First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic 187Pb

被引：6

作者：

Zhang, W. Q. ^{[1
,2
]}

Andreyev, A. N. ^{[3
,4
]}

Liu, Z. ^{[1
,2
]}

Seweryniak, D. ^{[5
]}

Huang, H. ^{[1
,2
]}

Li, Z. H. ^{[6
]}

Li, J. G. ^{[1
,6
]}

Guo, C. Y. ^{[6
]}

Doherty, D. T. ^{[7
]}

Barzakh, A. E. ^{[8
]}

Van Duppen, P. ^{[9
]}

Cubiss, J. G. ^{[3
]}

Andel, B. ^{[10
]}

Antalic, S. ^{[10
]}

Block, M. ^{[11
,12
,13
]}

Bronis, A. ^{[10
]}

Carpenter, M. P. ^{[5
]}

Copp, P. ^{[5
]}

Ding, B. ^{[1
,2
]}

Favier, Z. ^{[14
]}

Giacoppo, F.

Huang, T. H. ^{[1
,2
,5
]}

Yu, X. H. ^{[1
,2
]}

Kindler, B.

Kondev, F. G. ^{[5
]}

Lauritsen, T. ^{[5
]}

Li, G. S. ^{[2
]}

Lommel, B.

Lu, H. Y. ^{[1
,2
]}

Al Monthery, M. ^{[3
]}

Mosat, P. ^{[10
]}

Niu, Y. F. ^{[15
]}

Raison, C. ^{[3
]}

Reviol, W. ^{[5
]}

Savard, G. ^{[5
]}

Stolze, S. ^{[5
]}

Wilson, G. L. ^{[16
]}

Wu, H. Y. ^{[6
]}

Wang, Z. H. ^{[15
]}

Xu, F. R. ^{[6
]}

Zeng, Q. B. ^{[1
,2
]}

Zhou, X. H. ^{[1
,2
]}

机构：

[1] Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

[3] Univ York, Dept Phys, York YO10 5DD, England

[4] Japan Atom Energy Agcy, Adv Sci Res Ctr ASRC, Tokai, Japan

[5] Argonne Natl Lab, Phys Div, Argonne, IL 60439 USA

[6] Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China

[7] Univ Surrey, Dept Phys, Guildford GU2 7XH, England

[8] NRC Kurchatov Inst, Petersburg Nucl Phys Inst, Gatchina 188300, Russia

[9] Katholieke Univ Leuven, Inst Kern & Stralingsfys, B-3001 Leuven, Belgium

[10] Comenius Univ, Dept Nucl Phys & Biophys, Bratislava 84248, Slovakia

[11] Helmholtz Inst Mainz, D-55128 Mainz, Germany

[12] GSI Helmholtzzentrum Schwerionenforsch Darmstadt, D-64291 Darmstadt, Germany

[13] Johannes Gutenberg Univ Mainz, D-55099 Mainz, Germany

[14] CERN, Phys Dept, CH-1211 Geneva, Switzerland

[15] Lanzhou Univ, Lanzhou 23, Peoples R China

[16] Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA

来源：

PHYSICS LETTERS B | 2022年 / 829卷

基金：

中国国家自然科学基金; 英国科学技术设施理事会; 国家重点研发计划;

关键词：

Isomeric state; Rotational band; Shape coexistence; PES calculations; ROTATIONAL BAND; ALPHA-DECAY; IDENTIFICATION; SPECTROSCOPY; COEXISTENCE; MODEL;

D O I：

10.1016/j.physletb.2022.137129

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Prompt and delayed gamma-ray spectroscopy of the neutron-deficient, semi-magic isotope 187Pb has been performed using the recoil-decay and isomer-decay tagging techniques at the Argonne Gas-Filled Analyzer. A new 5.15(15)-mu s isomeric state at only 308 keV above the spherical 3/2(- )ground state is identified and classified as a shape isomer. A strongly-coupled band is observed on top of the isomer, which is nearly identical to the one built on the prolate 7/2(-)[514] Nilsson state in the isotone 185Hg. Based on this similarity and on the result of the potential-energy surface calculations, the new isomer in 187Pb is proposed to originate from the same configuration. The retarded character of the 308-keV (7/2(-))-> 3/2(gs)(-) transition with a deduced B(E2) = 5.6(2) x 10(-4) W.u. can be well explained by the significant difference between the prolate parent and spherical daughter configurations, leading to the shape isomerism. The excitation energy of the isomer is surprisingly low, being roughly half of the excitation energies of the known 0+ intruder bandheads in the neighboring 186,188Pb isotopes. The combined results of the present work and the previous alpha-decay and laser spectroscopy studies present evidence for triple shape coexistence at low energy in the negative-parity configurations of 187Pb, which is well reproduced by the potential-energy surface calculations. (C) 2022 The Author(s). Published by Elsevier B.V.

引用

页数：7

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