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126 results on '"P, Doornenbal"'

1. Mirror energy differences above the 0f7/2 shell: First γ-ray spectroscopy of the Tz = −2 nucleus 56Zn

Author

N. Imai, A. Jungclaus, M. A. Bentley, M.L. Cortés, T. Arici, S. Pigliapoco, Brenden Longfellow, D. R. Napoli, Victor Vaquero, R. Lozeva, X. Pereira-Lopez, Megumi Niikura, B. Mauss, P. Doornenbal, R. Yajzey, Dirk Rudolph, R. Taniuchi, Kathrin Wimmer, F. Recchia, Panu Ruotsalainen, Hiroyoshi Sakurai, F. Browne, N. Kitamura, S. Uthayakumaar, R. Wadsworth, A. Álvarez Fernández, T. Koiwai, S. M. Lenzi, Alfredo Poves, Spanish National Research Council [Madrid] (CSIC), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Istituto Nazionale di Fisica Nucleare (INFN), RIKEN Nishina Center for Accelerator-Based Science [Wako] (RIKEN RNC), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, UAM. Departamento de Física Teórica, RIKEN Nishina Center for Accelerator-Based Science, Ministerio de Ciencia e Innovación (España), Swedish Research Council, and Science and Technology Facilities Council (UK)

Subjects
Nuclear and High Energy Physics, sinkki (metallit), QC1-999, Nuclear Theory, 01 natural sciences, nucleon removal, mirror nuclei, 0103 physical sciences, Subatomic Physics, medicine, 010306 general physics, Spectroscopy, radioactive ion beams, Nuclear Experiment, Nucleons, Physics, [PHYS]Physics [physics], isotoopit, Valence (chemistry), Isovector, 010308 nuclear & particles physics, Yrast, Física, Symmetry Breaking, medicine.anatomical_structure, isospin symmetry, shell-model calculations, Excited state, Energy Difference, Atomic physics, Multipole expansion, ydinfysiikka, Nucleus, Beam (structure)
Abstract

5 pags., 4 figs., Excited states in Zn were populated following one-neutron removal from a Zn beam impinging on a Be target at intermediate energies in an experiment conducted at the Radioactive Isotope Beam Factory at RIKEN. Three γ rays were observed and tentatively assigned to the 6→4→2→0 yrast sequence. This turns Zn into the heaviest T=−2 nucleus in which excited states are known. The excitation-energy differences between these levels and the isobaric analogue states in the T=+2 mirror partner, Fe, are compared with large-scale shell-model calculations considering the full pf valence space and various isospin-breaking contributions. This comparison, together with an analysis of the mirror energy differences in the A=58, T=±1 pair Zn and Ni, provides valuable information with respect to the size of the monopole radial and the isovector multipole isospin-breaking terms in the region above doubly-magic Ni., We thank the RIKEN Nishina Center accelerator staff and the BigRIPS team for providing excellent beams to the experiment. This work was supported by the Spanish Ministerio de Ciencia e Inno- vación under contracts FPA2017-84756-C4-2-P, PGC-2018-94583, and SEV-2016-0597, the Swedish Research Council (Vetenskap- srådet, VR 2016-3969), and the UK Science and Technology Facil- ities Council (STFC) under grants ST/L005727/1 and ST/P003885/1. FB is supported by the RIKEN Special Postdoctoral Researcher Pro- gram

Published
2021

2. Investigation of the ground-state spin inversion in the neutron-rich Cl47,49 isotopes

Author

Jason D. Holt, Carlo Barbieri, Zaihong Yang, I. Murray, D. M. Rossi, K. I. Hahn, S. Y. Park, C. Hilaire, Kazuyuki Ogata, C. Lehr, H. Baba, Duo Yan, David Steppenbeck, H. Törnqvist, P. Koseoglou, Masahiro Yasuda, V. Lapoux, Yasuhiro Togano, N. L. Achouri, R.-B. Gerst, Alessandra Corsi, T. Lokotko, B. D. Linh, L. Stuhl, H. Wang, Dóra Sohler, M. Gómez-Ramos, Igor Gašparić, H. N. Liu, Y. L. Sun, Takashi Nakamura, E. Sahin, Petr Navrátil, V. Panin, W. Rodriguez, N. Shimizu, J. M. Gheller, A. Moro, Victor Vaquero, L. X. Chung, Thomas Duguet, K. Moschner, Hiroyoshi Sakurai, Kathrin Wimmer, Dong-Wook Kim, A. Delbart, N. T. Khai, V. Wagner, N. Paul, P. Doornenbal, T. Motobayashi, V. Somà, D. Calvet, T. Isobe, K. Yoneda, O. Aktas, V. Werner, Y. Yamada, Thomas Aumann, F. Flavigny, N. D. Ton, T. Kobayashi, A. Giganon, X. X. Xu, F. Château, Hideaki Otsu, Julien Gibelin, Si-Ge Chen, N. T. T. Phuc, P. A. Söderström, A. Gillibert, Nobuyuki Chiga, A. Obertelli, T. Koiwai, Tomohiro Uesaka, F. Browne, M. MacCormick, Satoshi Takeuchi, M. L. Cortés, Masaki Sasano, S. Franchoo, Yutaka Utsuno, Jenny Lee, Yuya Kubota, L. Zanetti, and Yosuke Kondo

Subjects
Physics, Isotope, 010308 nuclear & particles physics, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spin (physics), Ground state, 01 natural sciences, Inversion (discrete mathematics), Nuclear theory
Published
2021

3. Three-quasiparticle isomers in odd-even Pm159,161 : Calling for modified spin-orbit interaction for the neutron-rich region

Author

Tetsuro Komatsubara, Toshiyuki Kubo, Long-Jun Wang, I. Kojouharov, H. Baba, Y. F. Fang, Giuseppe Lorusso, Jan Taprogge, F. L. Bello Garrote, I. Nishizuka, Hirofumi Watanabe, Masafumi Matsushita, Shunji Nishimura, S. Inabe, A. Gottardo, H. Schaffner, Z. H. Li, Motoki Kobayashi, L. Sinclair, F. Browne, G. Benzoni, Nori Aoi, M. Tanaka, D. Kameda, E. Sahin, Gary Simpson, Cui Juan Lv, Zhengyu Xu, Toshiyuki Sumikama, Guillaume Gey, Shintaro Go, Chang-Bum Moon, P. Doornenbal, Hiroyuki Takeda, Zena Patel, T. Isobe, Hiroshi Suzuki, Atsuko Odahara, R. Yokoyama, N. Kurz, Naoki Fukuda, Stephen Rice, Zs. Vajta, Yang Sun, Hiroyoshi Sakurai, Shin'ichiro Michimasa, P. A. Söderström, Ayumi Yagi, Eiji Ideguchi, Yan Xin Liu, István Kuti, K. Kobayashi, R. Daido, Jinguang Wu, and Hiroki Nishibata

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Fission, Spin–orbit interaction, 01 natural sciences, Ion, 0103 physical sciences, Quasiparticle, Neutron, Atomic physics, 010306 general physics, Spectroscopy, Nucleon
Abstract

Neutron-rich Pm ( Z = 61 ) isotopes were studied by delayed γ -ray spectroscopy at RIBF, RIKEN Nishina Center using the in-flight fission of a 345 MeV/nucleon U 238 beam. A cluster-type Ge detector array, EURICA, was used to measure the delayed γ rays from stopped ions. Isomeric γ decays were observed in Pm 159 and Pm 161 with half-lives of 4.97(12) μ s and 0.79(4) μ s , respectively. Level schemes for Pm 159 and Pm 161 were constructed in this study. The isomeric states of Pm 159 and Pm 161 could be interpreted as two quasiparticle excitations of neutrons with the configurations of ν ( 7 / 2 [ 633 ] ⊗ 5 / 2 [ 523 ] ) and ν ( 7 / 2 [ 633 ] ⊗ 1 / 2 [ 521 ] ) , respectively. They are analogous to the isomers that have been observed systematically in other even-mass N = 98 and N = 100 isotones in this region. A projected shell model calculation was performed and it reproduced the order of three-quasiparticle states only if new Nilsson parameters with an N -dependent spin-orbit interaction were used. This work demonstrates that the strength of spin-orbit interactions in standard Nilsson parameters needs to be modified to study the properties of neutron-rich rare-earth nuclei around A = 165 , and provides new evidence supporting the existence of the deformed N = 98 subshell gap in odd-mass nuclei for the first time.

Published
2021

4. Spectroscopy of Cd98 by two-nucleon removal from In100

Author

Joochun Park, Cenxi Yuan, K. Wimmer, F. Browne, I. Zanon, S. T. Wang, Luis Sarmiento Pico, Sidong Chen, P Liang, T. Lokotko, Alessandra Corsi, Ryo Taniuchi, Zhengtai Liu, K. Kokubun, T. Koiwa, Jenny Lee, D. Brugnara, Hiroyoshi Sakurai, Joakim Cederkäll, P. Doornenbal, Jinjia Liu, Sun Zhipeng, W. Xian, P. Li, Shan Jin, J. Gerl, G. Häfner, Shigeru Kubono, Alejandro Algora, M. L. Cortés, M. Górska, and P. Koseoglou

Subjects
Physics, Proton, 010308 nuclear & particles physics, Space (mathematics), 01 natural sciences, 7. Clean energy, Atomic orbital, Yield (chemistry), 0103 physical sciences, Level structure, Atomic physics, 010306 general physics, Spectroscopy, Nucleon, Excitation
Abstract

Low-lying states of Cd-98 have been populated by the two-nucleon removal reaction (In-100, Cd-98+gamma) and studied using in-beam gamma-ray spectroscopy at the Radioactive Isotope Beam Factory at RIKEN. Two new gamma transitions were identified and assigned as decays from a previously unknown state. This state is suggested to be based on a pi 1g(/9/2)(-1)2p(1/2)(-2) configuration with J(pi) = 5(-). The present observation extends the systematics of the excitation energies of the first 5(-) state in N = 50 isotones toward Sn-100. The determined energy of the 5(- )state in Cd-98 continues a smooth trend along the N = 50 isotones. The systematics are compared with shell-model calculations in different model spaces. Good agreement is achieved when considering a model space consisting of the pi(1f(5/2), 2p(3/2), 2p(1/2), 1g(9/2)) orbitals. The calculations with a smaller model space omitting the orbitals below the Z = 38 subshell could not reproduce the experimental energy difference between the ground and first 5(-) states in N = 50 isotones, because proton excitations across Z = 38 subshell yield a large amount of correlation energy that lowers the ground states. (Less)

Published
2021

5. Persistence of the Z=28 shell gap in A=75 isobars: Identification of a possible (1/2−) μs isomer in Co75 and β decay to Ni75

Author

Hiroki Nishibata, A. I. Morales, Hirofumi Watanabe, Shin-Ichiro Nishimura, Megumi Niikura, Daisuke Suzuki, H. S. Jung, V. Werner, Ryo Taniuchi, D. Sohler, D. R. Napoli, Jan Taprogge, T. Isobe, N. Kurz, I. Kojouharov, Toshiyuki Sumikama, Jinguang Wu, P. A. Söderström, Ayumi Yagi, I. Matea, P. Morfouace, P. R. John, S. Franchoo, Shigeru Kubono, S. Escrig, F. Naqvi, Alfredo Poves, Atsuko Odahara, K. Matsui, Giuseppe Lorusso, H. Baba, Hiroyoshi Sakurai, Zhengyu Xu, Z. H. Li, E. Sahin, P. Doornenbal, D. Mengoni, Zs. Vajta, H. Schaffner, K. Yoshinaga, I. Stefan, F. Browne, and Guillaume Gey

Subjects
Physics, Proton, 010308 nuclear & particles physics, Center (category theory), Nuclear structure, Nuclear isomer, 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Nucleosynthesis, Excited state, 0103 physical sciences, Isobar, 010306 general physics
Abstract

Background: The evolution of shell structure around doubly-magic exotic nuclei is of great interest in nuclear physics and astrophysics. In the `south-west' region of $^{78}$Ni, the development of deformation might trigger a major shift in our understanding of explosive nucleosynthesis. To this end, new spectroscopic information on key close-lying nuclei is very valuable. Purpose: We intend to measure the isomeric and $\beta$ decay of $^{75}$Co, with one proton- and two neutron-holes relative to $^{78}$Ni, to access new nuclear structure information in $^{75}$Co and its $\beta$-decay daughters $^{75}$Ni and $^{74}$Ni. Methods: The nucleus $^{75}$Co is produced in relativistic in-flight fission reactions of $^{238}$U at the Radioactive Ion Beam Factory (RIBF) in the RIKEN Nishina Center. Its isomeric and $\beta$ decay are studied exploiting the BigRIPS and EURICA setups. Results: We obtain partial $\beta$-decay spectra for $^{75}$Ni and $^{74}$Ni, and report a new isomeric transition in $^{75}$Co. The energy ($E_{\gamma}=1914(2)$ keV) and half-life ($t_{1/2}=13(6)$ $\mu$s) of the delayed $\gamma$ ray lend support for the existence of a $J^{\pi}=(1/2^-)$ isomeric state at 1914(2) keV. A comparison with PFSDG-U shell-model calculations provides good account for the observed states in $^{75}$Ni, but the first calculated $1/2^-$ level in $^{75}$Co, a prolate $K=1/2$ state, is predicted about 1 MeV below the observed $(1/2^-)$ level. Conclusions: The spherical-like structure of the lowest-lying excited states in $^{75}$Ni is proved. In the case of $^{75}$Co, the results suggest that the dominance of the spherical configurations over the deformed ones might be stronger than expected below $^{78}$Ni. Further experimental efforts to discern the nature of the $J^{\pi}=(1/2^-)$ isomer are necessary.

