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1. Evolution of the two-neutron configuration from 11Li to 13Li

Author

P. André, A. Corsi, A. Revel, Y. Kubota, J. Casal, K. Fossez, J. Gómez-Camacho, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Quasi-free scattering, Three-body model, Dineutron decay, Physics, QC1-999
Abstract

In this work we investigate the two-neutron decay of 13Li and of the excited states of 11Li populated via one-proton removal from 14Be and 12Be, respectively. A phenomenological model is used to describe the decay of 11Li and 13Li. While the first one displays important sequential components, the second one appears dominated by the direct two-neutron decay. A microscopic three-body model is used to extract information on the spatial configuration of the emitted neutrons before the decay and shows that the average distance between the neutrons increases going from 11Li to 13Li.

Published
2024
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2. Spectroscopy of deeply bound orbitals in neutron-rich Ca isotopes

Author

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

Subjects
Unbound states, Knockout reaction, Single-particle strength, Shell evolution, Physics, QC1-999
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 53Ca and 55Ca, populated from 54,56Ca(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 53Ca and 6000(250)keV in 55Ca indicate a significant l =3 component, providing the first experimental evidence for the ν0f7/2 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 ν0f7/2 orbital in 55Ca. These results are in good agreement with predictions from shell-model calculations using the effective GXPF1Bs interaction and ab initio calculations and diverge markedly from the experimental distributions in the nickel isotones at Z=28.

Published
2024
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3. Shape coexistence in 66Se

Author

Z. Elekes, V. Panin, T.R. Rodríguez, K. Sieja, D.S. Ahn, A. Al-Adili, H. Baba, A.I. Stefanescu, K.J. Cook, Cs. Dósa, N. Fukuda, J. Gao, J. Gibelin, K.I. Hahn, Z. Halász, S.W. Huang, T. Isobe, M.M. Juhász, D. Kim, T. Kobayashi, Y. Kondo, Z. Korkulu, A. Kurihara, I. Kuti, H. Miki, K. Miki, T. Motobayashi, H. Otsu, A. Saastamoinen, M. Sasano, H. Sato, T. Shimada, Y. Shimizu, L.G. Sobotka, I. Stefanescu, L. Stuhl, H. Suzuki, H. Takeda, Y. Togano, T. Tomai, L. Trache, D. Tudor, T. Uesaka, Y. Utsuki, H. Wang, A. Yasuda, K. Yoneda, and Y. Yoshitome

Subjects
Neutron knock-out reaction, γ-ray spectroscopy, Nuclear structure, Shape coexistence, Physics, QC1-999
Abstract

The nuclear structure of 66Se, nucleus beyond the N=Z line on the proton-rich side of the valley of stability, was investigated by the neutron knock-out reaction 67Se(12C,X)66Se using a 12C target. The analysis of the singles spectrum of the γ-rays emitted during the de-excitation of the populated low-lying excited states revealed two previously detected (927(4) keV, 1460(32) keV) and three new (744(6) keV, 1210(17) keV, 1661(23) keV) transitions. The 744-keV, the 1210-keV, and the 1460-keV transitions were found to be in coincidence with the one at 927 keV. The spectrum coincident with the 927-keV transition showed a further possible transition at 299(35) keV, which was obscured by significant atomic background in the singles spectrum. This transition might correspond to a peak previously reported at 273(5) keV that could not be assigned to 66Se unambiguously. Based on a comparison of the experimental data to theoretical calculations, four new excited states are proposed which suggest that 66Se exhibits shape coexistence.

Published
2023
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4. Level structures of 56,58Ca cast doubt on a doubly magic 60Ca

Author

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

Subjects
Shell evolution, γ Ray spectroscopy, Physics, QC1-999
Abstract

Gamma decays were observed in 56Ca and 58Ca following quasi-free one-proton knockout reactions from 57,59Sc beams at ≈200 MeV/nucleon. For 56Ca, a γ ray transition was measured to be 1456(12) keV, while for 58Ca 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 60Ca and potentially drives the dripline of Ca isotopes to 70Ca or even beyond.

