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24 results on '"J.-M. Gheller"'

1. 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

2. 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

3. 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

4. Quasifree Neutron Knockout Reaction Reveals a Small s -Orbital Component in the Borromean Nucleus B17

Author

Shuichi Ota, V. Panin, A. Ohkura, Toshiyuki Sumikama, Y. Kiyokawa, Takashi Nakamura, J. Yasuda, T. Isobe, S. Kawakami, Y. Kanaya, Ji Feng, H. Sato, A. Giganon, K. Hasegawa, D. Kim, C. Caesar, Toshio Kobayashi, K. Yoneda, Masanori Dozono, Noritsugu Nakatsuka, Motoki Kobayashi, Juzo Zenihiro, Atsumi Saito, Tsuyoshi Miyazaki, Shoko Koyama, J.-Y. Roussé, Y.L. Sun, Z. Korkulu, Nagao Kobayashi, C. Santamaria, Y. Shindo, Stefanos Paschalis, F. Flavigny, Nicolas Michel, E. C. Pollacco, Yasuhiro Togano, A. Corsi, Yukie Maeda, C. X. Yuan, N. A. Orr, L. Stuhl, Hideaki Otsu, Shan-Gui Zhou, D. Calvet, Tomohiro Uesaka, F. M. Marqués, A. Delbart, G. Authelet, J. M. Gheller, M. Sako, Yohei Shimizu, Yuya Kubota, A. Gillibert, Y. Nishio, T. Ozaki, S. Reichert, J. Tsubota, Kazuyuki Ogata, Wei Zuo, Zaihong Yang, M. Shikata, K. Yoshida, Qiang Yuan, J. Gibelin, V. Lapoux, Masaki Sasano, H. Baba, Furong Xu, A. Obertelli, Masaaki Kimura, Xianping Sun, Yosuke Kondo, M. Tabata, T. Motobayashi, Satoshi Sakaguchi, and J. G. Li

Subjects
Physics, Component (thermodynamics), Nuclear Theory, General Physics and Astronomy, 01 natural sciences, Momentum, Nuclear physics, Atomic orbital, Borromean nucleus, 0103 physical sciences, Neutron, Continuum (set theory), Halo, 010306 general physics, Astrophysics::Galaxy Astrophysics
Abstract

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

Published
2021

5. 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

6. Surface Localization of the Dineutron in Li11

Author

V. Lapoux, Nagao Kobayashi, Stefanos Paschalis, A. Ohkura, C. Caesar, Atsumi Saito, K. Yoneda, Masanori Dozono, Y. L. Sun, A. Obertelli, J. Tsubota, Zaihong Yang, Yohei Shimizu, M. Shikata, H. Baba, Masaki Sasano, L. Stuhl, Y. Kikuchi, T. Ozaki, F. M. Marqués, J. Yasuda, Toshio Kobayashi, V. Panin, S. Reichert, M. Tabata, Noritsugu Nakatsuka, G. Authelet, T. Motobayashi, C. Santamaria, D. Calvet, Juzo Zenihiro, N. A. Orr, T. Isobe, E. C. Pollacco, Tomohiro Uesaka, Yuya Kubota, J. M. Gheller, A. Gillibert, Motoki Kobayashi, Shoko Koyama, Hideaki Otsu, Toshiyuki Sumikama, K. Hasegawa, Z. Korkulu, Julien Gibelin, Y. Kiyokawa, Yosuke Kondo, M. Sako, A. Corsi, Satoshi Sakaguchi, A. Giganon, Y. Nishio, A. Delbart, S. Kawakami, Shuichi Ota, F. Flavigny, Yukie Maeda, Takashi Nakamura, Ji Feng, H. Sato, J.-Y. Roussé, Yasuhiro Togano, Kazuyuki Ogata, D. Kim, Y. Kanaya, Tsuyoshi Miyazaki, and Y. Shindo

Subjects
Surface (mathematics), Physics, Nuclear Theory, General Physics and Astronomy, Nuclear matter, 7. Clean energy, 01 natural sciences, Nuclear physics, Momentum, medicine.anatomical_structure, 0103 physical sciences, medicine, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus
Abstract

The formation of a dineutron in the nucleus $^{11}$Li is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in $^{11}$Li via the $(p,pn)$ knockout reaction at 246 MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at $r\sim3.6$ fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

