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1. Spectroscopy of deeply bound orbitals in neutron-rich Ca isotopes

Author

Li, P. J., Lee, J., Doornenbal, P., Chen, S., Wang, S., Obertelli, A., Chazono, Y., Holt, J. D., Hu, B. S., Ogata, K., Utsuno, Y., Yoshida, K., Achouri, N. L., 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., 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., Kahlbow, J., Kim, D., Koiwai, T., Kondo, Y., Körper, D., Koseoglou, P., 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., Toernqvist, H., Tscheuschner, J., Vaquero, V., Wagner, V., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The calcium isotopes are an ideal system to investigate the evolution of shell structure and magic numbers. Although the properties of surface nucleons in calcium have been well studied, probing the structure of deeply bound nucleons remains a challenge. Here, we report on the first measurement of unbound states in $^{53}$Ca and $^{55}$Ca, populated from \ts{54,56}Ca($p,pn$) reactions at a beam energy of around 216 MeV/nucleon at the RIKEN Radioactive Isotopes Beam Factory. The resonance properties, partial cross sections, and momentum distributions of these unbound states were analyzed. Orbital angular momentum $l$ assignments were extracted from momentum distributions based on calculations using the distorted wave impulse approximation (DWIA) reaction model. The resonances at excitation energies of 5516(41)\,keV in $^{53}$Ca and 6000(250)\,keV in $^{55}$Ca indicate a significant $l$\, =\,3 component, providing the first experimental evidence for the $\nu 0f_{7/2}$ single-particle strength of unbound hole states in the neutron-rich Ca isotopes. The observed excitation energies and cross-sections point towards extremely localized and well separated strength distributions, with some fragmentation for the $\nu 0f_{7/2}$ orbital in $^{55}$Ca. These results are in good agreement with predictions from shell-model calculations using the effective GXPF1Bs interaction and \textit{ab initio} calculations and diverge markedly from the experimental distributions in the nickel isotones at $Z=28$., Comment: 13 pages, 7 figures

Published
2024
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2. Isospin symmetry in the $T = 1, A = 62$ triplet

Author

Wimmer, K., Ruotsalainen, P., Lenzi, S. M., Poves, A., Hüyük, T., Browne, F., Doornenbal, P., Koiwai, T., Arici, T., Auranen, K., Bentley, M. A., Cortés, M. L., Delafosse, C., Eronen, T., Ge, Z., Grahn, T., Greenlees, P. T., Illana, A., Imai, N., Joukainen, H., Julin, R., Jungclaus, A., Jutila, H., Kankainen, A., Kitamura, N., Longfellow, B., Louko, J., Lozeva, R., Luoma, M., Mauss, B., Napoli, D. R., Niikura, M., Ojala, J., Pakarinen, J., Pereira-Lopez, X., Rahkila, P., Recchia, F., Sandzelius, M., Sarén, J., Taniuchi, R., Tann, H., Uthayakumaar, S., Uusitalo, J., Vaquero, V., Wadsworth, R., Zimba, G., and Yajzey, R.

Subjects
Nuclear Experiment
Abstract

Excited states in the $T_z = 0, -1$ nuclei $^{62}$Ga and $^{62}$Ge were populated in direct reactions of relativistic radioactive ion beams at the RIBF. Coincident \grays were measured with the DALI2$^+$ array and uniquely assigned to the $A=62$ isobars. In addition, $^{62}$Ge was also studied independently at JYFL-ACCLAB using the ${}^{24}$Mg(${}^{40}$Ca,$2n$)${}^{62}$Ge fusion-evaporation reaction. The first excited $T=1, J^\pi =2^+$ states in $^{62}$Ga and $^{62}$Ge were identified at $979(1)$ and $965(1)$~keV, respectively, resolving discrepant interpretations in the literature. States beyond the first $2^+$ state in $^{62}$Ge were also identified for the first time in the present work. The results are compared with shell-model calculations in the $fp$ model space. Mirror and triplet energy differences are analyzed in terms of individual charge-symmetry and charge-independence breaking contributions. The MED results confirm the shrinkage of the $p$-orbits' radii when they are occupied by at least one nucleon on average., Comment: aceepted Phys. Lett. B

Published
2023

3. 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., and Zanetti, L.

Subjects
Nuclear Experiment, Nuclear Theory
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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4. A new study of the $N=32$ and $N=34$ shell gap for Ti and V by the first high-precision MRTOF mass measurements at BigRIPS-SLOWRI

Author

Iimura, S., Rosenbusch, M., Takamine, A., Tsunoda, Y., Wada, M., Chen, S., Hou, D. S., Xian, W., Ishiyama, H., Yan, S., Schury, P., Crawford, H., Doornenbal, P., Hirayama, Y., Ito, Y., Kimura, S., Koiwai, T., Kojima, T. M., Koura, H., Lee, J., Liu, J., Michimasa, S., Miyatake, H., Moon, J. Y., Nishimura, S., Naimi, S., Niwase, T., Odahara, A., Otsuka, T., Paschalis, S., Petri, M., Shimizu, N., Sonoda, T., Suzuki, D., Watanabe, Y. X., Wimmer, K., and Wollnik, H.

