1. Tests of the standard model from superallowed Fermi β-decay studies: The 74Rb β-decay
- Author
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Zganjar, E.F., Piechaczek, A., Ball, G.C., Bricault, P., D'Auria, J.M., Hardy, J.C., Hodgson, D.F., Iacob, V., Klages, P., Kulp, W.D., Leslie, J.R., Lipoglavsek, M., Macdonald, J.A., Mak, H.-B., Moltz, D.M., Savard, G., von Schwarzenberg, J., Svensson, C.E., Towner, I.S., and Wood, J.L.
- Abstract
Precise measurements of the intensities of superallowed Fermi 0+→ 0+β-decays have provided a powerful test of the CVC hypothesis at the level of 3×10-4and also led to a result in disagreement with unitarity for the CKM matrix at the 98% confidence level. It is essential to address possible trivial explanations for the apparent non-unitarity such as uncertainties in the isospin symmetry-breaking corrections. We have carefully studied the 74Rb →74Kr β-decay in order to measure the non-analog β-decay branching to the 0+state at 508 keV in 74Kr. We have determined that this branching is < 3×10-4, far smaller than any published theoretical estimate. We also show that high-precision, complete spectroscopy, measuring the major β-branches to excited 0+and 1+states, must be performed if one is to obtain a meaningful branching ratio to the excited 0+state and concomitantly deal, in a substantial way, with the possibility of β feeding to an array of 1+states.
- Published
- 2002
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