Analytic Solutions to the RG Equations of the Neutrino Physical Parameters

In the case of two generation neutrinos, the energy-scale dependence of thelepton-flavor mixing matrix with Majorana phase can be governed by only oneparameter r, which is the ratio between the diagonal elements of neutrino massmatrix. By using this parameter r, we derive the analytic solutions to therenormalization group equations of the physical parameters, which are themixing angle, Majorana phase, and the ratio of the mass-squared difference tothe mass squared of the heaviest neutrino. The energy-scale dependence of theMajorana phase is clarified by using these analytic solutions. The instabilityof the Majorana phase causes in the same parameter region in which the mixingangle is unstable against quantum corrections.Comment: LaTeX2e, 9 pages, 6 figure