  We assess the model discriminating power of a combined phenomenological
analysis of mu -> e gamma and mu -> e conversion on different target nuclei,
including the current hadronic uncertainties. We find that the theoretical
uncertainties can be largely reduced by using input from lattice QCD and do not
constitute a limiting factor in discriminating models where one or at most two
underlying operators (dipole, scalar, vector) provide the dominant source of
lepton flavor violation. Our results show that a realistic discrimination among
underlying mechanisms requires a measurement of the ratio of conversion rates
at the 5% level (two light nuclei) or at the 20% level (one light and one heavy
nucleus). We have illustrated these main conclusions also in the context of a
supersymmetric model.