Published
2023
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5. Intruder configurations in 29Ne at the transition into the island of inversion: Detailed structure study of 28Ne

Author

H. Wang, M. Yasuda, Y. Kondo, T. Nakamura, J.A. Tostevin, K. Ogata, T. Otsuka, A. Poves, N. Shimizu, K. Yoshida, N.L. Achouri, H. Al Falou, L. Atar, T. Aumann, H. Baba, K. Boretzky, C. Caesar, D. Calvet, H. Chae, N. Chiga, A. Corsi, H.L. Crawford, F. Delaunay, A. Delbart, Q. Deshayes, Zs. Dombrádi, C. Douma, Z. Elekes, P. Fallon, I. Gašparić, J.-M. Gheller, J. Gibelin, A. Gillibert, M.N. Harakeh, A. Hirayama, C.R. Hoffman, M. Holl, A. Horvat, Á. Horváth, J.W. Hwang, T. Isobe, J. Kahlbow, N. Kalantar-Nayestanaki, S. Kawase, S. Kim, K. Kisamori, T. Kobayashi, D. Körper, S. Koyama, I. Kuti, V. Lapoux, S. Lindberg, F.M. Marqués, S. Masuoka, J. Mayer, K. Miki, T. Murakami, M.A. Najafi, K. Nakano, N. Nakatsuka, T. Nilsson, A. Obertelli, N.A. Orr, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, A. Revel, D. Rossi, A.T. Saito, T. Saito, M. Sasano, H. Sato, Y. Satou, H. Scheit, F. Schindler, P. Schrock, M. Shikata, Y. Shimizu, H. Simon, D. Sohler, O. Sorlin, L. Stuhl, S. Takeuchi, M. Tanaka, M. Thoennessen, H. Törnqvist, Y. Togano, T. Tomai, J. Tscheuschner, J. Tsubota, T. Uesaka, Z. Yang, and K. Yoneda

Subjects
In-beam γ-ray spectroscopy, Island of inversion, Shell evolution, Physics, QC1-999
Abstract

Detailed γ-ray spectroscopy of the exotic neon isotope 28Ne has been performed for the first time using the one-neutron removal reaction from 29Ne on a liquid hydrogen target at 240 MeV/nucleon. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for 28Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N=20 and N=28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

Published
2023
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6. Searching for universality of dineutron correlation at the surface of Borromean nuclei

Author

A. Corsi, Y. Kubota, J. Casal, M. Gómez-Ramos, A.M. Moro, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Quasi-free scattering, Borromean nuclei, Three-body model, Jacobi coordinates, Dineutron, Physics, QC1-999
Abstract

The dineutron correlation is systematically studied in three different Borromean nuclei near the neutron dripline, 11Li, 14Be and 17B, via the (p,pn) knockout reaction measured at the RIBF facility in RIKEN. For the three nuclei, the correlation angle between the valence neutrons is found to be largest in the same range of intrinsic momenta, which can be associated to the nuclear surface. This result reinforces the prediction that the formation of the dineutron is universal in environments with low neutron density, such as the surface of neutron-rich Borromean nuclei.

Published
2023
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7. Isovector density and isospin impurity in 40Ca

Author

H. Sagawa, S. Yoshida, T. Naito, T. Uesaka, J. Zenihiro, J. Tanaka, and T. Suzuki

Subjects
IS and IV densities, Isospin impurity, Hartree-Fock model, Particle-vibration coupling model, Charge symmetry breaking interaction, Charge independence breaking interaction, Physics, QC1-999
Abstract

We study isoscalar (IS) and isovector (IV) densities in Ca40 in comparison with theoretical densities calculated by Skyrme Hatree-Fock (HF) models. The charge symmetry breaking and the charge independence breaking forces are introduced to study the effect on the IV density. The effect of isospin mixing in the ground-state density is examined by using the particle-vibration coupling model taking into account the collective IV giant monopole excitation. We show a clear correlations in the IV density and isospin impurity of Ca40 within the HF and the particle-vibration coupling model. We extract for the first time the experimental information of isospin impurity from the magnitude of IV density.

Published
2022
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8. A first glimpse at the shell structure beyond 54Ca: Spectroscopy of 55K, 55Ca, and 57Ca

Author

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

Subjects
Radioactive beams, γ-ray spectroscopy, Shell evolution, Physics, QC1-999
Abstract

States in the N=35 and 37 isotopes 55,57Ca have been populated by direct proton-induced nucleon removal reactions from 56,58Sc and 56Ca beams at the RIBF. In addition, the (p,2p) quasi-free single-proton removal reaction from 56Ca was studied. Excited states in 55K, 55Ca, and 57Ca were established for the first time via in-beam γ-ray spectroscopy. Results for the proton and neutron removal reactions from 56Ca to states in 55K and 55Ca 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 57Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at N=35 to collective excitations at N=37.