Published
2021

6. Pairing Forces Govern Population of Doubly Magic Ca54 from Direct Reactions

Author

J. M. Gheller, S. Y. Park, K. Yoneda, Masaki Sasano, P. A. Söderström, D. Sohler, D. Körper, H. Simon, A. Gillibert, K. Miki, Satoshi Takeuchi, Yasuhiro Togano, M. MacCormick, R.-B. Gerst, Duo Yan, Tomohiro Uesaka, Fabia Schindler, V. Wagner, B. D. Linh, M. Holl, A. Corsi, N. Paul, Igor Gašparić, H. N. Liu, P. Koseoglou, E. Sahin, Yosuke Kondo, T. Lokotko, T. Isobe, Victor Vaquero, M. L. Cortés, V. Werner, Takashi Nakamura, W. Rodriguez, Zaihong Yang, A. Delbart, S. Franchoo, F. Château, V. Lapoux, P. Doornenbal, K. I. Hahn, L. Stuhl, I. Murray, C. Caesar, Kazuyuki Ogata, C. Lehr, T. Kobayashi, X. X. Xu, C. Hilaire, Si-Ge Chen, Yutaka Utsuno, V. Panin, A. Giganon, Jenny Lee, N. L. Achouri, L. X. Chung, Y. L. Sun, K. Moschner, Yuya Kubota, D. M. Rossi, H. Baba, F. Flavigny, Masahiro Yasuda, L. Zanetti, Kathrin Wimmer, Dong-Wook Kim, O. Aktas, F. Browne, S. Wang, A. Obertelli, J. Kahlbow, Hiroyoshi Sakurai, T. Motobayashi, Julien Gibelin, K. Boretzky, D. Calvet, David Steppenbeck, H. Törnqvist, Thomas Aumann, Nobuyuki Chiga, T. Koiwai, Kazuki Yoshida, Hideaki Otsu, Hirofumi Yamada, and J. Tscheuschner

Subjects
Physics, education.field_of_study, Proton, 010308 nuclear & particles physics, Nuclear Theory, Population, Nuclear shell model, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Pairing, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Ground state, education
Abstract

Direct proton-knockout reactions of ^{55}Sc at ∼220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of ^{54}Ca were investigated through γ-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological internucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the ^{55}Sc ground state with states in ^{54}Ca. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of ^{55}Sc, valence proton removals populated predominantly the ground state of ^{54}Ca. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

Published
2021

7. First spectroscopic study of V63 at the N=40 island of inversion

Author

K. Moschner, David Steppenbeck, F. Browne, Jenny Lee, H. Törnqvist, Y. L. Sun, Kathrin Wimmer, Yuya Kubota, A. Gillibert, V. Panin, E. Sahin, L. X. Chung, D. Calvet, T. Isobe, Alessandra Corsi, Dóra Sohler, R.-B. Gerst, M. MacCormick, Yosuke Kondo, F. Château, Hideaki Otsu, P. Doornenbal, Hirofumi Yamada, N. Paul, V. Werner, Satoshi Takeuchi, M. L. Cortés, Masahiro Yasuda, D. M. Rossi, S. Franchoo, C. Lehr, W. Rodriguez, H. Baba, S. Y. Park, Z. Elekes, A. Giganon, Kazuyuki Ogata, Nobuyuki Chiga, Duo Yan, T. Lokotko, L. Zanetti, L. Stuhl, K. Yoneda, T. Koiwai, Takashi Nakamura, A. Delbart, Masaki Sasano, N. L. Achouri, S. Wang, B. D. Linh, Igor Gašparić, H. N. Liu, Yasuhiro Togano, V. Wagner, P. Koseoglou, F. Flavigny, J. M. Gheller, Tomohiro Uesaka, A. Obertelli, Zs. Dombrádi, Hiroyoshi Sakurai, T. Motobayashi, Julien Gibelin, Dong-Wook Kim, O. Aktas, V. Lapoux, K. Yoshida, M. M. Juhász, Kamila Sieja, Zaihong Yang, I. Murray, K. I. Hahn, T. Kobayashi, X. X. Xu, Si-Ge Chen, P. A. Söderström, Victor Vaquero, Thomas Aumann, and C. Hilaire

Subjects
Physics, 010308 nuclear & particles physics, Island of inversion, 0103 physical sciences, Geophysics, 010306 general physics, 01 natural sciences
Published
2021

8. Erratum: Properties of γ -decaying isomers and isomeric ratios in the Sn100 region [Phys. Rev. C 96 , 044311 (2017)]

Author

J. Park, R. Krücken, D. Lubos, R. Gernhäuser, M. Lewitowicz, S. Nishimura, D. S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, I. Čeliković, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, H. Grawe, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, K. Moschner, D. Murai, I. Nishizuka, Z. Patel, M. M. Rajabali, S. Rice, H. Sakurai, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Y. Xu

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Atomic physics, 010306 general physics, 01 natural sciences
Published
2021

9. Experimental Study of $^{4}n$ by Directly Detecting the Decay Neutrons

Author

Atsumi Saito, Yohei Shimizu, H. Törnqvist, B. Monteagudo, T. Isobe, M. Caamaño, H. Scheit, S. Kiyotake, J. Tscheuschner, M. L. Cortés, F. M. Marqués, N. Fukuda, N. A. Orr, J. M. Gheller, A. Gillibert, A. Matta, K. Yoneda, L. Stuhl, Z. Elekes, I. Kuti, V. Wagner, M. Miwa, Z. Halász, A. Obertelli, S. Kim, A. Revel, L. Zanetti, N. L. Achouri, S. Takeuchi, F. Dufter, C. A. Douma, S. Masuoka, Stefanos Paschalis, R. Gernhäuser, S. Chen, Nobuyuki Chiga, S. Storck, T. Shimada, M.N. Harakeh, P. Koseoglou, T. Harada, B. Yang, M. Matsumoto, H. Takeda, D. S. Ahn, Yuya Kubota, H. Yamada, Yasuhiro Togano, A. Hirayama, Y. Yasuda, T. Fujino, D. M. Rossi, Nasser Kalantar-Nayestanaki, J. Tanaka, M. Böhmer, N. Inabe, Didier Beaumel, S. Park, Thomas Aumann, H. Baba, Tomohiro Uesaka, F. Schindler, J. Feng, Zaihong Yang, I. Murray, Julien Gibelin, K. Boretzky, S. W. Huang, B. Fernández-Domínguez, S. Reichert, Takashi Nakamura, Yu-xin Liu, K. Wimmer, Yukie Maeda, L. Yang, H. Sato, E. Tronchin, P. Doornenbal, Dmytro Symochko, D. Cortina, J. Kahlbow, S. Shimoura, H. Suzuki, Hideaki Otsu, M. Potlog, P. J. Li, J. Mayer, H. Miki, Masaki Sasano, Toshio Kobayashi, Z. Ge, D. Kim, Juzo Zenihiro, T. Tomai, I. Stefan, M. Parlog, H. Simon, V. Panin, Igor Gašparić, C. Lehr, Yosuke Kondo, C. Lenain, U. Forsberg, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Research unit Nuclear & Hadron Physics, and Nuclear Energy

Subjects
Nuclear structure and force, tetraneutron, direct reactions, radioactive beams, Physics, Nuclear physics, 010308 nuclear & particles physics, 0103 physical sciences, Tetraneutron, Neutron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, 3. Good health
Abstract

The tetraneutron has attracted the attention of nuclear physicists during the past decades, but there is still no unambiguous confirmation of its existence or non-existence. A new experiment based on $$^{8}$$ He(p, 2p) $$^{7}$$ H{t+ $$^{4}n$$ } reaction, with direct detection of the four neutrons, has been carried out at RIBF, which can hopefully help to draw a definite conclusion on the tetraneutron system.

Published
2021

10. β decay of the very neutron-deficient Ge60 and Ge62 nuclei

Author

Momoko Tanaka, E. Ganioǧlu, Gabor Kiss, F. Diel, Daiki Nishimura, G. de Angelis, F. Molina, Naohito Inabe, Toshiyuki Kubo, T. Kurtukian-Nieto, D. R. Napoli, A. Montaner-Pizá, P. A. Söderström, A. Boso, P. Ascher, S. Grévy, A. I. Morales, V. H. Phong, Shunji Nishimura, J. Giovinazzo, P. Aguilera, C. Sidong, Shigeru Kubono, J. Chiba, R. B. Cakirli, Y. Fujita, Hiroyoshi Sakurai, S. Yagi, C. Magron, J. Agramunt, V. Guadilla, B. Rubio, Y. Shimizu, M. Gerbaux, H. Oikawa, D. Lubos, D. S. Ahn, P. Doornenbal, C. Borcea, Shintaro Go, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, S. E.A. Orrigo, N. Fukuda, Jin Wu, Y. Takei, H. Suzuki, Alejandro Algora, T. Goigoux, and W. Gelletly

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Branching fraction, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Ground state, 7. Clean energy, 01 natural sciences, Fermi Gamma-ray Space Telescope
Abstract

We report here the results of a study of the $\beta$ decay of the proton-rich Ge isotopes, $^{60}$Ge and $^{62}$Ge, produced in an experiment at the RIKEN Nishina Center. We have improved our knowledge of the half-lives of $^{62}$Ge (73.5(1) ms), $^{60}$Ge (25.0(3) ms) and its daughter nucleus, $^{60}$Ga (69.4(2) ms). We measured individual $\beta$-delayed proton and $\gamma$ emissions and their related branching ratios. Decay schemes and absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. A total $\beta$-delayed proton-emission branching ratio of 67(3)% has been obtained for $^{60}$Ge. New information has been obtained on the energy levels populated in $^{60}$Ga and on the 1/2$^-$ excited state in the $\beta p$ daughter $^{59}$Zn. We extracted a ground state to ground state feeding of 85.3(3)% for the decay of $^{62}$Ge. Eight new $\gamma$ lines have been added to the de-excitation of levels populated in the $^{62}$Ga daughter.

Published
2021

11. Observation of new neutron-rich isotopes in the vicinity of Zr 110

Author

Takashi Kubo, Zena Patel, H. Takeda, Eiji Ideguchi, F. Didierjean, G. Lorusso, Zhengyu Xu, T. Isobe, Raymond J. Carroll, Jan Taprogge, Y. F. Fang, Naoki Fukuda, Zs. Podolyák, Kenichi Yoshida, R. Daido, O. Wieland, Toshiyuki Sumikama, R. Lozeva, H. Baba, Z. H. Li, F. Browne, Ayumi Yagi, Hiroyoshi Sakurai, D. Kameda, Shin-Ichiro Nishimura, Guillaume Gey, Hiroshi Suzuki, P. Doornenbal, S. Lalkovski, P. H. Regan, Atsuko Odahara, Stephen Rice, L. Sinclair, Momoko Tanaka, I. Nishizuka, Nobuyuki Chiga, Gary Simpson, Y. Shimizu, Alison Bruce, P. A. Söderström, Naohito Inabe, Hirofumi Watanabe, Hiroki Nishibata, Oliver J. Roberts, V. Werner, Jin Wu, RIKEN Nishina Center for Accelerator-Based Science, University of Tokyo, Japan Society for the Promotion of Science, National Research Foundation of Korea, Science and Technology Facilities Council (UK), Department of Energy (US), Federal Ministry of Education and Research (Germany), Ministerio de Ciencia e Innovación (España), Department for Business, Energy and Industrial Strategy (UK), National Measurement System (UK), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Isotope, Spectrometer, 010308 nuclear & particles physics, Fission, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Time of flight, 0103 physical sciences, Nuclear Reactions, Physics::Accelerator Physics, Neutron, 010306 general physics, Nucleon, Nuclear Experiment, Beam (structure)
Abstract

5 pags., 3 figs., 2 tabs., Neutron-rich radioactive isotope (RI) beams in the vicinity of Zr110 were produced using the in-flight fission of a 345-MeV/nucleon U238 beam at the RIKEN Radioactive Isotope Beam Factory. The RI beams were separated in flight by the large-acceptance two-stage fragment separator BigRIPS. Isotopes were clearly identified in a low-background particle-identification plot, which was obtained from the measurements of time of flight, magnetic rigidity, and energy loss using beam-line detectors placed in the BigRIPS separator and the ZeroDegree spectrometer. Nine new isotopes, Br101, Kr102, Rb105,106, Sr108, Y110,111, Zr114, and Nb117, are reported for the first time, with their measured production cross sections compared with the extrapolations of lighter isotopes down to the femtobarn regime., This experiment was carried out at the RIBF operated by the RIKEN Nishina Center, and the Center for Nuclear Study, the University of Tokyo. The authors acknowledge the RIBF accelerator staffs for their efforts in delivering an intense 238U beam. This work was supported by JSPS KAKENHI Grants No. 2301752, No. 24740188, No. 25247045, No. 26800117, and No. 16K17680, NRF Grant No. 2016K1A3A7A09005575, STFC Grants No. ST/J000132/1, No. ST/J000051/1, No. ST/K502431/1, No. ST/L005743/1, No. ST/P003885/1, No. ST/P003982/1, and No. ST/P005314/1, DOE Grant No. DE-FG02-91ER 40609, BMBF Grant No. 05P19RDFN1, and Spanish Ministerio de Ciencia e Innovación under Contracts No. FPA2009- 13377-C02 and No. FPA2011-29854-C04. P.H.R. and G.L. acknowledge additional support from the UK Department for Business, Energy and Industrial Strategy (BEIS) via funding for the UK National Measurement System. P.-A.S. was financed by the RIKEN Foreign Postdoctoral Researcher Program

Published
2021

12. Nuclear structure of Te isotopes beyond neutron magic number N=82

Author

Y. Shimizu, Giuseppe Lorusso, F. L. Bello Garrote, I. Nishizuka, T. Isobe, Chang-Bum Moon, A. Jungclaus, S. Morimoto, Naohito Inabe, Y. F. Fang, Zs. Vajta, Hiroshi Watanabe, Roman Gernhäuser, C. S. Lee, Hiroshi Suzuki, Toshiyuki Sumikama, Shunji Nishimura, H. Schaffner, M. Si, D. Mücher, Hiroyuki Takeda, Daichi Murai, F. Browne, Hiroki Nishibata, Atsuko Odahara, Anna Wendt, J. M. Daugas, Guillaume Gey, L. Sinclair, Hiroyoshi Sakurai, I. Kojouharov, P. A. Söderström, Ayumi Yagi, S. Bönig, Byung-Sik Hong, Gary Simpson, R. Orlandi, Younghun Kwon, A. Montaner-Pizá, Stephen Rice, D. Kameda, J. M. Keatings, Eiji Ideguchi, Rin Yokoyama, K. Moschner, A. Gargano, S. Ilieva, Jan Taprogge, K. Yoshinaga, Hyo Soon Jung, B. Moon, R. Daido, Zena Patel, D. S. Ahn, P. Doornenbal, Jin Wu, H. Naïdja, K. Tshoo, N. Kurz, K. Steiger, Naoki Fukuda, Megumi Niikura, P. Lee, F. Didierjean, Tetsuro Komatsubara, Toshiyuki Kubo, T. Kröll, R. Lozeva, F. Drouet, Z. H. Li, H. Baba, Zhengyu Xu, T. Ishigaki, RIKEN Nishina Center for Accelerator-Based Science, University of Tokyo, Institute for Basic Science (South Korea), National Research Foundation of Korea, Ministerio de Economía y Competitividad (España), Japan Society for the Promotion of Science, National Research, Development and Innovation Office (Hungary), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut Laue-Langevin (ILL), ILL, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Nuclear Theory, Nuclear structure, Nuclear Structure, 7. Clean energy, 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Neutron, 010306 general physics, Nucleon, Nuclear Experiment, Beam (structure), Magic number (physics)
Abstract

15 pags., 10 figs., 4 tabs., Newly observed decay schemes of the nuclei Sb137 and Sb138 are reported. The neutron-rich Sb isotopes were produced by the in-flight fragmentation of a U238 primary beam with an energy of 345 MeV/nucleon. Several new excited states of Te137 with tentatively assigned spin-parities of (5/2-), (9/2-), and (7/2) have been established which play an important role in the evolution of neutron levels beyond N=82. The study of the ß decay of Sb138 led to a considerable extension of the level scheme of Te138 including the identification of several nonyrast states. The structure of Te137 and Te138 is discussed on the basis of large-scale shell-model calculations performed using two different effective interactions., This work was carried out at the RIBF operated by RIKEN Nishina Center and CNS, University of Tokyo. 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 National Research Foundation (NRF) of the Republic of Korea (Grant No. 2013M7A1A1075764). This research was supported by NRF of the Republic of Korea (Grants No. 2019R1A6A3A03031564 and No. 2018R1A5A1025563), IBS of the Republic of Korea (Grants No. IBS-R031-D1 and No. IBS-R031-Y1), the Spanish Ministerio de Economía y Competitividad (Grant No. FPA2017-84756-C4-2-P), and JSPS KAKENHI of Japan (Grant No. 25247045). The support from FR-JP LIA is also acknowledged. C.S.L. acknowledges the support from NRF of the Republic of Korea (Grants No. 2017M2A2A6A02071071 and No. 2016R1D1A1A09917463). Z.V. acknowledges the supports from the National Research, Development and Innovation Fund of Hungary, financed under the K18 funding scheme with Project No. K128947 and by the European Regional Development Fund (Grant No. GINOP-2.3.3-15-2016- 00034), as well as by the National Research, Development and Innovation Office NKFIH (Grant No. PD 124717).