Published
2020

7. Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei

Author

Megumi Niikura, K. Yoneda, Tomohiro Uesaka, T. Miyazaki, J.-Y. Roussé, A. Jungclaus, I. G. Stefan, Masaki Sasano, A. Gillibert, Jian Liu, Hiroyoshi Sakurai, David Steppenbeck, Zs. Dombradi, K. Moschner, M. Gómez-Ramos, Satoshi Takeuchi, D. Calvet, T. Isobe, Shunji Nishimura, T. Saito, V. Lapoux, H. Wang, T. Motobayashi, L. Olivier, R. Lozeva, A. Gottardo, S. Franchoo, C. Péron, H. Baba, Jinguang Wu, G. Authelet, A. Delbart, A. Blazhev, J. M. Gheller, Hideaki Otsu, F. Château, Masafumi Matsushita, Zs. Vajta, Zena Patel, Victor Vaquero, Kathrin Wimmer, M. L. Cortés, K. Matsui, Shuichi Ota, C. Santamaria, E. C. Pollacco, M. Dewald, Alessandra Corsi, F. Browne, C. R. Nita, M. Rudigier, Z. Korkulu, Jenny Lee, Yoshiaki Shiga, K. Hadynska-Klek, S. Nagamine, Satoru Momiyama, A. Frotscher, T. Arici, Ryo Taniuchi, Noritaka Shimizu, C. R. Nobs, Toshiyuki Sumikama, Alison Bruce, C. Louchart, E. Sahin, Toshiaki Ando, Zhenci Xu, F. Giacoppo, Y. Kubota, L. X. Chung, B. D. Linh, P. Doornenbal, F. Flavigny, A. Giganon, N. Paul, C. M. Shand, Noritsugu Nakatsuka, Zi Hong Liu, V. Werner, M. Górska, Si-Ge Chen, P. A. Söderström, D. Suzuki, M. Lettmann, R. Orlandi, C. Lizarazo, A. Obertelli, Raymond J. Carroll, Bing Ding, Zs. Podolyák, Shoko Koyama, and Alan Peyaud

Subjects
Physics, Hydrogen, Proton, Projectile, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, 01 natural sciences, Coincidence, Nuclear physics, medicine.anatomical_structure, chemistry, MINOS, 0103 physical sciences, medicine, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus
Abstract

Twenty-one two-proton knockout (p; 3p) cross sections from neutron-rich nuclei at ~ 250 MeV/nucleon were measured. For the first time, the angular distribution of the three emitted protons were measured in coincidence with the tracker and hydrogen target MINOS, demonstrating that the (p; 3p) kinematics is consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p; 3p) over (p; 2p) inclusive cross sections follow the trend of other many-proton (neutron) removal reactions, further reinforcing the sequential nature of (p; 3p) in neutron-rich nuclei.

Published
2020

8. 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

9. Extending the Southern Shore of the Island of Inversion to F28

Author

J. Mayer, Noritsugu Nakatsuka, Michael Thoennessen, A. Gillibert, Ákos Horváth, Q. Deshayes, Yosuke Kondo, J. Tscheuschner, Nasser Kalantar-Nayestanaki, J. M. Gheller, István Kuti, M. Shikata, Thomas Aumann, C. Caesar, J. Tsubota, A. Revel, N. L. Achouri, W. He, Z. Elekes, Calem Hoffman, Shoichiro Kawase, Heiko Scheit, J. Kahlbow, Masahiro Yasuda, H. Simon, H. Sato, K. Yoneda, A. Horvat, K. Nakano, Igor Gašparić, T. Ozaki, H. Chae, J. A. Tostevin, L. Stuhl, K. Miki, F. de Oliveira Santos, H. L. Crawford, D. Calvet, Stefanos Paschalis, S. Masuoka, T. Isobe, A. Obertelli, Tomoki Saito, Momoko Tanaka, N. A. Orr, Shoko Koyama, Nobuyuki Chiga, L. Atar, Y. Satou, P. Fallon, Atsumi Saito, Zsolt Dombrádi, H. Törnqvist, Jongwon Hwang, A. Corsi, Julien Gibelin, K. Boretzky, A. Delbart, D. M. Rossi, H. Baba, Masaki Sasano, D. Sohler, V. Lapoux, M. A. Najafi, S. K. Kim, A. Hirayama, H. Al Falou, K. Kisamori, T. Tomai, V. Panin, P. Schrock, Takashi Nakamura, Yasuhiro Togano, M.N. Harakeh, M. Holl, Zaihong Yang, F. Nowacki, T. Kobayashi, Cenxi Yuan, D. Körper, Tomohiro Uesaka, Thomas Nilsson, C. A. Douma, Simon Lindberg, Hideaki Otsu, O. Sorlin, T. Murakami, Yohei Shimizu, Fabia Schindler, Franck Delaunay, F. M. Marqués, and Satoshi Takeuchi

