Abstract
We have investigated the β decay to the levels of . A detailed decay scheme comprised of 63 γ rays and 44 energy levels has been obtained from γ singles, γ multispectral scaling, and γ-γ and E0-γ coincidences. was measured using the β-γ coincidence technique, while absolute E0 and γ-ray intensities were obtained from singles conversion electron and γ-ray spectra measured at beam saturation. The high sensitivity of the study was aimed at investigating the β feeding of levels with excitation enegy above 4 MeV. Although most of the new levels were found in this region, their total β feeding was found to be below 0.6%. The first-forbidden β-decay rate for → has been calculated within the framework of the spherical shell model using a model space of π(0,0,1,1,0) 1,0)ν (,1,1,2) with limitations on the orbit occupancies. Additional evidence for meson enhancement of the timelike component of the axial current is obtained; the meson-exchange enhancement factor was found to be 1.75±0.30, where the uncertainty arises from the calculation.
- Received 13 June 1989
DOI:https://doi.org/10.1103/PhysRevC.41.226
©1990 American Physical Society