Upper limits for lepton-flavor violation from the exotic μ− ν e− conversion.

The transition matrix elements for coherent and incoherent channels of the neutrinoless μ⁻ ν e⁻ conversion are investigated. The results refer to the ²⁷Al nucleus which has recently been chosen as a target in the MECO experiment at Brookhaven aiming to search for μ-e conversion events with a sensitivity 10^-17. These results are compared to those obtained previously for ⁴⁸Ti and ²⁰⁸Pb targets. We focus on the contributions to the branching ratio ℛ_μe⁻ originating from scalar, vector and axial vector interactions resulting in conventional extentions of the standard model and minimal supersymmetric models with and without ℛ-parity violation. With our calculations we extract very severe constraints for the flavor violation parameters. [ABSTRACT FROM AUTHOR]