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arXiv 2312.11366nucl-ex
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质子滴线晕候选核$^{22}$Al的精密质量测量

Precision Mass Measurement of Proton-Dripline Halo Candidate $^{22}$Al

S. E. Campbell, G. Bollen, B. A. Brown, A. Dockery, K. Fossez, C. M. Ireland, K. Minamisono, D. Puentes, A. Ortiz-Cortez, B. J. Rickey, R. Ringle, S. Schwarz, C… 展开作者

S. E. Campbell, G. Bollen, B. A. Brown, A. Dockery, K. Fossez, C. M. Ireland, K. Minamisono, D. Puentes, A. Ortiz-Cortez, B. J. Rickey, R. Ringle, S. Schwarz, C. S. Sumithrarachchi, A. C. C. Villari, I. T. Yandow

AI总结:

本研究利用FRIB的LEBIT Penning阱首次精密测量质子滴线晕候选核$^{22}$Al质量,获得极小质子分离能,支持其质子晕可能性并指出需电荷半径测量验证。

摘要:

我们报告了在FRIB利用LEBIT装置的9.4 T Penning阱质谱仪对质子晕候选核$^{22}$Al进行的首次质量测量。该测量补全了Penning阱可测量的、最轻的剩余质子滴线核的质量信息。由于观测到异常大的同位旋不对称性[Phys. Rev. Lett. \ extbf{125} 192503 (2020)],$^{22}$Al近来因其可能具有晕结构而受到关注。测得的质量过剩值为$\ ext{ME}=18\;093.6(7)$~keV,对应于异常小的质子分离能$S_p = 99.2(1.0)$~keV,这与所提出的晕结构相符。我们的结果与sd壳USD哈密顿量的预测高度一致。尽管USD哈密顿量预测$^{22}$Al基态存在形变,且质子壳层中$1s_{1/2}$占据极少,但连续介质中的粒子加转子模型表明,在大四极形变下可能形成质子晕。这些结果强调,需要进行电荷半径测量以最终确定其晕性质。

英文摘要:

We report the first mass measurement of the proton-halo candidate $^{22}$Al performed with the LEBIT facility's 9.4~T Penning trap mass spectrometer at FRIB. This measurement completes the mass information for the lightest remaining proton-dripline nucleus achievable with Penning traps. $^{22}$Al has been the subject of recent interest regarding a possible halo structure from the observation of an exceptionally large isospin asymmetry [Phys. Rev. Lett. \textbf{125} 192503 (2020)]. The measured mass excess value of $\text{ME}=18\;093.6(7)$~keV, corresponding to an exceptionally small proton separation energy of $S_p = 99.2(1.0)$~keV, is compatible with the suggested halo structure. Our result agrees well with predictions from \textit{sd}-shell USD Hamiltonians. While USD Hamiltonians predict deformation in $^{22}$Al ground-state with minimal $1s_{1/2}$ occupation in the proton shell, a particle-plus-rotor model in the continuum suggests that a proton halo could form at large quadrupole deformation. These results emphasize the need for a charge radius measurement to conclusively determine the halo nature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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