Subjects
Nuclear Experiment
Abstract

The atomic masses of $^{55}$Sc, $^{56,58}$Ti, and $^{56-59}$V have been determined using the high-precision multi-reflection time-of-flight technique. The radioisotopes have been produced at RIKEN's RIBF facility and delivered to the novel designed gas cell and multi-reflection system (ZD MRTOF), which has been recently commissioned downstream of the ZeroDegree spectrometer following the BigRIPS separator. For $^{56,58}$Ti and $^{56-59}$V the mass uncertainties have been reduced down to the order of $10\,\mathrm{keV}$, shedding new light on the $N=34$ shell effect in Ti and V isotopes by the first high-precision mass measurements of the critical species $^{58}$Ti and $^{59}$V. With the new precision achieved, we reveal the non-existence of the $N=34$ empirical two-neutron shell gaps for Ti and V, and the enhanced energy gap above the occupied $\nu p_{3/2}$ orbit is identified as a feature unique to Ca. We perform new Monte Carlo shell model calculations including the $\nu d_{5/2}$ and $\nu g_{9/2}$ orbits and compare the results with conventional shell model calculations, which exclude the $\nu g_{9/2}$ and the $\nu d_{5/2}$ orbits. The comparison indicates that the shell gap reduction in Ti is related to a partial occupation of the higher orbitals for the outer two valence neutrons at $N=34$.

Published
2022
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5. A First Glimpse at the Shell Structure beyond $^{54}$Ca: Spectroscopy of $^{55}$K, $^{55}$Ca, and $^{57}$Ca

Author

Koiwai, T., Wimmer, K., Doornenbal, P., Obertelli, A., Barbieri, C., Duguet, T., Holt, J. D., Miyagi, T., Navrátil, P., Ogata, K., Shimizu, N., Somà, V., Utsuno, Y., Yoshida, K., Achouri, N. L., Baba, H., Browne, F., f, D. Calvet, 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., Yoneda, K., Aktas, O., Aumann, T., Chung, L. X., Flavigny, F., Franchoo v, S., Gasparic, I., Gerst, R. -B., Gibelin, J., Hahn, K. I., Kim, D., 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., 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.

Subjects
Nuclear Experiment
Abstract

States in the $N=35$ and 37 isotopes $^{55,57}$Ca have been populated by direct proton-induced nucleon removal reactions from $^{56,58}$Sc and $^{56}$Ca beams at the RIBF. In addition, the $(p,2p)$ quasi-free single-proton removal reaction from $^{56}$Ca was studied. Excited states in $^{55}$K, $^{55}$Ca, and $^{57}$Ca were established for the first time via in-beam $\gamma$-ray spectroscopy. Results for the proton and neutron removal reactions from $^{56}$Ca to states in $^{55}$K and $^{55}$Ca for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in $^{57}$Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at $N=35$ to collective excitations at $N=37$., Comment: accepted Phys. Lett. B

Published
2022
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6. Investigation of the ground-state spin inversion in the neutron-rich 47,49Cl 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, E., 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., and Zanetti, L.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

A first gamma-ray study of 47,49Cl spectroscopy was performed at the Radioactive Isotope Beam Factory with 50Ar projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt de-excitation gamma-rays were measured with the NaI(Tl) array DALI2+. Through the one-proton knockout reaction 50Ar(p,2p), a spin assignment could be determined for the low-lying states of 49Cl from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity J = 3/2+ is deduced for the ground state of 49Cl, similar to the recently studied N = 32 isotope 51K.

Published
2021
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7. $\boldsymbol{N=32}$ shell closure below calcium: Low-lying structure of $^{50}$Ar

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., 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., 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.

Subjects
Nuclear Experiment
Abstract

Low-lying excited states in the $N=32$ isotope $^{50}$Ar were investigated by in-beam $\gamma$-ray spectroscopy following proton- and neutron-knockout, multi-nucleon 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 $\gamma\gamma$ 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 $4^+$ state could also correspond to a $2^+$ state., Comment: Accepted for Phys. Rev. C

Published
2020
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8. Shell evolution of $N=40$ isotones towards $^{60}$Ca: First spectroscopy of $^{62}$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.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Excited states in the $N=40$ isotone $^{62}$Ti were populated via the $^{63}$V$(p,2p)$$^{62}$Ti reaction at $\sim$200~MeV/u at the Radioactive Isotope Beam Factory and studied using $\gamma$-ray spectroscopy. The energies of the $2^+_1 \rightarrow 0^{+}_{\mathrm{gs}}$ and $4^+_1 \rightarrow 2^+_1$ 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
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9. 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., 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., 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.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The first $\gamma$-ray spectroscopy of $^{52}$Ar, with the neutron number N = 34, was measured using the $^{53}$K(p,2p) one-proton removal reaction at $\sim$210 MeV/u at the RIBF facility. The 2$^{+}_{1}$ 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 $^{54}$Ca, i.e., below the magic proton number Z = 20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2$^{+}_{1}$ systematics of neutron-rich Ar isotopes, and support a N = 34 subshell closure in $^{52}$Ar.