Subjects
Physics, Proton, Island of inversion, General Physics and Astronomy, 01 natural sciences, Spectral line, Momentum, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Nucleon, Spectroscopy, Ground state
Abstract

Detailed spectroscopy of the neutron-unbound nucleus 28 F has been performed for the first time following proton/neutron removal from 29 Ne / 29 F beams at energies around 230 MeV / nucleon . The invariant-mass spectra were reconstructed for both the 27 F ( * ) + n and 26 F ( * ) + 2 n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the 28 F ground state, with S n ( 28 F ) = − 199 ( 6 ) keV , while analysis of the 2 n decay channel allowed a considerably improved S n ( 27 F ) = 1620 ( 60 ) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of 28 F . Importantly, in the case of the ground state, the reconstructed 27 F + n momentum distribution following neutron removal from 29 F indicates that it arises mainly from the 1 p 3 / 2 neutron intruder configuration. This demonstrates that the island of inversion around N = 20 includes 28 F , and most probably 29 F , and suggests that 28 O is not doubly magic.

Published
2020

10. 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

11. 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

12. 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

13. Quasifree Neutron Knockout from Ca54 Corroborates Arising N=34 Neutron Magic Number

Author

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

Subjects
Physics, Hydrogen, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, Impulse (physics), 01 natural sciences, Vertex (geometry), Isotopes of calcium, Transverse plane, chemistry, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Excitation
Abstract

Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a ^{54}Ca beam striking on a liquid hydrogen target at ∼200 MeV/u. A significantly larger cross section to the p_{3/2} state compared to the f_{5/2} state observed in the excitation of ^{53}Ca provides direct evidence for the nature of the N=34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

Published
2019

14. Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei

Author

A. Corsi, V. Lapoux, Zs. Dombradi, K. Matsui, David Steppenbeck, A. Gillibert, Alan Peyaud, Shoko Koyama, Toshiaki Ando, C. M. Shand, Hiroyoshi Sakurai, M. Rudigier, F. Browne, L. Olivier, Raymond J. Carroll, K. Yoneda, E. Sahin, Yoshiaki Shiga, Bing Ding, F. Château, Pieter Doornenbal, Hidetada Baba, Tomoyuki Saito, Tohru Motobayashi, Zs. Podolyák, Satoru Momiyama, F. Giacoppo, C. R. Nita, T. Sumikama, H. Wang, Megumi Niikura, A. Gottardo, Jenny Lee, M. Dewald, Zs. Vajta, R. Orlandi, Shuichi Ota, E. C. Pollacco, K. Hadynska-Klek, F. Flavigny, P. A. Söderström, Daisuke Suzuki, Yuya Kubota, C. Lizarazo, D. Calvet, S. Nagamine, C. Péron, Tomohiro Uesaka, R. Lozeva, Hideaki Otsu, N. Paul, Shenjian Chen, G. Authelet, Noritsugu Nakatsuka, Ryo Taniuchi, A. Delbart, Carlos A. Bertulani, J. M. Gheller, Zi Hong Liu, V. Werner, T. Arici, M. Matsushita, Masaki Sasano, M. Lettmann, B. D. Linh, C. Santamaria, Alison Bruce, J. L. Rodriguez-Sanchez, Satoshi Takeuchi, I. Stefan, M. Górska, S. Franchoo, C. Louchart, Zhengyu Xu, Zena Patel, J.-Y. Roussé, Tadaaki Isobe, S. Nishimura, A. Jungclaus, Victor Vaquero, T. Miyazaki, M. L. Cortés, A. Obertelli, K. Moschner, Kathrin Wimmer, Z. Korkulu, Jin Wu, L. X. Chung, C. R. Nobs, Jian Liu, A. Blazhev, and A. Giganon