Published
2021

13. First spectroscopic study of $^{51}$Ar by the (p,2p) reaction

Author

Zs. Dombradi, S. Y. Park, T. Isobe, F. Browne, K. Moschner, Thomas Aumann, R.-B. Gerst, F. Château, Kathrin Wimmer, X. X. Xu, Z. Elekes, L. Zanetti, Hideaki Otsu, B. D. Linh, Hirofumi Yamada, Si-Ge Chen, P. A. Söderström, Yutaka Utsuno, Igor Gašparić, H. N. Liu, Jenny Lee, Zaihong Yang, I. Murray, Yasuhiro Togano, F. Flavigny, K. I. Hahn, L. Stuhl, Yuya Kubota, V. Wagner, Tomohiro Uesaka, A. Giganon, D. Kim, M. MacCormick, C. Lehr, V. Panin, L. X. Chung, P. Koseoglou, T. Lokotko, Y.L. Sun, E. Sahin, K. Yoneda, Victor Vaquero, M. L. Cortés, Takashi Nakamura, S. Franchoo, P. Doornenbal, Satoshi Takeuchi, Masahiro Yasuda, O. Aktas, A. Gillibert, V. Lapoux, Nobuyuki Chiga, Takaharu Otsuka, T. Koiwai, Hiroyoshi Sakurai, T. Motobayashi, M. M. Juhász, Kazuki Yoshida, David Steppenbeck, Julien Gibelin, H. Törnqvist, Toshio Kobayashi, Kazuyuki Ogata, W. Rodriguez, N. L. Achouri, C. Hilaire, S. Wang, Donghang Yan, N. Paul, A. Obertelli, J. M. Gheller, Yosuke Kondo, V. Werner, D. Calvet, D. M. Rossi, Masaki Sasano, H. Baba, D. Sohler, A. Corsi, A. Delbart, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), RIKEN Nishina Center for Accelerator-Based Science, European Research Council, European Commission, Helmholtz International Center for FAIR, German Research Foundation, Alexander von Humboldt Foundation, Ministry of Science and Technology of Vietnam, Government of South Korea, Agencia Estatal de Investigación (España), Federal Ministry of Education and Research (Germany), Helmholtz Graduate School for Hadron and Ion Research, and National Research, Development and Innovation Office (Hungary)

Subjects
Nuclear and High Energy Physics, Shell closure, γ -ray spectroscopy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 0103 physical sciences, Bound state, nuclear shell model, proton knock-out reaction, gamma-ray spectroscopy, invariant-mass method, radioactive beams, Invariant mass, Neutron, ddc:530, Nuclear structure, 010306 general physics, Spectroscopy, Physics, Valence (chemistry), Proton knock-out reaction, 010308 nuclear & particles physics, Invariant mass method, Isotopes of argon, lcsh:QC1-999, Excited state, γ-ray spectroscopy, Atomic physics, lcsh:Physics
Abstract

8 pags., 4 figs., 3 tabs., The nuclear structure of 51Ar, an uncharted territory so far, was studied by the (p,2p) reaction using γ-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the γ-ray spectrum and six peaks were observed in the 50Ar+n relative energy spectrum. Comparing the results to our shell-model calculations, two bound and six unbound states were established. Three of the unbound states could only be placed tentatively due to the low number of counts in the relative energy spectrum of events associated with the decay through the first excited state of 50Ar. The low cross sections populating the two bound states of 51Ar could be interpreted as a clear signature for the presence of significant subshell closures at neutron numbers 32 and 34 in argon isotopes. It was also revealed that due to the two valence holes, unbound collective states coexist with individual-particle states in 51Ar., We are very grateful to the RIKEN Nishina Center accelerator staff for providing the stable beam and to the BigRIPS team for the smooth operation of the secondary beams. The development of the MINOS device has been supported by the European Research Council through the ERC Grant No. MINOS-258567. F. B. was supported by the RIKEN Special Postdoctoral Researcher Program. K. O. acknowledges the support by Grant-in-Aid for Scientific Research JP16K05352. Y. U. acknowledges the support by Grant-in-Aid for Scientific Research 20K03981. Y. L. S. acknowledges the support of Marie Skłodowska-Curie Individual Fellowship (H2020-MSCA-IF-2015-705023) from the European Union and the support from the Helmholtz International Center for FAIR. H. N. L. acknowledges the support from the Enhanced Eurotalents program (PCOFUND-GA-2013-600382) co-funded by CEA and the European Union. T. A., C. L., D. R., H. T., V. W., L. Z., H. N. L., V. W. and A. O. acknowledge the support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Project No. 279384907-SFB 1245. R. B. G. acknowledges the support from the DFG under Grant No. BL 1513/1-1. Y. L. S. and A. O. acknowledge the support from the Alexander von Humboldt Foundation. B. D. L. and L. X. C. acknowledge the support from the Vietnam Ministry of Science and Technology under Grant No. ĐTCB.01/21/VKHKTHN. I. G. has been supported by HIC for FAIR and HRZZ under project No. 1257 and 7194. K. I. H., D. K. and S. Y. P. acknowledge the support from the NRF grant funded by the Korea government (No. 2017R1A2B2012382 and 2019M7A1A1033186). F. B. acknowledge the support from the RIKEN Special Postdoctoral Researcher Program. D. S. and Z. E. were supported by projects No. GINOP-2.3.3-15-2016-00034 and No. K128947. V. V. acknowledges support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. V. W. and P. K. acknowledge the support from BMBF grants 05P15RDFN1 and 05P19RDFN1. P. K. acknowledges support from HGS-HIRe. This work was also supported by NKFIH (114454).

Published
2021

14. Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag

Author

Hirofumi Watanabe, Young-Ki Kim, Chang-Bum Moon, A. Jungclaus, Younghun Kwon, A. Montaner-Pizá, Anna Wendt, Shunji Nishimura, Hiroshi Suzuki, F. Naqvi, Megumi Niikura, K. Yoshinaga, Ayumi Yagi, Z. H. Li, G. J. Lane, Giuseppe Lorusso, Hyo Soon Jung, F. Browne, D. Kameda, Hiroki Nishibata, Gary Simpson, P. Doornenbal, K. Steiger, Guillaume Gey, T. Isobe, F. G. Kondev, I. Kojouharov, Toshiyuki Sumikama, Zs. Vajta, R. Orlandi, Toshiyuki Kubo, Hiroyuki Takeda, Naohito Inabe, Atsuko Odahara, Jin Wu, G. D. Kim, H.K. Wang, Jan Taprogge, Roman Gernhäuser, G. Benzoni, F. C. L. Crespi, H. Schaffner, K. Moschner, H. Baba, Naoki Fukuda, Zs. Podolyák, K. Y. Chae, N. Kurz, Zhengyu Xu, P. A. Söderström, Daiki Nishimura, Hiroyoshi Sakurai, Zena Patel, Cenxi Yuan, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Ministry of Science and Technology (South Korea), Department of Energy (US), National Research Foundation of Korea, Ministerio de Economía y Competitividad (España), Federal Ministry of Education and Research (Germany), Japan Society for the Promotion of Science, National Natural Science Foundation of China, National Key Research and Development Program (China), and Science and Technology Facilities Council (UK)

Subjects
Nuclear and High Energy Physics, QC1-999, Nuclear Theory, Shell (structure), Shell evolution, Ag, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, decay, Gamow-Teller, 0103 physical sciences, medicine, Physics::Atomic and Molecular Clusters, Neutron, 010306 general physics, Spin (physics), Physics, 010308 nuclear & particles physics, Gamow-Teller β decay, Parity (physics), 127Ag, ddc, Isomer, medicine.anatomical_structure, 13. Climate action, Atomic nucleus, 127 Ag, Atomic physics, Radioactive isotope beam, Nucleus, Excitation
Abstract

6 pags., 4 figs., 2 tabs., The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the β decay in the region below 132Sn using the newly obtained experimental data on a long-lived isomer in 127Ag. The T1/2=67.5(9) ms isomer has been identified with a spin and parity of (27/2+) at an excitation energy of 1942−20+14 keV, and found to decay via an internal transition of an E3 character, which competes with the dominant β-decay branches towards the high-spin states in 127Cd. The underlying mechanism of a strong GT transition from the 127Ag isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach., Part of the WAS3ABi was supported by the Rare Isotope Science Project which is funded by MSIP and NRF of Korea. This work was supported by the Priority Centers Research Program in Korea (2009-0093817), OTKA contract number K100835, the U.S. DOE, Office of Nuclear Physics (Contract No. DE-AC02-06CH11357), NRF2016R1A5A1013277 and NRF-2013M7A1A1075764, the Spanish Ministerio de Economía y Competitividad under contract FPA2017- 84756-C4-2-P, the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF (Contract No. 300096), German BMBF under Contract No: 05P12PKFNE, JSPS KAKENHI Grant No. 24740188 and 25247045, the National Natural Science Foundation of China (Nos. 11505302, 11575112, 11775316), the National Key Program for S&T Research and Development (No. 2016YFA0400501), and STFC (UK).

Published
2021

15. N=32 shell closure below calcium: Low-lying structure of Ar50

Author

Nobuyuki Chiga, K. Moschner, T. Koiwai, Hiroyoshi Sakurai, V. Lapoux, A. Gillibert, Yutaka Utsuno, D. Calvet, T. Isobe, Kathrin Wimmer, T. Motobayashi, Jenny Lee, Achim Schwenk, H. Toernqvist, Yuya Kubota, Victor Vaquero, R.-B. Gerst, F. Château, W. Rodriguez, N. Shimizu, B. D. Linh, D. M. Rossi, Masahiro Yasuda, Tomohiro Uesaka, Hideaki Otsu, Igor Gašparić, H. N. Liu, V. Panin, H. Baba, Kazuyuki Ogata, L. X. Chung, S. Y. Park, Julien Gibelin, Hirofumi Yamada, K. Yoshida, C. Lehr, Duo Yan, L. Achouri, Zaihong Yang, L. Stuhl, A. Giganon, I. Murray, S. Wang, N. Paul, L. Zanetti, E. Sahin, Y. L. Sun, J. Simonis, A. Obertelli, K. Yoneda, C. Hilaire, K. I. Hahn, V. Werner, David Steppenbeck, Jason D. Holt, P. Doornenbal, A. Delbart, M. MacCormick, P. Koseoglou, J. M. Gheller, Alessandra Corsi, Thomas Aumann, Masaki Sasano, Dóra Sohler, Satoshi Takeuchi, M. L. Cortés, S. Franchoo, T. Kobayashi, F. Flavigny, X. X. Xu, Si-Ge Chen, P. A. Söderström, Dong-Wook Kim, F. Browne, O. Aktas, Yosuke Kondo, Yasuhiro Togano, T. Lokotko, Takashi Nakamura, Javier Fernandez Menendez, and V. Wagner

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Closure (topology), Shell (structure), Calcium low, 010306 general physics, 01 natural sciences, Molecular physics
Published
2020

16. Evolution of proton single-particle states in neutron-rich Sb isotopes beyond N=82

Author

A. Jungclaus, Y. Shimizu, H. Schaffner, Hiroshi Suzuki, T. Isobe, I. Kojouharov, Hiroshi Watanabe, G. D. Kim, J. M. Daugas, Hiroki Nishibata, Jinguang Wu, Hiroyoshi Sakurai, D. Kameda, Toshiyuki Kubo, Shunji Nishimura, A. Gargano, Gary Simpson, P. Doornenbal, Atsuko Odahara, H. Baba, K. Moschner, Roman Gernhäuser, F. Browne, Z. H. Li, Z Vajta, Ayumi Yagi, Naohito Inabe, S. Bönig, Marcus Scheck, Guillaume Gey, T. Kröll, K. Yoshinaga, S. Ilieva, N. Kurz, Jan Taprogge, Naoki Fukuda, K. Steiger, Hyo Soon Jung, R. Orlandi, J. M. Keatings, Young-Ki Kim, P. A. Söderström, Younghun Kwon, A. Montaner-Pizá, Giuseppe Lorusso, Anna Wendt, D. Mücher, Toshiyuki Sumikama, Hiroyuki Takeda, H. Naïdja, Zhengyu Xu, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut Laue-Langevin (ILL), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ILL, RIKEN Nishina Center for Accelerator-Based Science, Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), and National Research, Development and Innovation Office (Hungary)

Subjects
Physics, Proton, Isotope, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear structure, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, 7. Clean energy, 01 natural sciences, Beta decay, Nuclear physics, Neutron number, Excited state, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Excitation
Abstract

11 pags., 8 figs., 2 tabs., The β decay of the semimagic Sn isotopes Sn136,137,138 has been studied at the Radioactive Isotope Beam Factory at the RIKEN Nishina Center. The first experimental information on excited states was obtained for Sb137 while, in the case of Sb136, the established excitation scheme could be extended by ten previously unidentified levels. In the decay of the most-neutron-rich isotope Sn138, two γ rays were observed for the first time. The new experimental results, in combination with state-of-the-art shell-model calculations, provide the first information with respect to the evolution of the 0g7/2 and 1d5/2 proton single-particle states with increasing neutron number beyond N=84., We thank the staff of the RIKEN Nishina Center accelerator complex for providing high-intensity beams to the experiment. This work was supported by the Spanish Ministerio de Ciencia e Innovación under contracts FPA2014-57196-C5-4-P and FPA2017-84756-C4-2-P and the UK Science and Technology Facilities Council under Grant No. ST/P005101/1. Zs.V. was supported by the European Regional Development Fund (Contract No. GINOP-2.3.3- 15-2016-00034), the National Research Development and Innovation Fund of Hungary (Grant No. K128947), and by RIKEN as short-term International Program Associate.

Published
2020

17. Isomeric and β -decay spectroscopy of Ho173,174

Author

P. Lee, Zs. Dombrádi, I. Nishizuka, P. M. Walker, C. M. Shand, Naohito Inabe, F. G. Kondev, Jinguang Wu, Zs. Vajta, Eiji Ideguchi, Jenny Lee, Shigeru Kubono, C. S. Lee, S. Kanaya, N. Kurz, Oliver J. Roberts, Ayumi Yagi, C. R. Nita, Atsuko Odahara, Zhengyu Xu, C. J. Griffin, Y. Shimizu, Z. Patel, G. X. Zhang, D. S. Ahn, H. Baba, V. H. Phong, Naoki Fukuda, Raymond J. Carroll, Hiroyoshi Sakurai, Gavin Lotay, S. Lalkovski, Zs. Podolyák, Toshiyuki Kubo, Shunji Nishimura, F. Browne, Eunji Lee, T. Isobe, A. Estrade, István Kuti, Satoru Terashima, G. J. Lane, Giuseppe Lorusso, Z. Korkulu, A. C. Dai, P. Doornenbal, P. H. Regan, Hiroshi Watanabe, H. Kanaoka, Furong Xu, Thamer Alharbi, H. Schaffner, K. Y. Chae, P. A. Söderström, Toshiyuki Sumikama, Hiroyuki Takeda, Alison Bruce, J. J. Valiente-Dobón, J. Liu, Chang-Bum Moon, Hiroshi Suzuki, and I. Kojouharov

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Physical chemistry, 010306 general physics, Spectroscopy, 01 natural sciences, Beta decay
Published
2020

18. Transition strengths in the neutron-rich Ni73,74,75 isotopes

Author

P. A. Söderström, T. Furumoto, K. Kaneko, D. Mengoni, J. J. Valiente-Dobón, K. Matsui, István Kuti, Nunzio Itaco, Yoshiaki Shiga, Zhengyu Xu, G. de Angelis, F. Browne, Dóra Sohler, S. Ceruti, A. Gargano, Zs. Vajta, D. R. Napoli, Rin Yokoyama, M. Yalcinkaya, L. Coraggio, Satoshi Takeuchi, H. Liu, R. Orlandi, V. Modamio-Hoybjor, Jinguang Wu, E. Sahin, L. Sinclair, Ryo Taniuchi, F. L. Bello Garrote, F. C. L. Crespi, T. Isobe, G. Benzoni, P. Doornenbal, Stephen Rice, A. Gottardo, Jenny Lee, Satoru Momiyama, Hiroshi Watanabe, D. Fang, Giuseppe Lorusso, Hiroyoshi Sakurai, Jan Taprogge, M. C. Delattre, Masafumi Matsushita, R. Avigo, Megumi Niikura, T. Motobayashi, B. Melon, O. Wieland, R. Daido, Zs. Dombrádi, H. Wang, N. Blasi, H. Baba, Toshiyuki Sumikama, Z. Patel, Shunji Nishimura, Tsuyoshi Miyazaki, and P. Van Isacker

Subjects
Physics, Proton, Isotope, 010308 nuclear & particles physics, Shell (structure), Coulomb excitation, 01 natural sciences, medicine.anatomical_structure, 0103 physical sciences, medicine, Neutron, Atomic physics, 010306 general physics, Nucleus, Excitation, Line (formation)
Abstract

Reduced transition probabilities have been measured for the neutron-rich Ni73,74,75 nuclei with relativistic Coulomb excitation performed at the RIKEN Nishina Center. For the even-even Ni isotope the determined B(E2;0+→2+) value is compatible within errors with the result of a previous intermediate energy Coulomb excitation experiment, although being somewhat larger. For the odd Ni isotopes B(E2) values have been determined for the first time. In the middle νg9/2 shell nucleus Ni73 three peak candidates have been observed and tentatively assigned to the (5/2+), (13/2+), and (11/2+) excitations. Two peak candidates have been observed in Ni75 and tentatively assigned to the (13/2+) and (11/2+) levels. The measured B(E2) values are in line with the large B(E2) reported in Ni70 and at variance with the small strength measured in Ni72. Excitation energies compare well with the result of large-scale shell-model calculations, while B(E2) values are larger than predicted. This could indicate an increasing contribution of proton excitations across the Z=28 shell closure when approaching Ni78.