Published
2018
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10. Position of the single-particle 3/2− state in 135Sn and the N=90 subshell closure

Author

Jungclaus, A., primary, Doornenbal, P., additional, Acosta, J., additional, Vaquero, V., additional, Browne, F., additional, Cortes, M.L., additional, Gargano, A., additional, Koiwai, T., additional, Naïdja, H., additional, Taniuchi, R., additional, Tostevin, J.A., additional, Wimmer, K., additional, Algora, A., additional, Baba, H., additional, Fernández, A., additional, Lalović, N., additional, Nácher, E., additional, Rubio, B., additional, and Sakurai, H., additional

Published
2024
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11. Isospin symmetry in the T = 1,A = 62 triplet

Author

Wimmer, K., primary, Ruotsalainen, P., additional, Lenzi, S.M., additional, Poves, A., additional, Hüyük, T., additional, Browne, F., additional, Doornenbal, P., additional, Koiwai, T., additional, Arici, T., additional, Auranen, K., additional, Bentley, M.A., additional, Cortés, M.L., additional, Delafosse, C., additional, Eronen, T., additional, Ge, Z., additional, Grahn, T., additional, Greenlees, P.T., additional, Illana, A., additional, Imai, N., additional, Joukainen, H., additional, Julin, R., additional, Jungclaus, A., additional, Jutila, H., additional, Kankainen, A., additional, Kitamura, N., additional, Longfellow, B., additional, Louko, J., additional, Lozeva, R., additional, Luoma, M., additional, Mauss, B., additional, Napoli, D.R., additional, Niikura, M., additional, Ojala, J., additional, Pakarinen, J., additional, Pereira-Lopez, X., additional, Rahkila, P., additional, Recchia, F., additional, Sandzelius, M., additional, Sarén, J., additional, Taniuchi, R., additional, Tann, H., additional, Uthayakumaar, S., additional, Uusitalo, J., additional, Vaquero, V., additional, Wadsworth, R., additional, Zimba, G., additional, and Yajzey, R., additional

Published
2023
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12. Gamma-ray spectroscopy of exotic neutron-rich nuclei in the doubly magic 132Sn region

Author

Parry, T, primary, Armstrong, M, additional, Podolyák, Zs, additional, Górska, M, additional, Acosta, J, additional, Chen, Z Q, additional, Jungclaus, A, additional, Wimmer, K, additional, Doornenbal, P, additional, Aoi, N, additional, Baba, H, additional, Bartram, G, additional, Browne, F, additional, Campbell, C, additional, Crawford, H, additional, De Witte, H, additional, Fransen, C, additional, Hess, H, additional, Iwazaki, S, additional, Kim, J, additional, Kohda, A, additional, Koiwai, T, additional, Mauss, B, additional, Moon, B, additional, Reiter, P, additional, Suzuki, D, additional, Taniuchi, R, additional, Thiel, S, additional, Tostevin, J A, additional, Yamamoto, Y, additional, Yaneva, A, additional, and Yuan, C, additional

Published
2023
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13. 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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14. 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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15. 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

16. Study of the N=32 and N=34 Shell Gap for Ti and V by the First High-Precision Multireflection Time-of-Flight Mass Measurements at BigRIPS-SLOWRI

Author

Iimura, S., primary, Rosenbusch, M., additional, Takamine, A., additional, Tsunoda, Y., additional, Wada, M., additional, Chen, S., additional, Hou, D. S., additional, Xian, W., additional, Ishiyama, H., additional, Yan, S., additional, Schury, P., additional, Crawford, H., additional, Doornenbal, P., additional, Hirayama, Y., additional, Ito, Y., additional, Kimura, S., additional, Koiwai, T., additional, Kojima, T. M., additional, Koura, H., additional, Lee, J., additional, Liu, J., additional, Michimasa, S., additional, Miyatake, H., additional, Moon, J. Y., additional, Naimi, S., additional, Nishimura, S., additional, Niwase, T., additional, Odahara, A., additional, Otsuka, T., additional, Paschalis, S., additional, Petri, M., additional, Shimizu, N., additional, Sonoda, T., additional, Suzuki, D., additional, Watanabe, Y. X., additional, Wimmer, K., additional, and Wollnik, H., additional

Published
2023
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17. A first glimpse at the shell structure beyond Ca-54: Spectroscopy of K-55, Ca-55, and Ca-57

Author

Koiwai, T, Wimmer, K, Doornenbal, P, Obertelli, A, Barbieri, C, Duguet, T, Holt, JD, Miyagi, T, Navratil, P, Ogata, K, Shimizu, N, Soma, V, Utsuno, Y, Yoshida, K, Achouri, NL, Baba, H, Browne, F, Calvet, D, Chateau, F, Chen, S, Chiga, N, Corsi, A, Cortes, ML, Delbart, A, Gheller, J-M, Giganon, A, Gillibert, A, Hilaire, C, Isobe, T, Kobayashi, T, Kubota, Y, Lapoux, V, Liu, HN, Motobayashi, T, Murray, I, Otsu, H, Panin, V, Paul, N, Rodriguez, W, Sakurai, H, Sasano, M, Steppenbeck, D, Stuhl, L, Sun, YL, Togano, Y, Uesaka, T, Yoneda, K, Aktas, O, Aumann, T, Chung, LX, Flavigny, F, Franchoo, S, Gasparic, I, Gerst, R-B, Gibelin, J, Hahn, K, Kim, D, Kondo, Y, Koseoglou, P, Lee, J, Lehr, C, Linh, BD, Lokotko, T, MacCormick, M, Moschner, K, Nakamura, T, Park, SY, Rossi, D, Sahin, E, Soderstrom, 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

Subjects
MODEL, Science & Technology, Physics, Nuclear, gamma-ray spectroscopy, Physics, Physical Sciences, SCATTERING, Shell evolution, Astronomy & Astrophysics, MASSES, Physics, Particles & Fields, Radioactive beams
Abstract

ispartof: PHYSICS LETTERS B vol:827 status: published

Published
2022

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

Author

Koiwai, T., Wimmer, K., Liu, Hongna, Aktas, Özge, Zanetti, L., Koiwai, T., Wimmer, K., Liu, Hongna, Aktas, Özge, and Zanetti, L.

