Current state of the investigation of superallowed Fermi? decays

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

“…These features have encouraged new measurements of the asymmetry parameters. At the present all new experimental results [8][9][10][11] are in very good overall agreement and it is currently accepted that the data of c~p~ provide a strong evidence against an axial SCC [8][9][10][11][12][13][14][15][16]. Hitherto all the publications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] which tackled this matter have been mainly focused to the question if the asymmetry parameters c~ can be interpreted without invoking the existence of the IPT interaction.…”

“…The formulas to be used in the next sections have been already derived in our previous works [3,14,15]. In the present paper we summarize the main results and indicate the way for their derivation to keep some degree of selfconsistency.…”

“…Indeed the coefficients Co, F o and F 1 correspond strictly to the coefficients A0, D O and D 1 of [3,15]. In the present paper we adopt the notation of [14] because it is appropriate for Gamow-Teller as well as for Fermi fi-transitions.…”

“…On the other hand, in the case of the (8-16)POT interaction we have also carried out calculations evaluating the radial integrals for radial wave functions generated in a WoodsSaxon potential which includes isospin breaking effects. The corresponding results have been reported in a series of papers [3,15,21]. In order to test the quality of the theoretical description we calculated the chi-square function, Z 2, expressed as in (21) …”

“…However, by now precise differential, energy dependent, data of a#, [9][10][11]17] which can be analyzed to test the goodness of our knowledge about the nuclear structure of the A= 12 nuclei are available. Following these ideas, the aim of the present work is to investigate the energy dependence of the asymmetry parameters c~# (W) and a#+(W) taking advantage of the results obtained in our previous works [3,14,15]. We give the relevant formulas in Sect.…”