Published
2020

19. Spectroscopy of Cd99 and In101 from β decays of In99 and Sn101

Author

F. Browne, Zhengyu Xu, I. Kojouharov, Y. F. Fang, A. Blazhev, Jinguang Wu, D. S. Ahn, Roman Gernhäuser, P. A. Söderström, D. Kameda, B. Blank, Igor T. Čeliković, T. Isobe, Shunji Nishimura, R. Krücken, H. Schaffner, M. Górska, P. Doornenbal, Z. Wang, I. Nishizuka, Toshiyuki Kubo, Stephen Rice, D. Lubos, K. Steiger, S. Ilieva, M. M. Rajabali, Naohito Inabe, Joochun Park, Young-Ki Kim, Younghun Kwon, A. Jungclaus, Hiroshi Suzuki, Hirofumi Watanabe, Y. Shimizu, T. Faestermann, H. Grawe, N. Kurz, P. Boutachkov, Naoki Fukuda, L. Sinclair, Giuseppe Lorusso, H. Baba, N. Goel, Hiroyoshi Sakurai, Toshiyuki Sumikama, K. Moschner, J. Giovinazzo, Hiroyuki Takeda, G. D. Kim, Daichi Murai, M. Lewitowicz, and Zena Patel

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Excited state, 0103 physical sciences, SHELL model, Atomic physics, 010306 general physics, Spectroscopy, Branching (polymer chemistry), 01 natural sciences, Coincidence, Spectral line
Abstract

We report on new γ-ray spectroscopy results from β decays of In99 and Sn101. 30 new γ rays were observed following the β decay of In99, and inconsistencies in the literature with respect to the γ rays following the β decay of Sn101 were addressed with two confirmed cases and two new transitions. The experimental γ-ray energies, intensities, and coincidence relationships are discussed with shell model calculations, where theoretical β-decay branching ratios from the parent nuclei and γ-ray cascades of excited states from the daughter nuclei were combined to generate hypothetical βγ spectra and βγγ coincidence matrices. The most intense β-delayed γ-ray branches in both Cd99 and In101 were well reproduced with this approach, and several γ rays were assigned to new excited states based on their good agreement with shell model predictions.

Published
2020

20. Metastable States of Se92,94 : Identification of an Oblate K Isomer of Se94 and the Ground-State Shape Transition between N=58 and 60

Author

L. Olivier, I. Kojouharov, G. Authelet, J. M. Gheller, V. Lapoux, Jenny Lee, J.-Y. Roussé, J. Gerl, C. Lizarazo, N. Paul, Noritsugu Nakatsuka, Hiroyoshi Sakurai, H. Schaffner, P. M. Walker, Zi Hong Liu, V. Werner, David Steppenbeck, T. Motobayashi, A. Blazhev, P. Doornenbal, Shunji Nishimura, I. Stefan, M. L. Cortés, T. Arici, J. J. Liu, Tomás R. Rodríguez, Alison Bruce, A. Giganon, C. Santamaria, F. Château, Megumi Niikura, Zhengyu Xu, F. Browne, Tomohiro Uesaka, M. Rudigier, C. R. Niţă, P. A. Söderström, Zena Patel, T. Saito, N. Kurz, M. Górska, S. Franchoo, A. Gillibert, G. X. Dong, A. Gottardo, C. M. Shand, Satoru Momiyama, L. X. Chung, C. R. Nobs, B. D. Linh, S. Nagamine, Ryo Taniuchi, A. Obertelli, M. Dewald, K. Moschner, Kathrin Wimmer, H. Baba, R. J. Caroll, D. Calvet, F. Flavigny, Bing Ding, Zs. Podolyák, Furong Xu, Toshiaki Ando, Si-Ge Chen, Victor Vaquero, M. Lettmann, A. Corsi, Norbert Pietralla, and A. Delbart

Subjects
Physics, 010308 nuclear & particles physics, General Physics and Astronomy, chemistry.chemical_element, Germanium, 01 natural sciences, Hafnium, medicine.anatomical_structure, chemistry, Atomic orbital, Metastability, 0103 physical sciences, Physics::Atomic and Molecular Clusters, medicine, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Spectroscopy, Nucleus
Abstract

Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of β∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band.

Published
2020

21. β -decay half-lives of 55 neutron-rich isotopes beyond the N=82 shell gap

Author

Hiroyoshi Sakurai, Trevor M. Sprouse, Atsuko Odahara, J. M. Daugas, Hiroki Nishibata, R. Daido, B. Moon, Shunji Nishimura, L. Sinclair, Y. F. Fang, Y. Wakabayashi, Ayumi Yagi, Toshiyuki Sumikama, Matthew Mumpower, I. Kojouharov, Rin Yokoyama, P. A. Söderström, D. Kameda, Hiroyuki Takeda, Stephen Rice, K. Y. Kwon, M. Haroon, D. S. Ahn, R. Lozeva, Giuseppe Lorusso, Zena Patel, Daichi Murai, Peter Möller, H. Baba, T. Ishigaki, P. Doornenbal, F. L. Bello Garrote, N. Kurz, Jin Wu, K. Tshoo, Hirofumi Watanabe, Y. Shimizu, Chang-Bum Moon, Naoki Fukuda, Hyo Soon Jung, F. Didierjean, Tetsuro Komatsubara, F. Browne, Toshiyuki Kubo, Hiroshi Suzuki, S. Morimoto, Naohito Inabe, T. Isobe, H. Schaffner, Zhengyu Xu, and Momoko Tanaka

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Fission, Shell (structure), Context (language use), 01 natural sciences, 7. Clean energy, Nuclear physics, 13. Climate action, Nucleosynthesis, 0103 physical sciences, Level structure, Neutron, 010306 general physics, Beam (structure)
Abstract

The $\beta$-decay half-lives of 55 neutron-rich nuclei $^{134-139}$Sn, $^{134-142}$Sb, $^{137-144}$Te, $^{140-146}$I, $^{142-148}$Xe, $^{145-151}$Cs, $^{148-153}$Ba, $^{151-155}$La were measured at the Radioactive Isotope Beam Factory (RIBF) employing the projectile fission fragments of $^{238}$U. The nuclear level structure, which relates to deformation, has a large effect on the half-lives. The impact of newly-measured half-lives on modeling the astrophysical origin of the heavy elements is studied in the context of $r$ process nucleosynthesis. For a wide variety of astrophysical conditions, including those in which fission recycling occurs, the half-lives have an important local impact on the second ($A$ $\approx$ 130) peak.

Published
2020

22. Shape evolution of neutron-rich Mo106,108,110 isotopes in the triaxial degree of freedom

Author

I. Nishizuka, Hiroyoshi Sakurai, S. Choi, Eiji Ideguchi, Stephen Rice, Nobuyuki Chiga, T. Isobe, Hiroki Nishibata, Toshiyuki Sumikama, F. Browne, D. Kameda, Alison Bruce, V. Werner, G. Gey, I. Kojouharov, G. S. Simpson, Zhou Li, Jinguang Wu, S. Lalkovski, Zhengyu Xu, Naohito Inabe, Raymond J. Carroll, P. H. Regan, Ayumi Yagi, Shin-Ichiro Nishimura, P. Doornenbal, Giuseppe Lorusso, Zs. Podolyák, Jan Taprogge, Nobuo Hinohara, Oliver J. Roberts, H. Baba, Naoki Fukuda, J. H. Ha, F. Didierjean, R. Daido, L. Sinclair, Hiroshi Suzuki, O. Wieland, Hirofumi Watanabe, Momoko Tanaka, Y. F. Fang, N. Kurz, P. A. Söderström, H. Schaffner, R. Lozeva, Atsuko Odahara, Zena Patel, Takashi Kubo, and H. Takeda

Subjects
Mass number, Physics, 010308 nuclear & particles physics, Nuclear structure, Moment of inertia, 7. Clean energy, 01 natural sciences, Molecular physics, Excited state, 0103 physical sciences, Quadrupole, Neutron, 010306 general physics, Spectroscopy, Wave function
Abstract

Background: Neutron-rich nuclei with mass number between 100 and 110 attract much attention, since several kinds of shapes, such as spherical, prolate, oblate, and triaxial shapes, are predicted. In particular, for neutron-rich Mo isotopes, different models predict different magnitudes and rigidity of triaxial deformation. Previous interpretations of experimental results based solely on low-lying 2+2 states are insufficient to distinguish between the rigid triaxial shape, γ vibration, or γ -soft rotor. Purpose: The shape evolution of 106Mo, 108Mo, and 110Mo is investigated through their 2+1-state lifetimes, decay-branching ratios of the 2+2 state, and energies of the low-lying collective excited states with Kπ = 0+, 2+, and 4+. Method: β -delayed γ -ray spectroscopy was employed for neutron-rich Nb and Zr isotopes produced at the RIKEN RI Beam Factory to populate excited states in 106Mo , 108Mo , and 110Mo . The EUroball-RIKEN Cluster Array was used for high-resolution γ -ray detection and lifetimes of the 2+1 states were determined using the UK fast-timing array of LaBr3(Ce) detectors. Results: New γ -ray transitions and levels are reported, including newly assigned 0+2 states in 108,110Mo . Quadrupole deformations were obtained for 106,108,110Mo from their 2+1 energies and lifetimes. The β -delayed neutron-emission probabilities of 108 Nb and 110 Nb were determined by examining the γ rays of their respective daughter decays. Conclusions: The even-odd energy staggering in the 2+2 band was compared with typical patterns of the γ -vibrational band, rigid triaxial rotor, and γ -soft rotor. The very small even-odd staggering of 106 Mo, 108Mo, and 110Mo favors a γ -vibrational band assignment. The kinematic moment of inertia for the 2+2 band showed a trend similar to the ground-state band, which is as expected for the γ -vibrational band. Beyond-mean-field calculations employing the constrained Hartree-Fock-Bogoliubov and local quasiparticle-random-phase approximation method using the SLy 5 + T interaction reproduced the ground and 2+2 bands in 106Mo and 108Mo . The collective wave functions are consistent with the interpretation of the 2+2 band as the γ -vibrational band of the prolate shape. However, the staggering pattern observed in 110Mo differs from the one suggested in the calculations which predict a γ -soft rotor. There was no experimental indication of the oblate shape or the γ -soft rotor predicted in these Mo isotopes.

Published
2020

23. Shell structure of the neutron-rich isotopes Co69,71,73

Author

M. Lettmann, A. Gillibert, Alessandra Corsi, David Steppenbeck, S. Leblond, Yoshiaki Shiga, K. Yoshida, Toshiyuki Sumikama, Ryo Taniuchi, A. Gottardo, F. Nowacki, Jenny Lee, V. Lapoux, Yuya Kubota, C. Péron, A. Delbart, Shunji Nishimura, G. Authelet, Si-Ge Chen, P. A. Söderström, C. Louchart, J. M. Gheller, T. Miyazaki, Alan Peyaud, C. M. Shand, Satoshi Takeuchi, Masafumi Matsushita, F. Giacoppo, H. Baba, Satoru Momiyama, S. Franchoo, E. Sahin, Zhenci Xu, Jinguang Wu, Shuichi Ota, V. Werner, Hideaki Otsu, Alfredo Poves, L. X. Chung, Megumi Niikura, C. Santamaria, Tomohiro Uesaka, I. Stefan, K. Matsui, P. Doornenbal, Kazuyuki Ogata, F. Browne, Masaki Sasano, Zs. Dombrádi, Shoko Koyama, Z. Korkulu, Zs. Vajta, K. Hadynska-Klek, T. Lokotko, Z. Patel, L. Olivier, H. Wang, R. Lozeva, A. Obertelli, Hiroyoshi Sakurai, T. Motobayashi, E. C. Pollacco, J.-Y. Roussé, D. Calvet, T. Isobe, F. Château, and Daisuke Suzuki

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear structure, Impulse (physics), 7. Clean energy, 01 natural sciences, Coincidence, Nuclear physics, MINOS, 0103 physical sciences, Neutron, Detector array, Nuclear Experiment, 010306 general physics, Excitation
Abstract

The structures of the neutron-rich Co69,71,73 isotopes were investigated via (p,2p) knockout reactions at the Radioactive Isotope Beam Factory, RIKEN. Isotopes of interest were studied using the DALI2 γ-ray detector array combined with the MINOS target and tracker system. Level schemes were reconstructed using the γ-γ coincidence technique, with tentative spin-parity assignments based on the measured inclusive and exclusive cross sections. Comparison with shell-model calculations using the Lenzi-Nowacki-Poves-Sieja LNPS and PFSDG-U interactions suggests coexistence of spherical and deformed shapes at low excitation energies in the Co69,71,73 isotopes. The distorted-wave impulse approximation (DWIA) framework was used to calculate the single-particle cross sections. These values were compared with the experimental findings.

