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3. Signatures of triaxiality in low-spin spectra of ⁸⁶Ge

Author

Lettmann, M., Werner, V., Pietralla, N., Doornenbal, P., Obertelli, A., Rodríguez, T.R., Sieja, K., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J.-Y., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A., Caroll, R.J., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jungclaus, A., Lee, J., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C., Nobs, C.R., Olivier, L., Patel, Z., Podolyák, Zs., Rudigier, M., Saito, T., Shand, C., Söderström, P.-A., Stefan, I., Vaquero, V., Wimmer, K., Xu, Z., Lettmann, M., Werner, V., Pietralla, N., Doornenbal, P., Obertelli, A., Rodríguez, T.R., Sieja, K., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J.-Y., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A., Caroll, R.J., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jungclaus, A., Lee, J., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C., Nobs, C.R., Olivier, L., Patel, Z., Podolyák, Zs., Rudigier, M., Saito, T., Shand, C., Söderström, P.-A., Stefan, I., Vaquero, V., Wimmer, K., and Xu, Z.

Published
2024

4. Level structures of 56,58Ca cast doubt on a doubly magic 60Ca

Author

Chen, S., primary, Browne, F., additional, Doornenbal, P., additional, Lee, J., additional, Obertelli, A., additional, Tsunoda, Y., additional, Otsuka, T., additional, Chazono, Y., additional, Hagen, G., additional, Holt, J.D., additional, Jansen, G.R., additional, Ogata, K., additional, Shimizu, N., additional, Utsuno, Y., additional, Yoshida, K., additional, Achouri, N.L., additional, Baba, H., additional, Calvet, D., additional, Château, F., additional, Chiga, N., additional, Corsi, A., additional, Cortés, M.L., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Hilaire, C., additional, Isobe, T., additional, Kobayashi, T., additional, Kubota, Y., additional, Lapoux, V., additional, Liu, H.N., additional, Motobayashi, T., additional, Murray, I., additional, Otsu, H., additional, Panin, V., additional, Paul, N., additional, Rodriguez, W., additional, Sakurai, H., additional, Sasano, M., additional, Steppenbeck, D., additional, Stuhl, L., additional, Sun, Y.L., additional, Togano, Y., additional, Uesaka, T., additional, Wimmer, K., additional, Yoneda, K., additional, Aktas, O., additional, Aumann, T., additional, Chung, L.X., additional, Flavigny, F., additional, Franchoo, S., additional, Gasparic, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K.I., additional, Kim, D., additional, Koiwai, T., additional, Kondo, Y., additional, Koseoglou, P., additional, Lehr, C., additional, Linh, B.D., additional, Lokotko, T., additional, MacCormick, M., additional, Moschner, K., additional, Nakamura, T., additional, Park, S.Y., additional, Rossi, D., additional, Sahin, E., additional, Söderström, P.-A., additional, Sohler, D., additional, Takeuchi, S., additional, Törnqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., additional, Werner, V., additional, Xu, X., additional, Yamada, H., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2023
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5. Level Structures of $^{56,58}$Ca Cast Doubt on a doubly magic $^{60}$Ca

Author

Chen, S, Browne, F, Doornenbal, P, Lee, J, Obertelli, A, Tsunoda, Y, Otsuka, T, Chazono, Y, Hagen, G, Holt, J.D, Jansen, G.R, Ogata, K, Shimizu, N, Utsuno, Y, Yoshida, K, Achouri, N.L, Baba, H, Calvet, D, Château, F, Chiga, N, Corsi, A, Cortés, M.L, Delbart, A, Gheller, J.-M, Giganon, A, Gillibert, A, Hilaire, C, Isobe, T, Kobayashi, T, Kubota, Y, Lapoux, V, Liu, H.N, Motobayashi, T, Murray, I, Otsu, H, Panin, V, Paul, N, Rodriguez, W, Sakurai, H, Sasano, M, Steppenbeck, D, Stuhl, L, Sun, Y.L, Togano, Y, Uesaka, T, Wimmer, K, Yoneda, K, Aktas, O, Aumann, T, Chung, L.X, Flavigny, F, Franchoo, S, Gasparic, I, Gerst, R.-B, Gibelin, J, Hahn, K.I, Kim, D, Koiwai, T, Kondo, Y, Koseoglou, P, Lehr, C, Linh, B.D, Lokotko, T, Maccormick, M, Moschner, K, Nakamura, T, Park, S.Y, Rossi, D, Sahin, E, Söderström, P.-A, Sohler, D, Takeuchi, S, Törnqvist, H, Vaquero, V, Wagner, V, Wang, S, Werner, V, Xu, X, Yamada, H, Yan, D, Yang, Z, Yasuda, M, Zanetti, L, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), 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 Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory (nucl-th), [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, FOS: Physical sciences, Shell evolution, Nuclear Experiment (nucl-ex), Nuclear Experiment, Ray spectroscopy
Abstract

Gamma decays were observed in $^{56}$Ca and $^{58}$Ca following quasi-free one-proton knockout reactions from $^{57,59}$Sc beams at $\approx 200$ MeV/nucleon. For $^{56}$Ca, a $\gamma$ ray transition was measured to be 1456(12) keV, while for $^{58}$Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the $2^+_1 \rightarrow 0^+_{gs}$ decays, and were compared to results from ab initio and conventional shell-model approaches. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for $2^+_1$ level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the $N$ = 34 shell. Its constituents, the $0f_{5/2}$ and $0g_{9/2}$ orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic $^{60}$Ca and potentially drives the dripline of Ca isotopes to $^{70}$Ca or even beyond., Comment: 8 pages, 3 figures

Published
2023
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6. Level structures of Ca cast doubt on a doubly magic Ca

Author

Chen, S., Browne, F., Doornenbal, P., Lee, J., Obertelli, A., Tsunoda, Y., Otsuka, T., Chazono, Y., Hagen, G., Holt, J.D., Jansen, G.R., Ogata, K., Shimizu, N., Utsuno, Y., Yoshida, K., Achouri, N.L., Baba, H., Calvet, D., Château, F., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gasparic, I., Gerst, R.B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lehr, C., Linh, B.D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Söderström, P.A., Sohler, D., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

Gamma decays were observed in $^{56}$Ca and $^{58}$Ca following quasi-free one-proton knockout reactions from $^{57,59}$Sc beams at ≈200 MeV/nucleon. For $^{56}$Ca, a γ ray transition was measured to be 1456(12) keV, while for $^{58}$Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the 21+→0gs+ decays, and were compared to results from ab initio and conventional shell-model approaches. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for 21+ level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the 0f5/2 and 0g9/2 orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic $^{60}$Ca and potentially drives the dripline of Ca isotopes to $^{70}$Ca or even beyond.

Published
2023

7. A first glimpse at the shell structure beyond 54Ca: Spectroscopy of 55K, 55Ca, and 57Ca

Author

Koiwai, T., primary, Wimmer, K., additional, Doornenbal, P., additional, Obertelli, A., additional, Barbieri, C., additional, Duguet, T., additional, Holt, J.D., additional, Miyagi, T., additional, Navrátil, P., additional, Ogata, K., additional, Shimizu, N., additional, Somà, V., additional, Utsuno, Y., additional, Yoshida, K., additional, Achouri, N.L., additional, Baba, H., additional, Browne, F., additional, Calvet, D., additional, Château, F., additional, Chen, S., additional, Chiga, N., additional, Corsi, A., additional, Cortés, M.L., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Hilaire, C., additional, Isobe, T., additional, Kobayashi, T., additional, Kubota, Y., additional, Lapoux, V., additional, Liu, H.N., additional, Motobayashi, T., additional, Murray, I., additional, Otsu, H., additional, Panin, V., additional, Paul, N., additional, Rodriguez, W., additional, Sakurai, H., additional, Sasano, M., additional, Steppenbeck, D., additional, Stuhl, L., additional, Sun, Y.L., additional, Togano, Y., additional, Uesaka, T., additional, Yoneda, K., additional, Aktas, O., additional, Aumann, T., additional, Chung, L.X., additional, Flavigny, F., additional, Franchoo, S., additional, Gasparic, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K.I., additional, Kim, D., additional, Kondo, Y., additional, Koseoglou, P., additional, Lee, J., additional, Lehr, C., additional, Linh, B.D., additional, Lokotko, T., additional, MacCormick, M., additional, Moschner, K., additional, Nakamura, T., additional, Park, S.Y., additional, Rossi, D., additional, Sahin, E., additional, Söderström, P.-A., additional, Sohler, D., additional, Takeuchi, S., additional, Toernqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., additional, Werner, V., additional, Xu, X., additional, Yamada, H., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2022
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8. Extended p3/2 Neutron Orbital and the N=32 Shell Closure in Ca 52

Author

Enciu, M., Liu, H.N., Obertelli, A., Doornenbal, P., Nowacki, F., Ogata, K., Poves, A., Yoshida, K., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gasparic, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Kim, D., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Li, P.J., Linh, B.D., Lokotko, T., Maccormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, Eda, Söderström, P.-A., Sohler, D., Takeuchi, S., Toernqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

The one-neutron knockout from 52Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states in 51Ca and the momentum distributions corresponding to the removal of 1f7/2 and 2p3/2 neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f7/2 and 2p3/2 orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p3/2 orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.

Published
2022

9. 'Southwestern' boundary of the <math><mrow><mi>N</mi><mo>=</mo><mn>40</mn></mrow></math> island of inversion: First study of low-lying bound excited states in <math><mmultiscripts><mi mathvariant='normal'>V</mi><mprescripts/><none/><mn>59</mn></mmultiscripts></math> and <math><mmultiscripts><mi mathvariant='normal'>V</mi><mprescripts/><none/><mn>61</mn></mmultiscripts></math>

Author

Elekes, Z., Juhász, M.M., Sohler, D., Sieja, K., Yoshida, K., Ogata, K., Doornenbal, P., Obertelli, A., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Dombrádi, Zs., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., Maccormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Söderström, P.-A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., 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, 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), 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 Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Sunflower

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; The low-lying level structure of V59 and V61 was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V61 while the neutron knock-out reaction provided the data for V59. Four and five new transitions were determined for V59 and V61, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed γ rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2− and 9/2− levels. The (p,p′) excitation cross sections for V61 were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V61 could not be unambiguously placed on the island of inversion.

