The decay of theT=1 isospin triplet inA=12 systems: IV. The energy dependence of the asymmetry coefficients $$\alpha _{\beta ^ \mp } $$ of the beta-ray angular distribution in aligned12B and12N and the induced pseudotensor interaction

Abstract

Nuclear Structure: calculation of the energy dependence of the asymmetry c~ (W) of/~-rays emitted from polarized ~2B and 12N nuclei and comparison with experimental data. Determination of the coupling constant fr corresponding to the induced pseudotensor interaction.The asymmetry parameters ~ of the beta-ray emitted from aligned 12B and ~2N are evaluated as a function of the energy. The agreement with experimental differential data is excellent for both c~_(W) and c~+(W). This work confirms, using available nuclear model information, that no induced pseudotensor (IPT) interaction is required for a correct theoretical interpretation of the data. An upper limit for the IPT coupling constant fr is determined from a simultaneous fit of eB (W) and e~ + (W).