Published
2020

24. Shell evolution of $N=40$ isotones towards $^{60}$Ca: First spectroscopy of $^{62}$Ti

Author

Masaki Sasano, S. M. Lenzi, Kazuki Yoshida, E. Sahin, V. Wagner, Hiroyoshi Sakurai, F. Nowacki, T. Isobe, W. Rodriguez, P. Doornenbal, Donghang Yan, D. Kim, T. Motobayashi, M.L. Cortés, Jason D. Holt, V. Lapoux, D. M. Rossi, Toshio Kobayashi, F. Flavigny, A. Giganon, B. D. Linh, F. Château, V. Panin, H. Baba, N. Paul, L. X. Chung, D. Calvet, X. X. Xu, David Steppenbeck, V. Werner, Igor Gašparić, H. N. Liu, A. Delbart, Yosuke Kondo, Si-Ge Chen, L. Achouri, Julien Gibelin, Tomohiro Uesaka, J. M. Gheller, A. Corsi, S. R. Stroberg, Alfredo Poves, Achim Schwenk, Satoshi Takeuchi, Thomas Aumann, R.-B. Gerst, C. Lehr, Jenny Lee, Yasuhiro Togano, C. Hilaire, Y.L. Sun, P. Koseoglou, Nobuyuki Chiga, K. Yoneda, F. Browne, Victor Vaquero, Yuya Kubota, T. Lokotko, T. Koiwai, Zaihong Yang, Takashi Nakamura, S. Wang, J. Simonis, I. Murray, Javier Fernandez Menendez, A. Obertelli, Kazuyuki Ogata, A. Gillibert, H. Toernqvist, M. MacCormick, Masahiro Yasuda, Hideaki Otsu, K. I. Hahn, L. Stuhl, O. Aktas, Hirofumi Yamada, Dóra Sohler, S. Franchoo, Tomás R. Rodríguez, L. Zanetti, K. Moschner, Kathrin Wimmer, S. Y. Park, P. A. Söderström, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), UAM. Departamento de Física Teórica, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), RIKEN Nishina Center for Accelerator-Based Science, Japan Society for the Promotion of Science, Ministerio de Ciencia, Innovación y Universidades (España), Ministry of Science and Technology of Vietnam, Helmholtz International Center for FAIR, Croatian Science Foundation, National Research, Development and Innovation Office (Hungary), Ministerio de Economía y Competitividad (España), National Research Foundation of Korea, European Commission, Natural Sciences and Engineering Research Council of Canada, Federal Ministry of Education and Research (Germany), and National Research Council of Canada

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Ab initio, FOS: Physical sciences, Shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Radioactive beams, Gamma-ray spectroscopy, Nuclear Theory (nucl-th), 0103 physical sciences, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Island of inversion, Isotone, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Física, lcsh:QC1-999, Excited state, Quadrupole, Atomic physics, Nucleon, Ground state, lcsh:Physics
Abstract

7 pags., 4 figs., 1 tab., Excited states in the N=40 isotone Ti were populated via the V(p,2p)Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 2 →0 and 4 →2 transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring Cr and Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for Ti show a dominant configuration with four neutrons excited across the N=40 gap. Likewise, they indicate that the N=40 island of inversion extends down to Z=20, disfavoring a possible doubly magic character of the elusive Ca., We thank the RIKEN Nishina Center accelerator staff and the Bi-gRIPS team for the stable operation of the high-intensity Zn beam and for the preparation of the secondary beam setting. K.O. ac-knowledges the support by Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science (JSPS) JP16K05352. A.P. is supported in part by the Ministerio de Ciencia, Innovación y Universidades (Spain), Severo Ochoa Programme SEV-2016-0597 and grant PGC-2018-94583. F.B. is supported by the RIKEN Spe-cial Postdoctoral Researcher Program. L.X.C. and B.D.L. would like to thank the Vietnam Ministry of Science and Technology (MOST) for its support through the Physics Development Program Grant No. ÐTÐLCN.25/18. I.G. has been supported by HIC for FAIR and Croatian Science Foundation under projects no. 1257 and 7194. D. So. was supported by the the European Regional Develop-ment Fund contract No. GINOP-2.3.3-15-2016-00034 and the National Research, Development and Innovation Fund of Hungary via Project No. K128947. V.V. acknowledges support from the Span-ish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. K.I.H., D.K. and S.Y.P. acknowledge the sup-port from the National Research Foundation of Korea grant No. 2018R1A5A1025563 and 2019M7A1A1033186. The development of MINOS was supported by the European Research Council through the ERC Grant No. MINOS-258567. This work was also supported by the JSPS KAKENHI Grant No. 18K03639, MEXT as “Priority is-sue on post-K computer” (Elucidation of the fundamental laws and evolution of the universe), the Joint Institute for Computational Fundamental Science (JICFuS), the CNS-RIKEN joint project for large-scale nuclear structure calculations, Natural Sciences and Engineering Research Council (NSERC) of Canada, the Deutsche Forschungsgemeinschaft – Projektnummer 279384907 – SFB 1245, the PRISMA Cluster of Excellence, and the BMBF under Contracts No. 05P18RDFN1 and 05P19RDFN1. TRIUMF receives funding via a contribution through the National Research Council Canada. Com-putations were performed at the Jülich Supercomputing Center (JURECA)

Published
2020

25. Experimental study of 4 n with 8He(p,2p) reaction

Author

M. Böhmer, Masaki Sasano, S. Reichert, Naohito Inabe, S. Chen, T. Shimada, M. Matsumoto, Susumu Shimoura, I. Stefan, J. Kahlbow, N. Kalantar-Nayestanaki, T. Harada, D. Symochko, István Kuti, S. W. Huang, D. Cortina, Tomohiro Uesaka, Z. Ge, N. L. Achouri, Yosuke Kondo, Hiroyuki Takeda, K. Yoneda, B. Fernández-Domínguez, U. Forsberg, Z. Elekes, Roman Gernhäuser, Y. Yasuda, H. Suzuki, Yohei Shimizu, D. Beaumel, D. Kim, C. A. Douma, Yukie Maeda, A. Hirayama, J. M. Gheller, Heiko Scheit, F. Dufter, T. Elidiano, Yasuhiro Togano, M. L. Cortés, M. Potlog, Nobuyuki Chiga, P. J. Li, Juzo Zenihiro, B. Yang, T. Isobe, M. Caamaño, Thomas Aumann, H. T. Törnqvsit, A. Gillibert, D. S. Ahn, F. Schindler, M.N. Harakeh, J. Feng, J. Tscheuschner, S. Kim, Atsumi Saito, L. Zanetti, P. Koseoglou, V. Wagner, M. Parlog, B. M. Godoy, N. Orr, Takashi Nakamura, Yu-xin Liu, J. Mayer, A. Obertelli, Yuya Kubota, Hideaki Otsu, S. Storck, S. Masuoka, K. Boretzky, Kathrin Wimmer, H. Miki, T. Tomai, F. M. Marqués, V. Panin, P. Doornenbal, Stefanos Paschalis, L. Yang, Satoshi Takeuchi, M. A. Knösel, Igor Gašparić, T. Kobayashi, C. Lehr, H. Yang, C. Lenain, M. Miwa, Z. Halász, A. Revel, H. Sato, T. Fujino, D. M. Rossi, H. Baba, S. Park, I. Murray, L. Stuhl, H. Yamada, J. Gibelin, J. Tanaka, Naoki Fukuda, RIKEN Nishina Center for Accelerator-Based Science, German Research Foundation, Federal Ministry of Education and Research (Germany), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Paper, History, 010308 nuclear & particles physics, tetraneutron, nuclear force, proton knock-out, radioactive beams, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Computer Science Applications, Education, ddc, Nuclear physics, 0103 physical sciences, Tetraneutron, Neutron, ddc:530, 010306 general physics
Abstract

7 pags., 3 figs. -- 27th International Nuclear Physics Conference (INPC2019), The tetraneutron has attracted the attention of nuclear physicists during the past decades, but there is still no unambiguous confirmation of its existence or nonexistence. A new experiment based on 8 He(p,2p)7H{t+4n} reaction, with direct detection of the four neutrons, has been carried out at RIBF, which can hopefully help to draw a definite conclusion on the tetraneutron system., We acknowledge the support of the RIBF accelerator staff and the BigRIPS team for providing the high-quality beam. Z. H. Yang acknowledges the financial support from the Foreign Postdoctoral Researcher program of RIKEN. T. Aumann acknowledges the support by DFG via SFB 1245. P. Koseoglou acknowledges the support from BMBF (NUSTAR.DA grant No.05P 15RDFN1).

Published
2020

26. Spectroscopy of the Most Exotic Nuclei with SEASTAR at the RIBF

Author

Alexandre Obertelli and P. Doornenbal

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, Spectroscopy, 01 natural sciences
Published
2018

27. Spectroscopy of 2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

K. Matsui, H. Otsu, W.Q. Zhang, J.-Y. Roussé, Tadaaki Isobe, R. Lozeva, X.H. Zhou, Satoshi Takeuchi, X.Y. Liu, E. Sahin, Shunpei Koyama, P. Doornenbal, S. Franchoo, Zs. Dombradi, F. Nowacki, Shuichi Ota, C. Santamaria, A. Obertelli, A. Gottardo, Daisuke Suzuki, K. Hadynska-Klek, Jin Wu, L. X. Chung, Masaki Sasano, Ryo Taniuchi, Hiroyoshi Sakurai, Jenny Lee, K. Yoneda, Megumi Niikura, H.S. Xu, P. A. Söderström, C. Louchart, T. Motobayashi, Tomohiro Uesaka, Yuya Kubota, C. Péron, Tsuyoshi Miyazaki, H. Lu, G. Authelet, G. L. Stefan, V. Werner, B. D. Linh, F. Château, A. Delbart, J. M. Gheller, A. Gillibert, C. M. Shand, H. Wang, Z. Liu, S. Nishimura, Zs. Vajta, Philip M Walker, Masafumi Matsushita, Satoru Momiyama, M. Lettmann, F. Browne, S. M. Lenzi, Yoshiaki Shiga, Toshiyuki Sumikama, L. Olivier, E. C. Pollacco, Feng-Shou Zhang, F. Giacoppo, David Steppenbeck, V. Lapoux, T.H. Huang, Zena Patel, H. Baba, M. D. Sun, Y.H. Zhang, D. Calvet, Zhengyu Xu, Alan Peyaud, B. Ding, A. Corsi, Z. Korkulu, Y.H. Lam, and De-fu Hou

Subjects
Physics, Coupling, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Island of inversion, Nuclear structure, Decoupling (cosmology), 01 natural sciences, Molecular physics, Excited state, 0103 physical sciences, Neutron, 010306 general physics, Spectroscopy, Line (formation)
Abstract

Excited states in 63,65,67Mn were studied via in-beam γ-ray spectroscopy following knockout reactions from 68Fe. Similar level schemes, consisting of the 11/2−, 9/2−, 7/2− and 5/2 g.s.− level sequence, connected by I→I−1 transitions, were established, the first time for 65,67Mn. Their level structures show features consistent with strongly-coupled rotational bands with K=5/2 . State-of-the-art shell-model calculations with the modified LNPS effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole neutron configurations for all the states. The data on the low-lying excited states of odd-mass 53−67Mn provide a textbook example of nuclear structure evolution from weak coupling through decoupling to strong coupling along a single isotopic chain on the n-rich side of the β stability line. These results help to deepen our understanding of the N=40 “island of inversion”.

Published
2018

28. The (6+) isomer in 102Sn revisited: Neutron and proton effective charges close to the double shell closure

Author

Shunji Nishimura, Yu. A. Litvinov, T. Davinson, H. J. Wollersheim, F. Nebel, K. Straub, T. Habermann, S. Schwertel, T. Faestermann, Igor T. Čeliković, P. Boutachkov, F. Farinon, C. Hinke, P. Strmeň, Hans Geissel, H. Schaffner, M. Karny, F. Nowacki, M. Lewitowicz, H. Grawe, N. Kurz, M. Górska, P. A. Söderström, G. F. Farrelly, Andreas Stolz, Zs. Podolyák, A. Atac, J. Grȩbosz, A. Prochazka, Robert Hoischen, I. Kojouharov, R. Janik, C. Scheidenberger, P. J. Woods, P. H. Regan, S. J. Steer, S. Pietri, S. Myalski, N. Braun, Roman Gernhäuser, M. Böhmer, A. Blazhev, N. Al-Dahan, Johan Nyberg, R. Krücken, A. Kaşkaş, J. Gerl, N. Alkhomashi, L. Maier, N. Goel, C. Nociforo, A. Gottardo, Zhi Liu, Catherine Rigollet, C. Domingo-Pardo, Helmut Weick, P. Doornenbal, Iris Dillmann, A. Parikh, K. Steiger, Th. Kröll, CoSee GmbH [Darmstadt], Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, Polish Academy of Sciences (PAN), Department of Physics, University of Surrey, University of Surrey (UNIS), Department of Physics, Faculty of Science, Middle East Technical University, Ankara, Turkey, Department of Fusion Plasma Physics [Stockholm] (KTH), Royal Institute of Technology [Stockholm] (KTH ), University of Cologne, Vinča Institute of Nuclear Sciences, University of Belgrade [Belgrade], Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Comenius University in Bratislava, University of Warsaw (UW), Faculty of Science Astronomy, Ankara University, Tandogan Ankara, TR-06100 Turkey, obasturk@ankara.edu.tr, Polska Akademia Nauk = Polish Academy of Sciences (PAN), RIKEN Nishina Center for Accelerator-Based Science [Wako] (RIKEN RNC), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Uppsala Universitet [Uppsala], Kernfysisch Versneller Instituut (KVI), University of Groningen [Groningen], Uppsala University, Michigan State University [East Lansing], Michigan State University System, RISING, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Blank, B., and Technische Universität München [München] (TUM)

Subjects
Sn, Nuclear and High Energy Physics, Proton, QC1-999, SHELL model, Closure (topology), Shell (structure), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Space (mathematics), 01 natural sciences, Subatomär fysik, Shell model, Fragmentation (mass spectrometry), Subatomic Physics, 0103 physical sciences, ddc:530, Neutron, 010306 general physics, Effective charges near Sn, Physics, 010308 nuclear & particles physics, Effective charges near, Polarization (waves), ddc, Effective charges near Sn-100, Electromagnetic transitions, Effective charges near 100Sn, Atomic physics
Abstract

Physics letters / B 820, 136591 (2021). doi:10.1016/j.physletb.2021.136591, Published by North-Holland Publ., Amsterdam

Published
2021

29. Isomer spectroscopy of neutron-rich 168Tb103

Author

J. J. Valiente-Dobón, Hiroyoshi Sakurai, P. H. Regan, K. Y. Chae, H. L. Liu, P. Lee, A Yag, V. H. Phong, Zhengyu Xu, H. Baba, Shigeru Kubono, Gavin Lotay, Eunji Lee, Shunji Nishimura, I. Nishizuka, Furong Xu, H. Kanaoka, Eiji Ideguchi, N. Kurz, C-B Moon, Zs. Vajta, C. S. Lee, Philip M Walker, W. N. Catford, C. J. Griffin, F. G. Kondev, Naoki Fukuda, Raymond J. Carroll, T. Isobe, L. A. Gurgi, Alison Bruce, Atsuko Odahara, J. J. Liu, Toshiyuki Kubo, S. Yoshida, Jin Wu, Thamer Alharbi, P-A Soderstrom, István Kuti, Satoru Terashima, C. R. Nita, C. M. Shand, Oliver J. Roberts, Gregory Lane, Giuseppe Lorusso, Zs. Dombrádi, Zena Patel, Zsolt Podolyak, S. Lalkovski, P. Doornenbal, H. Schaffner, Toshiyuki Sumikama, T. Berry, F. Browne, Hiroshi Suzuki, I. Kojouharov, Hiroyuki Takeda, A. Estrade, Naohito Inabe, Hirofumi Watanabe, Z. Korkulu, and G. X. Zhang

Subjects
Radiation, Spectrometer, 010308 nuclear & particles physics, Chemistry, Fission, Nuclear Theory, chemistry.chemical_element, Germanium, 01 natural sciences, Semiconductor detector, Nuclear physics, Excited state, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Spectroscopy
Abstract

In-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm thick 9Be target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus 170Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified eventby- event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent β-decay. Discrete γ-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3)

Published
2017

30. Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84 Zn

Author

L. Olivier, K. Moschner, Kathrin Wimmer, E. C. Pollacco, A. Gillibert, C. R. Nita, C. M. Shand, J.-Y. Roussé, Satoru Momiyama, M. Lettmann, Jian Liu, A. Jungclaus, Hideaki Otsu, Z. Korkulu, Ryo Taniuchi, C. Péron, David Steppenbeck, A. Blazhev, Tsuyoshi Miyazaki, G. Authelet, K. Matsui, Satoshi Takeuchi, A. Château, A. Obertelli, F. Nowacki, S. Franchoo, Kamila Sieja, Toshiaki Ando, J. M. Gheller, Alan Peyaud, Jin Wu, L. X. Chung, Shuichi Ota, C. R. Nobs, B. D. Linh, Zs. Vajta, Y. Kubota, Megumi Niikura, M. Rudigier, I. Stefan, H. Wang, R. Orlandi, J. A. Tostevin, Takaharu Otsuka, Si-Ge Chen, P. A. Söderström, Tomohiro Uesaka, C. Lizarazo, S. Nishimura, Zs. Dombradi, Toshiyuki Sumikama, K. Hadynska-Klek, M. Nagamine, Yusuke Tsunoda, T. Isobe, E. Sahin, C. Louchart, Hiroyoshi Sakurai, V. Lapoux, C. Santamaria, T. Motobayashi, Victor Vaquero, F. Giacoppo, T. Arici, A. Corsi, Zena Patel, P. Doornenbal, Masafumi Matsushita, A. Delbart, P. H. Regan, M. Dewald, Zsolt Podolyak, A. Giganon, A. Gottardo, Jenny Lee, F. Flavigny, M. Górska, N. Paul, Noritsugu Nakatsuka, M. L. Cortés, Zi Hong Liu, V. Werner, Raymond J. Carroll, Daisuke Suzuki, D. Calvet, M. Sasano, Bing Ding, Shoko Koyama, Zhengyu Xu, T. Saito, Alison Bruce, R. Lozeva, K. Yoneda, F. Browne, H. Baba, Yoshiaki Shiga, SCOAP, RIKEN Nishina Center for Accelerator-Based Science, Science and Technology Facilities Council (UK), European Commission, European Research Council, Vietnam Academy of Science and Technology, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Isotope, 010308 nuclear & particles physics, SHELL model, Analytical chemistry, Shell (structure), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, lcsh:QC1-999, Atomic orbital, Neutron number, 0103 physical sciences, ddc:530, Atomic physics, 010306 general physics, Spectroscopy, lcsh:Physics
Abstract

C.M. Shand et al. -- 6 pags., 3 figs., tab. --Open Access funded by Creative Commons Atribution Licence 4.0, We report on the measurement of new low-lying states in the neutron-rich Zn nuclei via in-beam γ-ray spectroscopy. These include the 4 →2 transition in Zn, the 2 →0 and 4 →2 transitions in Zn, and low-lying states in Zn were observed for the first time. The reduced E(2 ) energies and increased E(4 )/E(2 ) ratios at N=52, 54 compared to those in Zn attest that the magicity is confined to the neutron number N=50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2 and 4 levels in Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models., All UK authors are supported by the Science and Technology Facilities Council (STFC). The development of MINOS and the core MINOS team have been supported by the European Research Council through the ERC Grant No. MINOS-258567. A. Jungclaus was supported by the Spanish Ministerio de Economía y Competitividad under contract FPA2014-57196-C5-4-P. Authors from Cologne were supported by German BMBF Grant No. 05P15PKFNA. Authors from TU Darmstadt were supported by German BMBF Grant No. 05P12RDFN8 and 05P15RDFN1. L.X. Chung and B.D. Linh would like to acknowledge Vietnam Ministry of Science and Technology for the support, and Radioactive Isotope Physics Laboratory of the RIKEN Nishina Center for supporting their stay during the experiments.