Published
2022
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10. $\gamma$-ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich $^{94,95,96}\mathrm{Kr}$

Author

Gerst, R.-B., Blazhev, A., Moschner, K., Doornenbal, P., Obertelli, A., Nomura, K., Ebran, J.-P., Hilaire, S., Libert, J., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J.-Y., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Browne, F., Bruce, A.M., Caroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jolie, J., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podolyák, Zs., Rudigier, M., Saito, T., Shand, C., Söderström, P.-A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., Xu, Z., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-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), Institut de Physique Nucléaire d'Orsay (IPNO), 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
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; We report on γ-ray spectroscopy of low-lying excited states in the neutron-rich Kr94,95,96 isotopes measured as part of the “Shell Evolution And Search for Two-plus energies At RIBF” (SEASTAR) campaign at the RIKEN Radioactive Isotope Beam Factory. Excited yrast and non-yrast states were observed, and half-lives extracted via geant4 simulations. In Kr94,96 candidates for the 31− state were identified. For Kr95, the prompt SEASTAR data were combined with delayed spectroscopic data measured with the EURICA array to observe transitions on top of the known (7/2)+ isomer at a level energy of 195.5(3) keV. The comparison of the new experimental results with five-dimensional collective Hamiltonian (5DCH) and mapped interacting boson model (IBM) calculations, both using the Gogny D1M interaction, could suggest oblate-prolate shape coexistence already in Kr96.

Published
2022
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11. First spectroscopic study of Ar by the (p,2p) reaction

Author

Juhász, M.M., Elekes, Z., Sohler, D., Utsuno, Y., Yoshida, K., Otsuka, T., Ogata, K., Doornenbal, P., Obertelli, A., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Achouri, N.L., Aktas, O., Aumann, T., Chung, L.X., Dombrádi, Zs., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Liu, H.N., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Söderström, P.A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

The nuclear structure of $^{51}$Ar, 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 $^{50}$Ar+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 $^{50}$Ar. The low cross sections populating the two bound states of $^{51}$Ar 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 $^{51}$Ar.

Published
2021

12. Pairing Forces Govern Population of Doubly Magic $^{54}$Ca from Direct Reactions

Author

Browne, F., Chen, S., Doornenbal, P., Obertelli, A., Ogata, K., Utsuno, Y., Yoshida, K., Achouri, N.L., Baba, H., Calvet, D., Château, F., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Boretzky, K., Caesar, C., Chung, L.X., Flavigny, F., Franchoo, S., Gasparic, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Holl, M., Kahlbow, J., Kim, D., Körper, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., Maccormick, M., Miki, K., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Schindler, F., Simon, H., Söderström, P-A., Sohler, D., Takeuchi, S., Törnqvist, H., Tscheuschner, J., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), RIKEN Nishina Center for Accelerator-Based Science, Japan Society for the Promotion of Science, German Research Foundation, Technische Universität Darmstadt, Federal Ministry of Education and Research (Germany), Swedish Research Council, Ministry of Science and Technology of Vietnam, European Commission, National Research, Development and Innovation Office (Hungary), 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
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th]
Abstract

7 pags., 3 figs., 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., Our gratitude is extended to the RIKEN Nishina Center accelerator staff for the stable and high-intensity transport of the Zn primary beam, and the BigRIPS team for their preparation of the magnetic settings of the secondary beam. F. B. is supported by the RIKEN Special Postdoctoral Researcher Program. S. C. acknowledges support from the IPA program at the RIKEN Nishina Center. K. O. and K. Y. acknowledge the support from Grants-in-Aid of the Japan Society for the Promotion of Science under Grants No. JP16K05352. This work was supported by JSPS KAKENHI Grants No. JP16H02179 and No. JP18H05404, the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Grant No. BL 1513/1-1 HGS-HIRe and Project-ID 279384907-SFB 1245 and the GSI-TU Darmstadt cooperation agreement, the BMBF (Grant No. 05P19RDFN1), Swedish Research Council under Grants No. 621-2014-5558 and No. 2019-04880. L. X. C. and B. D. L. are supported by the Vietnam MOST via the Physics Development Program Grant No. TĐLCN.25/18. D. So. was supported by the European Regional Development Fund Contract No. GINOP-2.3.3-15-2016-00034 and the National Research, Development and Innovation Fund of Hungary via Project No. K128947. L. S, K. I. H., D. K., and S. Y. P. acknowledge the support from the IBS grant funded by the Korea government (No. IBS-R031-D1).

Published
2021
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13. Investigation of the ground-state spin inversion in the neutron-rich Cl47,49 isotopes

Author

Linh, B.D., Corsi, A., Gillibert, A., Obertelli, A., Doornenbal, P., Barbieri, C., Chen, S., Chung, L.X., Duguet, T., Gómez-Ramos, M., Holt, J.D., Moro, A., Navrátil, P., Ogata, K., Phuc, N. T. T., Shimizu, N., Somà, V., Utsuno, Y., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Khai, N.T., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, Eda, Sohler, D., Söderström, P.-A., Takeuchi, S., Ton, N.D., Törnqvist, H., Vaquero, V., Wagner, V., Wang, H., Werner, V., Xu, X., Yamada, Y., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), Laboratoire Kastler Brossel (LKB [Collège de France]), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)), 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory (nucl-th), Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

International audience; A first γ-ray study of Cl47,49 spectroscopy was performed at the Radioactive Isotope Beam Factory with Ar50 projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation γ rays were measured with the NaI(Tl) array DALI2+. Through the one-proton knockout reaction Ar50(p,2p), a spin assignment could be determined for the low-lying states of Cl49 from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity Jπ=3/2+ is deduced for the ground state of Cl49, similar to the recently studied N=32 isotope K51. The evolution of the energy difference E(1/21+)−E(3/21+) is compared to state-of-the-art theoretical predictions.

Published
2021
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14. Investigation of the ground-state spin inversion in the neutron-rich isotopes

Author

Linh, B.D., Corsi, A., Gillibert, A., Obertelli, A., Doornenbal, P., Barbieri, C., Chen, S., Chung, L.X., Duguet, Thomas, Gómez-Ramos, M., Holt, J.D., Moro, A., Navrátil, P., Ogata, K., Phuc, N.T.T., Shimizu, N., Somà, V., Utsuno, Y., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, European Commission, Ministry of Science and Technology of Vietnam, Ministerio de Ciencia, Innovación y Universidades (España), Helmholtz International Center for FAIR, Croatian Science Foundation, German Research Foundation, Institute for Basic Science (South Korea), Federal Ministry of Education and Research (Germany), National Research, Development and Innovation Office (Hungary), Japan Society for the Promotion of Science, National Research Council of Canada, Department of Energy (US), Oak Ridge National Laboratory (US), University of Leicester, Science and Technology Facilities Council (UK), and Natural Sciences and Engineering Research Council of Canada

Abstract

16 pags., 9 figs., 5 tabs., A first -ray study of spectroscopy was performed at the Radioactive Isotope Beam Factory with projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation rays were measured with the NaI(Tl) array DALI2. Through the one-proton knockout reaction , a spin assignment could be determined for the low-lying states of from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity is deduced for the ground state of , similar to the recently studied isotope . The evolution of the energy difference is compared to state-of-the-art theoretical predictions., We thank the RIKEN Nishina Center accelerator staff for their work in the primary beam delivery and the BigRIPS team for preparing the secondary beams. The development of MINOS has been supported by the European Research Council through the ERC Grant No. MINOS258567. B.D.L., L.X.C., and N.D.T. acknowledge support from the Vietnam Ministry of Science and Technology under Grant No. ĐTCB.01/21/VKHKTHN. M.G.R. and A.M.M. are supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (including FEDER funds) under project FIS2017-88410-P. F.B. was supported by the RIKEN Special Postdoctoral Researcher Program. Y.L.S. acknowledges the support of Marie Skłodowska-Curie Individual Fellowship (H2020-MSCAIF-2015-705023) from the European Union. I.G. has been supported by HIC for FAIR and Croatian Science Foundation. R.-B.G. is supported by the Deutsche Forschungsgemeinschaft (DFG) under Grant No. BL 1513/1-1. K.I.H., D.K., and S.Y.P. acknowledge the support from the IBS grant funded by the Korea government (No. IBS-R031-D1). P.K. was supported in part by the BMBF Grant No. 05P19RDFN1 and HGS-HIRe. D.So. has been supported by the European Regional Development Fund Contract No. GINOP-2.3.3-15-2016-00034 and the National Research, Development and Innovation Fund of Hungary via Project No. K128947. This work was supported in part by JSPS KAKENHI Grants No. JP16H02179, No. JP18H05404, and No. JP20K03981. J.D.H. and R.S. acknowledge the support from NSERC and the National Research Council Canada. This work was supported by the Office of Nuclear Physics, U.S. Department of Energy, under Grants No. de-sc0018223 (NUCLEI SciDAC-4 collaboration) and the FieldWork Proposal ERKBP72 at Oak Ridge National Laboratory (ORNL). Computer time was provided by the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program. This research used resources of the Oak Ridge Leadership Computing Facility located at ORNL, which is supported by the Office of Science of the Department of Energy under Contract No. DE-AC05-00OR22725. GGF calculations were performed by using HPC resources from GENCI-TGCC (Contracts No. A007057392 and No. A009057392) and at the DiRAC Complexity system at the University of Leicester (BIS National E-infrastructure capital Grant No. ST/K000373/1 and STFC Grant No. ST/K0003259/1). This work was supported by the United Kingdom Science and Technology Facilities Council (STFC) under Grant No. ST/L005816/1 and in part by the NSERC Grants No. SAPIN-2016-00033, No. SAPIN-2018-00027, and No. RGPAS-2018-522453. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. J.D.H. thanks S. R. Stroberg for the IMSRG++ code used to perform the VSIMSRG calculations [86]. N.T.T.P. was funded by Vingroup Joint Stock Company and supported by the Domestic Ph.D. Scholarship Programme of Vingroup Innovation Foundation (VINIF), Vingroup Big Data Institute (VINBIGDATA), code VINIF.2020.TS.52.

