Experimental investigation of ground-state properties of 7H with transfer reactions
Experimental investigation of ground-state properties of 7H with transfer reactions
复制标题
7H基态性质与转移反应的实验研究
DOI：
10.1016/j.physletb.2022.137067
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发表时间：
2022
影响因子：
4.4
通讯作者：
Vandebrouck M.
中科院分区：
文献类型：
--
作者：
Caamao M.;Roger T.;Moro A.M.;Grinyer G.F.;Pancin J.;Bagchi S.;Sambi S.;Gibelin J.;Fern?ndez?Dom?nguez B.;Itagaki N.;Benlliure J.;CortinaGil D.;Farget F.;Jacquot B.;PrezLoureiro D.;Pietras B.;Raabe R.;Ramos D.;Rodr?guez Tajes C.;Savajols H.;Vandebrouck M.
具有极端中子与质子比率的原子核的性质，与地球上自然发生的原子核不同，是理解核力以及核子如何结合在一起形成原子核的关键。7 H有六个中子和一个质子，是迄今为止已知的中子质子比最不平衡的核系统。然而，它的存在和性质仍然是实验工作和理论模型的挑战。在这里，我们报告的实验证据形成的7 H作为一个共振，检测与独立的观测，并首次测量其基态的结构。在3 H+4 n质量以上发现了一个能量为0.7MeV的共振，共振宽度为0.2MeV，自旋为1/2+，宇称为1。这些数据与7 H作为3 H核心被扩展的四中子晕包围一致，具有独特的四中子衰变和相对较长的半衰期，这要归功于中子配对;这是我们在实验室中可以获得的最纯中子核物质中发生的新现象的一个主要例子。
The properties of nuclei with extreme neutron–to–proton ratios, far from those naturally occurring on Earth, are key to understand nuclear forces and how nucleons hold together to form nuclei. 7 H, with six neutrons and a single proton, is the nuclear system with the most unbalanced neutron–to–proton ratio known so far. However, its sheer existence and properties are still a challenge for experimental efforts and theoretical models. Here we report experimental evidences on the formation of 7 H as a resonance, detected with independent observables, and the first measurement of the structure of its ground state. The resonance is found at∼ 0.7 MeV above the 3 H+ 4n mass, with a narrow width of∼ 0.2 MeV and a 1/2+ spin and parity. These data are consistent with a 7 H as a 3 H core surrounded by an extended four-neutron halo, with a unique four-neutron decay and a relatively long half-life thanks to neutron pairing; a prime example of new phenomena occurring in what would be the most pure-neutron nuclear matter we can access in the laboratory.