g Factor of the ^{99}Zr (7/2^{+}) Isomer: Monopole Evolution in the Shape-Coexisting Region

F Boulay; G S Simpson; Y Ichikawa; S Kisyov; D Bucurescu; A Takamine; D S Ahn; K Asahi; H Baba; D L Balabanski; T Egami; T Fujita; N Fukuda; C Funayama; T Furukawa; G Georgiev; A Gladkov; M Hass; K Imamura; N Inabe; Y Ishibashi; T Kawaguchi; T Kawamura; W Kim; Y Kobayashi; S Kojima; A Kusoglu; R Lozeva; S Momiyama; I Mukul; M Niikura; H Nishibata; T Nishizaka; A Odahara; Y Ohtomo; D Ralet; T Sato; Y Shimizu; T Sumikama; H Suzuki; H Takeda; L C Tao; Y Togano; D Tominaga; H Ueno; H Yamazaki; X F Yang; J M Daugas

doi:10.1103/PhysRevLett.124.112501

g Factor of the ^{99}Zr (7/2^{+}) Isomer: Monopole Evolution in the Shape-Coexisting Region

Phys Rev Lett. 2020 Mar 20;124(11):112501. doi: 10.1103/PhysRevLett.124.112501.

Authors

F Boulay^{1

2

3}, G S Simpson⁴, Y Ichikawa², S Kisyov⁵, D Bucurescu⁵, A Takamine², D S Ahn², K Asahi^{2

6}, H Baba², D L Balabanski^{2

7}, T Egami^{2

8}, T Fujita^{2

9}, N Fukuda², C Funayama^{2

6}, T Furukawa^{2

10}, G Georgiev¹¹, A Gladkov^{2

12}, M Hass¹³, K Imamura^{2

14}, N Inabe², Y Ishibashi^{2

15}, T Kawaguchi^{2

8}, T Kawamura⁹, W Kim¹², Y Kobayashi¹⁶, S Kojima^{2

6}, A Kusoglu^{11

17}, R Lozeva¹¹, S Momiyama¹⁸, I Mukul¹³, M Niikura¹⁸, H Nishibata^{2

9}, T Nishizaka^{2

8}, A Odahara⁹, Y Ohtomo^{2

6}, D Ralet¹¹, T Sato^{2

6}, Y Shimizu², T Sumikama², H Suzuki², H Takeda², L C Tao^{2

19}, Y Togano⁶, D Tominaga^{2

8}, H Ueno², H Yamazaki², X F Yang²⁰, J M Daugas^{1

2}

Affiliations

¹ CEA, DAM, DIF, 91297 Arpajon cedex, France.
² RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
³ GANIL, CEA/DSM-CNRS/IN2P3, BP55027, 14076 Caen cedex 5, France.
⁴ LPSC, CNRS/IN2P3, Université Joseph Fourier Grenoble 1, INPG, 38026 Grenoble Cedex, France.
⁵ Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), 077125 Bucharest-Măgurele, Romania.
⁶ Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro, Tokyo 152-8551, Japan.
⁷ Extreme Light Infrastructure-Nuclear Physics (ELI-NP), Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), 077125 Bucharest-Măgurele, Romania.
⁸ Department of Advanced Sciences, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584, Japan.
⁹ Department of Physics, Osaka University, Machikaneyama 1-1 Toyonaka, Osaka 560-0034, Japan.
¹⁰ Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, Japan.
¹¹ CSNSM, Université Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay Campus, France.
¹² Department of Physics, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 702-701, South Korea.
¹³ Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
¹⁴ Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571, Japan.
¹⁵ Department of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-5877, Japan.
¹⁶ Department of Informatics and Engineering, University of Electro-Communication, 1-5-1 Chofugaoka, Chohu, Tokyo 182-8585, Japan.
¹⁷ Department of Physics, Faculty of Science, Istanbul University, Vezneciler/Faith, 34134 Istanbul, Turkey.
¹⁸ Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
¹⁹ State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
²⁰ Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium.

PMID: 32242689
DOI: 10.1103/PhysRevLett.124.112501

Abstract

The gyromagnetic factor of the low-lying E=251.96(9) keV isomeric state of the nucleus ^{99}Zr was measured using the time-dependent perturbed angular distribution technique. This level is assigned a spin and parity of J^{π}=7/2^{+}, with a half-life of T_{1/2}=336(5) ns. The isomer was produced and spin aligned via the abrasion-fission of a ^{238}U primary beam at RIKEN RIBF. A magnetic moment |μ|=2.31(14)μ_{N} was deduced showing that this isomer is not single particle in nature. A comparison of the experimental values with interacting boson-fermion model IBFM-1 results shows that this state is strongly mixed with a main νd_{5/2} composition. Furthermore, it was found that monopole single-particle evolution changes significantly with the appearance of collective modes, likely due to type-II shell evolution.