Abstract
Background: Measurements of decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies.
Purpose: To measure the -delayed decay of and compare the results with previous experimental results and shell-model calculations.
Method: A fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its -delayed -ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background.
Results: The absolute intensities of -delayed rays were determined. A total of six new -decay branches and 15 new -ray lines have been observed for the first time in decay. A complete -decay scheme was built for the allowed transitions to bound excited states of . values and Gamow-Teller strengths were also determined for these transitions and compared with shell-model calculations and the mirror decay of , revealing significant mirror asymmetries.
Conclusions: A very good agreement with theoretical predictions based on the USDB shell model is observed. The significant mirror asymmetry observed for the transition to the first excited state may be evidence for a proton halo in .
3 More- Received 27 April 2016
DOI:https://doi.org/10.1103/PhysRevC.93.064320
©2016 American Physical Society