학술논문
Beta-decay spectroscopy of $^{27}$S
Document Type
Working Paper
Author
Sun, L. J.; Xu, X. X.; Hou, S. Q.; Lin, C. J.; José, J.; Lee, J.; He, J. J.; Li, Z. H.; Wang, J. S.; Yuan, C. X.; Wang, D. X.; Wu, H. Y.; Liang, P. F.; Yang, Y. Y.; Lam, Y. H.; Ma, P.; Duan, F. F.; Gao, Z. H.; Hu, Q.; Bai, Z.; Ma, J. B.; Wang, J. G.; Zhong, F. P.; Wu, C. G.; Luo, D. W.; Jiang, Y.; Liu, Y.; Hou, D. S.; Li, R.; Ma, N. R.; Ma, W. H.; Shi, G. Z.; Yu, G. M.; Patel, D.; Jin, S. Y.; Wang, Y. F.; Yu, Y. C.; Zhou, Q. W.; Wang, P.; Hu, L. Y.; Wang, X.; Zang, H. L.; Li, P. J.; Zhao, Q. Q.; Yang, L.; Wen, P. W.; Yang, F.; Jia, H. M.; Zhang, G. L.; Pan, M.; Wang, X. Y.; Sun, H. H.; Hu, Z. G.; Chen, R. F.; Liu, M. L.; Yang, W. Q.; Zhao, Y. M.; Zhang, H. Q.
Source
Phys. Rev. C 99, 064312 (2019)
Subject
Language
Abstract
Background: Beta-decay spectroscopy provides valuable nuclear physics input for thermonuclear reaction rates of astrophysical interest and stringent test for shell-model theories far from the stability line. Purpose: The available decay properties of proton drip-line nucleus $^{27}$S is insufficient to constrain the properties of the key resonance in $^{26}$Si$(p,\gamma)^{27}$P reaction rate and probe the possible isospin asymmetry. The decay scheme of $^{27}$S is complicated and far from being understood, which has motivated but also presented challenges for our experiment. Method: The $^{27}$S ions were implanted into a double-sided silicon strip detector array surrounded by the high-purity germanium detectors, where the $\beta$-delayed protons and $\gamma$ rays were measured simultaneously. Results: The improved spectroscopic properties including the precise half-life of $^{27}$S, the excitation energies, $\beta$-decay branching ratios, log~$ft$ values, and $B$(GT) values for the states of $^{27}$P populated in the $\beta$ decay of $^{27}$S were measured and compared to the $^{27}$Mg mirror states and the shell-model calculations. The present work has expanded greatly on the previously established decay scheme of $^{27}$S. Conclusions: The precise proton-separation energy of $^{27}$P, the energy and the ratio between $\gamma$ and proton partial widths of the $3/2^+$ resonance were obtained, thereby determining the $^{26}$Si$(p,\gamma)^{27}$P reaction rate based mainly on experimental constraints. The first evidence for the observation of a large isospin asymmetry for the mirror decays of $^{27}$S and $^{27}$Na is also provided. The experimental spectroscopic information can be reproduced by the shell-model calculation taking the weakly bound effect of the proton $1s_{1/2}$ orbit into account.