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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. 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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3. 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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4. 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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5. Simulations of the SIMBA array towards the determination of Qβ values

Author

Warr N., Blazhev A., and Moschner K.

Subjects
Physics, QC1-999
Abstract

In an experiment at RIKEN, radioactive ions were implanted in the SIMBA silicon detector array and the β particles from the subsequent decay detected. However, as SIMBA is not capable of complete calorimetry, it is not possible to extract Qβ values directly from the data. Geant4 simulations have been used to determine the response of SIMBA to a given β-emission spectrum. By simulating with different β spectra and calculating the detector response to each spectrum, it is possible to compare with experiment and deduce the Qβ values. The technique is validated using two nuclei, for which the expected β spectrum is known from the literature.

Published
2015
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6. Do nuclei go pear-shaped? Coulomb excitation of 220Rn and 224Ra at REX-ISOLDE (CERN)

Author

Scheck M., Gaffney L. P., Butler P. A., Hayes A. B., Wenander F., Albers M., Bastin B., Bauer C., Blazhev A., Boenig S., Bree N., Cederkall J., Chupp T., Cline D., Cocolios T. E., Davinson T., De Witte H., Diriken J., Grahn T., Herzan A., Huyse M., Jenkins D. G., Joss D. T., Kesteloot N., Konki J., Kowalczyk M., Kroell Th., Kwan E., Lutter R., Moschner K., Napiorkowski P., Pakarinen J., Pfeiffer M., Radeck D., Reiter P., Reynders K., Rigby S. V., Robledo L. M., Rudigier M., Sambi S., Seidlitz M., Siebeck B., Stora T., Thoele P., Van Duppen P., Vermeulen M. J., von Schmid M., Voulot D., Warr N., Wimmer K., Wrzosek-Lipska K., Wu C. Y., and Zielinska M.

Subjects
Physics, QC1-999
Abstract

The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam: 2.83 MeV/u) were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted ‹3−||E3||0+› matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. This finding has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.

Published
2015
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7. Onset of collectivity in 96,98Sr studied via Coulomb excitation

Author

Clément E., Görgen A., Dijon A., France G. de, Bastin B., Blazhev A., Bree N., Butler P., Delahaye P., Ekstrom A., Georgiev G., Hasan N., Iwanicki J., Jenkins D., Korten W., Larsen A. C., Ljungvall J., Moschner K., Napiorkowski P., Pakarinen J., Petts A., Renstrom T., Seidlitz M., Siem S., Sotty C., Srebrny J., Stefanescu I., Tveten G. M., Walle J. Van de, Warr N., Wrzosek-Lipska K., Zielińska M., Bauer C., Bruyneel B., Butterworth J., Fitzpatrick C., Fransen C., Gernhäuser R., Hess H., Lutter R., Marley P., Reiter P., Siebeck B., Vermeulen M., Wiens A., and De Witte H.

Subjects
Physics, QC1-999
Abstract

A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

Published
2014
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8. Isomer and beta decay spectroscopy in the 132Sn region with EURICA

Author

Jungclaus A., Simpson G.S., Gey G., Taprogge J., Nishimura S., Doornenbal P., Lorusso G., Söderström P.-A., Sumikama T., Xu Z., Baba H., Browne F., Fukuda N., Inabe N., Isobe T., Jung H.S., Kameda D., Kim G.D., Kim Y.-K., Kojouharov I., Kubo T., Kurz N., Kwon Y.K., Li Z., Sakurai H., Schaffner H., Suzuki H., Takeda H., Vajta Z., Watanabe H., Wu J., Yagi A., Yoshinaga K., Bönig S., Daugas J.-M., Drouet F., Gernhäuser R., Ilieva S., Kröll T., Montaner-Pizá A., Moschner K., Mücher D., Nishibata H., Orlandi R., Steiger K., and Wendt A.

Subjects
Physics, QC1-999
Abstract

The first EURICA campaign with high intensity Uranium beams took place at RIKEN in November/December 2012. Within this campaign experiment NP1112-RIBF85 was performed dedicated to the study of the isomeric and beta decays of neutronrich Cd, In, Sn and Sb isotopes towards and beyond the N=82 neutron shell closure. In this contribution we present a first status report of the analysis of the extensive data set obtained in this experiment.

Published
2014
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9. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

Author

Clément E., Görgen A., Dijon A., de France G., Bastin B., Blazhev A., Bree N., Butler P., Delahaye P., Ekstrom A., Georgiev G., Hasan N., Iwanicki J., Jenkins D., Korten W., Larsen A.C., Ljungvall J., Moschner K., Napiorkowski P., Pakarinen J., Petts A., Renstrom T., Seidlitz M., Siem S., Sotty C., Srebrny J., Stefanescu I., Tveten G.M., Van de Walle J., Warr N., Wrzosek-Lipska K., Zielińska M., Bauer C., Bruyneel B., Butterworth J., Fitzpatrick C., Fransen C., Gernhäuser R., Hess H., Lutter R., Marley P., Reiter P., Siebeck B., Vermeulen M., Wiens A., and De Witte H.

