Is seniority a partial dynamic symmetry in the first νg9/2 shell?

A. I. Morales; G. Benzoni; H. Watanabe; G. de Angelis; S. Nishimura; L. Coraggio; A. Gargano; N. Itaco; T. Otsuka; Y. Tsunoda; P. Van Isacker; F. Browne; R. Daido; P. Doornenbal; Y. Fang; G. Lorusso; Z. Patel; S. Rice; L. Sinclair; P. A. Söderström; T. Sumikama; J. J. Valiente-Dobón; J. Wu; Z. Y. Xu; A. Yagi; R. Yokoyama; H. Baba; R. Avigo; F. L. Bello Garrote; N. Blasi; A. Bracco; A. M. Bruce; F. Camera; S. Ceruti; F. C.L. Crespi; M. C. Delattre; Zs Dombradi; A. Gottardo; T. Isobe; I. Kojouharov; N. Kurz; I. Kuti; S. Lalkovski; K. Matsui; B. Melon; D. Mengoni; T. Miyazaki; V. Modamio-Hoybjor; S. Momiyama; D. R. Napoli; M. Niikura; R. Orlandi; Zs Podolyák; P. H. Regan; H. Sakurai; E. Sahin; D. Sohler; H. Schaffner; R. Taniuchi; J. Taprogge; Zs Vajta; O. Wieland; M. Yalcinkaya

doi:10.1016/j.physletb.2018.04.049

Is seniority a partial dynamic symmetry in the first νg_9/2 shell?

A. I. Morales^*, G. Benzoni, H. Watanabe, G. de Angelis, S. Nishimura, L. Coraggio, A. Gargano, N. Itaco, T. Otsuka, Y. Tsunoda, P. Van Isacker, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P. A. SöderströmT. Sumikama, J. J. Valiente-Dobón, J. Wu, Z. Y. Xu, A. Yagi, R. Yokoyama, H. Baba, R. Avigo, F. L. Bello Garrote, N. Blasi, A. Bracco, A. M. Bruce, F. Camera, S. Ceruti, F. C.L. Crespi, M. C. Delattre, Zs Dombradi, A. Gottardo, T. Isobe, I. Kojouharov, N. Kurz, I. Kuti, S. Lalkovski, K. Matsui, B. Melon, D. Mengoni, T. Miyazaki, V. Modamio-Hoybjor, S. Momiyama, D. R. Napoli, M. Niikura, R. Orlandi, Zs Podolyák, P. H. Regan, H. Sakurai, E. Sahin, D. Sohler, H. Schaffner, R. Taniuchi, J. Taprogge, Zs Vajta, O. Wieland, M. Yalcinkaya

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

The low-lying structures of the midshell νg_9/2 Ni isotopes ⁷²Ni and ⁷⁴Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei ⁷²Co and ⁷⁴Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8⁺) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g_9/2 shell. We find that the disappearance of the seniority isomerism in the (8₁ ⁺) states can be explained by a lowering of the seniority-four (6⁺) levels as predicted years ago. For ⁷⁴Ni, the internal de-excitation pattern of the newly observed (6₂ ⁺) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near ⁷⁸Ni.

Original language	English
Pages (from-to)	706-712
Number of pages	7
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	781
DOIs	https://doi.org/10.1016/j.physletb.2018.04.049
Publication status	Published - 10 Jun 2018

Bibliographical note

Funding Information:
The excellent work of the RIKEN accelerator staff for providing a stable and high intensity 238 U beam is acknowledged. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. Part of the WAS3ABi was supported by the Rare Isotope Science Project (RISP) of the Institute for Basic Science (IBS), funded by the Ministry of Science, ICT and Future Planning (MSIP) and the National Research Foundation ( NRF ) of South Korea (Grant No. 2013M7A1A1075764 ). The MCSM calculations were performed on the K computer at the RIKEN AICS (Project ID: hp150224). This work is co-financed by the European Union, the European Social Fund , and the European Regional Development Fund . Support from the Italian Ministero dell'Istruzione, dell'Università e della Ricerca through Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) No. 2001024324_01302 , the NuPNET-ERA-NET within the NuPNET GANAS project under grant agreement No. 202914 , and the European Union within the Seventh Framework Programme FP7/2007–2013 under grant agreement No. 262010 ENSAR-INDESYS is acknowledged. This work was also financed by the Spanish Ministerio de Ciencia e Innovación under Contracts No. IJCI-2014-19172 , No. FPA2009-13377-C02 and No. FPA2011-29854-C04 , the State of Hungary under Contract No. GINOP-2.3.3-15-2016-00034 , the STFC (UK), the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096 and by the Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045 .

