- Conference date: 4-9 September 2005
- Location: Notre Dame, Indiana (USA)
A careful determination of the lifetime and measurement of the branching ratio for decay of the first state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M 0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M 0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The transition energies, reduced transition probabilities and M 0 values are reproduced to a high degree of accuracy. The trend of M 0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.
- Shell model
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