Published
2022
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9. First spectroscopic study of 51Ar by the (p,2p) reaction

Author

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

Subjects
Proton knock-out reaction, γ-ray spectroscopy, Invariant mass method, Nuclear structure, Shell closure, Physics, QC1-999
Abstract

The nuclear structure of 51Ar, an uncharted territory so far, was studied by the (p,2p) reaction using γ-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the γ-ray spectrum and six peaks were observed in the 50Ar+n relative energy spectrum. Comparing the results to our shell-model calculations, two bound and six unbound states were established. Three of the unbound states could only be placed tentatively due to the low number of counts in the relative energy spectrum of events associated with the decay through the first excited state of 50Ar. The low cross sections populating the two bound states of 51Ar could be interpreted as a clear signature for the presence of significant subshell closures at neutron numbers 32 and 34 in argon isotopes. It was also revealed that due to the two valence holes, unbound collective states coexist with individual-particle states in 51Ar.

Published
2021
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10. Restoration of the natural E(1/21+) - E(3/21+) energy splitting in odd-K isotopes towards N = 40

Author

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

Subjects
Physics, QC1-999
Abstract

We report on the first γ-ray spectroscopy of 51,53K produced via the 52,54Ca(p,2p) reactions at ∼250 MeV/nucleon. Unambiguous final-state angular-momentum assignments were achieved for beam intensities down to few particles per second by using a new technique based on reaction vertex tracking combined with a thick liquid-hydrogen target. Through γ-ray spectroscopy and exclusive parallel momentum distribution analysis, 3/2+ ground states and 1/2+ first excited states in 51,53K were established quantifying the natural ordering of the 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. Keywords: Spectroscopy, Shell evolution, 51K, 53K

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

Author

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

Subjects
Physics, QC1-999
Abstract

Excited states in the N=40 isotone 62Ti were populated via the 63V(p,2p)62Ti 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 62Ti ground state. These energies are increased compared to the neighboring 64Cr and 66Fe 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 62Ti 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 60Ca. Keywords: Shell evolution, Radioactive beams, Gamma-ray spectroscopy

Published
2020
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12. Spectroscopy of 2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

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

Subjects
Physics, QC1-999
Abstract

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

Published
2018
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13. Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes

Author

Y.M. Xing, K.A. Li, Y.H. Zhang, X.H. Zhou, M. Wang, Yu.A. Litvinov, K. Blaum, S. Wanajo, S. Kubono, G. Martínez-Pinedo, A. Sieverding, R.J. Chen, P. Shuai, C.Y. Fu, X.L. Yan, W.J. Huang, X. Xu, X.D. Tang, H.S. Xu, T. Bao, X.C. Chen, B.S. Gao, J.J. He, Y.H. Lam, H.F. Li, J.H. Liu, X.W. Ma, R.S. Mao, M. Si, M.Z. Sun, X.L. Tu, Q. Wang, J.C. Yang, Y.J. Yuan, Q. Zeng, P. Zhang, X. Zhou, W.L. Zhan, S. Litvinov, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, C. Fröhlich, T. Rauscher, F.-K. Thielemann, B.H. Sun, Y. Sun, A.C. Dai, and F.R. Xu

Subjects
Physics, QC1-999
Abstract

Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations. Keywords: Atomic masses, Ion storage ring, Isochronous mass spectrometry, rp-Process, νp-Process

Published
2018
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14. Shell evolution beyond Z=28 and N=50: Spectroscopy of 81,82,83,84Zn

Author

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

Subjects
Physics, QC1-999
Abstract

We report on the measurement of new low-lying states in the neutron-rich 81,82,83,84Zn nuclei via in-beam γ-ray spectroscopy. These include the 41+→21+ transition in 82Zn, the 21+→0g.s.+ and 41+→21+ transitions in 84Zn, and low-lying states in 81,83Zn were observed for the first time. The reduced E(21+) energies and increased E(41+)/E(2+1) ratios at N=52, 54 compared to those in 80Zn attest that the magicity is confined to the neutron number N=50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2+ and 4+ levels in 84Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models.