Funding Information:
The excellent work of the RIKEN accelerator staff for providing a stable and high intensity 238U beam is acknowledged. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. Part of the WAS3ABi was supported by the Rare Isotope Science Project (RISP) of the Institute for Basic Science (IBS), funded by the Ministry of Science, ICT and Future Planning (MSIP) and the National Research Foundation (NRF) of South Korea (Grant No. 2013M7A1A1075764). The MCSM calculations were performed on the K computer at the RIKEN AICS (Project ID: hp150224). This work is co-financed by the European Union, the European Social Fund, and the European Regional Development Fund. Support from the Italian Ministero dell'Istruzione, dell'Università e della Ricerca through Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) No. 2001024324_01302, the NuPNET-ERA-NET within the NuPNET GANAS project under grant agreement No. 202914, and the European Union within the Seventh Framework Programme FP7/2007–2013 under grant agreement No. 262010 ENSAR-INDESYS is acknowledged. This work was also financed by the Spanish Ministerio de Ciencia e Innovación under Contracts No. IJCI-2014-19172, No. FPA2009-13377-C02 and No. FPA2011-29854-C04, the State of Hungary under Contract No. GINOP-2.3.3-15-2016-00034, the STFC (UK), the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096 and by the Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045.

Publisher Copyright:
© 2018 The Authors

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Cite this

Morales, A. I., Benzoni, G., Watanabe, H., de Angelis, G., Nishimura, S., Coraggio, L., Gargano, A., Itaco, N., Otsuka, T., Tsunoda, Y., Van Isacker, P., Browne, F., Daido, R., Doornenbal, P., Fang, Y., Lorusso, G., Patel, Z., Rice, S., Sinclair, L., ... Yalcinkaya, M. (2018). Is seniority a partial dynamic symmetry in the first νg_9/2 shell? Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 781, 706-712. https://doi.org/10.1016/j.physletb.2018.04.049

@article{5ba3840401cf4d4185d973ae77c88f46,

title = "Is seniority a partial dynamic symmetry in the first νg9/2 shell?",

abstract = "The low-lying structures of the midshell νg9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following β decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the (81 +) states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed (62 +) state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni.",

author = "Morales, {A. I.} and G. Benzoni and H. Watanabe and {de Angelis}, G. and S. Nishimura and L. Coraggio and A. Gargano and N. Itaco and T. Otsuka and Y. Tsunoda and {Van Isacker}, P. and F. Browne and R. Daido and P. Doornenbal and Y. Fang and G. Lorusso and Z. Patel and S. Rice and L. Sinclair and S{\"o}derstr{\"o}m, {P. A.} and T. Sumikama and Valiente-Dob{\'o}n, {J. J.} and J. Wu and Xu, {Z. Y.} and A. Yagi and R. Yokoyama and H. Baba and R. Avigo and {Bello Garrote}, {F. L.} and N. Blasi and A. Bracco and Bruce, {A. M.} and F. Camera and S. Ceruti and Crespi, {F. C.L.} and Delattre, {M. C.} and Zs Dombradi and A. Gottardo and T. Isobe and I. Kojouharov and N. Kurz and I. Kuti and S. Lalkovski and K. Matsui and B. Melon and D. Mengoni and T. Miyazaki and V. Modamio-Hoybjor and S. Momiyama and Napoli, {D. R.} and M. Niikura and R. Orlandi and Zs Podoly{\'a}k and Regan, {P. H.} and H. Sakurai and E. Sahin and D. Sohler and H. Schaffner and R. Taniuchi and J. Taprogge and Zs Vajta and O. Wieland and M. Yalcinkaya",