Published
2017

31. Single-neutron knockout from 20C and the structure of 19C

Author

T. Kubo, K. Yoneda, S. K. Kim, D. Kameda, Hiroshi Suzuki, T. Isobe, Takashi Nakamura, Y. Satou, Jongmin Lee, P. Doornenbal, Nagao Kobayashi, H. Baba, Ryuki Tanaka, T. Nakashima, S. Ogoshi, R. Minakata, H. Takeda, Toshio Kobayashi, Y. Shimizu, N. A. Orr, D. Kanno, Noritsugu Nakatsuka, Marine Vandebrouck, S. Leblond, K. Takahashi, Yasuhiro Togano, Yosuke Kondo, Hideaki Otsu, Jongwon Hwang, Thomas Aumann, N. L. Achouri, Hirohiko Sato, Daichi Murai, Naoki Fukuda, A. G. Tuff, S. Nishi, T. Motobayashi, Julien Gibelin, K. Muto, Franck Delaunay, Satoshi Takeuchi, F. M. Marqués, T. Murakami, A. Navin, and Naohito Inabe

Subjects
Physics, Nuclear and High Energy Physics, Valence (chemistry), 010308 nuclear & particles physics, Nuclear Theory, Magnetic monopole, Heavy-ion knockout, Shell evolution, Halo nucleus, 01 natural sciences, lcsh:QC1-999, 3. Good health, 0103 physical sciences, Invariant mass spectroscopy, Level structure, ddc:530, Neutron, Invariant mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Ground state, lcsh:Physics
Abstract

The low-lying unbound level structure of the halo nucleus 19C has been investigated using single-neutron knockout from 20C on a carbon target at 280 MeV/nucleon. The invariant mass spectrum, derived from the momenta of the forward going beam velocity 18C fragment and neutrons, was found to be dominated by a very narrow near threshold ( E rel = 0.036 ( 1 ) MeV) peak. Two less strongly populated resonance-like features were also observed at E rel = 0.84 ( 4 ) and 2.31 ( 3 ) MeV, both of which exhibit characteristics consistent with neutron p-shell hole states. Comparisons of the energies, measured cross sections and parallel momentum distributions to the results of shell-model and eikonal reaction calculations lead to spin-parity assignments of 5 / 2 1 + and 1 / 2 1 − for the levels at E x = 0.62 ( 9 ) and 2.89 ( 10 ) MeV with S n = 0.58 ( 9 ) MeV. Spectroscopic factors were also deduced and found to be in reasonable accord with shell-model calculations. The valence neutron configuration of the 20C ground state is thus seen to include, in addition to the known 1 s 1 / 2 2 component, a significant 0 d 5 / 2 2 contribution. The level scheme of 19C, including significantly the 1 / 2 1 − cross-shell state, is well accounted for by the YSOX shell-model interaction developed from the monopole-based universal interaction.

Published
2017

32. Observation of isoscalar and isovector dipole excitations in neutron-rich 20 O

Author

K. Yoneda, Ryo Taniuchi, Susumu Shimoura, H. Baba, T. Murakami, J. Tsubota, R. Avigo, Hideaki Otsu, Yosuke Kondo, Agnese Giaz, Noritsugu Nakatsuka, C. Caesar, Takeo Kawabata, F. Camera, S. Ceruti, Y. L. Yamaguchi, Hooi Jin Ong, Kathrin Wimmer, A. Horvat, Juzo Zenihiro, J. Tscheuschner, T. Ozaki, Toshiyuki Sumikama, Takashi Nakamura, B. Million, H. Wang, F. Schindler, Hiroyuki Takeda, A. Bracco, Heiko Scheit, Hiroyoshi Sakurai, Tsuyoshi Ohnishi, Shoko Koyama, M. Shikata, I. Syndikus, N. Imai, T. Motobayashi, Kazuo Ieki, T. Inakura, Yoshiaki Shiga, V. Derya, Shuichi Ota, P. Doornenbal, Shoichiro Masuoka, Yasuhiro Togano, P. Schrock, Masafumi Matsushita, S. Michimasa, Oliver Wieland, Shao-Long Chen, David Steppenbeck, Atsumi Saito, Satoshi Takeuchi, S.R. Banerjee, Thomas Aumann, M. Kurata-Nishimura, Atsushi Tamii, and Nagao Kobayashi

Subjects
O20, Nuclear and High Energy Physics, Inelastic α scattering, Isoscalar, Nuclear Theory, Inelastic alpha scattering, 01 natural sciences, Nuclear physics, 0103 physical sciences, ddc:530, Neutron, Born approximation, 010306 general physics, Physics, Isovector, 010308 nuclear & particles physics, Inelastic α scattering, Low-energy dipole excitation, Virtual-photon excitation, lcsh:QC1-999, Dipole, O-20, Isospin, Excited state, (20)O, Sum rule in quantum mechanics, Atomic physics, lcsh:Physics
Abstract

The isospin characters of low-energy dipole excitations in neutron-rich unstable nucleus 20O were investigated, for the first time in unstable nuclei. Two spectra obtained from a dominant isovector probe (View the MathML sourceO20+Au) and a dominant isoscalar probe (View the MathML sourceO20+α) were compared and analyzed by the distorted-wave Born approximation to extract independently the isovector and isoscalar dipole strengths. Two known 1−1− states with large isovector dipole strengths at energies of 5.36(5) MeV (View the MathML source11−) and 6.84(7) MeV (View the MathML source12−) were also excited by the isoscalar probe. These two states were found to have different isoscalar dipole strengths, 2.70(32)% (View the MathML source11−) and 0.67(12)% (View the MathML source12−), respectively, in exhaustion of the isoscalar dipole-energy-weighted sum rule. The difference in isoscalar strength indicated that they have different underlying structures. ispartof: Physics Letters B vol:768 pages:387-392 status: published

Published
2017

33. Intruder configurations in the ground state of 30Ne

Author

Yosuke Kondo, Yutaka Utsuno, Jenny Lee, Hiroyoshi Sakurai, Handing Wang, Ka Li, David Steppenbeck, T. Motobayashi, Satoshi Takeuchi, Shin'ichiro Michimasa, Eiji Ideguchi, H. N. Liu, Nori Aoi, M. Takechi, H. Scheit, G Lee, H. Baba, J. A. Tostevin, Masafumi Matsushita, Yasuhiro Togano, P. Doornenbal, Nagao Kobayashi, and Alfredo Poves

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Island of inversion, Shell (structure), Intruder configurations, Space (mathematics), 01 natural sciences, lcsh:QC1-999, Momentum, Amplitude, One-neutron knockout reactions 12C(30Ne, 29Ne+γ)X, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Ground state, Excitation, lcsh:Physics
Abstract

We report on the first detailed study of intruder configurations in the ground state of 30 Ne by means of the 12 C( 30 Ne, 29 Ne+ γ )X one-neutron knockout reaction at 228 MeV/nucleon. Using a combined analysis of individual parallel momentum distributions and partial cross sections we find: (a) comparable p - and d -wave removal strength to 29 Ne final states with excitation energies below 200 keV, and (b) significant p -wave removal strength to the 620 keV state of 29 Ne, and (c) no evidence for f -wave intruder strength leading to bound 29 Ne final states. The SDPF-U-MIX shell model calculation in the sd–pf model space provides a better overall agreement with the measured energy levels of 29 Ne and the fp -intruder amplitudes in 30 Ne than the SDPF-M prediction, suggesting that the refinement of the sd–pf cross shell interaction and extension of the model space to include the 2p1/2 and 1f5/2 levels are important for understanding the island of inversion.

Published
2017

34. Half-lives of Sr73 and Y76 and the consequences for the proton dripline

Author

F. Browne, V. Werner, T. Isobe, Shin-Ichiro Nishimura, Hirofumi Watanabe, L. Sinclair, P. J. Davies, Toshiyuki Sumikama, Giuseppe Lorusso, D. Lubos, R. Wadsworth, Naoki Fukuda, Jacek Dobaczewski, Zena Patel, Peter Schury, Shigeru Kubono, P. A. Söderström, H. Baba, Hiroyoshi Sakurai, P. Doornenbal, I. Nishizuka, Z. H. Li, Jin Wu, Jack Henderson, Zhengyu Xu, D. G. Jenkins, D. S. Ahn, Alessandro Pastore, Y. F. Fang, Hiroshi Suzuki, A. Estrade, Stephen Rice, Y. Shimizu, and H. Takeda

Subjects
Physics, Proton, 010308 nuclear & particles physics, Proton decay, Nuclear Theory, 7. Clean energy, 01 natural sciences, Beta decay, Nuclear physics, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, medicine, Physics::Accelerator Physics, Density functional theory, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Beam (structure)
Abstract

The half-lives of seven nuclei have been determined in the neutron-deficient mass-70 region following their production via fragmentation of a 345 MeV/nucleon Xe124 primary beam on a 740 mg/cm2 Be9 target at the RI Beam Factory, RIKEN. The results include two new (Sr73 and Y76) half-lives and a more precise measurement for the ground-state half-life of Sr74. The new results are discussed with reference to previously published calculations that predict the location of the proton dripline in the light Sr and Y region of the nuclear chart. In addition, differences in the ground-state structure of Rb72 and Y76 are discussed with the aid of density functional theory calculations. These provide a possible explanation for why Rb72 undergoes proton decay while the α-conjugate nucleus Y76 predominantly undergoes β+ decay.

Published
2019

35. Properties of γ -decaying isomers in the Sn100 region populated in fragmentation of a Xe124 beam

Author

V. Werner, Torbjörn Bäck, Toshiyuki Sumikama, H. Grawe, K. Moschner, N. Warr, N. Kurz, T. Isobe, Giuseppe Lorusso, M. Górska, M. Dewald, P. J. Davies, F. Ameil, P. Doornenbal, A. Gengelbach, J. Gerl, Hyo Soon Jung, Shin-Ichiro Nishimura, H. Baba, F. Naqvi, E. Gregor, K. Steiger, P. A. Söderström, M. Lewitowicz, Daiki Nishimura, T. Faestermann, D. G. Jenkins, Jan Taprogge, Zhengyu Xu, H. Hotaka, P. Thöle, P. Boutachkov, Ayumi Yagi, H. Watanbe, R. Wadsworth, H. Schaffner, A. Blazhev, G. Häfner, R. Lozeva, Norbert Pietralla, J. Jolie, K. Yoshinaga, I. Kojouharov, E. Merchan, Hiroki Nishibata, Roman Gernhäuser, Shintaro Go, and Y. Zhu

Subjects
Physics, Microsecond, Ion beam, Fragmentation (mass spectrometry), 010308 nuclear & particles physics, 0103 physical sciences, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics, 01 natural sciences
Abstract

A systematic study was performed of microsecond γ-decaying isomers around Sn100 produced in a fragmentation reaction of a Xe124 beam at 345 MeV/u at the Radioactive Ion Beam Factory of the RIKEN Nishina Center in Saitama, Japan. Half-lives of isomeric states in that region were remeasured allowing us to improve the currently available experimental information. Reduced transition probabilities were deduced and compared to shell-model calculations in various model spaces. The recently reported low-energy transitions in Rh92 and Ag96 were remeasured with improved precision. Additionally, experimental information on isomeric ratios, including five new ones, were extracted and compared to a previous experimental study and the sharp cutoff model of fragmentation reaction.

Published
2019

36. Determination of beta-delayed neutron emission probability limits of rhodium isotopes by gamma-ray spectroscopy

Author

Shunji Nishimura, Naohito Inabe, Roman Gernhäuser, A. Boso, Z. H. Li, T. Isobe, Toshiyuki Kubo, H. Baba, F. G. Kondev, H. Schaffner, Megumi Niikura, Gary Simpson, G. Benzoni, F. C. L. Crespi, Hirofumi Watanabe, Zs. Vajta, Anna Wendt, Y. Shimizu, Atsuko Odahara, Jinguang Wu, A. Jungclaus, Hiroyoshi Sakurai, Hiroshi Suzuki, R. Orlandi, I. Kajouharov, Hyo Soon Jung, Zhengyu Xu, F. Browne, K. Yoshinaga, Jan Taprogge, Toshiyuki Sumikama, Guillaume Gey, Hiroyuki Takeda, P. H. Regan, G. J. Lane, Giuseppe Lorusso, Zena Patel, G. D. Kim, K. Moschner, S. Shibagaki, Bradley S. Meyer, R. Shearman, F. Naqvi, D. Kameda, Ayumi Yagi, P. Doornenbal, P. Schury, K. Steiger, Toshitaka Kajino, Young-Ki Kim, P. A. Söderström, Younghun Kwon, A. Montaner-Pizá, K. Y. Chae, N. Kurz, Naoki Fukuda, Zs. Podolyák, Hiroki Nishibata, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Science and Technology Facilities Council (UK), Department for Business, Energy and Industrial Strategy (UK), National Measurement System (UK), and Department of Energy (US)

Subjects
Paper, History, Fission, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Education, Nuclear physics, 0103 physical sciences, Gamma spectroscopy, Nuclear drip line, Nuclide, 010306 general physics, Nuclear Experiment, Physics, Isotope, 010308 nuclear & particles physics, 3. Good health, Computer Science Applications, ddc, chemistry, Physics::Accelerator Physics, Beryllium, Delayed neutron
Abstract

9 pags., 5 figs., 5 tabs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK, The decay of five neutron-heavy rhodium isotopes were studied at the Radioactive Isotope Beam Factory (RIBF) Facility at the RIKEN Nishina Center after relativistic fission of 238U beam on a thick beryllium target. Previously unknown associated gamma-ray decay energies are reported for each nuclide, and through evaluating the intensity of the 2+ → 0+ E2 transition in the even-even palladium daughter nuclei, 120,122,124Pd, from the beta-tagged gamma-ray spectra an upper or lower limit of beta-delayed neutron emission is deduced for each nuclei. A general, expected trend of increasing Pn is observed in the direction of the neutron drip line., This work was partially supported by the STFC UK (grant numbers ST/L005743/1 and ST/P005314) and UK Department of Business, Energy and Industrial Strategy (BEIS) via the National Measurement System. RS thanks the Nuclear Decommissioning Authority (NDA) for the award of an NDA Bursary. FGK acknowledges funding by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