Abstract

States in the N = 35 and 37 isotopes Ca-55,Ca-57 have been populated by direct proton-induced nucleon removal reactions from Sc-56,Sc-58 and Ca-56 beams at the RIBF. In addition, the (p, 2p) quasi-free single-proton removal reaction from Ca-56 was studied. Excited states in K-55, Ca-55, and Ca-57 were established for the first time via in-beam gamma-ray spectroscopy. Results for the proton and neutron removal reactions from Ca-56 to states in K-55 and Ca-55 for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in Ca-57 suggests a transition in the calcium isotopic chain from single-particle dominated states at N = 35 to collective excitations at N = 37., QC 20220728

Published
2022
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19. Southwestern boundary of the N=40 island of inversion: First study of low-lying bound excited states in 59V and 61V

Author

Elekes, Z., Juhasz, M. M., Sohler, D., Sieja, K., Yoshida, K., Ogata, K., Doornenbal, P., Obertelli, A., Achouri, N. L., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Dombradi, Zs, Flavigny, F., Franchoo, S., Gasparic, 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., Soderstrom, P-A, Takeuchi, S., Tornqvist, H., Vaquero, V., Wagner, V, Wang, S., Werner, V, Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Elekes, Z., Juhasz, M. M., Sohler, D., Sieja, K., Yoshida, K., Ogata, K., Doornenbal, P., Obertelli, A., Achouri, N. L., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Dombradi, Zs, Flavigny, F., Franchoo, S., Gasparic, 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., Soderstrom, P-A, Takeuchi, S., Tornqvist, H., Vaquero, V., Wagner, V, Wang, S., Werner, V, Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., and Zanetti, L.

Abstract

The low-lying level structure of 59V and 61V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for 61V while the neutron knock-out reaction provided the data for 59V. Four and five new transitions were determined for 59V and 61V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed ?? 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 61V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, 61V could not be unambiguously placed on the island of inversion.

Published
2022

20. 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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21. '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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22. Mirror energy differences above the 0 shell: First -ray Spectroscopy of the = −2 Nucleus Zn

Author

Fernández, A., Jungclaus, A., Doornenbal, P., Bentley, M.A., Lenzi, S.M., Rudolph, D., Browne, F., Cortés, M.L., Koiwai, T., Taniuchi, R., Vaquero, V., Wimmer, K., Arici, T., Imai, N., Kitamura, N., Longfellow, B., Lozeva, R., Mauss, B., Napoli, D.R., Niikura, M., Pereira-Lopez, X., Pigliapoco, S., Poves, A., Recchia, F., Ruotsalainen, P., Sakurai, H., Uthayakumaar, S., Wadsworth, R., and Yajzey, R.

Abstract

Excited states in $^{56}$Zn were populated following one-neutron removal from a $^{57}$Zn beam impinging on a Be target at intermediate energies in an experiment conducted at the Radioactive Isotope Beam Factory at RIKEN. Three γ rays were observed and tentatively assigned to the 6+→4+→2+→0+ yrast sequence. This turns $^{56}$Zn into the heaviest Tz=−2 nucleus in which excited states are known. The excitation-energy differences between these levels and the isobaric analogue states in the Tz=+2 mirror partner, $^{56}$Fe, are compared with large-scale shell-model calculations considering the full pf valence space and various isospin-breaking contributions. This comparison, together with an analysis of the mirror energy differences in the A=58, Tz=±1 pair $^{58}$Zn and $^{58}$Ni, provides valuable information with respect to the size of the monopole radial and the isovector multipole isospin-breaking terms in the region above doubly-magic $^{56}$Ni.

Published
2021

23. Spectroscopy of Cd 98 by two-nucleon removal from in 100

Author

Jin, S. Y., Wang, S. T., Lee, J., Corsi, A., Wimmer, K., Browne, F., Chen, S., Cortés, M.L., Doornenbal, P., Koiwai, T., Yuan, C. X., Algora, Alejandro, Brugnara, D., Cederkäll, J., Gerl, J., Górska, M., Häfner, G., Kokubun, K., Koseoglou, P., Kubono, S., Li, P., Liang, P., Liu, J., Liu, Z., Lokotko, T., Park, J., Sakurai, H., Sarmiento, L. G., Sun, Z. Y., Taniuchi, R., Xian, W., Zanon, I., RIKEN Nishina Center for Accelerator-Based Science, National Natural Science Foundation of China, Research Grants Council (Hong Kong), Knut and Alice Wallenberg Foundation, Japan Society for the Promotion of Science, Agencia Estatal de Investigación (España), and Federal Ministry of Education and Research (Germany)