Published
2021

15. N=32 shell closure below calcium: Low-lying structure of Ar 50

Author

Cortés, M.L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J.D., Menéndez, J., Ogata, K., Schwenk, A., Shimizu, N., Simonis, J., Utsuno, Y., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, Japan Society for the Promotion of Science, 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, Ministerio de Ciencia, Innovación y Universidades (España), Natural Sciences and Engineering Research Council of Canada, German Research Foundation, Federal Ministry of Education and Research (Germany), National Research Council of Canada, University of British Columbia, and European Commission

Abstract

9 pags., 6 figs., 4 tabs., Low-lying excited states in the N=32 isotope Ar50 were investigated by in-beam γ-ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3- state. The level scheme built using γγ coincidences was compared to shell-model calculations in the sd-pf model space and to ab initio predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2+ states, while the previously proposed 41+ state could also correspond to a 2+ state., We thank the RIKEN Nishina Center accelerator staff and the BigRIPS team for the stable operation of the high-intensity Zn beam and for the preparation of the secondary beam setting. This work has been supported by the JSPS Grant-in-Aid for Scientific Research JP16K05352, JP18K03639, JP16H02179, and JP18H05404, the RIKEN Special Postdoctoral Researcher Program, Colciencias–Convocatoria 617 Becas Doctorados Nacionales, the Ministry of Science and Technology of Vietnam through the Physics Development Program Grant No. ĐTĐLCN.25/18, HIC for FAIR, the Croatian Science Foundation under Projects No. 1257 and No. 7194, the European Regional Development Fund GINOP-2.3.3-15- 2016-00034 and the National Research, Development and Innovation Fund K128947 projects, the NKFIH (128072), the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P, the NRF Grants No. 2018R1A5A1025563 and No. 2019M7A1A1033186 funded by the Korean government, the MEXT as “Priority issue on post-K computer” (Elucidation of the fundamental laws and evolution of the universe), the Joint Institute for Computational Fundamental Science (JICFuS), the Ramón y Cajal program RYC-2017-22781 of the Spanish Ministry of Science, Innovation and Universities, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project-ID 279384907–SFB 1245 and Grant No. BL 1513/1-1, the PRISMA Cluster of Excellence, and the BMBF under Contracts No. 05P15RDFN1, No. 05P18RDFN1, and No. 05P19RDFN1. TRIUMF receives funding via a contribution through the National Research Council Canada. Computations were performed with an allocation of computing resources on Cedar at WestGrid and Compute Canada, and on the Oak Cluster at TRIUMF managed by the University of British Columbia, Department of Advanced Research Computing (ARC). The development of MINOS was supported by the European Research Council (ERC) through Grant No. MINOS-258567.

Published
2020

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

Author

Frotscher, A., Gómez-Ramos, M., Obertelli, A., Doornenbal, P., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Paul, N., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Shimizu, N., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Jungclaus, Andrea, Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, German Research Foundation, Alexander von Humboldt Foundation, European Research Council, Japan Society for the Promotion of Science, Federal Ministry of Education and Research (Germany), Ministry of Science and Technology of Vietnam, Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, and Chinese Academy of Sciences

Abstract

7 pags., 4 figs., Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250 MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are 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-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei., We thank the RIBF and BigRIPS teams for providing a stable beam and optimum settings over the two experimental campaigns. A. F. acknowledges support from the DFG under Grant No. SFB1245. M. G.-R. acknowledges support from the Alexander von Humboldt foundation. A. O. thanks the European Research Council for its support through ERC Grant No. MINOS-258567, the JSPS Japanese Society for the Promotion of Science for the long-term fellowship L-13520, the German DFG for its support from the SFB Grant No. 1245, and the Alexander von Humboldt Foundation for its support. K. Mo. acknowledges support from German BMBF Grant No. 05P15PKFNA. M. L. C., M. L., and V. W. acknowledge support from German BMBF Grants No. 05P15RDFN1, and No. 05P19RDFN1, as well as DFG Grant No. SFB 1245. L. X. C. and B. D. L. are supported by the Vietnam MOST through Physics Development Program Grant No. Ð TÐ LCN.25/18 and acknowledge the Radioactive Isotope Physics Laboratory of the RIKEN Nishina Center for supporting their stay during the experiment. A. J. and V. V. acknowledge support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2- P. U.K. participants acknowledge support from the Science and Technology Facilities Council (STFC). Collaborators from I. M. P. were supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences. R. T. was supported by the JSPS Grant-in-Aid for JSPS Research Fellows JP14J08718. Zs. D., Z. K., and Zs. V. acknowledge the support from Projects No. OTKA K128947 and No. GINOP-2.3.3-15-2016-00034. C. Santamaria acknowledges support by the IPA program at the RIKEN Nishina Center.

Published
2020

17. Identification of an oblate K-isomer of 94Se60 and implications for a ground-state shape transition between N = 58 - 60

Author

Lizarazo, C., Soderstrom, P.A, Werner, V., Pietralla, N., Walker, P., Dong, G.X, Xu, F.R, Rodriguez, T.R, Browne, F., Doornenbal, P., Nishimura, S., Nita, C.R, Obertelli, A., Ando, T., Arici, T., Authelet, G., Baba, H., Blazhev, A., Bruce, A.M, Calvet, D., Caroll, R.J, Chateau, F., Chen, S., Chung, L.X, Corsi, A., Cortes, M.L, Delbart, A., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Gerl, J., Gheller, J.M, Giagnon, A., Gillibert, A., Gorska, M., Gottardo, A., Kojouharov, I., Kurz, N., Lapoux, V., Lee, J., Lettmann, M., Linh, B.D, Liu, J.J, Liu, Z., Momiyama, S., Moschner, K., Motobayashi, T., Nagamine, S., Nakatsuka, N., Niikura, M., Nobs, C., Olivier, L., Patel, Z., Paul, N., Podolyak, Zsolt, Rousse, J.Y, Rudigier, M., Saito, T.Y, Sakurai, H., Santamaria, C., Schaffner, H., Shand, C., Stefan, I., Steppenbeck, D., Taniuchi, R., Uesaka, T., Vaquero, V., Wimmer, K., and Xu, Z.

Subjects
Nuclear Experiment
Abstract

In this letter we report on new information on the shape evolution of the very neutron-rich 92;94Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed -rays emitted following the decay of these nuclei. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasi-neutron states with an oblate deformation of B ~ - 0:25, with the high-K state in 94Se being metastable and K hindered. Following this, 94Se is the lowest-mass nucleus known to date with K-forbidden decay and a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. From the decay patterns, an oblate deformation is suggested for the 94Se60 ground-state band, in line with the predictions of recent beyond-mean-field calculations.

Published
2020

18. Investigation of the ground-state spin inversion in the neutron-rich isotopes

Author

RIKEN Nishina Center for Accelerator-Based Science, European Commission, Ministry of Science and Technology of Vietnam, Ministerio de Ciencia, Innovación y Universidades (España), Helmholtz International Center for FAIR, Croatian Science Foundation, German Research Foundation, Institute for Basic Science (South Korea), Federal Ministry of Education and Research (Germany), National Research, Development and Innovation Office (Hungary), Japan Society for the Promotion of Science, National Research Council of Canada, Department of Energy (US), Oak Ridge National Laboratory (US), University of Leicester, Science and Technology Facilities Council (UK), Natural Sciences and Engineering Research Council of Canada, Linh, B.D., Corsi, A., Gillibert, A., Obertelli, A., Doornenbal, P., Barbieri, C., Chen, S., Chung, L.X., Duguet, Thomas, Gómez-Ramos, M., Holt, J.D., Moro, A., Navrátil, P., Ogata, K., Phuc, N.T.T., Shimizu, N., Somà, V., Utsuno, Y., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H. N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, European Commission, Ministry of Science and Technology of Vietnam, Ministerio de Ciencia, Innovación y Universidades (España), Helmholtz International Center for FAIR, Croatian Science Foundation, German Research Foundation, Institute for Basic Science (South Korea), Federal Ministry of Education and Research (Germany), National Research, Development and Innovation Office (Hungary), Japan Society for the Promotion of Science, National Research Council of Canada, Department of Energy (US), Oak Ridge National Laboratory (US), University of Leicester, Science and Technology Facilities Council (UK), Natural Sciences and Engineering Research Council of Canada, Linh, B.D., Corsi, A., Gillibert, A., Obertelli, A., Doornenbal, P., Barbieri, C., Chen, S., Chung, L.X., Duguet, Thomas, Gómez-Ramos, M., Holt, J.D., Moro, A., Navrátil, P., Ogata, K., Phuc, N.T.T., Shimizu, N., Somà, V., Utsuno, Y., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H. N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., and Vaquero, Victor

Abstract

A first -ray study of spectroscopy was performed at the Radioactive Isotope Beam Factory with projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation rays were measured with the NaI(Tl) array DALI2. Through the one-proton knockout reaction , a spin assignment could be determined for the low-lying states of from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity is deduced for the ground state of , similar to the recently studied isotope . The evolution of the energy difference is compared to state-of-the-art theoretical predictions.

