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

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

Polarisation effects of second-class currents in the direct and inverse β decay of nuclei

A general expression for the modulus squared of matrix elements of semileptonic weak processes including the polarisation of the initial (final) nucleus is obtained. The influence of second-class currents (SCC) on various characteristics (the charge asymmetry, the angular and spin correlation coefficients, etc) of the beta decay of 12B, 12N and 6He and of the iso-elastic scattering of nu ( nu ) on 12C is studied. It is shown that experiments with a polarised nucleus will allow new effects, induced by SCC, to be extracted. An optimum geometrical configuration of the test for conducting experiments to observe these effects is found

Study of the Β decay of6He with allowance for second-class currents and the antineutrino mass

The effects of the rest mass of the electron antineutrino are studied with allowance for the induced tensor form-factor Fc of the second-class current according to the Weinberg classification during the Β decay of the6He nucleus. We calculate the contribution of mΝ and Fc to the electron-antineutron angular correlation coefficient AeΝ and the degree of longitudinal polarization Pe of the decay electrons. When mΝ is nonzero, the coefficient AeΝ tends asymptotically to zero both at the beginning and endpoint of the Β spectrum, whether or not the second-class currents are taken into account. The series of qualitatively new experiments planned for the near future to measure the e-Ν correlation for pure Gamow-Teller transitions (the6He nucleus could be a suitable nucleus here) with an accuracy of the order of 1% would allow the available estimate of the form-factor Fc to be improved substantially. © 1990 Plenum Publishing Corporation

Study of the Β decay of6He with allowance for second-class currents and the antineutrino mass

The effects of the rest mass of the electron antineutrino are studied with allowance for the induced tensor form-factor Fc of the second-class current according to the Weinberg classification during the Β decay of the6He nucleus. We calculate the contribution of mΝ and Fc to the electron-antineutron angular correlation coefficient AeΝ and the degree of longitudinal polarization Pe of the decay electrons. When mΝ is nonzero, the coefficient AeΝ tends asymptotically to zero both at the beginning and endpoint of the Β spectrum, whether or not the second-class currents are taken into account. The series of qualitatively new experiments planned for the near future to measure the e-Ν correlation for pure Gamow-Teller transitions (the6He nucleus could be a suitable nucleus here) with an accuracy of the order of 1% would allow the available estimate of the form-factor Fc to be improved substantially. © 1990 Plenum Publishing Corporation

Polarisation effects of second-class currents in the direct and inverse β decay of nuclei

A general expression for the modulus squared of matrix elements of semileptonic weak processes including the polarisation of the initial (final) nucleus is obtained. The influence of second-class currents (SCC) on various characteristics (the charge asymmetry, the angular and spin correlation coefficients, etc) of the beta decay of 12B, 12N and 6He and of the iso-elastic scattering of nu ( nu ) on 12C is studied. It is shown that experiments with a polarised nucleus will allow new effects, induced by SCC, to be extracted. An optimum geometrical configuration of the test for conducting experiments to observe these effects is found