Subjects
Physics, QC1-999
Abstract

A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

Published
2013
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10. $\boldsymbol{N=32}$ 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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11. 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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12. 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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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

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. In-beam γ -ray spectroscopy of 94 Ag

Author

Pereira-Lopez, X., Bentley, M. A., Wadsworth, R., Ruotsalainen, P., Lenzi, S. M., Forsberg, U., Auranen, K., Blazhev, A., Cederwall, B., Grahn, T., Greenlees, P., Illana, A., Jenkins, D. G., Julin, R., Jutila, H., Juutinen, S., Liu, X., Llewelyn, R., Luoma, M., Moschner, K., Müller-Gatermann, C., Singh, B. S. Nara, Nowacki, F., Ojala, J., Pakarinen, J., Papadakis, P., Rahkila, P., Romero, J., Sandzelius, M., Saren, J., Tann, H., Uthayakumaar, S., Uusitalo, J., Vega-Romero, J. G., Vilhena, J. M., Yajzey, R., Zhang, W., Zimba, G., and Helsinki Institute of Physics

Subjects
Coulomb energy differences, Excited-states, Proton, Decay, Ag, 114 Physical sciences, Isomer
Published
2023

17. In-beam γ-ray spectroscopy of 94Ag

Author

Pereira-López, X., Bentley, M. A., Wadsworth, R., Ruotsalainen, P., Lenzi, S. M., Forsberg, U., Auranen, K., Blazhev, A., Cederwall, B., Grahn, T., Greenlees, P., Illana, A., Jenkins, D. G., Julin, R., Jutila, H., Juutinen, S., Liu, X., Llewelyn, R., Luoma, M., Moschner, K., Müller-Gatermann, C., Nara Singh, B. S., Nowacki, F., Ojala, J., Pakarinen, J., Papadakis, P., Rahkila, P., Romero, J., Sandzelius, M., Sarén, J., Tann, H., Uthayakumaar, S., Uusitalo, J., Vega-Romero, J. G., Vilhena, J. M., Yajzey, R., Zhang, W., and Zimba, G.

Subjects
spektroskopia, hopea, ydinfysiikka
Abstract

A recoil-beta-tagging experiment has been per formed to study the excited T = 0 and T = 1 states in the odd–odd N = Z nucleus 94Ag, populated via the 40Ca(58Ni,1p3n)94Ag reaction. The experiment was con ducted using the MARA recoil separator and JUROGAM3 array at the Accelerator Laboratory of the University of Jyväskylä. Through correlating fast, high-energy beta decays at the MARA focal plane with prompt γ rays emitted at the reaction target, a number of transitions between excited states in 94Ag have been identified. The timing characteris tics of these transitions confirm that they fall within decay sequences that feed the short-lived T = 1 ground state of 94Ag. The transitions are proposed to proceed within and between the sets of states with T = 0 and T = 1. Possi ble correspondence between some of these transitions from analog states in 94Pd has been discussed, and shell-model cal culations including multipole and monopole electromagnetic effects have been presented, in order to enable predictions of the decay patterns between the T = 0 and T = 1 states and to allow a theoretical set of Coulomb energy differences to be calculated for the A = 94 T = 1 analog states. peerReviewed

Published
2023

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, 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

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

Author

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

Published
2022

21. Extended ${p}_{3/2}$ Neutron Orbital and the $N=32$ Shell Closure in $^{52}\mathrm{Ca}$

Author

Enciu, M., Liu, H. N., Obertelli, A., Doornenbal, P., Nowacki, F., Ogata, K., Poves, A., Yoshida, K., Achouri, N. L., Baba, H., Browne, F., Calvet, D., Château, F., Chen, S., Chiga, N., Corsi, A., Cortés, M. L., Delbart, A., Gheller, J-M., Giganon, A., Gillibert, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y. L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Chung, L. X., Flavigny, F., Franchoo, S., Gasparic, I., Gerst, R.-B., Gibelin, J., Hahn, K. I., Kim, D., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Li, P. J., Linh, B. D., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S. Y., Rossi, D., Sahin, Elif, 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., 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)-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), 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
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], ddc:530
Abstract

Physical review letters 129(26), 262501 (2022). doi:10.1103/PhysRevLett.129.262501, Published by APS, College Park, Md.