Subjects
Physics, Hydrogen, Proton, Nuclear Theory, General Physics and Astronomy, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Nuclear physics, chemistry, Cascade, Pairing, 0103 physical sciences, Bound state, Physics::Accelerator Physics, Neutron, Nuclear Experiment, 010306 general physics, Nucleon, Beam (structure)
Abstract

Fifty-five inclusive single nucleon removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at � 250 MeV/nucleon were measured at the RIKEN Radioactive Isotope Beam Factory. Systematically higher cross sections are found for proton removal from nuclei with an even number of protons compared to odd-proton number projectiles for a given neutron separation energy. Neutron removal cross sections display no even-odd splitting contrary to nuclear cascade model predictions. Both effects are understood through simple considerations of neutron separation energies and bound state level densities originating in pairing correlations in the daughter nuclei. These conclusions are supported by comparison with semi-microscopic model predictions,highlighting the enhanced role of low-lying level densities in nucleon removal cross sections from loosely-bound nuclei.

Published
2019

15. Structure of 13Be probed via quasi-free scattering

Author

M. Gómez-Ramos, Yuya Kubota, Takashi Nakamura, Tsuyoshi Miyazaki, Yukie Maeda, J. Casal, H. Sato, J. Tsubota, A. Gillibert, Michikazu Kobayashi, J. Gibelin, C. Caesar, V. Lapoux, Y. Shindo, M. Sako, K. Hasegawa, Y. Nishio, A. Ohkura, K. Yoneda, S. Kawakami, V. Panin, A. M. Moro, A. Obertelli, T. Uesaka, G. Authelet, Yosuke Kondo, Masanori Dozono, J.-Y. Roussé, J. M. Gheller, T. Ozaki, C. Santamaria, Yohei Shimizu, S. Reichert, Y. Kiyokawa, Zaihong Yang, Hidetada Baba, Y. Kanaya, T. Isobe, D. Kim, Yasuhiro Togano, E. C. Pollacco, A. Giganon, M. Shikata, F. M. Marqués, M. Tabata, Hideaki Otsu, T. Motobayashi, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, Shoko Koyama, A. Delbart, L. Stuhl, Z. Korkulu, Satoshi Sakaguchi, Masaki Sasano, A. Corsi, S. Ota, Y.L. Sun, D. Calvet, Atsumi Saito, Toshiyuki Sumikama, Toshio Kobayashi, Noritsugu Nakatsuka, Juzo Zenihiro, J. Feng, N.A. Orr, J. Yasuda, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Département des Accélérateurs, de Cryogénie et de Magnétisme (ex SACM) (DACM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), 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), 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 Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Interpretation (model theory), Nuclear Theory (nucl-th), 0103 physical sciences, Three-body model, medicine, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Wave function, Nuclear Experiment, Quasi-free scattering, Physics, Borromean nuclei, Resonances, Inverse kinematics, 010308 nuclear & particles physics, Scattering, Spectrum (functional analysis), lcsh:QC1-999, medicine.anatomical_structure, Atomic physics, Nucleon, Nucleus, lcsh:Physics
Abstract

We present an investigation of the structure of 13Be obtained via a kinematically complete measurement of the (p,pn) reaction in inverse kinematics at 265 MeV/nucleon. The relative energy spectrum of 13Be is compared to Transfer-to-the-Continuum calculations which use as structure inputs the overlaps of the 14Be ground-state wave function, computed in a three-body model, with the unbound states of the 13Be residual nucleus. The key role of neutron p-wave orbital in the interpretation of the low-relative-energy part of the spectrum is discussed. Keywords: Quasi-free scattering, Borromean nuclei, Three-body model, Resonances