Published
2019

37. New and comprehensive β - and βp -decay spectroscopy results in the vicinity of Sn100

Author

Toshiyuki Sumikama, J. Giovinazzo, Hiroyuki Takeda, Hiroyoshi Sakurai, D. Kameda, Hidetada Baba, T. Faestermann, Stephen Rice, Y. Shimizu, Shunji Nishimura, T. Isobe, I. Kojouharov, S. Ilieva, P. Doornenbal, L. Sinclair, Young-Ki Kim, F. Browne, Y. F. Fang, Giuseppe Lorusso, Younghun Kwon, Hiroshi Watanabe, Igor T. Čeliković, Z. Wang, N. Goel, P. Boutachkov, Jinguang Wu, Joochun Park, K. Steiger, Bertram Blank, D. Lubos, Z. Patel, Naohito Inabe, A. Jungclaus, I. Nishizuka, Zhengyu Xu, Toshiyuki Kubo, Roman Gernhäuser, Mustafa Rajabali, Hiroshi Suzuki, A. Blazhev, P. A. Söderström, D. S. Ahn, G. D. Kim, Daichi Murai, M. Lewitowicz, R. Krücken, H. Schaffner, K. Moschner, H. Grawe, N. Kurz, M. Górska, and Naoki Fukuda

Subjects
Physics, Spins, 010308 nuclear & particles physics, Nuclear structure, 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Neutron, Proton emission, Nuclear Experiment, 010306 general physics, Spectroscopy, Excitation
Abstract

A decay spectroscopy experiment on proton-rich nuclei in the vicinity of the doubly magic Sn100 was carried out at RIKEN Nishina Center. More than 20 nuclei with 43≤Z≤50 and N≤51, produced by fragmentation reactions were investigated via analyses of β-decay, βp-decay, and subsequent γ-ray data. Owing to higher statistics, the precision on the half-lives of many of the ground states and isomers was improved. β-decay endpoint energies of 11 states in 8 nuclei were measured for the first time, and the corresponding QEC and excitation energies were generally consistent with various mass models. Many β-delayed proton emission branching ratios were measured either for the first time or with higher precision compared to literature values, and some of them differed by more than 2σ. Many of the large discrepancies were associated with nuclei with long-lived isomeric states, highlighting large systematic uncertainties involved in these measurements. Twenty-five new γ rays were observed, and ten new states are proposed with unambiguous excitation energies, spins, and parities. Most of the energies of the excited states were consistent within 300 keV or 20%, whichever was greater, compared to shell model predictions in the proton/neutron (p1/2,g9/2) model space assuming a Sr76 core. A signature of a new (1/2-) isomer in Cd97 with T1/2=0.73(7) s was found, in good agreement with shell model predictions.

Published
2019

38. First spectroscopy of 61Ti and the transition to the Island of Inversion at N = 40

Author

Kathrin Wimmer, M. A. M. AlAqeel, C. R. Nita, D. Kahl, V. Werner, S. Bae, F. Nowacki, Satoru Momiyama, Toshiaki Ando, S. M. Lenzi, L. J. Harkness-Brennan, I. Kojouharov, Megumi Niikura, S. Riccetto, P. A. Söderström, Hiroyoshi Sakurai, Toshiyuki Sumikama, Shin-Ichiro Nishimura, K. Matsui, Philip Woods, G. G. Kiss, P. Schrock, H. Baba, T. Isobe, D. R. Napoli, Y. Saito, M. Labiche, H. Schaffner, J. Ha, W. Witt, S. Choi, P. R. John, Thomas Davinson, V. H. Phong, O. Aktas, Alfredo Poves, C. J. Griffin, C. Stahl, P. Doornenbal, F. Recchia, N. Kurz, A. Estrade, UAM. Departamento de Física Teórica, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, SHELL model, FOS: Physical sciences, Shell evolution, Island of Inversion, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 0103 physical sciences, Gamma spectroscopy, Gamma-ray spectroscopy, Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Projectile fragmentation, Physics, Spins, 010308 nuclear & particles physics, Island of inversion, Isomeric decay, Física, lcsh:QC1-999, Radioactive beams, Atomic physics, Ground state, Beam (structure), lcsh:Physics
Abstract

Isomeric states in 59,61Ti have been populated in the projectile fragmentation of a 345 AMeV 238U beam at the Radioactive Isotope Beam Factory. The decay lifetimes and delayed gamma-ray transitions were measured with the EURICA array. Besides the known isomeric state in 59Ti, two isomeric states in 61Ti are observed for the first time. Based on the measured lifetimes, transition multipolarities as well as tentative spins and parities are assigned. Large-scale shell model calculations based on the modified LNPS interaction show that both 59Ti and 61Ti belong to the Island of Inversion at N=40 with ground state configurations dominated by particle-hole excitations to the g_9/2 and d_5/2 orbits., Phys. Lett. B accepted

Published
2019

39. In-beam γ -ray spectroscopy of Te136 at relativistic energies

Author

Yoshiaki Shiga, Takane Saito, Ryo Taniuchi, E. Sahin, P. Doornenbal, David Steppenbeck, Gry Merete Tveten, R. Orlandi, A. Jungclaus, Jinjia Liu, S. Franchoo, H. Baba, S. Nagamine, F. L. Bello Garrote, Kazuyuki Ogata, Enrique Nácher, K. Hadynska-Klek, M. Yalcinkaya, T. Lokotko, Kathrin Wimmer, Takenori Furumoto, A. Kusoglu, Megumi Niikura, Hiroyoshi Sakurai, T. Motobayashi, Nathan Nakatsuka, Ziye Xu, Toshiaki Ando, Si-Ge Chen, P. A. Söderström, Victor Vaquero, A. M. Moro, Satoru Momiyama, and Zs. Vajta

Subjects
Physics, 010308 nuclear & particles physics, Coulomb excitation, Inelastic scattering, 01 natural sciences, Excited state, 0103 physical sciences, Coulomb, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, Excitation, Beam (structure)
Abstract

The reduced transition probability B(E2;01+→21+) to the first excited 2+ state of the neutron-rich nucleus Te136, with two protons and two neutrons outside the doubly magic Sn132 core, was measured via Coulomb excitation at relativistic energies at the RIKEN Radioactive Isotope Beam Factory. A value of B(E2)=0.191(26) e2b2 was extracted from the measured inelastic scattering cross section on an Au target taking into account the contributions from both Coulomb and nuclear excitations. In addition, an upper limit for the transition strength to a 2+ state of mixed-symmetry character in the excitation energy range of 1.5-2.2 MeV was determined and compared to the predictions of various theoretical calculations. Because of the high statistics gathered in the present experiment the error of the deduced B(E2) value is dominated by the systematic uncertainties involved in the analysis of Coulomb excitation experiments at beam energies around 150 MeV/u. Therefore, the latter are for the first time assessed in detail in the present work.

Published
2019

40. Nuclear structure of Ni76 from the ( p,2p ) reaction

Author

Kamila Sieja, L. Olivier, Shuichi Ota, H. Wang, Ryo Taniuchi, C. Santamaria, P. A. Söderström, Z. Patel, A. Gillibert, K. Yoneda, E. Sahin, V. Lapoux, Zhenci Xu, R. Lozeva, Kazuyuki Ogata, Jinguang Wu, David Steppenbeck, C. M. Shand, P. Doornenbal, Z. Elekes, Megumi Niikura, K. Hadynska-Klek, Á. Kripkó, Tomohiro Uesaka, I. Stefan, M. Lettmann, Shunji Nishimura, Zs. Dombrádi, C. Louchart, K. Yoshida, T. Miyazaki, F. Flavigny, A. Delbart, Toshiyuki Sumikama, Alan Peyaud, D. Calvet, C. Péron, G. Authelet, T. Isobe, J.-Y. Roussé, J. M. Gheller, V. Werner, Hiroyoshi Sakurai, Daisuke Suzuki, H. Baba, T. Motobayashi, F. Château, E. C. Pollacco, F. Giacoppo, Masafumi Matsushita, Alessandra Corsi, A. Obertelli, Yoshiaki Shiga, L. X. Chung, Dóra Sohler, Shoko Koyama, Z. Korkulu, Satoshi Takeuchi, S. Franchoo, A. Gottardo, Jenny Lee, Yuya Kubota, Hideaki Otsu, K. Matsui, F. Browne, Zs. Vajta, and Satoru Momiyama

Subjects
Physics, Proton, Isotope, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Shell (structure), Nuclear structure, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Coincidence, Spectral line, Nickel, medicine.anatomical_structure, chemistry, 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Nucleus
Abstract

The nuclear structure of the Ni76 nucleus was investigated by (p,2p) reaction using a NaI(Tl) array to detect the deexciting prompt γ rays. A new transition with an energy of 2227 keV was identified by γγ and γγγ coincidences. According to these coincidence spectra the observed transition connects a new state at 4147 keV and the previously known 41+ state at 1920 keV. Two weaker transitions were also obtained at 2441 and 2838 keV, which could be tentatively placed to feed the known 21+ state at 990 keV. Our shell-model calculations using the Lenzi, Nowacki, Poves, and Sieja interaction produced good candidates for the experimental proton hole states in the observed energy region, and the theoretical cross sections showed good agreement with the experimental values. Although we could not assign all the experimental states to the theoretical ones unambiguously, the results are consistent with a reasonably large Z=28 shell gap for nickel isotopes in accordance with previous studies.

Published
2019

41. Spectroscopy of strongly deformed Ne32 by proton knockout reactions

Author

Shuichi Takeuchi, Heiko Scheit, K. Li, Nori Aoi, I. Murray, P. Fallon, H. Baba, Hua-Lei Wang, David Steppenbeck, D. Bazin, J. A. Tostevin, K. Yoneda, Masafumi Matsushita, Yutaka Utsuno, P. Doornenbal, Jenny Lee, Hiroyoshi Sakurai, T. Motobayashi, Naofumi Tsunoda, H. L. Crawford, M. MacCormick, and Takaharu Otsuka

Subjects
Physics, Quenching, Proton, 010308 nuclear & particles physics, Nuclear Theory, Nuclear structure, 01 natural sciences, 7. Clean energy, Isotopes of neon, 0103 physical sciences, Rigid rotor, Deformation (engineering), Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, Beam (structure)
Abstract

Low lying states of neutron-rich 32Ne were populated by means of one- and two-proton knock- out reactions at the RIKEN Radioactive Isotope Beam Factory. A new transition is observed at 1410(15) keV and assigned to the 4+ 1 → 2+ 1 decay. With this energy the R4/2 ratio is calculated to be 2.99(6), lying close to the rigid rotor limit and suggests a high degree of collectivity and strongest deformation among neutron-rich Neon isotopes. Comparisons of experimental inclusive and exclu- sive reaction cross sections with shell model and eikonal reaction dynamical calculations reveals considerable quenching for this highly asymmetric system and contributes to systematic trends.

Published
2019

42. New isomers in $^{125}$Pd$_{79}$ and $^{127}$Pd$_{81}$: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the $N = 82$ shell closure

Author

Gary Simpson, Naohito Inabe, Hirofumi Watanabe, G. D. Kim, Chang-Bum Moon, A. Jungclaus, Ayumi Yagi, Megumi Niikura, Toshiyuki Sumikama, T. Isobe, Hiroshi Suzuki, Toshiyuki Kubo, Hyo Soon Jung, Shunji Nishimura, Hiroyuki Takeda, Atsuko Odahara, Jan Taprogge, G. Benzoni, F. C. L. Crespi, K. Yoshinaga, H. Baba, G. J. Lane, Giuseppe Lorusso, F. Browne, F. G. Kondev, I. Kojouharov, Guillaume Gey, H.K. Wang, Roman Gernhäuser, R. Orlandi, Z. H. Li, Hiroki Nishibata, Anna Wendt, H. Schaffner, Zs. Vajta, Zhengyu Xu, Young-Ki Kim, Younghun Kwon, A. Montaner-Pizá, Hiroyoshi Sakurai, Zena Patel, Daiki Nishimura, Yang Sun, Jin Wu, K. Moschner, K. Steiger, Naoki Fukuda, D. Kameda, Zs. Podolyák, P. A. Söderström, P. Doornenbal, F. Naqvi, K. Y. Chae, N. Kurz, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Proton, 010308 nuclear & particles physics, Fission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, lcsh:QC1-999, chemistry, Nucleosynthesis, Excited state, 0103 physical sciences, Neutron, Nuclide, Atomic physics, 010306 general physics, Nuclear Experiment, lcsh:Physics, Palladium
Abstract

The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in Pd and Pd studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2 ) and (19/2 ) in Pd and Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitations and neutron excitations in the proton-hole and neutron-hole systems in the vicinity of the doubly magic nucleus Sn.

Published
2019

43. Discovery of $^{68}$Br in secondary reactions of radioactive beams

Author

Ryo Taniuchi, A. Corsi, W. Korten, G. de Angelis, P. J. Davies, A. Obertelli, Kathrin Wimmer, Hiroyoshi Sakurai, T. Motobayashi, R. Wadsworth, Berta Rubio, M. Zielińska, T. Saito, Megumi Niikura, E. Sahin, D. T. Doherty, H. Baba, Shoko Koyama, P. Aguilera, D. Lubos, S. Nagamine, P. Doornenbal, D. G. Jenkins, B. Blank, T. Arici, J. Gerl, A. Boso, Alejandro Algora, David Steppenbeck, Toshiaki Ando, L. Sinclair, Si-Ge Chen, Roman Gernhäuser, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Direct reaction, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Particle identification, Nuclear physics, Direct production, Fragmentation (mass spectrometry), 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Projectile, lcsh:QC1-999, Physics::Accelerator Physics, New isotope, Radioactive beams, Nucleon, lcsh:Physics
Abstract

The proton-rich isotope 68Br was discovered in secondary fragmentation reactions of fast radioactive beams. Proton-rich secondary beams of 70,71,72Kr and 70Br, produced at the RIKEN Nishina Center and identified by the BigRIPS fragment separator, impinged on a secondary 9Be target. Unambiguous particle identification behind the secondary target was achieved with the ZeroDegree spectrometer. Based on the expected direct production cross sections from neighboring isotopes, the lifetime of the ground or long-lived isomeric state of 68Br was estimated. The results suggest that secondary fragmentation reactions, where relatively few nucleons are removed from the projectile, offer an alternative way to search for new isotopes, as these reactions populate preferentially low-lying states., Comment: Phys. Lett. B accepted

Published
2019

44. First Observation of B20 and B21

Author

T. Murakami, Tomio Kubo, Hiroshi Suzuki, Yosuke Kondo, Y. Shimizu, D. Kameda, K. Takahashi, Thomas Aumann, Q. Deshayes, Yasuhiro Togano, M Vandebrouck, P. Doornenbal, K. Muto, T. Isobe, T. Motobayashi, A. Navin, Hiroshi Sato, T. Kobayashi, Jongwon Hwang, S. K. Kim, J. Bonnard, N. A. Orr, D. Kanno, Hideaki Otsu, Y. Satou, A. G. Tuff, Naoki Fukuda, R. Minakata, Nagao Kobayashi, Julien Gibelin, Nicolas Michel, K. Yoneda, Franck Delaunay, Takashi Nakamura, F. M. Marqués, H. Baba, Ryuki Tanaka, S. Ogoshi, Satoshi Takeuchi, S. Nishi, N. L. Achouri, Noritsugu Nakatsuka, J.H. Lee, Daichi Murai, Naohito Inabe, H. Takeda, S. Leblond, and T. Nakashima

Subjects
Physics, education.field_of_study, Proton, 010308 nuclear & particles physics, Nuclear Theory, SHELL model, Population, General Physics and Astronomy, Resonance, Isotopes of boron, 01 natural sciences, 0103 physical sciences, Quark–gluon plasma, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, education
Abstract

The most neutron-rich boron isotopes ^{20}B and ^{21}B have been observed for the first time following proton removal from ^{22}N and ^{22}C at energies around 230 MeV/nucleon. Both nuclei were found to exist as resonances which were detected through their decay into ^{19}B and one or two neutrons. Two-proton removal from ^{22}N populated a prominent resonancelike structure in ^{20}B at around 2.5 MeV above the one-neutron decay threshold, which is interpreted as arising from the closely spaced 1^{-},2^{-} ground-state doublet predicted by the shell model. In the case of proton removal from ^{22}C, the ^{19}B plus one- and two-neutron channels were consistent with the population of a resonance in ^{21}B 2.47±0.19 MeV above the two-neutron decay threshold, which is found to exhibit direct two-neutron decay. The ground-state mass excesses determined for ^{20,21}B are found to be in agreement with mass surface extrapolations derived within the latest atomic-mass evaluations.