Published
2022

22. γ -ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich Kr 94,95,96

Author

Gerst, R. B., Blazhev, A., Moschner, K., Doornenbal, P., Obertelli, A., Nomura, K., Ebran, J. P., Hilaire, S., Libert, J., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J. M., Giganon, A., Gillibert, A., Lapoux, V., Motobayashi, T., Niikura, M., Paul, N., Roussé, J. Y., Sakurai, H., Santamaria, C., Steppenbeck, D., Taniuchi, R., Uesaka, T., Ando, T., Arici, T., Browne, F., Bruce, A. M., Caroll, R., Chung, L. X., Cortés, M. L., Dewald, M., Ding, B., Flavigny, F., Franchoo, S., Górska, M., Gottardo, A., Jolie, J., Jungclaus, Andrea, Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Momiyama, S., Nagamine, S., Nakatsuka, N., Nita, C.R., Nobs, C., Olivier, L., Orlandi, R., Patel, Z., Podolyák, Zs, Rudigier, M., Saito, T., Shand, C., Söderström, P. A., Stefan, I., Vaquero, Victor, Werner, V., Wimmer, K., Xu, Z., German Research Foundation, Federal Ministry of Education and Research (Germany), RIKEN Nishina Center for Accelerator-Based Science, Science and Technology Facilities Council (UK), Croatian Science Foundation, École Polytechnique Fédérale de Lausanne, National Natural Science Foundation of China, and Japan Society for the Promotion of Science

Abstract

11 pags., 16 figs., 1 tab., We report on γ-ray spectroscopy of low-lying excited states in the neutron-rich Kr94,95,96 isotopes measured as part of the "Shell Evolution And Search for Two-plus energies At RIBF"(SEASTAR) campaign at the RIKEN Radioactive Isotope Beam Factory. Excited yrast and non-yrast states were observed, and half-lives extracted via geant4 simulations. In Kr94,96 candidates for the 31- state were identified. For Kr95, the prompt SEASTAR data were combined with delayed spectroscopic data measured with the EURICA array to observe transitions on top of the known (7/2)+ isomer at a level energy of 195.5(3) keV. The comparison of the new experimental results with five-dimensional collective Hamiltonian (5DCH) and mapped interacting boson model (IBM) calculations, both using the Gogny D1M interaction, could suggest oblate-prolate shape coexistence already in Kr96., This work is supported by the Deutsche Forschungsgemeinschaft (DFG—German Research Foundation) under Grant No. BL 1513/1-1 and by the BMBF under Grants No. 05P15PKFNA, No. 05P19PKFNA, No. 05P15RDFN1, No. 05P19RDFN1, and No. 05P21RDFN1. We thank the RIKEN Nishina Centre accelerator staff and the BigRIPS team for providing the stable and high-intensity uranium beam and secondary beams, and the STFC (UK). The work of K. Nomura was supported by the Tenure Track Pilot Programme of the Croatian Science Foundation, the École Polytechnique Fédérale de Lausanne, and Project No. TTP-2018-07-3554, Exotic Nuclear Structure and Dynamics, with funds of the Croatian-Swiss Research Programme. B.D. and Z.L. were supported by the National Natural Science Foundation of China (Grants No. 12135004, No. 11635003, and No. 11961141004). R.T. was supported by JSPS Grant-in-Aid for JSPS Research Fellows JP14J08718.

Published
2022

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

Author

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

Abstract

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

Published
2022

24. Impact of shell evolution on Gamow-Teller Decay From a High-spin Long-lived Isomer in Ag

Author

Watanabe, H., Yuan, C.X., Lorusso, G., Nishimura, S., Xu, Z.Y., Sumikama, T., Söderström, P.A., Doornenbal, P., Browne, F., Gey, G., Jung, H.S., Taprogge, J., Vajta, Zs., Wang, H.K., Wu, J., Yagi, A., Baba, H., Benzoni, G., Chae, K.Y., Crespi, F.C.L., Fukuda, N., Gernhäuser, R., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kondev, F.G., Kubo, T., Kurz, N., Kwon, Y.K., Lane, G.J., Li, Z., Moon, C.B., Montaner-Pizá, A., Moschner, K., Naqvi, F., Niikura, M., Nishibata, H., Nishimura, D., Odahara, A., Orlandi, R., Patel, Z., Podolyák, Zs., Sakurai, H., Schaffner, H., Simpson, G.S., Steiger, K., Suzuki, H., Takeda, H., Wendt, A., and Yoshinaga, K.

Abstract

The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the β decay in the region below $^{132}$Sn using the newly obtained experimental data on a long-lived isomer in $^{127}$Ag. The T1/2=67.5(9) ms isomer has been identified with a spin and parity of (27/2+) at an excitation energy of 1942−20+14 keV, and found to decay via an internal transition of an E3 character, which competes with the dominant β-decay branches towards the high-spin states in $^{127}$Cd. The underlying mechanism of a strong GT transition from the $^{127}$Ag isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach.