Abstract

6 pags., 5 figs., Low-lying states of Cd98 have been populated by the two-nucleon removal reaction (In100,Cd98+γ) and studied using in-beam γ-ray spectroscopy at the Radioactive Isotope Beam Factory at RIKEN. Two new γ transitions were identified and assigned as decays from a previously unknown state. This state is suggested to be based on a π1g9/2-12p1/2-1 configuration with Jπ=5-. The present observation extends the systematics of the excitation energies of the first 5- state in N=50 isotones toward Sn100. The determined energy of the 5- state in Cd98 continues a smooth trend along the N=50 isotones. The systematics are compared with shell-model calculations in different model spaces. Good agreement is achieved when considering a model space consisting of the π(1f5/2, 2p3/2, 2p1/2, 1g9/2) orbitals. The calculations with a smaller model space omitting the orbitals below the Z=38 subshell could not reproduce the experimental energy difference between the ground and first 5- states in N=50 isotones, because proton excitations across Z=38 subshell yield a large amount of correlation energy that lowers the ground states., The authors thank the RIKEN Nishina Center accelerator staff for providing a stable and high-intensity 124Xe beam and the BigRIPS team for the smooth operation of the secondary beam. This work was supported by the National Natural Science Foundation of China (Grants No. U1732134, No. 11775316, and No. 11961141004). J.L. acknowledges the support from Research Grants Council (RGC) of Hong Kong with grant of General Research Fund (GRF-17307716). G.H. acknowledges the support from the IDEX-API grant. L.G.S. is indebted to a grant from the Knut and Alice Wallenberg Foundation (KAW 2015.0021). A.A. acknowledges the support from the JSPS Invitational Fellowship contract L19555, and the Spanish PID2019-104714GB-C21 grant. F.B. acknowledges the support by the RIKEN Special Postdoctoral Researcher Program. The IN2P3/LIA2019 RIKEN grant of R. Lozeva is acknowledged for the participation of G.H. in the experiment. P.K. acknowledges the support from the BMBF Grant No. 05P19RDFN1.

Published
2021

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

Author

Fernández, A., primary, Jungclaus, A., additional, Doornenbal, P., additional, Bentley, M.A., additional, Lenzi, S.M., additional, Rudolph, D., additional, Browne, F., additional, Cortés, M.L., additional, Koiwai, T., additional, Taniuchi, R., additional, Vaquero, V., additional, Wimmer, K., additional, Arici, T., additional, Imai, N., additional, Kitamura, N., additional, Longfellow, B., additional, Lozeva, R., additional, Mauss, B., additional, Napoli, D.R., additional, Niikura, M., additional, Pereira-Lopez, X., additional, Pigliapoco, S., additional, Poves, A., additional, Recchia, F., additional, Ruotsalainen, P., additional, Sakurai, H., additional, Uthayakumaar, S., additional, Wadsworth, R., additional, and Yajzey, R., additional

Published
2021
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25. First spectroscopic study of v 63 at the N=40 island of inversion

Author

Juhász, M. M., Elekes, Z., Sohler, D., Sieja, K., Yoshida, K., 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, Victor, Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., RIKEN Nishina Center for Accelerator-Based Science, European Commission, Helmholtz International Center for FAIR, German Research Foundation, Ministry of Science and Technology of Vietnam, Agencia Estatal de Investigación (España), Federal Ministry of Education and Research (Germany), Swedish Research Council, and Japan Society for the Promotion of Science

Subjects
Nuclear Theory
Abstract

9 pags., 3 figs., The low-lying level structure of V63 was studied for the first time by the inelastic proton scattering and the proton knock-out reaction in inverse kinematics. The comparison of the newly observed γ-ray transitions at 696(8) keV and 889(16) keV with our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja interaction established two excited states proposed to be the first 11/2- and 9/2- levels. The (p,p′) excitation cross sections were analyzed by the coupled channel formalism assuming pure quadrupole as well as quadrupole+hexadecapole deformations. This resulted in large deformation parameters placing V63 in the island of inversion located below Ni68., We are very grateful to the RIKEN Nishina Center accelerator staff for providing the stable beam and to the BigRIPS team for the smooth operation of the secondary beams. The development of the MINOS device has been supported by the European Research Council through the ERC Grant No. MINOS-258567. F.B. was supported by the RIKEN Special Postdoctoral Researcher Program. K.O. acknowledges the support by Grant-in-Aid for Scientific Research JP16K05352. Y.U. acknowledges the support by Grant-in-Aid for Scientific Research No. 20K03981. Y.L.S. acknowledges the support of Marie Skłodowska-Curie Individual Fellowship (H2020-MSCA-IF-2015-705023) from the European Union and the support from the Helmholtz International Center for FAIR. H.N.L. acknowledges the support from the Enhanced Eurotalents program (PCOFUND-GA-2013-600382) co-funded by CEA and the European Union. T.A., C.L., D.R., H.T., V.W., L.Z., H.N.L., V.W., and A.O. acknowledge the support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Project No. 279384907-SFB 1245. R.B.G. acknowledges the support from the DFG under Grant No. BL 1513/1-1. Y.L.S. and A.O. acknowledge the support from the Alexander von Humboldt Foundation. B.D.L. and L.X.C. acknowledge the support from the Vietnam Ministry of Science and Technology under Grant No. ĐTCB.01/21/VKHKTHN. I.G. has been supported by HIC for FAIR and HRZZ under Projects No. 1257 and No. 7194. F.B. acknowledge the support from the RIKEN Special Postdoctoral Researcher Program. D.S. and Z.E. were supported by Projects No. GINOP-2.3.3-15-2016-00034 and K128947. V.V. acknowledges support from the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. V.W. and P.K. acknowledge the support from BMBF Grants No. 05P15RDFN1 and No. 05P19RDFN1. P.K. acknowledges support from HGSHIRe. This work was also supported by NKFIH (114454) and by Swedish Research Council under Grants No. 621-2014-5558 and No. 2019-04880. 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). T.N. and Y.K. acknowledge the support by JSPS Grant-in-Aid for Scientific Research Grants No. JP16H02179, No. JP18H05404, and No. JP21H04465.