Published
2019

16. $^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation

Author

Frédéric Nowacki, L. Olivier, K. Yoneda, Tsuyoshi Miyazaki, H. Wang, I. Stefan, J. Simonis, Zhengyu Xu, C. Santamaria, Javier Fernandez Menendez, Ertan Şahin, D. Calvet, Kazuyuki Ogata, R. Lozeva, C. Louchart, Takaharu Otsuka, Satoshi Takeuchi, Alexandre Obertelli, Yusuke Tsunoda, J.-Y. Roussé, Tadaaki Isobe, F. Giacoppo, F. Château, A. Gottardo, E. C. Pollacco, Jenny Lee, T. Sumikama, K. Matsui, Zs. Vajta, David Steppenbeck, Sophie Péru, S. Nishimura, Zena Patel, Frank Browne, C. M. Shand, Tohru Motobayashi, Shinsuke Ota, S. Momiyama, Hiroyoshi Sakurai, K. Hadynska-Klek, H. Otsu, Alfredo Poves, A. Gillibert, Daisuke Suzuki, Hidetada Baba, A. Delbart, S. Franchoo, Yuki Kubota, V. Lapoux, V. Werner, Pär-Anders Söderström, M. Matsushita, Shunpei Koyama, M. Lettmann, Jason D. Holt, Z. Korkulu, A. Corsi, Alan Peyaud, Achim Schwenk, Yoshiaki Shiga, R. Taniuchi, Jin Wu, L. X. Chung, S. R. Stroberg, M. Niikura, Tomohiro Uesaka, Zs. Dombrádi, Pieter Doornenbal, C. Péron, G. Authelet, J. M. Gheller, 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), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), 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)-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
Proton, Nuclear Theory, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Strong interaction, FOS: Physical sciences, 01 natural sciences, Asymmetry, Nuclear Theory (nucl-th), Magic number (programming), 0103 physical sciences, Effective field theory, Physics::Atomic and Molecular Clusters, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, [PHYS]Physics [physics], Multidisciplinary, 010308 nuclear & particles physics, Magic (programming), Atomic nucleus, Atomic physics
Abstract

Nuclear magic numbers, which emerge from the strong nuclear force based on quantum chromodynamics, correspond to fully occupied energy shells of protons, or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. While the sequence of magic numbers is well established for stable nuclei, evidence reveals modifications for nuclei with a large proton-to-neutron asymmetry. Here, we provide the first spectroscopic study of the doubly magic nucleus $^{78}$Ni, fourteen neutrons beyond the last stable nickel isotope. We provide direct evidence for its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective field theory interactions and the quasi-particle random-phase approximation. However, our results also provide the first indication of the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting further a rapid transition from spherical to deformed ground states with $^{78}$Ni as turning point.

Published
2019

17. 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

18. Spectroscopic Study in Neutron-Rich Mn Isotopes Around the $N=40$ 'Island of Inversion'

Author

X. D. Tang, C. Péron, G. Authelet, Y. H. Lam, Shunji Nishimura, J. M. Gheller, V. Lapoux, Megumi Niikura, Tomohiro Uesaka, Masaki Sasano, D. Calvet, De-fu Hou, A. Gillibert, K. Matsui, G. L. Stefan, C. M. Shand, F. Browne, H. Baba, Toshiyuki Sumikama, P. M. Walker, M. Lettmann, Feng-Shou Zhang, F. Giacoppo, K. Yoneda, C. Santamaria, Zs. Vajta, David Steppenbeck, L. Olivier, E. C. Pollacco, C. Louchart, Jinguang Wu, Hideaki Otsu, S. M. Lenzi, Yoshiaki Shiga, Bing Ding, M. D. Sun, T. Miyazaki, Satoru Momiyama, A. Obertelli, Shuichi Ota, T. H. Huang, F. Nowacki, Hiroyoshi Sakurai, B. D. Linh, T. Motobayashi, Jenny Lee, P. A. Söderström, H. Lu, R. Lozeva, X.Y. Liu, Zena Patel, K. Hadynska-Klek, E. Sahin, Zhenci Xu, Z. Korkulu, Zs. Dombradi, Yuya Kubota, X. H. Zhou, T. Isobe, P. Doornenbal, Zi Hong Liu, V. Werner, F. Château, Satoshi Takeuchi, W.Q. Zhang, S. Franchoo, H. Wang, Y. H. Zhang, J.-Y. Roussé, L. X. Chung, H. S. Xu, Daisuke Suzuki, Alan Peyaud, A. Corsi, A. Delbart, Ryo Taniuchi, Shoko Koyama, A. Gottardo, Masafumi Matsushita, 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), 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), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), 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)-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
Materials science, 21.10.-k, Isotope, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Island of inversion, structure evolution, Mineralogy, 23.20.Lv, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], island of inversion, Quansi-rotational band, 7. Clean energy, In-beam γ-ray spectroscopy, 21.60.Cs, Neutron, 21.10.Re
Abstract

