Abstract
Background: -decay spectroscopy provides valuable nuclear physics input for accurate modeling of nova and x-ray burst observables and a stringent test for shell-model theories far from the stability line. The decay scheme of is complicated and far from being understood due to a lack of experimental data prior to this work.
Purpose: We aim to experimentally constrain the thermonuclear reaction rate and to probe the possible mirror asymmetry in and decays.
Method: The ions were collected by double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors, so the positrons, protons, and rays emitted in the decay were measured simultaneously.
Results: The precise resonance energy and the ratio between and proton partial widths of the key resonance were obtained, thereby determining the reaction rate based mainly on experimental constraints. The half-life of , the excitation energies, -feeding intensities, log ft values, and Gamow-Teller transition strengths for the states of populated in the decay of were determined. A more complete -decay scheme was constructed and compared to the decay of mirror nucleus and to the shell-model calculations with the universal sd (USD) Hamiltonian taking into account the shift of single-particle energies and the reduction of two-body matrix elements.
Conclusions: This work yields a new reaction rate two orders of magnitude lower than the rate recommended in the reaction rate libraries at around 0.1 GK. Experimental evidence for the observation of mirror asymmetries for the Gamow-Teller transitions of and is also provided. The shell-model calculations using a modified USD interaction related to the weakly bound proton orbit give a reasonable description of the decay properties of .
5 More- Received 26 October 2018
- Revised 16 November 2018
DOI:https://doi.org/10.1103/PhysRevC.99.064312
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