Published
2021

19. Nuclear matter distributions in the neutron-rich carbon isotopes 14−17C from intermediate-energy proton elastic scattering in inverse kinematics

Author

Dobrovolsky, A.V., primary, Korolev, G.A., additional, Tang, S., additional, Alkhazov, G.D., additional, Colò, G., additional, Dillmann, I., additional, Egelhof, P., additional, Estradé, A., additional, Farinon, F., additional, Geissel, H., additional, Ilieva, S., additional, Inglessi, A.G., additional, Ke, Y., additional, Khanzadeev, A.V., additional, Kiselev, O.A., additional, Kurcewicz, J., additional, Chung, L.X., additional, Litvinov, Yu.A., additional, Petrov, G.E., additional, Prochazka, A., additional, Scheidenberger, C., additional, Sergeev, L.O., additional, Simon, H., additional, Takechi, M., additional, Volkov, V., additional, Vorobyov, A.A., additional, Weick, H., additional, and Yatsoura, V.I., additional

Published
2021
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20. First spectroscopic study of 51Ar by the (p,2p) reaction

Author

Juhász, M.M., primary, Elekes, Z., additional, Sohler, D., additional, Utsuno, Y., additional, Yoshida, K., additional, Otsuka, T., additional, Ogata, K., additional, Doornenbal, P., additional, Obertelli, A., additional, Baba, H., additional, Browne, F., additional, Calvet, D., additional, Château, F., additional, Chen, S., additional, Chiga, N., additional, Corsi, A., additional, Cortés, M.L., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Hilaire, C., additional, Isobe, T., additional, Kobayashi, T., additional, Kubota, Y., additional, Lapoux, V., additional, Motobayashi, T., additional, Murray, I., additional, Otsu, H., additional, Panin, V., additional, Paul, N., additional, Rodriguez, W., additional, Sakurai, H., additional, Sasano, M., additional, Steppenbeck, D., additional, Stuhl, L., additional, Sun, Y.L., additional, Togano, Y., additional, Uesaka, T., additional, Wimmer, K., additional, Yoneda, K., additional, Achouri, N.L., additional, Aktas, O., additional, Aumann, T., additional, Chung, L.X., additional, Dombrádi, Zs., additional, Flavigny, F., additional, Franchoo, S., additional, Gašparić, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K.I., additional, Kim, D., additional, Koiwai, T., additional, Kondo, Y., additional, Koseoglou, P., additional, Lee, J., additional, Lehr, C., additional, Linh, B.D., additional, Liu, H.N., additional, Lokotko, T., additional, MacCormick, M., additional, Moschner, K., additional, Nakamura, T., additional, Park, S.Y., additional, Rossi, D., additional, Sahin, E., additional, Söderström, P.-A., additional, Takeuchi, S., additional, Törnqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., additional, Werner, V., additional, Xu, X., additional, Yamada, H., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2021
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21. Collectivity of neutron-rich Cr and Fe toward N=50

Author

Werner V., Santamaria C., Louchart C., Obertelli A., Doornenbal P., Nowacki F., Authelet G., Baba H., Calvet D., Château F., Corsi A., Delbart A., Gheller J.-M., Gillibert A., Isobe T., Lapoux V., Matsushita M., Momiyama S., Motobayashi T., Niikura M., Otsu H., Péron C., Peyaud A., Pollacco E.C., Roussé J.-Y., Sakurai H., Sasano M., Shiga Y., Takeuchi S., Taniuchi R., Uesaka T., Wang H., Yoneda K., Browne F., Chung L.X., Dombradi Zs., Franchoo S., Giacoppo F., Gottardo A., Hadynska-Klek K., Korkulu Z., Koyama S., Kubota Y., Lee J., Lettmann M., Lozeva R., Matsui K., Miyazaki T., Nishimura S., Olivier L., Ota S., Patel Z., Pietralla N., Sahin E., Shand C., Söderström P.-A., Stefan I., Steppenbeck D., Sumikama T., Suzuki D., Vajta Zs., Wu J., and Xu Z.

Subjects
Physics, QC1-999
Abstract

Within the SEASTAR project at RIKEN-RIBF, 66Cr and 70,72Fe 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 238U 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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22. Restoration of the natural E(1/21+) - E(3/21+) energy splitting in odd-K isotopes towards N = 40

Author

Sun, Y.L., primary, Obertelli, A., additional, Doornenbal, P., additional, Barbieri, C., additional, Chazono, Y., additional, Duguet, T., additional, Liu, H.N., additional, Navrátil, P., additional, Nowacki, F., additional, Ogata, K., additional, Otsuka, T., additional, Raimondi, F., additional, Somà, V., additional, Utsuno, Y., additional, Yoshida, K., additional, Achouri, N., additional, Baba, H., additional, Browne, F., additional, Calvet, D., additional, Château, F., additional, Chen, S., additional, Chiga, N., additional, Corsi, A., additional, Cortés, M.L., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Hilaire, C., additional, Isobe, T., additional, Kobayashi, T., additional, Kubota, Y., additional, Lapoux, V., additional, Motobayashi, T., additional, Murray, I., additional, Otsu, H., additional, Panin, V., additional, Paul, N., additional, Rodriguez, W., additional, Sakurai, H., additional, Sasano, M., additional, Steppenbeck, D., additional, Stuhl, L., additional, Togano, Y., additional, Uesaka, T., additional, Wimmer, K., additional, Yoneda, K., additional, Aktas, O., additional, Aumann, T., additional, Chung, L.X., additional, Flavigny, F., additional, Franchoo, S., additional, Gašparić, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K.I., additional, Kim, D., additional, Koiwai, T., additional, Kondo, Y., additional, Koseoglou, P., additional, Lee, J., additional, Lehr, C., additional, Linh, B.D., additional, Lokotko, T., additional, MacCormick, M., additional, Moschner, K., additional, Nakamura, T., additional, Park, S.Y., additional, Rossi, D., additional, Sahin, E., additional, Sohler, D., additional, Söderström, P.-A., additional, Takeuchi, S., additional, Törnqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., additional, Werner, V., additional, Xu, X., additional, Yamada, H., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2020
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23. Restoration of the natural (1/2 ) - (3/2 ) energy splitting in odd-K isotopes towards = 40

Author

Sun, Y.L., Obertelli, A., Doornenbal, P., Barbieri, C., Chazono, Y., Duguet, T., Liu, H.N., Navrátil, P., Nowacki, F., Ogata, K., Otsuka, T., Raimondi, F., Somà, V., Utsuno, Y., Yoshida, K., Achouri, N., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Sohler, D., Söderström, P.A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

We report on the first γ-ray spectroscopy of $^{51,53}$K produced via the $^{52,54}$Ca(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 $^{51,53}$K were established quantifying the natural ordering of the 1d3/2 and 2s1/2 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(1/21+) - E(3/21+) energy differences towards N = 40.

Published
2020

24. Restoration of the natural $E (1/2_1^+ ) - E (3/2_1^+ )$ energy splitting in odd-K isotopes towards $N = 40$

Author

Sun, Y.L., Obertelli, A., Doornenbal, P., Barbieri, C., Chazono, Y., Duguet, T., Liu, H.N., Navrátil, P., Nowacki, F., Ogata, K., Otsuka, T., Raimondi, F., Somà, V., Utsuno, Y., Yoshida, K., Achouri, N., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Sohler, D., Söderström, P.-A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), 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), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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
CHARGE RADII, 53K, Science & Technology, 51K, NUCLEI, Physics, HOLE STATES, Shell evolution, Astronomy & Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Physics, Particles & Fields, Physics, Nuclear, K-51, Physical Sciences, SHELL-MODEL, 53 K, 51 K, K-53, Spectroscopy
Abstract

International audience; We report on the first γ -ray spectroscopy of 51,53 K produced via the 52,54 Ca( p ,2 p ) 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 51,53 K were established quantifying the natural ordering of the 1d3/2 and 2s1/2 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
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25. Metastable States of ^{92,94}Se: Identification of an Oblate K Isomer of ^{94}Se and the Ground-State Shape Transition between N=58 and 60

Author

Lizarazo, C., Söderström, P.A., Werner, V., Pietralla, N., Walker, P.M., Dong, G.X., Xu, F.R., Rodríguez, T.R., Browne, F., Doornenbal, P., Nishimura, S., Nita, C.R., Obertelli, A., Ando, T., Arici, T., Authelet, G., Baba, H., Blazhev, A., Bruce, A.M., Calvet, D., Caroll, R.J., Château, F., Chen, S., Chung, L.X., Corsi, A., Cortés, M.L., Delbart, A., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Gerl, J., Gheller, J.M., Giganon, A., Gillibert, A., Górska, M., Gottardo, A., Kojouharov, I., Kurz, N., Lapoux, V., Lee, J., Lettmann, M., Linh, B.D., Liu, J.J., Liu, Z., Momiyama, S., Moschner, K., Motobayashi, T., Nagamine, S., Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, University of Tokyo, Federal Ministry of Education and Research (Germany), European Research Council, Ministerio de Educación y Ciencia (España), National Natural Science Foundation of China, and Science and Technology Facilities Council (UK)

Abstract

6 pags., 4 figs., 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., This work was carried out at the RIBF operated by RIKEN Nishina Center, RIKEN and CNS, University of Tokyo. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. The authors thank the RIBF and BigRIPS teams for providing a stable high-intensity uranium beam and operating the secondary beams. We acknowledge support from the German BMBF Grants No. 05P15RDFN1, No. 05P19RDFN1, No. 05P15PKFNA, and No. 05P19PKFNA, the ERC Grant No. MINOS-258567, the Spanish MEC under Contracts No. FPA2014-57196-C5-4-P and No. FIS2014-53434, the National Key R&D Program of China (Contract No. 2018YFA0404402), the National Natural Science Foundation of China (Grants No. 11961141004, No. 11735017, No. 11675225, No. 11635003), the Vietnam MOST via the Physics Development Program Grant No. ĐTĐLCN.25/18, as well as from the Science and Technology Facilities Council (STFC). We further thank GSI for providing computing facilities.

Published
2020

26. Metastable States of $^{92,94}\mathrm{Se}$: Identification of an Oblate $K$ Isomer of $^{94}\mathrm{Se}$ and the Ground-State Shape Transition between $N=58\text{ }\text{and}\text{ }60$

Author

Lizarazo, C., Söderström, P.A., Werner, V., Pietralla, N., Walker, P.M., Dong, G.X., Xu, F.R., Rodríguez, T.R., Browne, F., Doornenbal, P., Nishimura, S., Niţă, C.R., Obertelli, A., Ando, T., Arici, T., Authelet, G., Baba, H., Blazhev, A., Bruce, A.M., Calvet, D., Caroll, R.J., Château, F., Chen, S., Chung, L.X., Corsi, A., Cortés, M.L., Delbart, A., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Gerl, J., Gheller, J.M., Giganon, A., Gillibert, A., Górska, M., Gottardo, A., Kojouharov, I., Kurz, N., Lapoux, V., Lee, J., Lettmann, M., Linh, B.D., Liu, J.J., Liu, Z., Momiyama, S., Moschner, K., Motobayashi, T., Nagamine, S., Nakatsuka, N., Niikura, M., Nobs, C., Olivier, L., Patel, Z., Paul, N., Podolyák, Zs., Roussé, J.Y., Rudigier, M., Saito, T.Y., Sakurai, H., Santamaria, C., Schaffner, H., Shand, C., Stefan, I., Steppenbeck, D., Taniuchi, R., Uesaka, T., Vaquero, V., Wimmer, K., Xu, Z., 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), 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::Atomic and Molecular Clusters, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
Abstract

International audience; Here we present new information on the shape evolution of the very neutron-rich Se92,94 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 Se94 being metastable and K hindered. Following this, Se94 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 Se6094 ground-state band.