International audience; Excited states in Mn isotopes with mass number A from 63 to 67 were studied via in-beam γ–ray spectroscopy following knockout reactions from 67,68Fe. In odd-A isotopes 63,65,67Mn, 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. Experimental results of odd-A Mn isotopes are compared with large-scale shell-model calculations in the model space that includes the vg9/2 and vd5/2 orbitals with the state-of-the-art LNPS effective interaction. The constructed level schemes in odd-odd isotopes 64,66Mn show rotational-like properties. Spin and parity of the excited states, as well as the πf7/2 ⊗ vg9/2 configuration of the bands are tentatively assigned based on the level systematics in the odd-odd isotopes. These new data extends the knowledge of the excited states in Mn isotopes. Discussion in terms of the systematics helps to deepen our understanding of the N = 40 “island of inversion”.

Published
2018

19. Study of multi-neutron systems with SAMURAI spectrometer

Author

K. Yoneda, Z. Elekes, Masaki Sasano, Heiko Scheit, Atsumi Saito, N. Inabe, I. Stefan, J. Tscheuschner, Mohsen Harakeh, Julien Gibelin, M. A. Knösel, K. Boretzky, Z. Ge, Takashi Nakamura, D. Kim, H. Sato, J. Kahlbow, Igor Gašparić, Y. Yasuda, Susumu Shimoura, T. Isobe, Juzo Zenihiro, M. Caamaño, Yosuke Kondo, S. Masuoka, H. Suzuki, A. Hirayama, S. W. Huang, C. A. Douma, B. M. Godoy, Z. Halász, H. Yamada, C. Lehr, M. Böhmer, Nobuyuki Chiga, A. Revel, N. L. Achouri, P. Koseoglou, Kathrin Wimmer, V. Wagner, N. A. Orr, M. Potlog, M. Miwa, B. Yang, A. Obertelli, T. Harada, H. T. Törnqvsit, S. Reichert, H. Miki, D. S. Ahn, T. Tomai, István Kuti, J. Mayer, J. Tanaka, S. Park, Yasuhiro Togano, M. Parlog, Naoki Fukuda, Yu-xin Liu, S. Chen, V. Panin, L. Zanetti, F. Schindler, S. Storck, T. Shimada, Tomohiro Uesaka, J. Feng, M. Matsumoto, Zaihong Yang, U. Forsberg, Roman Gernhäuser, I. Murray, F. Dufter, D. Symochko, L. Stuhl, J. M. Gheller, Hideaki Otsu, D. Beaumel, T. Kobayashi, H. Takeda, A. Gillibert, D. Cortina, P. Doornenbal, L. Yang, Nasser Kalantar-Nayestanaki, Satoshi Takeuchi, Thomas Aumann, Stefanos Paschalis, T. Fujino, D. M. Rossi, H. Baba, Yohei Shimizu, M. L. Cortés, F. M. Marqués, B. Fernández-Domínguez, Yuya Kubota, Yukie Maeda, S. K. Kim, P. J. Li, 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, Firm conclusion, Spectrometer, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 010305 fluids & plasmas, Nuclear physics, 0103 physical sciences, Tetraneutron, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

The tetraneutron has been drawing the attention of the nuclear physics community for decades, but a firm conclusion on its existence and properties is still far from being reached despite many experimental and theoretical efforts. New measurements have recently been performed at RIBF with the SAMURAI spectrometer by applying complementary reaction probes, which will help to pin down the properties of this four-neutron system., Comment: 5 pages, 2 figures, conference proceedings of XXII International Conference on Few-Body Problems in Physics (FB22), Caen, France, July 2018