Published
2021

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

Author

Watanabe, H., Yuan, C.X., Lorusso, G., Nishimura, S., Xu, Z.Y., Sumikama, T., Söderström, P.-A., Doornenbal, P., Browne, F., Gey, G., Jung, H.S., Taprogge, J., Vajta, Zs., Wang, H.K., Wu, J., Yagi, A., Baba, H., Benzoni, G., Chae, K.Y., Crespi, F.C.L., Fukuda, N., Gernhäuser, R., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kondev, F.G., Kubo, T., Kurz, N., Kwon, Y.K., Lane, G.J., Li, Z., Moon, C.-B., Montaner-Pizá, A., Moschner, K., Naqvi, F., Niikura, M., Nishibata, H., Nishimura, D., Odahara, A., Orlandi, R., Patel, Z., Podolyák, Zs., Sakurai, H., Schaffner, H., Simpson, G.S., Steiger, K., Suzuki, H., Takeda, H., Wendt, A., and Yoshinaga, K.

Published
2021
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26. 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

27. First spectroscopic study of 51Ar 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.

Published
2021
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28. 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

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

Author

Linh, B.D., Corsi, A., Gillibert, A., Obertelli, A., Doornenbal, P., Barbieri, C., Chen, S., Chung, L.X., Duguet, T., Gómez-Ramos, M., Holt, J.D., Moro, A., Navrátil, P., Ogata, K., Phuc, N. T. T., Shimizu, N., Somà, V., Utsuno, Y., Achouri, N.L., Baba, H., Browne, F., Calvet, D., Château, F., Chiga, N., Cortés, M.L., Delbart, A., Gheller, J.-M., Giganon, A., Hilaire, C., Isobe, T., Kobayashi, T., Kubota, Y., Lapoux, V., Liu, H.N., Motobayashi, T., Murray, I., Otsu, H., Panin, V., Paul, N., Rodriguez, W., Sakurai, H., Sasano, M., Steppenbeck, D., Stuhl, L., Sun, Y.L., Togano, Y., Uesaka, T., Wimmer, K., Yoneda, K., Aktas, O., Aumann, T., Flavigny, F., Franchoo, S., Gašparić, I., Gerst, R.-B., Gibelin, J., Hahn, K.I., Khai, N.T., Kim, D., Koiwai, T., Kondo, Y., Koseoglou, P., Lee, J., Lehr, C., Lokotko, T., MacCormick, M., Moschner, K., Nakamura, T., Park, S.Y., Rossi, D., Sahin, Eda, Sohler, D., Söderström, P.-A., Takeuchi, S., Ton, N.D., Törnqvist, H., Vaquero, V., Wagner, V., Wang, H., Werner, V., Xu, X., Yamada, Y., Yan, D., Yang, Z., Yasuda, M., Zanetti, L., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Kastler Brossel (LKB [Collège de France]), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

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

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

Published
2021

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

31. Restoration of the natural E(1/2[formula omitted]) - E(3/2[formula omitted]) 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., and Zanetti, L.

Published
2020
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32. Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti

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.

Published
2020
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33. 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

34. Restoration of the natural E(1/2) - E(3/2) 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, Eda, 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.

Published
2020

35. 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

36. 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

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

Author

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

Abstract

6 pags., 4 figs., Here we present new information on the shape evolution of the very neutron-rich ^{92,94}Se nuclei from an isomer-decay spectroscopy experiment at the Radioactive Isotope Beam Factory at RIKEN. High-resolution germanium detectors were used to identify delayed γ rays emitted following the decay of their isomers. New transitions are reported extending the previously known level schemes. The isomeric levels are interpreted as originating from high-K quasineutron states with an oblate deformation of β∼0.25, with the high-K state in ^{94}Se being metastable and K hindered. Following this, ^{94}Se is the lowest-mass neutron-rich nucleus known to date with such a substantial K hindrance. Furthermore, it is the first observation of an oblate K isomer in a deformed nucleus. This opens up the possibility for a new region of K isomers at low Z and at oblate deformation, involving the same neutron orbitals as the prolate orbitals within the classic Z∼72 deformed hafnium region. From an interpretation of the level scheme guided by theoretical calculations, an oblate deformation is also suggested for the ^{94}Se_{60} ground-state band., This work was carried out at the RIBF operated by RIKEN Nishina Center, RIKEN and CNS, University of Tokyo. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. The authors thank the RIBF and BigRIPS teams for providing a stable high-intensity uranium beam and operating the secondary beams. We acknowledge support from the German BMBF Grants No. 05P15RDFN1, No. 05P19RDFN1, No. 05P15PKFNA, and No. 05P19PKFNA, the ERC Grant No. MINOS-258567, the Spanish MEC under Contracts No. FPA2014-57196-C5-4-P and No. FIS2014-53434, the National Key R&D Program of China (Contract No. 2018YFA0404402), the National Natural Science Foundation of China (Grants No. 11961141004, No. 11735017, No. 11675225, No. 11635003), the Vietnam MOST via the Physics Development Program Grant No. ĐTĐLCN.25/18, as well as from the Science and Technology Facilities Council (STFC). We further thank GSI for providing computing facilities.

