基于自共轭核\(^{88}Ru\)能级结构的核配对关联的同位旋性质

Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus ^{88}Ru.

作者信息

Cederwall B, Liu X, Aktas Ö, Ertoprak A, Zhang W, Qi C, Clément E, de France G, Ralet D, Gadea A, Goasduff A, Jaworski G, Kuti I, Nyakó B M, Nyberg J, Palacz M, Wadsworth R, Valiente-Dobón J J, Al-Azri H, Ataç Nyberg A, Bäck T, de Angelis G, Doncel M, Dudouet J, Gottardo A, Jurado M, Ljungvall J, Mengoni D, Napoli D R, Petrache C M, Sohler D, Timár J, Barrientos D, Bednarczyk P, Benzoni G, Birkenbach B, Boston A J, Boston H C, Burrows I, Charles L, Ciemala M, Crespi F C L, Cullen D M, Désesquelles P, Domingo-Pardo C, Eberth J, Erduran N, Ertürk S, González V, Goupil J, Hess H, Huyuk T, Jungclaus A, Korten W, Lemasson A, Leoni S, Maj A, Menegazzo R, Million B, Perez-Vidal R M, Podolyak Zs, Pullia A, Recchia F, Reiter P, Saillant F, Salsac M D, Sanchis E, Simpson J, Stezowski O, Theisen Ch, Zielińska M

机构信息

KTH Royal Institute of Technology, 10691 Stockholm, Sweden.

Department of Physics, Faculty of Science, Istanbul University, Vezneciler/Fatih, 34134 Istanbul, Turkey.

出版信息

Phys Rev Lett. 2020 Feb 14;124(6):062501. doi: 10.1103/PhysRevLett.124.062501.

DOI:10.1103/PhysRevLett.124.062501

PMID:32109090

Abstract

The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N=Z) nuclide {44}^{88}Ru{44} has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in ^{88}Ru were populated via the ^{54}Fe(^{36}Ar,2nγ)^{88}Ru^{*} fusion-evaporation reaction at the Grand Accélérateur National d'Ions Lourds (GANIL) accelerator complex. The observed γ-ray cascade is assigned to ^{88}Ru using clean prompt γ-γ-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N>Z nuclides. The direct observation of such a "delayed" rotational alignment in a deformed N=Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.

摘要

利用先进伽马追踪阵列（AGATA）光谱仪、NEDA和中子壁中子探测器阵列以及DIAMANT带电粒子探测器阵列的组合，测量了极缺中子的自共轭（N = Z）核素({44}^{88}Ru{44})的低能谱。在法国国家重离子加速器（GANIL）复合体中，通过(^{54}Fe(^{36}Ar,2nγ)^{88}Ru^{*})熔合蒸发反应产生(^{88}Ru)的激发态。利用与带电粒子探测反符合的干净的瞬发γ-γ-2中子符合，将观测到的γ射线级联归属于(^{88}Ru)，证实并扩展了先前确定的低激发态序列。它与一个中等形变的转动系统一致，该系统在一个显著高于具有同位旋配对的标准理论预测的转动频率处呈现带交叉，以及与相邻N>Z核素中的观测结果一致。在一个形变的N = Z核中直接观测到这样的“延迟”转动对准，与与强同位旋标量中子-质子对关联的存在相关的理论预测一致。