Published
2021

26. First spectroscopic study of $^{63}\mathrm{V}$ at the $N=40$ island of inversion

Author

Juhász, M., Elekes, Z., Sohler, D., Sieja, K., Yoshida, K., Ogata, K., Doornenbal, P., Obertelli, A., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M., 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., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Achouri, N., Aktas, O., Aumann, T., Chung, L., Dombrádi, Zs., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Linh, B., Liu, H., Lokotko, T., Maccormick, M., Moschner, K., Nakamura, T., Park, S., 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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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 Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; The low-lying level structure of 63V was studied for the first time by the inelastic proton scattering and the proton knock-out reaction in inverse kinematics. The comparison of the newly observed γ-ray transitions at 696(8) keV and 889(16) keV with our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja interaction established two excited states proposed to be the first 11/2− and 9/2− levels. The (p,p′) excitation cross sections were analyzed by the coupled channel formalism assuming pure quadrupole as well as quadrupole+hexadecapole deformations. This resulted in large deformation parameters placing 63V in the island of inversion located below 68Ni.

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

Author

Linh, B. D., primary, Corsi, A., additional, Gillibert, A., additional, Obertelli, A., additional, Doornenbal, P., additional, Barbieri, C., additional, Chen, S., additional, Chung, L. X., additional, Duguet, T., additional, Gómez-Ramos, M., additional, Holt, J. D., additional, Moro, A., additional, Navrátil, P., additional, Ogata, K., additional, Phuc, N. T. T., additional, Shimizu, N., additional, Somà, V., additional, Utsuno, Y., additional, Achouri, N. L., additional, Baba, H., additional, Browne, F., additional, Calvet, D., additional, Château, F., additional, Chiga, N., additional, Cortés, M. L., additional, Delbart, A., additional, Gheller, J.-M., additional, Giganon, 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, Flavigny, F., additional, Franchoo, S., additional, Gašparić, I., additional, Gerst, R.-B., additional, Gibelin, J., additional, Hahn, K. I., additional, Khai, N. T., additional, Kim, D., additional, Koiwai, T., additional, Kondo, Y., additional, Koseoglou, P., additional, Lee, J., additional, Lehr, C., 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, Ton, N. D., additional, Törnqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, H., additional, Werner, V., additional, Xu, X., additional, Yamada, Y., additional, Yan, D., additional, Yang, Z., additional, Yasuda, M., additional, and Zanetti, L., additional

Published
2021
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28. Spectroscopy of Cd98 by two-nucleon removal from In100

Author

Jin, S. Y., primary, Wang, S. T., additional, Lee, J., additional, Corsi, A., additional, Wimmer, K., additional, Browne, F., additional, Chen, S., additional, Cortés, M. L., additional, Doornenbal, P., additional, Koiwai, T., additional, Yuan, C. X., additional, Algora, A., additional, Brugnara, D., additional, Cederkäll, J., additional, Gerl, J., additional, Górska, M., additional, Häfner, G., additional, Kokubun, K., additional, Koseoglou, P., additional, Kubono, S., additional, Li, P., additional, Liang, P., additional, Liu, J., additional, Liu, Z., additional, Lokotko, T., additional, Park, J., additional, Sakurai, H., additional, Sarmiento, L. G., additional, Sun, Z. Y., additional, Taniuchi, R., additional, Xian, W., additional, and Zanon, I., additional

Published
2021
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29. 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

30. 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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31. Spectroscopy of Cd98 by two-nucleon removal from In100

Author

Jin, S. Y., Wang, S. T., Lee, J., Corsi, A., Wimmer, K., Browne, F., Chen, S., Cortés, M. L., Doornenbal, P., Koiwai, T., Yuan, C. X., Algora, A., Brugnara, D., Cederkäll, J., Gerl, J., Górska, M., Häfner, G., Kokubun, K., Koseoglou, P., Kubono, S., Li, P., Liang, P., Liu, J., Liu, Z., Lokotko, T., Park, J., Sakurai, H., Sarmiento, L. G., Sun, Z. Y., Taniuchi, R., Xian, W., and Zanon, I.

Published
2021

32. Pairing Forces Govern Population of Doubly Magic Ca- 54 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., Gašparić, Igor, 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., and Zanetti, L.

Subjects
Nuclear structure, direct reactions, radioactive beams
Abstract

Direct proton-knockout reactions of Sc-55 at similar to 220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca-54 were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological intemucleon 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 Sc- 55 ground state with states in Ca-54. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc-55, valence proton removals populated predominantly the ground state of Ca-54. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

Published
2021
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33. Investigation of the ground-state spin inversion in the neutron-rich Cl-47,Cl-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, Igor, 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, E., 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., and Zanetti, L.

Subjects
Nuclear structure, direct reactions, radioactive beams
Abstract

A first gamma-ray study of Cl-47, Cl-49 spectroscopy was performed at the Radioactive Isotope Beam Factory with 50 Ar projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation gamma rays were measured with the NaI(T1) array DALI2(+). Through the one-proton knockout reaction Ar-50(p, 2p), a spin assignment could be determined for the low- lying states of Cl-49 from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity J(pi) = 3/2(+) is deduced for the ground state of Cl-49, similar to the recently studied N = 32 isotope K-51. The evolution of the energy difference E(1/2(1)(+)) - E (3/2(1)(+)) is compared to state-of-the-art theoretical predictions.