Published
2020

38. $N = 32$ 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
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39. Spectroscopy of $^{99}\mathrm{Cd}$ and $^{101}\mathrm{In}$ from ${\beta}$ decays of $^{99}\mathrm{In}$ and $^{101}\mathrm{Sn}$

Author

PARK, J., KRÜCKEN, R., BLAZHEV, A., LUBOS, D., GERNHÄUSER, R., LEWITOWICZ, M., NISHIMURA, S., AHN, D.S., BABA, H., BLANK, B., BOUTACHKOV, P., BROWNE, F., ČELIKOVIĆ, I., DE FRANCE, G., DOORNENBAL, P., FAESTERMANN, T., FANG, Y., FUKUDA, N., GIOVINAZZO, J., GOEL, N., GÓRSKA, M., GRAWE, H., ILIEVA, S., INABE, N., ISOBE, T., JUNGCLAUS, A., KAMEDA, D., KIM, G.D., KIM, Y.K., KOJOUHAROV, I., KUBO, T., KURZ, N., KWON, Y.K., LORUSSO, G., MOSCHNER, K., MURAI, D., NISHIZUKA, I., PATEL, Z., RAJABALI, M.M., RICE, S., SAKURAI, H., SCHAFFNER, H., SHIMIZU, Y., SINCLAIR, L., SÖDERSTRÖM, P.A., STEIGER, K., SUMIKAMA, T., SUZUKI, H., TAKEDA, H., WANG, Z., WATANABE, H., WU, J., XU, Z.Y., Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), TRIUMF, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Astrophysics::High Energy Astrophysical Phenomena, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure
Abstract

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

Published
2020

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

Author

Frotscher, A., Gómez-Ramos, M., Obertelli, A., Doornenbal, P., Authelet, G., Baba, H., Calvet, D., Château, F., Chen, S., Corsi, A., Delbart, A., Gheller, J.M., Giganon, A., Gillibert, A., Isobe, T., Lapoux, V., Matsushita, M., Momiyama, S., Motobayashi, T., Niikura, M., Otsu, H., Paul, N., Péron, C., Peyaud, A., Pollacco, E.C., Roussé, J.Y., Sakurai, H., Santamaria, C., Sasano, M., Shiga, Y., Shimizu, N., Steppenbeck, D., Takeuchi, S., Taniuchi, R., Uesaka, T., Wang, H., Yoneda, K., Ando, T., Arici, T., Blazhev, A., Browne, F., Bruce, A.M., Carroll, R., Chung, L.X., Cortés, M.L., Dewald, M., Ding, B., Dombradi, Zs., Flavigny, F., Franchoo, S., Giacoppo, F., Górska, M., Gottardo, A., Hadyńska-Klęk, K., Korkulu, Z., Koyama, S., Kubota, Y., Jungclaus, A., Lee, J., Lettmann, M., Linh, B.D., Liu, J., Liu, Z., Lizarazo, C., Louchart, C., Lozeva, R., Matsui, K., Miyazaki, T., Moschner, K., Nagamine, S., Nakatsuka, N., Nita, C., Nishimura, S., Nobs, C.R., Olivier, L., Ota, S., Patel, Z., Podolyák, Zs., Rudigier, M., Sahin, E., Saito, T.Y., Shand, C., Söderström, P.A., Stefan, I.G., Sumikama, T., Suzuki, D., Orlandi, R., Vaquero, V., Vajta, Zs., Werner, V., Wimmer, K., Wu, J., Xu, Z., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, ddc:530, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
Abstract