Published
2020
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27. Sequential Nature of $(p,3p)$ Two-Proton Knockout from Neutron-Rich Nuclei

Author

Frotscher, A., Gómez-Ramos, M., Obertelli, A., Doornenbal, P., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Paul, N., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Shimizu, N., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombradi, Zs., Flavigny, F., Franchoo, S., Giacoppo, F., Górska, M., Gottardo, A., Hadyńska-Klęk, K., Korkulu, Z., Koyama, S., Kubota, Y., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Louchart, C., Lozeva, R., Matsui, K., Miyazaki, T., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C., Nishimura, S., Nobs, C.R., Olivier, L., Ota, S., Patel, Z., Podolyák, Zs., Rudigier, M., Sahin, E., Saito, T.Y., Shand, C., Söderström, P.A., Stefan, I.G., Sumikama, T., Suzuki, D., Orlandi, R., Vaquero, V., Vajta, Zs., Werner, V., Wimmer, K., Wu, J., Xu, Z., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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 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), 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), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, ddc:530, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
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
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28. Shell evolution of = 40 Isotones Towards Ca: First spectroscopy of Ti

Author

Cortés, M.L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J.D., Lenzi, S.M., Menéndez, J., Nowacki, F., Ogata, K., Poves, A., Rodríguez, T.R., Schwenk, A., Simonis, J., Stroberg, S.R., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Sohler, D., Söderström, P.A., Takeuchi, S., Toernqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

Excited states in the N=40 isotone $^{62}$Ti were populated via the $^{63}$V(p,2p)$^{62}$Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 21+→0gs+ and 41+→21+ transitions, observed here for the first time, indicate a deformed $^{62}$Ti ground state. These energies are increased compared to the neighboring $^{64}$Cr and $^{66}$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 $^{62}$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 $^{60}$Ca.

Published
2019

29. In-beam γ Spectroscopy of Neutron-rich $^{63,65,67}$Mn

Author

Hongyang, Lu, Xiaoyu, Liu, Bing, Ding, Zhong, Liu, Doornenbal, P., Obertelli, A., Lenzi, S.M., Walker, P.M., Chung, L.X., Linh, B.D., Authelet, G., Baba, H., Calvet, D., Château, F., Corsi, A., Delbart, A., Gheller, J.M., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Nowacki, F., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Sasano, M., Shiga, Y., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., 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), 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
neutron-rich nuclei, in-beam γ-ray spectroscopy, shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], island of inversion
Abstract

International audience; The excited states in $^{63,65,67}$Mn have been studied via in-beam \begin{document}$\gamma$\end{document}-ray spectroscopy following the knockout reaction of $^{68}$Fe by bombarding a liquid hydrogen target. Similar level schemes have been established for the three isotopes, and the level schemes consist of the 11/2$^{–}$, 9/2$^{–}$, 7/2$^{–}$ and 5/2$_{g.s.}^{–}$ states, which are connected by \begin{document}$\Delta I = 1$\end{document}. The level sequences of $^{65,67}$Mn show features of strongly coupled rotational band with \begin{document}$K^{\pi} = 5/2^{-}$\end{document} expected for the well deformed nuclei. Large-scale shell-model calculations using the modified LNPS (LNPSm) effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole (\begin{document}$4p-4h$\end{document}) neutron configurations and 1-particle-1-hole (\begin{document}$1p-1h$\end{document}) proton configurations for all the states. The experimental results show an enhancement of Urca neutrino cooling in the accreted neutron crust associated with \begin{document}$A = 63$\end{document} nuclei and rule out significant cooling from \begin{document}$A = 65,67$\end{document}.

Published
2019
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30. Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei

Author

Paul, N., Obertelli, A., Bertulani, C. A., Corsi, A., Doornenbal, P., Rodriguez-Sanchez, J. L., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Péron, C., Peyaud, A., Pollacco, E. C., Roussé, J. Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Franchoo, S., Jungclaus, Andrea, Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, European Commission, Japan Society for the Promotion of Science, German Research Foundation, Alexander von Humboldt Foundation, Department of Energy (US), National Science Foundation (US), Xunta de Galicia, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, and Chinese Academy of Sciences

Abstract

7 pags. 4 figs., Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at ∼250 MeV/nucleon are 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 as 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 semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei., We express our gratitude to the RIKEN Nishina Center accelerator staff for providing the stable and high-intensity uranium beam . A. O. thanks the European Research Council for its support through ERC Grant No. MINOS-258567, the Japanese Society for the Promotion of Science for the long-term fellowship L-13520, the German DFG SFB Grant No. 1245, and the Alexander von Humboldt Foundation. C. S. acknowledges support by the IPA program at the RIKEN Nishina Center. C. A. B. acknowledges support by U.S. Department of Energy Grant No. DE-FG02- 08ER41533 and U.S. National Science Foundation Grant No. 1415656. J. L. R.-S. acknowledges support by the Regional Government of Galicia under the program of postdoctoral fellowships. K. M. acknowledges support from German BMBF Grant No. 05P15PKFNA. M. L. C., M. L., and V. W. acknowledge support from German BMBF Grants No. 05P12RDFN8, No. 05P15RDFN1, and No. 05P12RDFN8, as well as DFG Grant No. SFB 1245. L. X. C. and B. D. L. are supported by the Vietnam MOST through Physics Development Program Grant No. ĐTĐLCN.25/18 and acknowledge the Radioactive Isotope Physics Laboratory of the RIKEN Nishina Center for supporting their stay during the experiment. A. J. and V. V. acknowledge support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5-4-P. U.K. participants acknowledge support from the Science and Technology Facilities Council (STFC). Collaborators from I. M. P. were supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.

Published
2019

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

Author

RIKEN Nishina Center for Accelerator-Based Science, German Research Foundation, Alexander von Humboldt Foundation, European Research Council, Japan Society for the Promotion of Science, Federal Ministry of Education and Research (Germany), Ministry of Science and Technology of Vietnam, Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, Chinese Academy of Sciences, Frotscher, A., Gómez-Ramos, M., Obertelli, A., Doornenbal, P., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Paul, N., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Shimizu, N., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Jungclaus, Andrea, Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, German Research Foundation, Alexander von Humboldt Foundation, European Research Council, Japan Society for the Promotion of Science, Federal Ministry of Education and Research (Germany), Ministry of Science and Technology of Vietnam, Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, Chinese Academy of Sciences, Frotscher, A., Gómez-Ramos, M., Obertelli, A., Doornenbal, P., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Paul, N., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Shimizu, N., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Jungclaus, Andrea, and Vaquero, Victor

Abstract

Twenty-one two-proton knockout (p,3p) cross sections were measured from neutron-rich nuclei at ∼250 MeV/nucleon in inverse kinematics. The angular distribution of the three emitted protons was determined for the first time, demonstrating that the (p,3p) kinematics are 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-nucleon removal reactions, further reinforcing the sequential nature of (p,3p) in neutron-rich nuclei.

Published
2020

32. How Robust is the N=34 Subshell Closure? First Spectroscopy of Ar 52

Author

Liu, H. N., Obertelli, A., Doornenbal, P., Bertulani, C. A., Hagen, G., Holt, J.D., Jansen, G. R., Morris, T. D., Schwenk, A., Stroberg, R., Achouri, N., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y. L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, European Commission, German Research Foundation, National Science Foundation (US), Department of Energy (US), Natural Sciences and Engineering Research Council of Canada, National Research Council of Canada, National Research Foundation of Korea, Japan Society for the Promotion of Science, Oak Ridge National Laboratory (US), and SCOAP

Abstract

7 pags., 3 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0, The first γ-ray spectroscopy of Ar52, with the neutron number N=34, was measured using the K53(p,2p) one-proton removal reaction at ∼210 MeV/u at the RIBF facility. The 21+ excitation energy is found at 1656(18) keV, the highest among the Ar isotopes with N>20. This result is the first experimental signature of the persistence of the N=34 subshell closure beyond Ca54, i.e., below the magic proton number Z=20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 21+ systematics of neutron-rich Ar isotopes, and support a N=34 subshell closure in Ar52., We thank the RIKEN Nishina Center accelerator staff for their work in the primary beam delivery and the Big RIP Steam for preparing the secondary beams. The development of MINOS has been supported by the European Research Council through the ERC Grant No. MINOS 258567. Acknowledges the support from the Enhanced Eurotalents program (PCOFUND-GA-2013-600382) co-funded by CEA and the European Union. H.N.L., A.O. and A.S. acknowledge the support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project No. 279384907- SFB 1245. C.A.B. acknowledges support from the U.S. NSF Grant No. 1415656 and the U.S. DOE Grant No.DE-FG02-08ER41533.J.D.H.and R.S.acknowledge the support from NSERC and the National Research Council Canada. Y.L.S. acknowledges the support of Marie Skłodowska-Curie Individual Fellowship (H2020-MSCAIF-2015-705023) from the European Union. I.G. has been supported by HIC for FAIR andCroatianScienceFoundation. L.X.C. and B.D.L. have been supported by the Vietnam MOST through the Physics Development Program Grant No. ĐTĐLCN.25/18. K.I.H., D.K. and S.Y.P. have been supported by the NRF grant funded by the Korea government (No. 2017R1A2B2012382 and 2018R1A5A1025563). This work was supported in part by JSPS KAKENHI Grant No. 16H02179, MEXT KAKENHI Grants No. 24105005 and No. 18H05404. This work was also supported by the Office of Nuclear Physics,U.S.Department of Energy,under Grants No.de-sc 0018223 (NUCLEISciDAC-4collaboration) and the Field Work Proposal ERKBP72 at Oak Ridge National Laboratory (ORNL). Computer time was provided by the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program. Thisresearch used resources of the Oak Ridge Leadership Computing Facility located at ORNL, which is supported by the Office of Science of the Department of Energy under Contract No. DE-AC0500OR22725.

