High-precision mass measurements of the isomeric and ground states of V44 : Improving constraints on the isobaric multiplet mass equation parameters of the A=44 , 0+ quintet
High-precision mass measurements of the isomeric and ground states of V44 : Improving constraints on the isobaric multiplet mass equation parameters of the A=44 , 0+ quintet
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DOI：
10.1103/physrevc.101.064309
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发表时间：
2020-03
影响因子：
3.1
通讯作者：
D. Puentes;G. Bollen;M. Brodeur;M. Eibach;K. Gulyuz;A. Hamaker;C. Izzo;S. Lenzi;M. Maccormick;M. Redshaw;R. Ringle;R. Sandler;S. Schwarz;P. Schury;N. Smirnova;J. Surbrook;A. Valverde;A. Villari;I. Yandow
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文献类型：
--
作者：
D. Puentes;G. Bollen;M. Brodeur;M. Eibach;K. Gulyuz;A. Hamaker;C. Izzo;S. Lenzi;M. Maccormick;M. Redshaw;R. Ringle;R. Sandler;S. Schwarz;P. Schury;N. Smirnova;J. Surbrook;A. Valverde;A. Villari;I. Yandow
背景：二次等压多重态质量方程(IMME)在预测同一多重态中的同压模拟态的质量时非常成功，而它的系数随质量数的变化具有特定的趋势。原子质量评估2016[中国。太棒了。C41,030003(2017年)]$^{44}\mathm{V}$质量值导致imme二次项的反常负$c$系数；这是巨大的不确定性和未解决的同分异构态的结果。对于构造同位旋非守恒的哈密顿量，$b$和$c$系数可以提供有用的约束。此外，目前尚不清楚{44}/V}中{0}^{+}，T=2$能级的激发能。这种状态可以用来限制更奇异的物质的质量。目的：实验活动的目的是进行高精度的质量测量，以解决同分异构体和基态之间的差异，使用新的基态质量值来测试IMME，并为未来鉴定${44}\mathm{V}$中的${0}^{+}$，$T=2$状态提供必要的成分。方法：在国家超导回旋实验室的Lebit进行了高精度的Penning陷阱质谱分析为了测量[44g，m}\mathm{VO}]与[{{32}\mathm{SCO}]的回旋频率比，一个众所周知的参考质量，结果：测得基态和异构态的质量过剩分别为$\ensuremath{-}23\phantom{\rule{4pt}{0ex}}804.9(80)$kev/{c}^{2}$和$\ensuremath{-}23\phantom{\rule{4pt}{0ex}}537.0(55)$kev/${c}^{2}$。由此得到新的质子分离能为：{S}{p}=1\phantom{4pt}{0ex}}773(10)$keV。结论：利用基态和同质异构态质量的新值，推导出了A=44$中最低的{2}^{+}$和${6}^{+}$三元组的imme$b$和$c$系数。用最低多重态的IMME趋势验证了${2}^{+}\phantom{\Rule{4pt}{0ex}}c$系数，并与用依赖电荷的哈密顿量的壳层模型预测的结果符合得很好。确定了{44}与{Sc}之间的镜像能量差，符合该多重态的同位旋对称性。在10keV的不确定度下所确定的质子分离能的新值，对于确定{44}{V}中的{0}^+}$，$T=2$状态，从而预测{{44}\{Cr}$的质量过剩将是重要的。
Background: The quadratic isobaric multiplet mass equation (IMME) has been very successful at predicting the masses of isobaric analog states in the same multiplet, while its coefficients are known to follow specific trends as functions of mass number. The Atomic Mass Evaluation 2016 [Chin. Phys. C 41, 030003 (2017)] $^{44}\mathrm{V}$ mass value results in an anomalous negative $c$ coefficient for the IMME quadratic term; a consequence of large uncertainty and an unresolved isomeric state. The $b$ and $c$ coefficients can provide useful constraints for construction of the isospin-nonconserving Hamiltonians for the $pf$ shell. In addition, the excitation energy of the ${0}^{+},T=2$ level in $^{44}\mathrm{V}$ is currently unknown. This state can be used to constrain the mass of the more exotic $^{44}\mathrm{Cr}$.Purpose: The aim of the experimental campaign was to perform high-precision mass measurements to resolve the difference between $^{44}\mathrm{V}$ isomeric and ground states, to test the IMME using the new ground state mass value and to provide necessary ingredients for the future identification of the ${0}^{+}$, $T=2$ state in $^{44}\mathrm{V}$.Method: High-precision Penning trap mass spectrometry was performed at LEBIT, located at the National Superconducting Cyclotron Laboratory, to measure the cyclotron frequency ratios of [${^{44g,m}\mathrm{VO}]}^{+}$ versus [${^{32}\mathrm{SCO}]}^{+}$, a well-known reference mass, to extract both the isomeric and ground state masses of $^{44}\mathrm{V}$.Results: The mass excess of the ground and isomeric states in $^{44}\mathrm{V}$ were measured to be $\ensuremath{-}23\phantom{\rule{4pt}{0ex}}804.9(80)$ keV/${c}^{2}$ and $\ensuremath{-}23\phantom{\rule{4pt}{0ex}}537.0(55)$ keV/${c}^{2}$, respectively. This yielded a new proton separation energy of ${S}_{p}=1\phantom{\rule{4pt}{0ex}}773(10)$ keV.Conclusion: The new values of the ground state and isomeric state masses of $^{44}\mathrm{V}$ have been used to deduce the IMME $b$ and $c$ coefficients of the lowest ${2}^{+}$ and ${6}^{+}$ triplets in $A=44$. The ${2}^{+}\phantom{\rule{4pt}{0ex}}c$ coefficient is now verified with the IMME trend for lowest multiplets and is in good agreement with the shell-model predictions using charge-dependent Hamiltonians. The mirror energy differences were determined between $^{44}\mathrm{V}$ and $^{44}\mathrm{Sc}$, in line with isospin-symmetry for this multiplet. The new value of the proton separation energy determined, to an uncertainty of 10 keV, will be important for the determination of the ${0}^{+}$, $T=2$ state in $^{44}\mathrm{V}$ and, consequently, for prediction of the mass excess of $^{44}\mathrm{Cr}$.