\mu-e Conversion Versus \mu-->e \gamma

Abstract

We compare two most relevant loop induced muon number violating processes, \mu --> e \gamma and \mu-e conversion in nuclei, in constraining new physics. Because of much richer structure of the latter process it may be enhanced with respect to \mu --> e \gamma by a large $\ln (m_{\mu }^2/{\Lambda }^2),$ where $\Lambda$ is the scale of the new physics. After model-independent considerations we present two examples constraining the R-parity violating couplings of MSSM and the off-diagonal couplings of the doubly charged Higgs bosons from the non-observation of \mu-e conversion.

Comments: Talk given in the workshop Valencia 97: "Physics Beyond the SM," Oct. 13-17, 1997, 6 pages