Published
2019

33. How Robust is the $N = 34$ Subshell Closure? First Spectroscopy of $^{52}$Ar

Author

Liu, H.N., Obertelli, A., Doornenbal, P., Bertulani, C.A., Hagen, G., Holt, J.D., Jansen, G.R., Morris, T.D., Schwenk, A., Stroberg, R., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, Si, Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B.D., Lokotko, T., Maccormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Sohler, D., Söderström, P.-A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., 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), 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 Theory (nucl-th), Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Astrophysics::High Energy Astrophysical Phenomena, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, FOS: Physical sciences, ddc:530, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
Abstract

Physical review letters 122(7), 072502 (2019). doi:10.1103/PhysRevLett.122.072502, Published by APS, College Park, Md.

Published
2019
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34. Nuclear structure of $^{76}\mathrm{Ni}$ from the ($p,2p$) reaction

Author

Elekes, Z., Kripkó, Á., Sohler, D., Sieja, K., Ogata, K., Yoshida, K., Doornenbal, P., Obertelli, A., Authelet, G., Baba, H., Calvet, D., Château, F., Corsi, A., Delbart, A., Gheller, J.M., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Shiga, Y., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Browne, F., Chung, L.X., Dombrádi, Zs., Flavigny, F., Franchoo, S., Giacoppo, F., Gottardo, A., Hadyńska-Klęk, K., Korkulu, Z., Koyama, S., Kubota, Y., Lee, J., Lettmann, M., Louchart, C., Lozeva, R., Matsui, K., Miyazaki, T., Niikura, M., Nishimura, S., Olivier, L., Ota, S., Patel, Z., Sahin, E., Shand, C., Söderström, P.A., Stefan, I., Steppenbeck, D., Sumikama, T., Suzuki, D., Vajta, Zs., Werner, V., Wu, J., Xu, Z., 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), SunFlower, 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
Astrophysics::High Energy Astrophysical Phenomena, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure
Abstract

International audience; 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
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35. Quasifree Neutron Knockout from $^{54}\mathrm{Ca}$ Corroborates Arising $N=34$ Neutron Magic Number

Author

Chen, S., Lee, J., Doornenbal, P., Obertelli, A., Barbieri, C., Chazono, Y., Navrátil, P., Ogata, K., Otsuka, T., Raimondi, F., Somà, V., Utsuno, Y., Yoshida, K., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Corsi, A., Cortés, M.L., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kahlbow, J., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Achouri, N., Aktas, O., Aumann, T., Chung, L.X., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.B., Gibelin, J., Hahn, K.I., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lehr, C., Linh, B.D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, E., Sohler, D., Söderström, P.A., Takeuchi, S., Törnqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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 Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
Abstract

International audience; Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a Ca54 beam striking on a liquid hydrogen target at ∼200 MeV/u. A significantly larger cross section to the p3/2 state compared to the f5/2 state observed in the excitation of Ca53 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
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36. Nuclear structure of 76Ni from the (p,2p) reaction

Author

Elekes, Z, Kripkó, Á, Sohler, D, Sieja, K, Ogata, K., Yoshida, K, Doornenbal, P, Obertelli, A, Authelet, G, Baba, H, Calvet, D, Château, F, Corsi, A, Delbart, A, Gheller, J.-M., Gillibert, A, Isobe, T, Lapoux, V, Matsushita, M, Momiyama, S, Motobayashi, T, Otsu, H, Péron, C, Peyaud, A, Pollacco, E.C., Roussé, J-Y, Sakurai, H, Santamaria, C, Shiga, Y, Takeuchi, S, Taniuchi, R, Uesaka, T, Wang, H, Yoneda, K, Browne, F, Chung, L.X., Dombrádi, Zs, Flavigny, F., Franchoo, S, Giacoppo, Francesca, Gottardo, A, Hadynska-Klek, Katarzyna, Korkulu, Z, Koyama, S, Kubota, Y, Lee, J, Lettmann, M, Louchart, C, Lozeva, R, Matsui, K, Miyazaki, T, Niikura, M, Nishimura, S, Olivier, L, Ota, S, Patel, Z, Sahin, Eda, Shand, C, Söderström, P.-A., Stefan, I, Steppenbeck, D, Sumikama, T, Suzuki, D, Vajta, Zs, Werner, V, Wu, J, and Xu, Z

Subjects
Astrophysics::High Energy Astrophysical Phenomena
Abstract

The nuclear structure of the 76 Ni nucleus was investigated by ( p , 2 p ) 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 γ γ and γ γ γ coincidences. According to these coincidence spectra the observed transition connects a new state at 4147 keV and the previously known 4+1 state at 1920 keV. Two weaker transitions were also obtained at 2441 and 2838 keV, which could be tentatively placed to feed the known 2+1 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

37. Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti

Author

Cortés, M.L., primary, Rodriguez, W., additional, Doornenbal, P., additional, Obertelli, A., additional, Holt, J.D., additional, Lenzi, S.M., additional, Menéndez, J., additional, Nowacki, F., additional, Ogata, K., additional, Poves, A., additional, Rodríguez, T.R., additional, Schwenk, A., additional, Simonis, J., additional, Stroberg, S.R., additional, Yoshida, K., additional, Achouri, L., additional, Baba, H., additional, Browne, F., additional, Calvet, D., additional, Château, F., additional, Chen, S., additional, Chiga, N., additional, Corsi, A., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Hilaire, C., additional, Isobe, T., additional, Kobayashi, T., additional, Kubota, Y., additional, Lapoux, V., additional, Liu, H.N., additional, Motobayashi, T., additional, Murray, I., additional, Otsu, H., additional, Panin, V., additional, Paul, N., additional, Sakurai, H., additional, Sasano, M., additional, Steppenbeck, D., additional, Stuhl, L., additional, Sun, Y.L., additional, Togano, Y., additional, Uesaka, T., additional, Wimmer, K., additional, Yoneda, K., additional, Aktas, O., additional, Aumann, T., additional, Chung, L.X., additional, Flavigny, F., additional, Franchoo, S., additional, Gašparić, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K.I., additional, Kim, D., additional, Koiwai, T., additional, Kondo, Y., additional, Koseoglou, P., additional, Lee, J., additional, Lehr, C., additional, Linh, B.D., additional, Lokotko, T., additional, MacCormick, M., additional, Moschner, K., additional, Nakamura, T., additional, Park, S.Y., additional, Rossi, D., additional, Sahin, E., additional, Sohler, D., additional, Söderström, P.-A., additional, Takeuchi, S., additional, Toernqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., additional, Werner, V., additional, Xu, X., additional, Yamada, H., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2020
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38. Spectroscopy of Mn: Strong coupling in the = 40 'island of Inversion'

Author

Liu, X.Y., Liu, Z., Ding, B., Doornenbal, P., Obertelli, A., Lenzi, S.M., Walker, P.M., Chung, L.X., Linh, B.D., Authelet, G., Baba, H., Calvet, D., Château, F., Corsi, A., Delbart, A., Gheller, J.M., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Nowacki, F., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Sasano, M., Shiga, Y., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Lam, Y.H., Huang, T.H., Sun, M.D., Zhang, W.Q., Lu, H.Y., Hou, D.S., Browne, F., Dombradi, Zs., Franchoo, S., Giacoppo, F., Gottardo, A., Hadynska-Klek, K., Korkulu, Z., Koyama, S., Kubota, Y., Lee, J., Lettmann, M., Lozeva, R., Matsui, K., Miyazaki, T., Nishimura, S., Louchart, C., Olivier, L., Ota, S., Patel, Z., Sahin, E., Santamaria, C., Shand, C., Söderström, P.A., Stefan, G.L., Steppenbeck, D., Sumikama, T., Suzuki, D., Vajta, Zs., Werner, V., Wu, J., Xu, Z., Zhou, X.H., Zhang, Y.H., Xu, H.S., and Zhang, F.S.

Abstract

Excited states in $^{63,65,67}$Mn were studied via in-beam γ-ray spectroscopy following knockout reactions from $^{68}$Fe. Similar level schemes, consisting of the 11/2$^{−}$, 9/2$^{−}$, 7/2$^{−}$ and 5/2g.s.− level sequence, connected by I→I−1 transitions, were established, the first time for $^{65,67}$Mn. 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 $^{53−67}$Mn 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

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

Author

RIKEN Nishina Center for Accelerator-Based Science, European Commission, Japan Society for the Promotion of Science, German Research Foundation, Alexander von Humboldt Foundation, Department of Energy (US), National Science Foundation (US), Xunta de Galicia, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, Chinese Academy of Sciences, Paul, N., Obertelli, A., Bertulani, C. A., Corsi, A., Doornenbal, P., Rodriguez-Sanchez, J. L., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J. Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Franchoo, S., Jungclaus, Andrea, Vaquero, Victor, RIKEN Nishina Center for Accelerator-Based Science, European Commission, Japan Society for the Promotion of Science, German Research Foundation, Alexander von Humboldt Foundation, Department of Energy (US), National Science Foundation (US), Xunta de Galicia, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Science and Technology Facilities Council (UK), National Natural Science Foundation of China, Chinese Academy of Sciences, Paul, N., Obertelli, A., Bertulani, C. A., Corsi, A., Doornenbal, P., Rodriguez-Sanchez, J. L., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J. Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombrádi, Zs., Flavigny, F., Franchoo, S., Jungclaus, Andrea, and Vaquero, Victor

Abstract

Fifty-five inclusive single nucleon-removal cross sections from medium mass neutron-rich nuclei impinging on a hydrogen target at ∼250 MeV/nucleon are 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 as 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 semimicroscopic model predictions, highlighting the enhanced role of low-lying level densities in nucleon-removal cross sections from loosely bound nuclei.

