basic conditions on the particle content and the coupling matrices. For 1-loop diagrams, we also investigate how exactly a GIM-suppression can occur that will strongly reduce the rates of lepton flavour violating effects even if they are in principle present in a certain theory. In all chapters, we apply our criteria to several models which can in general induce lepton flavour violation, e.g. LR-symmetric models or the MSSM. In the end we give a summarizing table of the obtained results, thereby demonstrating the applicability of our criteria to a large class of models beyond the Standard Model.Note:
- 31 pages, 2 figures
- 11.30.Fs
- 12.60.Fr
- 12.60.Cn
- muon: radiative decay
- muon: leptonic decay
- muon: branching ratio
- flavor: violation
- neutral current: flavor changing
- perturbation theory: higher-order
- tree approximation
References(31)
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