Published
2021

34. Spectroscopy of $^{98}\mathrm{Cd}$ by two-nucleon removal from $^{100}\mathrm{In}$

Author

Jin, S. Y., Wang, S. T., Lee, J., Corsi, A., Wimmer, K., Browne, F., Chen, S., Cortés, M. L., Doornenbal, P., Koiwai, T., Yuan, C. X., Algora, A., Brugnara, D., Cederkäll, J., Gerl, J., Górska, M., Häfner, G., Kokubun, K., Koseoglou, P., Kubono, S., Li, P., Liang, P., Liu, J., Liu, Z., Lokotko, T., Park, J., Sakurai, H., Sarmiento, L. G., Sun, Z. Y., Taniuchi, R., Xian, W., Zanon, I., 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 des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Low-lying states of Cd98 have been populated by the two-nucleon removal reaction (In100,Cd98+γ) and studied using in-beam γ-ray spectroscopy at the Radioactive Isotope Beam Factory at RIKEN. Two new γ transitions were identified and assigned as decays from a previously unknown state. This state is suggested to be based on a π1g9/2−12p1/2−1 configuration with Jπ=5−. The present observation extends the systematics of the excitation energies of the first 5− state in N=50 isotones toward Sn100. The determined energy of the 5− state in Cd98 continues a smooth trend along the N=50 isotones. The systematics are compared with shell-model calculations in different model spaces. Good agreement is achieved when considering a model space consisting of the π(1f5/2, 2p3/2, 2p1/2, 1g9/2) orbitals. The calculations with a smaller model space omitting the orbitals below the Z=38 subshell could not reproduce the experimental energy difference between the ground and first 5− states in N=50 isotones, because proton excitations across Z=38 subshell yield a large amount of correlation energy that lowers the ground states.

Published
2021
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35. Pairing Forces Govern Population of Doubly Magic Ca54 from Direct Reactions

Author

Browne, F., primary, Chen, S., additional, Doornenbal, P., additional, Obertelli, A., additional, Ogata, K., 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, Boretzky, K., additional, Caesar, C., 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, Holl, M., additional, Kahlbow, J., additional, Kim, D., additional, Körper, 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, Miki, K., additional, Moschner, K., additional, Nakamura, T., additional, Park, S. Y., additional, Rossi, D., additional, Sahin, E., additional, Schindler, F., additional, Simon, H., additional, Söderström, P-A., additional, Sohler, D., additional, Takeuchi, S., additional, Törnqvist, H., additional, Tscheuschner, J., 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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36. First spectroscopic study of V63 at the N=40 island of inversion

Author

Juhász, M. M., primary, Elekes, Z., additional, Sohler, D., additional, Sieja, K., additional, Yoshida, K., 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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37. First spectroscopic study of( 51)Ar by the (p,2p) reaction

Author

Juhasz, M. M., Elekes, Z., Sohler, D., Utsuno, Y., Yoshida, K., Otsuka, T., Ogata, K., Doornenbal, P., Obertelli, A., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Dombradi, Zs, Flavigny, F., Franchoo, S., Gasparic, 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., Soderstrom, P-A, Takeuchi, S., Tornqvist, H., Vaquero, V., Wagner, V, Wang, S., Werner, V, Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Juhasz, M. M., Elekes, Z., Sohler, D., Utsuno, Y., Yoshida, K., Otsuka, T., Ogata, K., Doornenbal, P., Obertelli, A., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Dombradi, Zs, Flavigny, F., Franchoo, S., Gasparic, 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., Soderstrom, P-A, Takeuchi, S., Tornqvist, 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 Ar-51, an uncharted territory so far, was studied by the (p,2p) reaction using gamma-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the gamma-ray spectrum and six peaks were observed in the Ar-50+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 Ar-50. The low cross sections populating the two bound states of Ar-51 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 Ar-51. (C) 2021 The Author(s). Published by Elsevier B.V.

Published
2021

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

Author

Cortés, M. L., primary, Rodriguez, W., additional, Doornenbal, P., additional, Obertelli, A., additional, Holt, J. D., additional, Menéndez, J., additional, Ogata, K., additional, Schwenk, A., additional, Shimizu, N., additional, Simonis, J., additional, Utsuno, Y., 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, 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
2020
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40. Spectroscopy of neutron-rich scandium isotopes

Author

Koseoglou, P., primary, Werner, V., additional, Pietralla, N., additional, Söderström, P.-A., additional, Doornenbal, P., additional, Obertelli, A., 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, Liu, H., 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, Lee, J., additional, Lehr, C., additional, Lettmann, M., 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, Takeuchi, S., additional, Toernqvist, H., additional, Vaquero, V., additional, Wagner, V., additional, Wang, S., 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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41. 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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42. 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

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

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., Gašparić, Igor, 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., 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.

Subjects
Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment, nuclear shell model, magic numbers, gamma-ray spectroscopy, radioactive beams
Abstract

Low-lying excited states in the N = 32 isotope Ar-50 were investigated by in-beam gamma-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 gamma gamma 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 4(1)(+) state could also correspond to a 2(+) state.