Published
2017
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15. High-precision QEC values of superallowed 0+→0+ β-emitters 46Cr, 50Fe and 54Ni

Author

P. Zhang, X. Xu, P. Shuai, R.J. Chen, X.L. Yan, Y.H. Zhang, M. Wang, Yu.A. Litvinov, K. Blaum, H.S. Xu, T. Bao, X.C. Chen, H. Chen, C.Y. Fu, J.J. He, S. Kubono, Y.H. Lam, D.W. Liu, R.S. Mao, X.W. Ma, M.Z. Sun, X.L. Tu, Y.M. Xing, J.C. Yang, Y.J. Yuan, Q. Zeng, X. Zhou, X.H. Zhou, W.L. Zhan, S. Litvinov, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, B.H. Sun, Y. Sun, and F.R. Xu

Subjects
Storage rings, QEC values, Superallowed 0+→0+ β-emitters, CVC test, Physics, QC1-999
Abstract

Short-lived 46Cr, 50Fe and 54Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46Cr, 50Fe and 54Ni are −29471(11) keV, −34477(6) keV and −39278(4) keV, respectively. The superallowed 0+→0+ β-decay Q values were derived to be QEC(Cr46)=7604(11) keV, QEC(Fe50)=8150(6) keV and QEC(Ni54)=8731(4) keV. The values for 50Fe and 54Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected Ft values to be Ft(Fe50)=3103(70) s and Ft(Ni54)=3076(50) s. The main contribution to the Ft uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.

Published
2017
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16. First measurement of isoscalar giant resonances in a stored-beam experiment

Author

J.C. Zamora, T. Aumann, S. Bagchi, S. Bönig, M. Csatlós, I. Dillmann, C. Dimopoulou, P. Egelhof, V. Eremin, T. Furuno, H. Geissel, R. Gernhäuser, M.N. Harakeh, A.-L. Hartig, S. Ilieva, N. Kalantar-Nayestanaki, O. Kiselev, H. Kollmus, C. Kozhuharov, A. Krasznahorkay, Th. Kröll, M. Kuilman, S. Litvinov, Yu.A. Litvinov, M. Mahjour-Shafiei, M. Mutterer, D. Nagae, M.A. Najafi, C. Nociforo, F. Nolden, U. Popp, C. Rigollet, S. Roy, C. Scheidenberger, M. von Schmid, M. Steck, B. Streicher, L. Stuhl, M. Thürauf, T. Uesaka, H. Weick, J.S. Winfield, D. Winters, P.J. Woods, T. Yamaguchi, K. Yue, and J. Zenihiro

Subjects
Physics, QC1-999
Abstract

A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment was carried out at the experimental heavy-ion storage ring (ESR) at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm≤1.5°) were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79−11+12% of the energy-weighted sum rule (EWSR), which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams. Keywords: Storage ring, Inverse kinematics, Isoscalar giant resonances

Published
2016
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17. Structure of 13Be probed via quasi-free scattering

Author

A. Corsi, Y. Kubota, J. Casal, M. Gómez-Ramos, A.M. Moro, G. Authelet, H. Baba, C. Caesar, D. Calvet, A. Delbart, M. Dozono, J. Feng, F. Flavigny, J.-M. Gheller, J. Gibelin, A. Giganon, A. Gillibert, K. Hasegawa, T. Isobe, Y. Kanaya, S. Kawakami, D. Kim, Y. Kiyokawa, M. Kobayashi, N. Kobayashi, T. Kobayashi, Y. Kondo, Z. Korkulu, S. Koyama, V. Lapoux, Y. Maeda, F.M. Marqués, T. Motobayashi, T. Miyazaki, T. Nakamura, N. Nakatsuka, Y. Nishio, A. Obertelli, A. Ohkura, N.A. Orr, S. Ota, H. Otsu, T. Ozaki, V. Panin, S. Paschalis, E.C. Pollacco, S. Reichert, J.-Y. Rousse, A.T. Saito, S. Sakaguchi, M. Sako, C. Santamaria, M. Sasano, H. Sato, M. Shikata, Y. Shimizu, Y. Shindo, L. Stuhl, T. Sumikama, Y.L. Sun, M. Tabata, Y. Togano, J. Tsubota, T. Uesaka, Z.H. Yang, J. Yasuda, K. Yoneda, and J. Zenihiro

Subjects
Physics, QC1-999
Abstract

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

Published
2019
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18. Multiple Mechanisms in Proton-Induced Nucleon Removal at ∼100 MeV/Nucleon