Published
2019

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

Author

Liu, X.Y., primary, Liu, Z., additional, Ding, B., additional, Doornenbal, P., additional, Obertelli, A., additional, Lenzi, S.M., additional, Walker, P.M., additional, Chung, L.X., additional, Linh, B.D., additional, Authelet, G., additional, Baba, H., additional, Calvet, D., additional, Château, F., additional, Corsi, A., additional, Delbart, A., additional, Gheller, J.-M., additional, Gillibert, A., additional, Isobe, T., additional, Lapoux, V., additional, Matsushita, M., additional, Momiyama, S., additional, Motobayashi, T., additional, Niikura, M., additional, Nowacki, F., additional, Otsu, H., additional, Péron, C., additional, Peyaud, A., additional, Pollacco, E.C., additional, Roussé, J.-Y., additional, Sakurai, H., additional, Sasano, M., additional, Shiga, Y., additional, Takeuchi, S., additional, Taniuchi, R., additional, Uesaka, T., additional, Wang, H., additional, Yoneda, K., additional, Lam, Y.H., additional, Huang, T.H., additional, Sun, M.D., additional, Zhang, W.Q., additional, Lu, H.Y., additional, Hou, D.S., additional, Browne, F., additional, Dombradi, Zs., additional, Franchoo, S., additional, Giacoppo, F., additional, Gottardo, A., additional, Hadynska-Klek, K., additional, Korkulu, Z., additional, Koyama, S., additional, Kubota, Y., additional, Lee, J., additional, Lettmann, M., additional, Lozeva, R., additional, Matsui, K., additional, Miyazaki, T., additional, Nishimura, S., additional, Louchart, C., additional, Olivier, L., additional, Ota, S., additional, Patel, Z., additional, Sahin, E., additional, Santamaria, C., additional, Shand, C., additional, Söderström, P.-A., additional, Stefan, G.L., additional, Steppenbeck, D., additional, Sumikama, T., additional, Suzuki, D., additional, Vajta, Zs., additional, Werner, V., additional, Wu, J., additional, Xu, Z., additional, Zhou, X.H., additional, Zhang, Y.H., additional, Xu, H.S., additional, and Zhang, F.S., additional

Published
2018
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41. Signatures of triaxiality in low-spin spectra of 86Ge

Author

Lettmann, M., primary, Werner, V., additional, Pietralla, N., additional, Doornenbal, P., additional, Obertelli, A., additional, Rodríguez, T.R., additional, Sieja, K., additional, Authelet, G., additional, Baba, H., additional, Calvet, D., additional, Château, F., additional, Chen, S., additional, Corsi, A., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, A., additional, Gillibert, A., additional, Lapoux, V., additional, Motobayashi, T., additional, Niikura, M., additional, Paul, N., additional, Roussé, J.-Y., additional, Sakurai, H., additional, Santamaria, C., additional, Steppenbeck, D., additional, Taniuchi, R., additional, Uesaka, T., additional, Ando, T., additional, Arici, T., additional, Blazhev, A., additional, Browne, F., additional, Bruce, A., additional, Caroll, R.J., additional, Chung, L.X., additional, Cortés, M.L., additional, Dewald, M., additional, Ding, B., additional, Flavigny, F., additional, Franchoo, S., additional, Górska, M., additional, Gottardo, A., additional, Jungclaus, A., additional, Lee, J., additional, Linh, B.D., additional, Liu, J., additional, Liu, Z., additional, Lizarazo, C., additional, Momiyama, S., additional, Moschner, K., additional, Nagamine, S., additional, Nakatsuka, N., additional, Nita, C., additional, Nobs, C.R., additional, Olivier, L., additional, Patel, Z., additional, Podolyák, Zs., additional, Rudigier, M., additional, Saito, T., additional, Shand, C., additional, Söderström, P.-A., additional, Stefan, I., additional, Vaquero, V., additional, Wimmer, K., additional, and Xu, Z., additional

Published
2018
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42. Signatures of triaxiality in low-spin spectra of Ge-86

Author

Federal Ministry of Education and Research (Germany), SCOAP, European Commission, Ministerio de Economía y Competitividad (España), Vietnam Academy of Science and Technology, Science and Technology Facilities Council (UK), Lettmann, M., Werner, V., Pietralla, N., Doornenbal, P., Obertelli, A., Rodríguez, T. R., Sieja, K., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J. Y., Sakurai, H., Santamaria, C., Teppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A., Caroll, R.J., Chung, L.X., Cortés, M.L., Dewald, M., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jungclaus, Andrea, Lee, H. C. J., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nita, C., Nobs, C. R., Olivier, L., Patel, Z., Podolyák, Z., Rudigier, M., Saito, T., Shand, C., Söderström, P. A., Stefan, I., Vaquero, Victor, Wimmer, K., Xu, Z., Ding, B., Nakatsuka, N., Federal Ministry of Education and Research (Germany), SCOAP, European Commission, Ministerio de Economía y Competitividad (España), Vietnam Academy of Science and Technology, Science and Technology Facilities Council (UK), Lettmann, M., Werner, V., Pietralla, N., Doornenbal, P., Obertelli, A., Rodríguez, T. R., Sieja, K., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J. Y., Sakurai, H., Santamaria, C., Teppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A., Caroll, R.J., Chung, L.X., Cortés, M.L., Dewald, M., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jungclaus, Andrea, Lee, H. C. J., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nita, C., Nobs, C. R., Olivier, L., Patel, Z., Podolyák, Z., Rudigier, M., Saito, T., Shand, C., Söderström, P. A., Stefan, I., Vaquero, Victor, Wimmer, K., Xu, Z., Ding, B., and Nakatsuka, N.

Abstract

Low-spin states of neutron-rich Ge-84,Ge-86,Ge-88 were measured by in-flight gamma-ray spectroscopy at 270 MeV/u at the RIKEN-RIBF facility. The exotic beams have been produced by primary U-238 in-flight fission reactions and impinged on the MINOS device. MINOS combines a 10-cm long LH2 target with a Time Projection Chamber (TPC) to reconstruct the reaction vertices. The reactions were selected by the BigRIPS and the ZeroDegree spectrometers for the incoming and outgoing channels, respectively. Emitted gamma radiation was detected by the NaI-array DALI2. De-excitations from the 6(1)(+), 4(1,2)(+), and 2(1,2)(+) states of Ge-84,Ge- 86 and 4(1)(+) and 26 states of Ge-88 were observed. The data are compared to state-of-the-art shell model and beyond-mean-field calculations. Furthermore, a candidate for a 3(1)(+) state of Ge-86 was identified. This state plays a key role in the discussion of ground-state triaxiality of Ge-86, along with other features of the low-energy level scheme.

Published
2018

43. Persistence of the $Z=28$ Shell Gap Around $^{78}\mathrm{Ni}$: First Spectroscopy of $^{79}\mathrm{Cu}$

Author

Olivier, L., Franchoo, S., Niikura, M., Vajta, Z., Sohler, D., Doornenbal, P., Obertelli, A., Tsunoda, Y., Otsuka, T., Authelet, G., Baba, H., Calvet, D., Château, F., Corsi, A., Delbart, A., Gheller, J.M., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Otsu, H., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Browne, F., Chung, L.X., Dombradi, Z., Flavigny, F., Giacoppo, F., Gottardo, A., Hadyńska-Klęk, K., Korkulu, Z., Koyama, S., Kubota, Y., Lee, J., Lettmann, M., Louchart, C., Lozeva, R., Matsui, K., Miyazaki, T., Nishimura, S., Ogata, K., Ota, S., Patel, Z., Sahin, E., Shand, C., Söderström, P.A., Stefan, I., Steppenbeck, D., Sumikama, T., Suzuki, D., Werner, V., Wu, J., Xu, Z., 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), 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)-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)-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), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, Physics::Accelerator Physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

International audience; In-beam γ-ray spectroscopy of Cu79 is performed at the Radioactive Isotope Beam Factory of RIKEN. The nucleus of interest is produced through proton knockout from a Zn80 beam at 270 MeV/nucleon. The level scheme up to 4.6 MeV is established for the first time and the results are compared to Monte Carlo shell-model calculations. We do not observe significant knockout feeding to the excited states below 2.2 MeV, which indicates that the Z=28 gap at N=50 remains large. The results show that the Cu79 nucleus can be described in terms of a valence proton outside a Ni78 core, implying the magic character of the latter.

Published
2017
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44. Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60 : First Spectroscopy of $^{98,100}$Kr

Author

Flavigny, F., Doornenbal, P., Obertelli, A., Delaroche, J.P., Girod, M., Libert, J., Rodriguez, T.R., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J.Y., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Franchoo, S., Górska, M., Gottardo, A., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C., Nobs, C.R., Olivier, L., Orlandi, R., Patel, Z., Podolyák, Zs., Rudigier, M., Saito, T., Shand, C., Söderström, P.A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., Xu, Z., 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, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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
Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

International audience; We report on the first γ-ray spectroscopy of low-lying states in neutron-rich $^{98,100}$Kr isotopes obtained from $^{99,101}$(p,2p) reactions at ∼220 MeV/nucleon. A reduction of the 21+ 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-the-art beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (02+, 22+) state in $^{98}$Kr 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
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45. Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84 Zn