Published
2020

44. 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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45. $N = 32$ shell closure below calcium: Low-lying structure of $^{50}Ar$

Author

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

Subjects
Nuclear Theory, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Physics::Accelerator Physics, ddc:530, Nuclear Experiment
Abstract

Physical review / C 102(6), 064320 (2020). doi:10.1103/PhysRevC.102.064320, Published by APS, Woodbury, NY

Published
2020
Full Text
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46. 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

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

Author

Cortes, M. L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J. D., Lenzi, S. M., Menendez, J., Nowacki, F., Ogata, K., Poves, A., Rodriguez, T. R., Schwenk, A., Simonis, J., Stroberg, S. R., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Chateau, 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., Gasparic, I, Gerst, R-B, Gibelin, J., Hahn, K., I, Kim, D., Koiwai, T., Kondo, Y., Koseoglou, R., Lee, J., Lehr, C., Linh, D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S. Y., Rossi, D., Sahin, E., Sohler, D., Soederstroem, R-A, Takeuchi, S., Toernqvist, H., Vaquero, V., Wagner, V, Wang, S., Werner, V, Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Cortes, M. L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J. D., Lenzi, S. M., Menendez, J., Nowacki, F., Ogata, K., Poves, A., Rodriguez, T. R., Schwenk, A., Simonis, J., Stroberg, S. R., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Chateau, 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., Gasparic, I, Gerst, R-B, Gibelin, J., Hahn, K., I, Kim, D., Koiwai, T., Kondo, Y., Koseoglou, R., Lee, J., Lehr, C., Linh, D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S. Y., Rossi, D., Sahin, E., Sohler, D., Soederstroem, R-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 Ti-62 were populated via the V-63( p, 2p)Ti-62 reaction at similar to 200MeV/nucleonat the Radioactive Isotope Beam Factory and studied using gamma-ray spectroscopy. The energies of the 2(1)(+) -> 0(gs)(+) and 4(1)(+) -> 2(1)(+) transitions, observed here for the first time, indicate a deformed Ti-62 ground state. These energies are increased compared to the neighboring Cr-64 and Fe-66 isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for Ti-62 show a dominant configuration with four neutrons excited across the N = 40 gap. Likewise, they indicate that the N = 40 island of inversion extends down to Z = 20, disfavoring a possible doubly magic character of the elusive Ca-60. (C) 2019 The Authors. Published by Elsevier B.V.

Published
2020

48. 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., Navratil, P., Nowacki, F., Ogata, K., Otsuka, T., Raimondi, F., Soma, V., Utsuno, Y., Yoshida, K., Achouri, N., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Gasparic, 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., Soederstroem, P. -A., Takeuchi, S., Toernqvist, H., Vaquero, V., Wagner, V., Wang, S., Werner, V., Xu, X., Yamada, H., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Sun, Y. L., Obertelli, A., Doornenbal, P., Barbieri, C., Chazono, Y., Duguet, T., Liu, H. N., Navratil, P., Nowacki, F., Ogata, K., Otsuka, T., Raimondi, F., Soma, V., Utsuno, Y., Yoshida, K., Achouri, N., Baba, H., Browne, F., Calvet, D., Chateau, F., Chen, S., Chiga, N., Corsi, A., Cortes, 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., Gasparic, 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., Soederstroem, 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

We report on the first gamma-ray spectroscopy of K-51,K-53 produced via the Ca-52,Ca-54(p,2p) reactions at similar to 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 gamma-ray spectroscopy and exclusive parallel momentum distribution analysis, 3/(2)+ ground states and 1/2(+) first excited states in K-51,K-53 were established quantifying the natural ordering of the 1d(3/2) and 2s(1/2) proton-hole states that are restored at N = 32 and 34. State-of-the-art ab initio calculations and shell-model calculations with improved phenomenological effective interactions reproduce the present data and predict consistently the increase of the E(1/4)- E(3/4) energy differences towards N = 40. (C) 2020 The Authors. Published by Elsevier B.V.

Published
2020

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

Author

Cortes, M. L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J. D., Menendez, J., Ogata, K., Schwenk, A., Shimizu, N., Simonis, J., Utsuno, Y., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Chateau, 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., Gasparic, 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., Soederstroem, 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., Zanetti, L., Cortes, M. L., Rodriguez, W., Doornenbal, P., Obertelli, A., Holt, J. D., Menendez, J., Ogata, K., Schwenk, A., Shimizu, N., Simonis, J., Utsuno, Y., Yoshida, K., Achouri, L., Baba, H., Browne, F., Calvet, D., Chateau, 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., Gasparic, 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., Soederstroem, 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

Low-lying excited states in the N = 32 isotope Ar-50 were investigated by in-beam gamma-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 gamma gamma 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 4(1)(+) state could also correspond to a 2(+) state.

Published
2020

50. How Robust is the N=34 Subshell Closure? First Spectroscopy of Ar52

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., 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.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Direct reactions, Electromagnetic transitions, Nuclear forces, Nuclear many-body theory, Shell model, Nuclear Experiment
Abstract

The first gamma-ray spectroscopy of Ar-52, with the neutron number N = 34, was measured using the K-53(p, 2p) one-proton removal reaction at similar to 210 MeV/u at the RIBF facility. The 2(1)(+) 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 Ca-54, i.e., below the magic proton number Z = 20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2(1)(+) systematics of neutron-rich Ar isotopes, and support a N = 34 subshell closure in Ar-52.

Published
2019
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