Author

T. Pohl, Y. L. Sun, A. Obertelli, J. Lee, M. Gómez-Ramos, K. Ogata, K. Yoshida, B. S. Cai, C. X. Yuan, B. A. Brown, H. Baba, D. Beaumel, A. Corsi, J. Gao, J. Gibelin, A. Gillibert, K. I. Hahn, T. Isobe, D. Kim, Y. Kondo, T. Kobayashi, Y. Kubota, P. Li, P. Liang, H. N. Liu, J. Liu, T. Lokotko, F. M. Marqués, Y. Matsuda, T. Motobayashi, T. Nakamura, N. A. Orr, H. Otsu, V. Panin, S. Y. Park, S. Sakaguchi, M. Sasano, H. Sato, H. Sakurai, Y. Shimizu, A. I. Stefanescu, L. Stuhl, D. Suzuki, Y. Togano, D. Tudor, T. Uesaka, H. Wang, X. Xu, Z. H. Yang, K. Yoneda, and J. Zenihiro

Subjects
General Physics and Astronomy
Published
2023

20. Extended p3/2 Neutron Orbital and the N=32 Shell Closure in Ca52

Author

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

Subjects
General Physics and Astronomy
Published
2022

21. PUMA, antiProton unstable matter annihilation PUMA collaboration

Author

T. Aumann, W. Bartmann, O. Boine-Frankenheim, A. Bouvard, A. Broche, F. Butin, D. Calvet, J. Carbonell, P. Chiggiato, H. De Gersem, R. De Oliveira, T. Dobers, F. Ehm, J. Ferreira Somoza, J. Fischer, M. Fraser, E. Friedrich, A. Frotscher, M. Gomez-Ramos, J.-L. Grenard, A. Hobl, G. Hupin, A. Husson, P. Indelicato, K. Johnston, C. Klink, Y. Kubota, R. Lazauskas, S. Malbrunot-Ettenauer, N. Marsic, W. F. O Müller, S. Naimi, N. Nakatsuka, R. Necca, D. Neidherr, G. Neyens, A. Obertelli, Y. Ono, S. Pasinelli, N. Paul, E. C. Pollacco, D. Rossi, H. Scheit, M. Schlaich, A. Schmidt, L. Schweikhard, R. Seki, S. Sels, E. Siesling, T. Uesaka, M. Vilén, M. Wada, F. Wienholtz, S. Wycech, and S. Zacarias

Subjects
Nuclear and High Energy Physics, Science & Technology, Physics, NONNEUTRAL PLASMAS, NUCLEAR PERIPHERY, PENNING-TRAP, STAINLESS-STEEL, Physics, Particles & Fields, HIGHLY-CHARGED IONS, Physics, Nuclear, INTERACTION CROSS-SECTIONS, NEUTRON HALO, ELECTRON PLASMAS, Physical Sciences, ADSORPTION-ISOTHERMS, LEVEL SHIFTS
Abstract

PUMA, antiProton Unstable Matter Annihilation, is a nuclear-physics experiment at CERN aiming at probing the surface properties of stable and rare isotopes by use of low-energy antiprotons. Low-energy antiprotons offer a very unique sensitivity to the neutron and proton densities at the annihilation site, i.e. in the tail of the nuclear density. Today, no facility provides a collider of low-energy radioactive ions and low-energy antiprotons: while not being a collider experiment, PUMA aims at transporting one billion antiprotons from ELENA, the Extra-Low-ENergy Antiproton ring, to ISOLDE, the rare-isotope beam facility of CERN. PUMA will enable the capture of low-energy antiprotons by short-lived nuclei and the measurement of the emitted radiations. In this way, PUMA will give access to the so-far largely unexplored isospin composition of the nuclear-radial-density tail of radioactive nuclei. The motivations, concept and current status of the PUMA experiment are presented.