note = "Funding Information: The excellent work of the RIKEN accelerator staff for providing a stable and high intensity 238 U beam is acknowledged. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. Part of the WAS3ABi was supported by the Rare Isotope Science Project (RISP) of the Institute for Basic Science (IBS), funded by the Ministry of Science, ICT and Future Planning (MSIP) and the National Research Foundation ( NRF ) of South Korea (Grant No. 2013M7A1A1075764 ). The MCSM calculations were performed on the K computer at the RIKEN AICS (Project ID: hp150224). This work is co-financed by the European Union, the European Social Fund , and the European Regional Development Fund . Support from the Italian Ministero dell'Istruzione, dell'Universit{\`a} e della Ricerca through Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) No. 2001024324_01302 , the NuPNET-ERA-NET within the NuPNET GANAS project under grant agreement No. 202914 , and the European Union within the Seventh Framework Programme FP7/2007–2013 under grant agreement No. 262010 ENSAR-INDESYS is acknowledged. This work was also financed by the Spanish Ministerio de Ciencia e Innovaci{\'o}n under Contracts No. IJCI-2014-19172 , No. FPA2009-13377-C02 and No. FPA2011-29854-C04 , the State of Hungary under Contract No. GINOP-2.3.3-15-2016-00034 , the STFC (UK), the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096 and by the Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045 . Funding Information: The excellent work of the RIKEN accelerator staff for providing a stable and high intensity 238U beam is acknowledged. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. Part of the WAS3ABi was supported by the Rare Isotope Science Project (RISP) of the Institute for Basic Science (IBS), funded by the Ministry of Science, ICT and Future Planning (MSIP) and the National Research Foundation (NRF) of South Korea (Grant No. 2013M7A1A1075764). The MCSM calculations were performed on the K computer at the RIKEN AICS (Project ID: hp150224). This work is co-financed by the European Union, the European Social Fund, and the European Regional Development Fund. Support from the Italian Ministero dell'Istruzione, dell'Universit{\`a} e della Ricerca through Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) No. 2001024324_01302, the NuPNET-ERA-NET within the NuPNET GANAS project under grant agreement No. 202914, and the European Union within the Seventh Framework Programme FP7/2007–2013 under grant agreement No. 262010 ENSAR-INDESYS is acknowledged. This work was also financed by the Spanish Ministerio de Ciencia e Innovaci{\'o}n under Contracts No. IJCI-2014-19172, No. FPA2009-13377-C02 and No. FPA2011-29854-C04, the State of Hungary under Contract No. GINOP-2.3.3-15-2016-00034, the STFC (UK), the European Commission through the Marie Curie Actions Contract No. PIEFGA-2001-30096 and by the Japanese JSPS KAKENHI Grants No. 24740188 and No. 25247045. Publisher Copyright: {\textcopyright} 2018 The Authors",

year = "2018",

month = jun,

day = "10",

doi = "10.1016/j.physletb.2018.04.049",

language = "English",

volume = "781",

pages = "706--712",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

}

Morales, AI, Benzoni, G, Watanabe, H, de Angelis, G, Nishimura, S, Coraggio, L, Gargano, A, Itaco, N, Otsuka, T, Tsunoda, Y, Van Isacker, P, Browne, F, Daido, R, Doornenbal, P, Fang, Y, Lorusso, G, Patel, Z, Rice, S, Sinclair, L, Söderström, PA, Sumikama, T, Valiente-Dobón, JJ, Wu, J, Xu, ZY, Yagi, A, Yokoyama, R, Baba, H, Avigo, R, Bello Garrote, FL, Blasi, N, Bracco, A, Bruce, AM, Camera, F, Ceruti, S, Crespi, FCL, Delattre, MC, Dombradi, Z, Gottardo, A, Isobe, T, Kojouharov, I, Kurz, N, Kuti, I, Lalkovski, S, Matsui, K, Melon, B, Mengoni, D, Miyazaki, T, Modamio-Hoybjor, V, Momiyama, S, Napoli, DR, Niikura, M, Orlandi, R, Podolyák, Z, Regan, PH, Sakurai, H, Sahin, E, Sohler, D, Schaffner, H, Taniuchi, R, Taprogge, J, Vajta, Z, Wieland, O & Yalcinkaya, M 2018, 'Is seniority a partial dynamic symmetry in the first νg_9/2 shell?', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 781, pp. 706-712. https://doi.org/10.1016/j.physletb.2018.04.049