Second class currents and neutrino mass in mirror transitions

The influence of the second class currents (SCC) on angular correlations, charge asymmetries and electron polarizations in beta decays of mirror nuclei are investigated in the Kubodera-Delorme-Rho (KDR) model. It is shown that these quantities depend in very different ways on the KDR-model parameters ζ and λ, which can be used for their experimental determination. In the middle of the β-spectrum the SCC effects dominate over those due to the neutrino rest mass, but the SCC can not modify the specific tail of the correlation coefficient Aev in the case of a non-zero neutrino mass. More rigorously, we can state that in the case of mv ≠ 0, and independently of the presence of SCC, the correlation coefficient Aev tends to zero (AevGT→0) at the upper end of the β-spectrum. This is contrary to the standard result (which assumes mv = 0), according to which this coefficient tends to a non-zero constant (AevGT = - 1 3βe→- 1 3). © 1989