Published
2018

20. Structure of Beryllium Isotopes Beyond the Neutron Dripline

Author

V. Panin, Tsuyoshi Miyazaki, K. Yoneda, T. Isobe, S. Reichert, T. Uesaka, K. Hasegawa, Y. Shindo, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, J. Gibelin, C. Caesar, T. Ozaki, D. Kim, J.-Y. Roussé, Yuya Kubota, Yasuhiro Togano, F. M. Marqués, Yohei Shimizu, Takashi Nakamura, Zaihong Yang, Ji Feng, M. Sako, G. Authelet, J. M. Gheller, T. Kobayashi, E. C. Pollacco, Hideaki Otsu, Masanori Dozono, Yukie Maeda, Atsumi Saito, V. Lapoux, L. Stuhl, D. Calvet, M. Shikata, Toshiyuki Sumikama, Satoshi Sakaguchi, Noritsugu Nakatsuka, Juzo Zenihiro, A. Corsi, A. Delbart, Masaki Sasano, A. Ohkura, J. Yasuda, Motoki Kobayashi, Shoko Koyama, Z. Korkulu, Y. Kanaya, H. Sato, Yosuke Kondo, A. Gillibert, Y. Kiyokawa, A. Obertelli, Y. Nishio, A. Giganon, M. Tabata, T. Motobayashi, S. Kawakami, H. Baba, B. Monteagudo, J. Tsubota, C. Santamaria, N. A. Orr, S. Ota, 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 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Nuclear structure, Structure (category theory), 01 natural sciences, 7. Clean energy, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, medicine, Spontaneous emission, Neutron, 010306 general physics, Isotopes of beryllium, Nuclear Experiment, Nucleus, Beam (structure)
Abstract

International audience; Dineutron decay is a forefront topic in nuclear structure that still lacks a firm experimental claim. The spontaneous emission of a dineutron should be favored in nuclei that are unbound with respect to two-neutron emission but bound with respect to single-neutron emission. A very interesting candidate can be found by adding two neutrons to the most neutron-rich Beryllium isotope,$^{14}$Be, a well-known 2n-halo nucleus. The intriguing nature of the phenomenon has motivated recent theoretical calculations and a new experimental campaign at RIKEN RIBF. In this work, the decay properties of$^{16}$Be and the structure of$^{15}$Be have been probed via the proton-knockout reaction from a$^{17}$B beam.

Published
2018

21. Inelastic scattering of neutron-rich Ni and Zn isotopes off a proton target

Author

R. Lozeva, M. Lettmann, J.-Y. Roussé, Tadaaki Isobe, Pieter Doornenbal, F. Nowacki, Zena Patel, Satoshi Takeuchi, H. Otsu, K. Matsui, M. L. Cortés, K. Yoneda, C. Santamaria, S. Franchoo, Tohru Motobayashi, Hidetada Baba, E. Sahin, Hiroyoshi Sakurai, Shuichi Ota, C. Péron, S. Nishimura, G. Authelet, F. Giacoppo, Shunpei Koyama, E. C. Pollacco, Alan Peyaud, Jin Wu, L. X. Chung, H. Wang, F. Château, F. Browne, Ryo Taniuchi, J. M. Gheller, Marc Dupuis, T. Sumikama, V. Lapoux, D. Calvet, Zs. Vajta, David Steppenbeck, A. Gillibert, A. Obertelli, Daisuke Suzuki, A. Gottardo, P. A. Söderström, Jenny Lee, S. M. Lenzi, Yoshiaki Shiga, A. Corsi, Kathrin Wimmer, K. Hadynska-Klek, Yuya Kubota, Megumi Niikura, Sophie Péru, Tomohiro Uesaka, I. Stefan, Zs. Dombrádi, C. M. Shand, Norbert Pietralla, A. Delbart, V. Werner, Z. Korkulu, Zhengyu Xu, T. Miyazaki, M. Matsushita, L. Olivier, C. Louchart, Masaki Sasano, Satoru Momiyama, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), 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), 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), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Scattering, Hadron, Nuclear Theory, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Isotopes of zinc, Gamma spectroscopy, Neutron, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

International audience; Proton inelastic scattering of Ni72,74 and Zn76,80 ions at energies around 235 MeV/nucleon was performed at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. Angular integrated cross sections for direct inelastic scattering to the 21+ and 41+ states were measured. The Jeukenne-Lejeune-Mahaux folding model, extended beyond 200 MeV, was used together with neutron and proton densities stemming from quasiparticle random-phase approximation (QRPA) calculations to interpret the experimental cross sections and to infer neutron to proton matrix element ratios. In addition, coupled-channels calculations with a phenomenological potential were used to determine deformation lengths. For the Ni isotopes, correlations favor neutron excitations, thus conserving the Z=28 gap. A dominance of proton excitation, on the other hand, is observed in the Zn isotopes, pointing to the conservation of the N=50 gap approaching Ni78. These results are in agreement with QRPA and large-scale shell-model calculations.