Published
2018

45. K-mixing in the doubly mid-shell nuclide 170Dy and the role of vibrational degeneracy

Author

P. A. Söderström, C. J. Griffin, Philip M Walker, Shunji Nishimura, Ayumi Yagi, István Kuti, Zhengyu Xu, A. Estrade, Gavin Lotay, N. Kurz, P. Lee, S. Lalkovski, S. Terashima, V. H. Phong, P. Doornenbal, F. Browne, Naoki Fukuda, Raymond J. Carroll, Thamer Alharbi, H. L. Liu, Zs. Vajta, Oliver J. Roberts, Zs. Podolyák, C. S. Lee, C. M. Shand, Hidetada Baba, D.S. Ahn, Zs. Dombrádi, Alison Bruce, Shigeru Kubono, K. Y. Chae, S. Kanaya, Furong Xu, J. J. Liu, H. Kanaoka, Zena Patel, C. R. Niţă, I. Nishizuka, Atsuko Odahara, Toshiyuki Sumikama, Hiroyuki Takeda, G. J. Lane, Toshiyuki Kubo, Hiroyoshi Sakurai, E. J. Lee, P. H. Regan, G. X. Zhang, H. Schaffner, Eiji Ideguchi, Naohito Inabe, Hirofumi Watanabe, Tadaaki Isobe, Chang-Bum Moon, Z. Korkulu, Hiroshi Suzuki, I. Kojouharov, J. J. Valiente-Dobón, Jin Wu, G. Lorusso, and F. G. Kondev

Subjects
Mid-shell, Nuclear and High Energy Physics, Shell (structure), chemistry.chemical_element, 01 natural sciences, K isomer, 0103 physical sciences, medicine, Physics::Atomic and Molecular Clusters, Dysprosium, Gamma spectroscopy, ddc:530, Nuclide, 010306 general physics, γ-Ray spectroscopy, Physics, 010308 nuclear & particles physics, Yrast, lcsh:QC1-999, medicine.anatomical_structure, chemistry, Atomic physics, Nucleus, Order of magnitude, Excitation, lcsh:Physics
Abstract

Physics letters / B 762, 404 - 408 (2016). doi:10.1016/j.physletb.2016.09.058, Published by North-Holland Publ., Amsterdam

Published
2016
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46. Decay spectroscopy of 160 Sm: The lightest four-quasiparticle K isomer

Author

Hiroyoshi Sakurai, P. H. Regan, István Kuti, M. Tanaka, Shunji Nishimura, H. Suzuki, Naohiro Inabe, Hiroki Nishibata, Tetsuro Komatsubara, T. Isobe, Toshiyuki Kubo, Rin Yokoyama, Shin'ichiro Michimasa, K. Kobayashi, Toshiyuki Sumikama, Zs. Dombrádi, N. Kurz, D. Kameda, E. Sahin, Ayumi Yagi, Zhengyu Xu, Atsuko Odahara, I. Kojouharov, R. Daido, Z. H. Li, Eiji Ideguchi, F. Browne, Stephen Rice, G. Benzoni, Zs. Podolyák, Jan Taprogge, Hiroyuki Takeda, H. Schaffner, P. Doornenbal, Guillaume Gey, H. L. Liu, Michikazu Kobayashi, Chang-Bum Moon, Hirofumi Watanabe, A. Gottardo, Nori Aoi, Zs. Vajta, Gary Simpson, F. L. Bello Garrote, I. Nishizuka, Shintaro Go, Zena Patel, P. M. Walker, N. Fukuda, L. Sinclair, P. A. Söderström, H. Baba, Y. F. Fang, Furong Xu, Masafumi Matsushita, Jin Wu, G. Lorusso, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Fizikai tudományok, State (functional analysis), 7. Clean energy, 01 natural sciences, lcsh:QC1-999, Természettudományok, 0103 physical sciences, Potential energy surface, Quasiparticle, ddc:530, Atomic physics, 010306 general physics, Ground state, Electronic band structure, Spectroscopy, ComputingMilieux_MISCELLANEOUS, lcsh:Physics, Excitation
Abstract

The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ-ray spectroscopy at the RIBF, RIKEN. The four-quasiparticle state is assigned a 2 π ⊗ 2 ν π 5 2 − [ 532 ] , π 5 2 + [ 413 ] , ν 5 2 − [ 523 ] , ν 7 2 + [ 633 ] configuration. The half-life of this ( 11 + ) state is measured to be 1.8(4) μs. The ( 11 + ) isomer decays into a rotational band structure, based on a ( 6 − ) ν 5 2 − [ 523 ] ⊗ ν 7 2 + [ 633 ] bandhead, consistent with the g K − g R values. This decays to a ( 5 − ) two-proton quasiparticle state, which in turn decays to the ground state band. Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm. They reveal a significant influence from β 6 deformation and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region. The relationship between reduced hindrance and isomer excitation energy for E1 transitions from multiquasiparticle states is considered with the new data from 160Sm. The E1 data are found to agree with the existing relationship for E2 transitions.

Published
2016

47. Spectroscopy of neutron-rich scandium isotopes

Author

A. Delbart, T. Motobayashi, L. Zanetti, Julien Gibelin, Tomohiro Uesaka, T. Kobayashi, X. X. Xu, H. Toernqvist, Si-Ge Chen, P. A. Söderström, S. Wang, F. Flavigny, A. Obertelli, V. Wagner, M. Lettmann, D. Calvet, J. M. Gheller, T. Isobe, A. Giganon, F. Château, Thomas Aumann, Makoto Yasuda, Victor Vaquero, A. Gillibert, V. Panin, L. X. Chung, E. Sahin, S. Y. Park, T. Lokotko, Duo Yan, P. Doornenbal, K. Moschner, M. MacCormick, C. Hilaire, Kathrin Wimmer, Alessandra Corsi, Satoshi Takeuchi, Takashi Nakamura, R.-B. Gerst, B. D. Linh, M. L. Cortés, S. Franchoo, Igor Gašparić, H. N. Liu, K. Yoneda, C. Lehr, Jenny Lee, F. Browne, Yuya Kubota, Masaki Sasano, N. Paul, D. M. Rossi, V. Werner, Yasuhiro Togano, Yosuke Kondo, H. Baba, N. L. Achouri, Hideaki Otsu, Hirofumi Yamada, Y. L. Sun, Dong-Wook Kim, O. Aktas, V. Lapoux, Zaihong Yang, I. Murray, K. I. Hahn, David Steppenbeck, L. Stuhl, W. Rodriguez, Nobuyuki Chiga, T. Koiwai, Norbert Pietralla, D. Sohler, P. Koseoglou, Hiroyoshi Sakurai, RIKEN Nishina Center for Accelerator-Based Science, Technische Universität Darmstadt, Helmholtz Centre for Heavy Ion Research, Federal Ministry of Education and Research (Germany), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, History, Isotope, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Computer Science Applications, Education, International school, Neutron physics, Nuclear physics, chemistry, 0103 physical sciences, Physics::Accelerator Physics, ddc:530, Neutron, Scandium, Nuclear Experiment, 010306 general physics, Spectroscopy
Abstract

7 pags., 7 figs. -- XXIII International School on Nuclear Physics, Neutron Physics and Applications 22-28 September 2019, Varna, Bulgaria, Within the SEASTAR III campaign at the Radioactive Isotope Beam Factory, at the RIKEN Nishina Center, neutron-rich isotopes in the vicinity of 53K were produced from the fragmentation of the primary 70Zn beam on a 9Be target. After nucleon knockout reactions on the secondary liquid hydrogen MINOS target the known γ rays of the neutron-rich 55Sc isotope were observed (shown in this proceedings) and γ rays from 57,59Sc isotopes have been identified for the first time. The evolution of the occupied nucleon orbitals of these nuclei in the ground and excited state is investigated under the prism of the tensor force., We are grateful to the RIKEN Nishina Center accelerator staff for their work in the primary beam delivery and the BigRIPS team for preparing the secondary beams. This work was supported by the cooperation between TU Darmstadt and the GSI Helmholtz Center for Heavy Ion Research, by the Helmholtz Graduate School for Hadron and Ion Research for FAIR and its abroad program and the BMBF under grant No. 05P19RDFN1. D.S. was supported by projects No. GINOP2.3.3-15-2016-00034 and No. K128947.

Published
2020

48. Restoration of the natural E(1/21+) - E(3/21+) energy splitting in odd-K isotopes towards N = 40

Author

David Steppenbeck, B. D. Linh, H. Törnqvist, Igor Gašparić, H. N. Liu, Kazuki Yoshida, Yosuke Kondo, Toshio Kobayashi, P. A. Söderström, K. Yoneda, N. Paul, Carlo Barbieri, S. Y. Park, D. M. Rossi, V. Lapoux, Donghang Yan, H. Baba, K. Moschner, Masaki Sasano, V. Werner, Yutaka Utsuno, Yoshiki Chazono, S. Wang, D. Sohler, Zaihong Yang, I. Murray, K. I. Hahn, L. Stuhl, Kathrin Wimmer, Jenny Lee, J. M. Gheller, Victor Vaquero, R.-B. Gerst, Takaharu Otsuka, F. Browne, A. Obertelli, Nobuyuki Chiga, D. Calvet, T. Isobe, Hiroyoshi Sakurai, T. Koiwai, Yuya Kubota, C. Hilaire, T. Motobayashi, F. Nowacki, F. Château, A. Delbart, C. Lehr, A. Gillibert, M. MacCormick, Julien Gibelin, A. Corsi, X. X. Xu, V. Panin, M. L. Cortés, Thomas Aumann, O. Aktas, S. Franchoo, Si-Ge Chen, L. X. Chung, L. Zanetti, A. Giganon, Francesco Raimondi, Hideaki Otsu, Hirofumi Yamada, Tomohiro Uesaka, W. Rodriguez, F. Flavigny, Yasuhiro Togano, T. Lokotko, E. Sahin, N.L. Achouri, Y.L. Sun, Takashi Nakamura, Petr Navrátil, P. Doornenbal, Thomas Duguet, V. Wagner, Satoshi Takeuchi, D. Kim, V. Somà, Masahiro Yasuda, Kazuyuki Ogata, and P. Koseoglou

Subjects
Physics, Nuclear and High Energy Physics, Chemical substance, Isotope, 010308 nuclear & particles physics, SHELL model, 01 natural sciences, Vertex (geometry), Ab initio quantum chemistry methods, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Spectroscopy
Abstract

We report on the first γ-ray spectroscopy of 51,53K produced via the 52,54Ca(p,2p) reactions at ∼250 MeV/nucleon. Unambiguous final-state angular-momentum assignments were achieved for beam intensities down to few particles per second by using a new technique based on reaction vertex tracking combined with a thick liquid-hydrogen target. Through γ-ray spectroscopy and exclusive parallel momentum distribution analysis, 3/2+ ground states and 1/2+ first excited states in 51,53K were established quantifying the natural ordering of the 1 d 3 / 2 and 2 s 1 / 2 proton-hole states that are restored at N = 32 and 34. State-of-the-art ab initio calculations and shell-model calculations with improved phenomenological effective interactions reproduce the present data and predict consistently the increase of the E(1/2 1 + ) - E(3/2 1 + ) energy differences towards N = 40.

Published
2020

49. Two-proton Radioactivity: the Interesting Case of \(^{67}\)Kr and Further Studies

Author

N. Fukuda, Y. Fujita, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, P. A. Söderström, Toshiyuki Kubo, P. Ascher, Kathrin Wimmer, D. S. Ahn, S. Grévy, Shunji Nishimura, A. Boso, S. Yagi, R. B. Cakirli, Shintaro Go, W. Gelletly, C. Sidong, Shigeru Kubono, C. Borcea, Jin Wu, A. Algora, C. Magron, H. Suzuki, Gabor Kiss, J. Giovinazzo, H. Oikawa, J. Chiba, P. Doornenbal, Y. Takei, P. Aguilera, V. Guadilla, A. I. Morales, S.E.A. Orrigo, Daiki Nishimura, G. de Angelis, M. Gerbaux, Naohito Inabe, Hiroyoshi Sakurai, B. A. Brown, P. Vi, Y. Shimizu, F. Diel, D. R. Napoli, Berta Rubio, F. Molina, T. Kurtukian-Nieto, D. Lubos, Jorge Agramunt, M. Tanaka, E. Ganioglu, A. Montaner-Piza, T. Goigoux, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Isotope, Proton, 010308 nuclear & particles physics, Nuclear Theory, Theoretical models, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics
Abstract

International audience; We report on the observation of 67Kr that has been produced in an experiment performed at the RIKEN/BigRIPS facility. The two-proton decay of 67Kr has been evidenced and this nucleus is thus the fourth observed long lived ground-state two-proton emitter, after 45Fe, 48Ni and 54Zn. In addition, the decay of several isotopes in the mass region has been investigated. While for previous cases of two-proton radioactivity, the theoretical models could reproduce the measured data, this is not the case anymore for 67Kr. Two interpretations have been proposed to explain this discrepancy: a transition between real two-proton and sequential decay or the influence of deformation. These hypotheses will be tested in future experiments by measuring the angular and energy correlations of the emitted protons.

Published
2020

50. Beta decay of the Tz=-2 nucleus 64Se and its descendants

Author

B. Blank, H. Takeda, Toshiyuki Sumikama, E. Ganioglu, G. G. Kiss, A. Algora, P. Aguilera, DeukSoon Ahn, A. I. Morales, Shin-Ichiro Nishimura, A. Montaner-Pizá, F. Molina, Shigeru Kubono, Daiki Nishimura, G. de Angelis, J. Giovinazzo, F. Diel, R. B. Cakirli, J. Chiba, H. Oikawa, Yoshitaka Fujita, W. Gelletly, V. Guadilla, Jorge Agramunt, Berta Rubio, T. Kurtukian, Momoko Tanaka, C. Sidong, Yoshifumi R. Shimizu, Tomio Kubo, P. A. Söderström, P. Vi, N. Fukuda, Y. Takei, A. Boso, C. Borcea, Shintaro Go, Naohito Inabe, C. Magron, S. E. A. Orrigo, S. Grévy, D. Lubos, H. Suzuki, D. R. Napoli, M. Gerbaux, P. Doornenbal, S. Yang, P. Asher, Jinguang Wu, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Paper, History, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Beta decay, Computer Science Applications, Education, ddc, Nuclear physics, Proton radiation, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, Bound state, medicine, 010306 general physics, Nucleus
Abstract

International audience; The beta decay of the Tz=-2 nucleus 64Se has been studied in a fragmentation reaction at RIKEN-Nishina Center. 64Se is the heavies Tz=-2 nucleus that decays to bound states in the daughter nucleus and the heaviest case where the mirror reaction 64Zn(3He,t)64Ga on the Tz=+2 64Zn stable target exists and can be compared. Beta-delayed gamma and proton radiation is reported for the 64Se and 64As cases. New levels have been observed in 64As, 64Ge (N=Z), 63Ge and 63Ga. The associated T1/2 values have been obtained.

Published
2018

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