Neutrino mixings as a source of lepton flavor violations

Abstract

Within the left-right symmetric model (LRM) the $Z$ boson decay into the channel $Z\to\tau\mu$ are investigated. The branching ratios of this decay is found in the third order of the perturbation theory. The obtained expression does not equal to zero only at the existence of the neutrino mixings. It means that from the point of view of the LRM nonconservation both of neutral and of charged lepton flavors has the same nature. As a result, elucidation of the decays $Z\to\l_i\overline{l}_k$ ($i\neq k$) could provide data concerned the neutrino sector structure of the LRM. The neutrino sector parameters which could be measured in that case are as follows: (i) difference of the heavy neutrino masses; (ii) heavy-heavy neutrino mixing; (iii) heavy-light neutrino mixing.