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

Published
2020

41. Spectroscopy of Cd 99 and in 101 from β decays of in 99 and Sn 101

Author

Park, J., Krücken, R., Blazhev, A., Lubos, D., Gernhäuser, R., Lewitowicz, M., Nishimura, S., Ahn, D.S., Baba, H., Blank, B., Boutachkov, P., Browne, F., Celikovic, I., De France, G., Doornenbal, P., Faestermann, T., Fang, Y., Fukuda, N., Giovinazzo, J., Goel, N., Górska, M., Grawe, H., Ilieva, S., Inabe, N., Isobe, T., Jungclaus, Andrea, Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kubo, T., Kurz, N., Kwon, Y.K., Lorusso, G., Moschner, K., Murai, D., Nishizuka, I., Patel, Z., Rajabali, M.M., Rice, S., Sakurai, H., Schaffner, H., Shimizu, Y., Sinclair, L., Söderström, P.A., Steiger, K., Sumikama, T., Suzuki, H., Takeda, H., RIKEN Nishina Center for Accelerator-Based Science, University of Tokyo, Ministry of Education, Science and Technology (South Korea), National Research Foundation of Korea, Japan Society for the Promotion of Science, German Research Foundation, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Natural Sciences and Engineering Research Council of Canada, and French-Japanese International Associated Laboratory for Nuclear Structure Problems

Abstract

11 pags., 10 figs., 3 tabs., We report on new γ-ray spectroscopy results from β decays of In99 and Sn101. 30 new γ rays were observed following the β decay of In99, and inconsistencies in the literature with respect to the γ rays following the β decay of Sn101 were addressed with two confirmed cases and two new transitions. The experimental γ-ray energies, intensities, and coincidence relationships are discussed with shell model calculations, where theoretical β-decay branching ratios from the parent nuclei and γ-ray cascades of excited states from the daughter nuclei were combined to generate hypothetical βγ spectra and βγγ coincidence matrices. The most intense β-delayed γ-ray branches in both Cd99 and In101 were well reproduced with this approach, and several γ rays were assigned to new excited states based on their good agreement with shell model predictions., The authors would like to thank the personnel at the RIKEN Nishina Center for providing the exotic radioactive isotope beam with record intensities. This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. We acknowledge the EUROBALL Owners Committee for loaning the germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors of EURICA. Support for the WAS3ABi setup was provided by the Rare Isotope Science Project, funded by the Ministry of Education, Science and Technology (MEST) and National Research Foundation (NRF) of Korea, as well as KAKENHI (Grant No. 25247045) of Japan Society for the Promotion of Science (JSPS). This work was supported by the Institute for Basic Science (IBS-R031-D1). The authors acknowledge also the support of the DFG cluster of excellence “Origin and Structure of the Universe,” German BMBF under Contracts No. 05P15PKFNA and No. 05P19PKFNA, and the Spanish Ministerio de Economía y Competitividad via Project No. FPA2017-84756-C4-2-P. Part of the research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada and also supported by FJNSP LIA (French-Japanese International Associated Laboratory for Nuclear Structure Problems)

Published
2020

42. 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

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

Author

Shearman, R, primary, Lorusso, G, additional, Boso, A, additional, Regan, P H, additional, Nishimura, S, additional, Xu, Z Y, additional, Jungclaus, A, additional, Shimizu, Y, additional, Simpson, G S, additional, Söderström, P-A, additional, Watanabe, H, additional, Browne, F, additional, Doornenbal, P, additional, Gey, G, additional, Jung, H S, additional, Meyer, B, additional, Sumikama, T, additional, Taprogge, J, additional, Vajta, Zs, additional, Wu, J, additional, Baba, H, additional, Benzoni, G, additional, Chae, K Y, additional, Crespi, F C L, additional, Fukuda, N, additional, Gernhäuser, R, additional, Inabe, N, additional, Isobe, T, additional, Kajino, T, additional, Kameda, D, additional, Kim, G D, additional, Kim, Y-K, additional, Kajouharov, I, additional, Kondev, F G, additional, Kubo, T, additional, Kurz, N, additional, Kwon, Y K, additional, Lane, G J, additional, Li, Z, additional, Montaner-Pizá, A, additional, Moschner, K, additional, Naqvi, F, additional, Niikura, M, additional, Nishibata, H, additional, Odahara, A, additional, Orlandi, R, additional, Patel, Z, additional, Podolyák, Zs, additional, Sakurai, H, additional, Schaffner, H, additional, Schury, P, additional, Shibagaki, S, additional, Steiger, K, additional, Suzuki, H, additional, Takeda, H, additional, Wendt, A, additional, Yagi, A, additional, and Yoshinaga, K, additional

Published
2020
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44. Studies of pear-shaped nuclei using accelerated radioactive beams

Author

Gaffney, L. P., Butler, P. A., Scheck, M., Hayes, A. B., Wenander, F., Albers, M., Bastin, B., Bauer, C., Blazhev, A., Bönig, S., Bree, N., Cederkäll, J., Chupp, T., Cline, D., Cocolios, T. E., Davinson, T., De Witte, H., Diriken, J., Grahn, T., Herzan, A., Huyse, M., Jenkins, D. G., Joss, D. T., Kesteloot, N., Konki, J., Kowalczyk, M., Kröll, Th., Kwan, E., Lutter, R., Moschner, K., Napiorkowski, P., Pakarinen, J., Pfeiffer, M., Radeck, D., Reiter, P., Reynders, K., Rigby, S. V., Robledo, L. M., Rudigier, M., Sambi, S., Seidlitz, M., Siebeck, B., Stora, T., Thoele, P., Van Duppen, P., Vermeulen, M. J., von Schmid, M., Voulot, D., Warr, N., Wimmer, K., Wrzosek-Lipska, K., Wu, C. Y., and Zielinska, M.

