扩展的p_{3/2}中子轨道与^{52}Ca中的N = 32壳层闭壳

Extended p_{3/2} Neutron Orbital and the N=32 Shell Closure in ^{52}Ca.

作者信息

Enciu M, Liu H N, Obertelli A, Doornenbal P, Nowacki F, Ogata K, Poves A, Yoshida K, Achouri N L, Baba H, Browne F, Calvet D, Château F, Chen S, Chiga N, Corsi A, Cortés M L, Delbart A, Gheller J-M, Giganon A, Gillibert A, Hilaire C, Isobe T, Kobayashi T, Kubota Y, Lapoux V, Motobayashi T, Murray I, Otsu H, Panin V, Paul N, Rodriguez W, Sakurai H, Sasano M, Steppenbeck D, Stuhl L, Sun Y L, Togano Y, Uesaka T, Wimmer K, Yoneda K, Aktas O, Aumann T, Chung L X, Flavigny F, Franchoo S, Gasparic I, Gerst R-B, Gibelin J, Hahn K I, Kim D, Kondo Y, Koseoglou P, Lee J, Lehr C, Li P J, Linh B D, Lokotko T, MacCormick M, Moschner K, Nakamura T, Park S Y, Rossi D, Sahin E, Söderström P-A, Sohler D, Takeuchi S, Toernqvist H, Vaquero V, Wagner V, Wang S, Werner V, Xu X, Yamada H, Yan D, Yang Z, Yasuda M, Zanetti L

机构信息

Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany.

Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China.

出版信息

Phys Rev Lett. 2022 Dec 23;129(26):262501. doi: 10.1103/PhysRevLett.129.262501.

DOI:10.1103/PhysRevLett.129.262501

PMID:36608181

Abstract

The one-neutron knockout from ^{52}Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states in ^{51}Ca and the momentum distributions corresponding to the removal of 1f_{7/2} and 2p_{3/2} neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f_{7/2} and 2p_{3/2} orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p_{3/2} orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.

摘要

在逆运动学中，以约230 MeV/核子的能量将(^{52}Ca)中的一个中子敲出到质子靶上，并结合瞬发γ谱学进行了实验。测量了到(^{51}Ca)束缚态的排他性准自由散射截面以及对应于移除(1f_{7/2})和(2p_{3/2})中子的动量分布。在扭曲波冲量近似反应框架内解释的截面，与中子数(N = 32)处的壳层闭合一致，从相同可观测量来看，其强度与钙同位素中(N = 28)和(N = 34)处的壳层闭合一样强。对动量分布的分析得出中子(1f_{7/2})和(2p_{3/2})轨道的均方根半径之差为0.61(23) fm，这与修正壳模型预测的0.7 fm一致，表明富中子钙同位素中(2p_{3/2})轨道较大的均方根半径是电荷半径随中子数意外线性增加的原因。