Author

Shand, C.M., primary, Podolyák, Zs., additional, Górska, M., additional, Doornenbal, P., additional, Obertelli, A., additional, Nowacki, F., additional, Otsuka, T., additional, Sieja, K., additional, Tostevin, J.A., additional, Tsunoda, Y., additional, Authelet, G., additional, Baba, H., additional, Calvet, D., additional, Château, A., additional, Chen, S., additional, Corsi, A., additional, Delbart, A., additional, Gheller, J.M., additional, Giganon, A., additional, Gillibert, A., additional, Isobe, T., additional, Lapoux, V., additional, Matsushita, M., additional, Momiyama, S., additional, Motobayashi, T., additional, Niikura, M., additional, Otsu, H., additional, Paul, N., additional, Péron, C., additional, Peyaud, A., additional, Pollacco, E.C., additional, Roussé, J.-Y., additional, Sakurai, H., additional, Santamaria, C., additional, Sasano, M., additional, Shiga, Y., additional, Steppenbeck, D., additional, Takeuchi, S., additional, Taniuchi, R., additional, Uesaka, T., additional, Wang, H., additional, Yoneda, K., additional, Ando, T., additional, Arici, T., additional, Blazhev, A., additional, Browne, F., additional, Bruce, A.M., additional, Carroll, R.J., additional, Chung, L.X., additional, Cortés, M.L., additional, Dewald, M., additional, Ding, B., additional, Dombrádi, Zs., additional, Flavigny, F., additional, Franchoo, S., additional, Giacoppo, F., additional, Gottardo, A., additional, Hadyńska-Klęk, K., additional, Jungclaus, A., additional, Korkulu, Z., additional, Koyama, S., additional, Kubota, Y., additional, Lee, J., additional, Lettmann, M., additional, Linh, B.D., additional, Liu, J., additional, Liu, Z., additional, Lizarazo, C., additional, Louchart, C., additional, Lozeva, R., additional, Matsui, K., additional, Miyazaki, T., additional, Moschner, K., additional, Nagamine, M., additional, Nakatsuka, N., additional, Nishimura, S., additional, Nita, C.R., additional, Nobs, C.R., additional, Olivier, L., additional, Ota, S., additional, Orlandi, R., additional, Patel, Z., additional, Regan, P.H., additional, Rudigier, M., additional, Şahin, E., additional, Saito, T., additional, Söderström, P.-A., additional, Stefan, I., additional, Sumikama, T., additional, Suzuki, D., additional, Vajta, Zs., additional, Vaquero, V., additional, Werner, V., additional, Wimmer, K., additional, Wu, J., additional, and Xu, Z.Y., additional

Published
2017
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46. Collectivity of neutron-rich Cr and Fe toward N=50

Author

Werner, Volker, Santamaria, C., Louchart, C., Obertelli, Alexandre, Doornenbal, Pieter, Nowacki, Frédéric, Authelet, Gilles, Baba, Hidetada, Calvet, Denis, Château, F., Corsi, Anna, Delbart, Alain, Gheller, Jean-Marc, Gillibert, Alain, Isobe, Tadaaki, Lapoux, Valérie, Matsushita, M., Momiyama, S., Motobayashi, Tohru, Niikura, Megumi, Otsu, Hideaki, Péron, Cedric, Peyaud, Alan, Pollacco, Emanuel C., Roussé, Jean-Yves Andre, Sakurai, Hiroyoshi, Sasano, Masaki, Shiga, Y., Takeuchi, Satoshi, Taniuchi, Ryo, Uesaka, Tomohiro, Wang, Haohao, Yoneda, Ken-ichiro, Browne, Frank, Chung, L.X., Dombrádi, Zsolt, Franchoo, Serge, Giacoppo, F., Gottardo, A., Hadyńska-Kęk, Katarzyna, Korkulu, Zeren, Koyama, Shunpei, Kubota, Yuichi, Lee, J., Lettmann, Marc, Lozeva, R., Matsui, K., Miyazaki, T., Nishimura, Shunji, Olivier, L., Ota, S., Patel, Z., Pietralla, Norbert, Sahin, E., Shand, C., Söderström, Pär-Anders, Stefan, I., Steppenbeck, David, Sumikama, Toshiyuki, Suzuki, Daisuke, Vajta, Zs., Wu, J., Xu, Z., Werner, Volker, Santamaria, C., Louchart, C., Obertelli, Alexandre, Doornenbal, Pieter, Nowacki, Frédéric, Authelet, Gilles, Baba, Hidetada, Calvet, Denis, Château, F., Corsi, Anna, Delbart, Alain, Gheller, Jean-Marc, Gillibert, Alain, Isobe, Tadaaki, Lapoux, Valérie, Matsushita, M., Momiyama, S., Motobayashi, Tohru, Niikura, Megumi, Otsu, Hideaki, Péron, Cedric, Peyaud, Alan, Pollacco, Emanuel C., Roussé, Jean-Yves Andre, Sakurai, Hiroyoshi, Sasano, Masaki, Shiga, Y., Takeuchi, Satoshi, Taniuchi, Ryo, Uesaka, Tomohiro, Wang, Haohao, Yoneda, Ken-ichiro, Browne, Frank, Chung, L.X., Dombrádi, Zsolt, Franchoo, Serge, Giacoppo, F., Gottardo, A., Hadyńska-Kęk, Katarzyna, Korkulu, Zeren, Koyama, Shunpei, Kubota, Yuichi, Lee, J., Lettmann, Marc, Lozeva, R., Matsui, K., Miyazaki, T., Nishimura, Shunji, Olivier, L., Ota, S., Patel, Z., Pietralla, Norbert, Sahin, E., Shand, C., Söderström, Pär-Anders, Stefan, I., Steppenbeck, David, Sumikama, Toshiyuki, Suzuki, Daisuke, Vajta, Zs., Wu, J., and Xu, Z.

Abstract

Within the SEASTAR project at RIKEN-RIBF, 66Cr and 70,72Fe 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 238U 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

47. First observation of γ-ray transitions in 111Mo

Author

Aktas, Özge, Cederwall, Bo, Wyss, Ramon, Nyberg, Ayse, Doornenbal, P., Obertelli, A., Corsi, Anna, Liu, Hongna, Authelet, G., Baba, H., Calvet, D., Ch\^{a}teau, F., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Nikura, M., Paul, N., Rouss\'{e}, J.-Y, Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chen, S., Chung, L.X., Cort\'{e}s, M.L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., G\'{o}rska, M., Gottardo, A., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podoly\'{a}k, Zs., Rudigier, M., Saito, T. Y., Shand, C., S\"{o}derstr\"{o}m, P.-A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., Xu, Z., Aktas, Özge, Cederwall, Bo, Wyss, Ramon, Nyberg, Ayse, Doornenbal, P., Obertelli, A., Corsi, Anna, Liu, Hongna, Authelet, G., Baba, H., Calvet, D., Ch\^{a}teau, F., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Nikura, M., Paul, N., Rouss\'{e}, J.-Y, Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chen, S., Chung, L.X., Cort\'{e}s, M.L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., G\'{o}rska, M., Gottardo, A., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podoly\'{a}k, Zs., Rudigier, M., Saito, T. Y., Shand, C., S\"{o}derstr\"{o}m, P.-A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., and Xu, Z.

Abstract

Excited states in the extremely neutron-rich nuclei 109Mo and 111Mo have been studied following nucleon knock-out reactions. Seven $\gamma$-ray transitions, some of them in prompt mutual coincidence, have been identified for the first time in 11Mo using the DALI2 and MINOS detector systems at the BigRIPS and ZeroDegree electromagnetic fragments separator at the RIBF, RIKEN, Japan. Total Routhian surface (TRS) and Particle- Plus Rotor calculations have been performed to investigate the predicted shape coexistence and its effect on the structure of nuclei in this region of the nuclear chart. Following the results of the calculations, theoretical level schemes are proposed for positive and negative parity states and compared with the experimental findings., QC 20210526

48. Single-particle structures in 85,87Ge

Author

Aktas, Özge, Cederwall, Bo, Qi, Chong, Nyberg, Ayse, Doornenbal, P., Ogata, K., Yoshida, K., Corsi, Anna, Liu, Hongna, Authelet, G., Baba, H., Calvet, D., Ch\^{a}teau, F., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Nikura, M., Paul, N., Y Rouss\'{e}, J., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chen, S., Chung, L.X., Cort\'{e}s, M.L., Dewald, M., Ding, B., Franchoo, S., G\'{o}rska, M., Gottardo, A., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podoly\'{a}k, Zs., Rudigier, M., Saito, T. Y., Shand, C., S\"{o}derstr\"{o}m, P.-A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., Xu, Z., Aktas, Özge, Cederwall, Bo, Qi, Chong, Nyberg, Ayse, Doornenbal, P., Ogata, K., Yoshida, K., Corsi, Anna, Liu, Hongna, Authelet, G., Baba, H., Calvet, D., Ch\^{a}teau, F., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Nikura, M., Paul, N., Y Rouss\'{e}, J., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chen, S., Chung, L.X., Cort\'{e}s, M.L., Dewald, M., Ding, B., Franchoo, S., G\'{o}rska, M., Gottardo, A., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podoly\'{a}k, Zs., Rudigier, M., Saito, T. Y., Shand, C., S\"{o}derstr\"{o}m, P.-A., Stefan, I., Vaquero, V., Werner, V., Wimmer, K., and Xu, Z.

Abstract

Gamma-ray transitions have been identified for the first time in the extremely neutron-rich (N =Z + 25) nucleus 87 Ge following nucleon knockout reactions studied at the RIBF, RIKEN, Japan.New γ-ray transitions from excited states in 85 Ge were also observed and placed in a tentative levelscheme. The exclusive parallel momentum distribution was measured for the 1/2 + state for theneutron knockout reaction leading to 85 Ge which is compared with calculated distorted wave impulseapproximation (DWIA) distributions. The 85,87 Ge results are compared with large-scale shell-modelcalculations and potential energy surface calculations based on the total Routhian surface formalism., QC 20210526

49. Spectroscopy of [formula omitted]Mn: Strong coupling in the N = 40 “island of inversion”.

Author

Liu, X.Y., Liu, Z., Ding, B., Doornenbal, P., Obertelli, A., Lenzi, S.M., Walker, P.M., Chung, L.X., Linh, B.D., Authelet, G., Baba, H., Calvet, D., Château, F., Corsi, A., Delbart, A., Gheller, J.-M., Gillibert, A., Isobe, T., Lapoux, V., and Matsushita, M.

Subjects
*NUCLEAR structure, *NUCLEAR physics, *MATHEMATICAL decoupling, *X-ray spectroscopy, *NUCLEAR shell theory
Abstract

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”. [ABSTRACT FROM AUTHOR]

Published
2018
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