通过\(^{26}P\)的β延迟双质子衰变对\(^{26}Si\)中一个强同位旋混合二重态的观测。

Observation of a Strongly Isospin-Mixed Doublet in ^{26}Si via β-Delayed Two-Proton Decay of ^{26}P.

作者信息

Liu J J, Xu X X, Sun L J, Yuan C X, Kaneko K, Sun Y, Liang P F, Wu H Y, Shi G Z, Lin C J, Lee J, Wang S M, Qi C, Li J G, Li H H, Xayavong Latsamy, Li Z H, Li P J, Yang Y Y, Jian H, Gao Y F, Fan R, Zha S X, Dai F C, Zhu H F, Li J H, Chang Z F, Qin S L, Zhang Z Z, Cai B S, Chen R F, Wang J S, Wang D X, Wang K, Duan F F, Lam Y H, Ma P, Gao Z H, Hu Q, Bai Z, Ma J B, Wang J G, Wu C G, Luo D W, Jiang Y, Liu Y, Hou D S, Li R, Ma N R, Ma W H, Yu G M, Patel D, Jin S Y, Wang Y F, Yu Y C, Hu L Y, Wang X, Zang H L, Wang K L, Ding B, Zhao Q Q, Yang L, Wen P W, Yang F, Jia H M, Zhang G L, Pan M, Wang X Y, Sun H H, Xu H S, Zhou X H, Zhang Y H, Hu Z G, Wang M, Liu M L, Ong H J, Yang W Q

机构信息

CAS Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.

Department of Physics, The University of Hong Kong, Hong Kong, China.

出版信息

Phys Rev Lett. 2022 Dec 9;129(24):242502. doi: 10.1103/PhysRevLett.129.242502.

DOI:10.1103/PhysRevLett.129.242502

PMID:36563237

Abstract

β decay of proton-rich nuclei plays an important role in exploring isospin mixing. The β decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through β-delayed two-proton emission (β2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P β decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in β-decay experiments.

摘要

富质子核的β衰变在探索同位旋混合方面起着重要作用。利用与高纯锗探测器联合工作的双面硅条探测器研究了质子滴线处(^{26}P)的β衰变。通过β延迟双质子发射（β2p）明确识别出(^{26}Si)中13055keV的(T = 2)等压类似态（IAS）以及13380keV和11912keV的两个新的高激发态。测量了由(^{26}P)β衰变产生的(^{26}Si)激发态发射的两个质子的角关联，这表明两个质子主要是相继发射的。我们报告了首次观察到一个主要通过双质子衰变退激的强同位旋混合双重态。确定了(^{26}Si) IAS与附近13380keV态之间的同位旋混合矩阵元为130(21)keV，这一结果代表了在β衰变实验中观察到的双重态中最强的混合、最高的激发能和最大的能级间距。