Charged lepton flavor violating decays: leading logarithmic approximation versus full RG results

In the context of the minimal supersymmetric extension of the Standard Model with the right-handed Majorana neutrinos, we study lepton flavor violating processes including full renormalization group running effects. We systematically compare our results with the commonly used leading logarithmic approximation, resorting to a "best fit" approach to fix all the high energy Yukawa matrices. We find significant deviations in large regions of the SUSY parameter space, which we outline in detail. We also give, within this setting, some results on the cosmo-phenomenologically preferred stau coannihilation region. Finally, we propose a parametrization, in terms of the SUSY input parameters, of the common SUSY mass appearing in the leading log and mass insertion approximation formula for the charged lepton flavor violating decay rates, which fits our full renormalization group results with high precision. (C) 2003 Elsevier B.V. All rights reserved.