Lepton Flavor Violation in the Standard Model with general Dimension-Six Operators

Abstract

We study lepton flavor observables in the Standard Model (SM) extended with all dimension-$6$ operators which are invariant under the SM gauge group. We calculate the complete one-loop predictions to the radiative lepton decays $\mu \to e\gamma$, $\tau \to \mu \gamma$ and $\tau \to e\gamma$ as well as to the closely related anomalous magnetic moments and electric dipole moments of charged leptons, taking into account all dimension-$6$ operators which can generate lepton flavor violation. Also the 3-body flavor violating charged lepton decays ${\tau }^{\pm }\to {\mu }^{\pm }{\mu }^{+}{\mu }^{-}$, ${\tau }^{\pm }\to e^{\pm }{e}^{+}{e}^{-}$, ${\tau }^{\pm }\to e^{\pm }{\mu }^{+}{\mu }^{-}$, ${\tau }^{\pm }\to {\mu }^{\pm }{e}^{+}{e}^{-}$, ${\tau }^{\pm }\to e^{\mp }{\mu }^{\pm }{\mu }^{\pm }$, ${\tau }^{\pm }\to {\mu }^{\mp }{e}^{\pm }{e}^{\pm }$ and ${\mu }^{\pm }\to e^{\pm }{e}^{+}{e}^{-}$ and the $Z^0$ decays $Z^0\to {\ell }_i^{+}{\ell }_j^{-}$ are considered, taking into account all tree-level contributions.

Comments: 33 pages, 7 figures, misprints corrected, references added