Majorana CP-violating phases, RG running of neutrino mixing parameters and charged lepton flavour violating decays Original Research Article

We consider the MSSM with see-saw mechanism of neutrino mass generation and soft SUSY breaking with flavour-universal boundary conditions at the GUT scale, in which the lepton flavour violating (LFV) decays image, image, etc., are predicted with rates that can be within the reach of present and planned experiments. These predictions depend critically on the matrix of neutrino Yukawa couplings image which can be expressed in terms of the light and heavy right-handed (RH) neutrino masses, neutrino mixing matrix image, and an orthogonal matrix R. We investigate the effects of Majorana CP-violation phases in image, and of the RG running of light neutrino masses and mixing angles from image to the RH Majorana neutrino mass scale image, on the predictions for the rates of LFV decays image, image and image. The case of quasi-degenerate heavy RH Majorana neutrinos is considered. Results for neutrino mass spectrum with normal hierarchy, values of the lightest ν-mass in the range image, and in the cases of image and complex matrix image are presented. We find that the effects of the Majorana CP-violation phases and of the RG evolution of neutrino mixing parameters can change by few orders of magnitude the predicted rates of the LFV decays image and image. The impact of these effects on the image decay rate is typically smaller and only possible for image. If the RG running effects are negligible, in a large region of soft SUSY breaking parameter space the ratio of the branching ratios of the image and image (image) decays is entirely determined in the case of image by the values of the neutrino mixing parameters at image.