Published
2013
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45. New isomers in 125Pd79 and 127Pd81: Competing proton and neutron excitations in neutron-rich palladium nuclides towards the N = 82 shell closure

Author

Watanabe, H., Wang, H.K., Lorusso, G., Nishimura, S., Xu, Z.Y., Sumikama, T., Söderström, P.-A., Doornenbal, P., Browne, F., Gey, G., Jung, H.S., Taprogge, J., Vajta, Zs., Wu, J., Yagi, A., Baba, H., Benzoni, G., Chae, K.Y., Crespi, F.C.L., Fukuda, N., Gernhäuser, R., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kondev, F.G., Kubo, T., Kurz, N., Kwon, Y.K., Lane, G.J., Li, Z., Moon, C.-B., Montaner-Pizá, A., Moschner, K., Naqvi, F., Niikura, M., Nishibata, H., Nishimura, D., Odahara, A., Orlandi, R., Patel, Z., Podolyák, Zs., Sakurai, H., Schaffner, H., Simpson, G.S., Steiger, K., Sun, Y., Suzuki, H., Takeda, H., Wendt, A., and Yoshinaga, K.

Published
2019
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46. 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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47. Improved Value for the Gamow-Teller Strength of the Sn 100 Beta Decay

Author

Lubos, D., Park, J., Faestermann, T., Gernhäuser, R., Krücken, R., Lewitowicz, M., Nishimura, S., Sakurai, H., Ahn, D.S., Baba, H., Blank, B., Blazhev, A., Boutachkov, P., Browne, F., Celikovic, I., De France, G., Doornenbal, P., Fang, Y., Fukuda, N., Giovinazzo, J., Goel, N., Górska, M., Ilieva, S., Inabe, N., Isobe, T., Jungclaus, Andrea, Kameda, D., Kim, Y. K., Kojouharov, I., Kubo, T., Kurz, N., Kwon, Y. K., Lorusso, G., Moschner, K., Murai, D., Nishizuka, I., Patel, Z., Rajabali, M. M., Rice, S., Schaffner, H., Shimizu, Y., Sinclair, L., Söderström, P. A., Steiger, K., Sumikama, T., Suzuki, H., Takeda, H., Wang, Z., Warr, N., RIKEN Nishina Center for Accelerator-Based Science, University of Tokyo, German Research Foundation, Federal Ministry of Science, Research and Economy (Germany), Ministry of Education, Science and Technology (South Korea), National Research Foundation of Korea, Natural Sciences and Engineering Research Council of Canada, and Ministerio de Ciencia, Innovación y Universidades (España)

Abstract

6 pags., 4 figs., A record number of Sn100 nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the β-decay end point energy of Sn100 were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0+→1+ Gamow-Teller decay was improved to BGT=4.4-0.7+0.9. A discrimination between different model calculations was possible for the first time, and the level scheme of In100 is investigated further., This work was carried out at the RIBF operated by RIKEN Nishina Center, RIKEN and CNS, University of Tokyo. It was supported and financed by the DFG cluster of excellence “Origin and Structure of the Universe,” the German BMBF under Contracts No. 05P12WOFNF and No. 05P15PKFNA, the Hanns-Seidel-Stiftung, and the RIKEN IPA Programme. We wish to acknowledge the EURICA RIBF09 collaboration as well as the support on the WAS3ABi setup from the Rare Isotope Science Project, funded by the Ministry of Education, Science and Technology and National Research Foundation of Korea KAKENHI (Grant No. 25247045). Part of the research was also funded by the Natural Sciences and Engineering Research Council of Canada, supported by FJNSP LIA (French-Japanese International Associated Laboratory for Nuclear Structure Problems) and by the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P.