Published
2018

22. Triaxiality of neutron-rich Ge84,86,88 from low-energy nuclear spectra

Author

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

Subjects
Physics, Low energy, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spectroscopy, 01 natural sciences, Spectral line
Abstract

ray transitions between low-spin states of the neutron-rich 84;86;88Ge were measured by means of in-flight -ray spectroscopy at 270 MeV/u. Excited 6+ 1 , 4+ 1;2 and 2+ 1;2 states of 84;86Ge and 4+ 1 and 2+ 1;2 states of 88Ge were observed. Furthermore a candidate for a 3+ 1 state of 86Ge was identified. This state plays a key role in the discussion of ground-state triaxiality of 86Ge, along with other features of its low-energy level scheme. A new region of triaxially deformed nuclei is proposed in the Ge isotopic chain.

Published
2017

23. Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60 : First Spectroscopy of Kr98,100

Author

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

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, Isotopes of krypton, 01 natural sciences, Neutron number, 0103 physical sciences, Isotopes of zirconium, Neutron, Gamma spectroscopy, Atomic physics, Nuclear Experiment, 010306 general physics, Spectroscopy, Nucleon
Abstract

We report on the first γ-ray spectroscopy of low-lying states in neutron-rich 98,100Kr isotopes obtained from 99,101Rb(p,2p) reactions at ∼ 220 MeV/nucleon. A reduction of the 2+ 1 state energies beyond N = 60 demonstrates a significant increase of deformation, shifted in neutron number compared to the sharper transition observed in strontium and zirconium isotopes. State-of-theart beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (0+ 2 , 2+ 2 ) state in 98Kr provides the first experimental evidence of a competing configuration at low energy in neutron-rich krypton isotopes consistent with the oblate-prolate shape coexistence picture suggested by theory

Published
2017

24. Collectivity of neutron-rich Cr and Fe toward N=50

Author

Hidetada Baba, Tohru Motobayashi, Jenny Lee, Yuya Kubota, A. Delbart, Shuichi Ota, R. Lozeva, T. Sumikama, E. Sahin, K. Hadynska-Klek, David Steppenbeck, A. Gottardo, M. Lettmann, C. M. Shand, E. C. Pollacco, S. Nishimura, R. Taniuchi, Alessandra Corsi, Satoshi Takeuchi, Zena Patel, Pieter Doornenbal, V. Lapoux, C. Santamaria, V. Werner, F. Nowacki, S. Franchoo, C. Louchart, Z. Korkulu, Norbert Pietralla, J.-Y. Roussé, Tadaaki Isobe, Zs. Vajta, Daisuke Suzuki, Satoru Momiyama, M. Matsushita, A. Gillibert, Megumi Niikura, Jin Wu, L. X. Chung, P. A. Söderström, Tomohiro Uesaka, Zhengyu Xu, Alan Peyaud, T. Miyazaki, H. Wang, D. Calvet, A. Obertelli, Masaki Sasano, F. Giacoppo, C. Péron, G. Authelet, J. M. Gheller, Hiroyoshi Sakurai, F. Browne, Shoko Koyama, L. Olivier, Zs. Dombradi, F. Château, Hideaki Otsu, I. Stefan, K. Yoneda, K. Matsui, and Yoshiaki Shiga

Subjects
Physics, Nuclear reaction, Isotopes of uranium, 010308 nuclear & particles physics, Island of inversion, Fission, QC1-999, 7. Clean energy, 01 natural sciences, Engineering physics, Uranium-238, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Spectrograph
Abstract

Within the SEASTAR project at RIKEN-RIBF, 66 Cr and 70,72 Fe have been produced via protonknockout reactions, and their first excited 2+ and 4+ states have been discovered. The combination of the liquid-hydrogen target and TPC system MINOS has been used in combination with the DALI2 detector array for the first time. A 345 MeV/u 238 U beam with a mean intensity of about 12 pnA impinged on a Be target. Fission fragments were separated and identified using the BigRIPS spectrograph, and reaction products were analyzed using the ZeroDegree spectrograph. A plateau of excitation energies, with a small change in the systematic trends past N = 44, reveals an extension of the N = 40 region of collectivity toward N = 50. Hence, the isotopes of interest are located within the N = 40 island of inversion. An interpretation of the observed trends is offered through large scale shell model calculations.

Published
2016

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