Regular Article - Theoretical Physics
Lepton mixing matrix in standard model extended by one sterile neutrino
Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, 04109, Leipzig, Germany
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Published online: 21 November 2006
We consider the simplest extension of the standard electroweak model by one sterile neutrino that allows for neutrino masses and mixing. We find that its leptonic sector contains much less free physical parameters than previously realized. In addition to the two neutrino masses, the lepton mixing matrix in charged current interactions involves (n-1) free physical mixing angles for n generations. The mixing matrix in neutral current interactions of neutrinos is completely fixed by the two masses. Both interactions conserve CP. We illustrate the phenomenological implications of the model by vacuum neutrino oscillations, tritium β decay and neutrinoless double β decay. It turns out that, due to the revealed specific structure in its mixing matrix, the model with any n generations cannot accommodate simultaneously the data by KamLAND, K2K and CHOOZ.
© Springer-Verlag Berlin Heidelberg, 2007