Published
2019

48. Proton Shell Evolution below Sn-132: First Measurement of Low-Lying beta-Emitting Isomers in Ag-123,Ag-325

Author

Chen, ZQ, Li, ZH, Hua, H, Watanabe, H, Yuan, CX, Zhang, SQ, Lorusso, G, Nishimura, S, Baba, H, Browne, F, Benzoni, G, Chae, KY, Crespi, FCL, Doornenbal, P, Fukuda, N, Gey, G, Gernhaeuser, R, Inabe, N, Isobe, T, Jiang, DX, Jungclaus, A, Jung, HS, Jin, Y, Kameda, D, Kim, GD, Kim, YK, Kojouharov, I, Kondev, FG, Kubo, T, Kurz, N, Kwon, YK, Li, XQ, Lou, JL, Lane, GJ, Li, CG, Luo, DW, Montaner-Piza, A, Moschner, K, Niu, CY, Naqvi, F, Niikura, M, Nishibata, H, Odahara, A, Orlandi, R, Patel, Z, Podolyak, Zs, Sumikama, T, Soderstrom, P-A, Sakurai, H, Schaffner, H, Simpson, GS, Steiger, K, Suzuki, H, Taprogge, J, Takeda, H, Vajta, Zs, Wang, HK, Wu, J, Wendt, A, Wang, CG, Wu, HY, Wang, X, Wu, CG, Xu, C, Xu, ZY, Yagi, A, Ye, YL, and Yoshinaga, K

Subjects
RIKEN, Science & Technology, IMPACT, Physics, Physical Sciences, Physics, Multidisciplinary, ISOTOPES, DECAY
Abstract

The β-delayed γ-ray spectroscopy of neutron-rich ^{123,125}Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2^{-} β-emitting isomers in ^{123,125}Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2^{+} and 1/2^{-} levels is extended in Ag isotopes up to N=78, providing a clear signal for the reduction of the Z=40 subshell gap in Ag towards N=82. Shell-model calculations with the state-of-the-art V_{MU} plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in ^{123,125}Ag. The tensor force is found to play a crucial role in the evolution of the size of the Z=40 subshell gap. The observed inversion of the single-particle levels around ^{123}Ag can be well interpreted in terms of the monopole shift of the π1g_{9/2} orbitals mainly caused by the increasing occupation of ν1h_{11/2} orbitals. ispartof: PHYSICAL REVIEW LETTERS vol:122 issue:21 ispartof: location:United States status: published

Published
2019

49. Improved Value for the Gamow-Teller Strength of the ^{100}Sn Beta Decay

Author

Lubos, D., Park, J., Faestermann, T., Gernhäuser, R., Krücken, R., Lewitowicz, M., Nishimura, S., Sakurai, H., Ahn, D.S., Baba, H., Blank, B., Blazhev, A., Boutachkov, P., Browne, F., Čeliković, I., De France, G., Doornenbal, P., Fang, Y., Fukuda, N., Giovinazzo, J., Goel, N., Górska, M., Ilieva, S., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, Y.K., Kojouharov, I., Kubo, T., Kurz, N., Kwon, Y.K., Lorusso, G., Moschner, K., Murai, D., Nishizuka, I., Patel, Z., Rajabali, M.M., Rice, S., Schaffner, H., Shimizu, Y., Sinclair, L., Söderström, P.A., Steiger, K., Sumikama, T., Suzuki, H., Takeda, H., Wang, Z., Warr, N., Watanabe, H., Wu, J., Xu, Z., Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; A record number of Sn100 nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the β-decay end point energy of Sn100 were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0+→1+ Gamow-Teller decay was improved to BGT=4.4-0.7+0.9. A discrimination between different model calculations was possible for the first time, and the level scheme of In100 is investigated further.

Published
2019

50. New isomers in Pd And Pd : Competing proton and neutron excitations in neutron-rich palladium nuclides towards the = 82 Shell Closure

Author

Watanabe, H., Wang, H.K., Lorusso, G., Nishimura, S., Xu, Z.Y., Sumikama, T., Söderström, P.A., Doornenbal, P., Browne, F., Gey, G., Jung, H.S., Taprogge, J., Vajta, Zs., Wu, J., Yagi, A., Baba, H., Benzoni, G., Chae, K.Y., Crespi, F.C.L., Fukuda, N., Gernhäuser, R., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kondev, F.G., Kubo, T., Kurz, N., Kwon, Y.K., Lane, G.J., Li, Z., Moon, C.B., Montaner-Pizá, A., Moschner, K., Naqvi, F., Niikura, M., Nishibata, H., Nishimura, D., Odahara, A., Orlandi, R., Patel, Z., Podolyák, Zs., Sakurai, H., Schaffner, H., Simpson, G.S., Steiger, K., Sun, Y., Suzuki, H., Takeda, H., Wendt, A., and Yoshinaga, K.

Abstract

The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N=82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in $^{125}$Pd$_{79}$ and $^{127}$Pd$_{81}$ studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity $^{238}$U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2+) and (19/2+) in $^{125}$Pd and $^{127}$Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitations and neutron excitations in the proton-hole and neutron-hole systems in the vicinity of the doubly magic nucleus $^{132}$Sn.

Published
2019

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