Published
2022

22. First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r -Process Abundance Trend at A=122 and A=123

Author

H. F. Li, S. Naimi, T. M. Sprouse, M. R. Mumpower, Y. Abe, Y. Yamaguchi, D. Nagae, F. Suzaki, M. Wakasugi, H. Arakawa, W. B. Dou, D. Hamakawa, S. Hosoi, Y. Inada, D. Kajiki, T. Kobayashi, M. Sakaue, Y. Yokoda, T. Yamaguchi, R. Kagesawa, D. Kamioka, T. Moriguchi, M. Mukai, A. Ozawa, S. Ota, N. Kitamura, S. Masuoka, S. Michimasa, H. Baba, N. Fukuda, Y. Shimizu, H. Suzuki, H. Takeda, D. S. Ahn, M. Wang, C. Y. Fu, Q. Wang, S. Suzuki, Z. Ge, Yu. A. Litvinov, G. Lorusso, P. M. Walker, Zs. Podolyak, and T. Uesaka

Subjects
General Physics and Astronomy
Published
2022

23. γ -ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich Kr94,95,96

Author

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

Published
2022

24. Observation of a correlated free four-neutron system

Author

M. Duer, T. Aumann, R. Gernhäuser, V. Panin, S. Paschalis, D. M. Rossi, N. L. Achouri, D. Ahn, H. Baba, C. A. Bertulani, M. Böhmer, K. Boretzky, C. Caesar, N. Chiga, A. Corsi, D. Cortina-Gil, C. A. Douma, F. Dufter, Z. Elekes, J. Feng, B. Fernández-Domínguez, U. Forsberg, N. Fukuda, I. Gasparic, Z. Ge, J. M. Gheller, J. Gibelin, A. Gillibert, K. I. Hahn, Z. Halász, M. N. Harakeh, A. Hirayama, M. Holl, N. Inabe, T. Isobe, J. Kahlbow, N. Kalantar-Nayestanaki, D. Kim, S. Kim, T. Kobayashi, Y. Kondo, D. Körper, P. Koseoglou, Y. Kubota, I. Kuti, P. J. Li, C. Lehr, S. Lindberg, Y. Liu, F. M. Marqués, S. Masuoka, M. Matsumoto, J. Mayer, K. Miki, B. Monteagudo, T. Nakamura, T. Nilsson, A. Obertelli, N. A. Orr, H. Otsu, S. Y. Park, M. Parlog, P. M. Potlog, S. Reichert, A. Revel, A. T. Saito, M. Sasano, H. Scheit, F. Schindler, S. Shimoura, H. Simon, L. Stuhl, H. Suzuki, D. Symochko, H. Takeda, J. Tanaka, Y. Togano, T. Tomai, H. T. Törnqvist, J. Tscheuschner, T. Uesaka, V. Wagner, H. Yamada, B. Yang, L. Yang, Z. H. Yang, M. Yasuda, K. Yoneda, L. Zanetti, J. Zenihiro, M. V. Zhukov, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Research unit Nuclear & Hadron Physics, and Nuclear Energy

Subjects
Multidisciplinary, Nuclear Force, Nuclear Structure, Tetraneutron, Reactions with Radioactive Beams, Physics, ddc:500, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

Nature 606(7915), 678 - 682 (2022). doi:10.1038/s41586-022-04827-6, Published by Nature Publ. Group, London [u.a.]

Published
2022

25. Silicon tracker array for RIB experiments at SAMURAI

Author

A. I. Stefanescu, V. Panin, L. Trache, T. Motobayashi, H. Otsu, A. Saastamoinen, T. Uesaka, L. Stuhl, J. Tanaka, D. Tudor, I. C. Stefanescu, A. E. Spiridon, K. Yoneda, H. Baba, M. Kurokawa, Y. Togano, Z. Halasz, M. Sasano, S. Ota, Y. Kubota, D. S. Ahn, T. Kobayashi, Z. Elekes, N. Fukuda, H. Takeda, D. Kim, E. Takada, H. Suzuki, K. Yoshida, Y. Shimizu, H. N. Liu, Y. L. Sun, T. Isobe, J. Gibelin, P. J. Li, J. Zenihiro, F. M. Marqués, M. N. Harakeh, G. G. Kiss, A. Kurihara, M. Yasuda, T. Nakamura, S. Park, Z. Yang, T. Harada, M. Nishimura, H. Sato, I. S. Hahn, K. Y. Chae, J. M. Elson, L. G. Sobotka, C. A. Bertulani, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment (nucl-ex), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Nuclear Experiment
Abstract

International audience; This work describes a silicon tracker system developed for experiments with proton-rich radioactive ion beams at the SAMURAI superconducting spectrometer of RIBF at RIKEN. The system is designed for accurate angular reconstruction and atomic number identification of relativistic heavy ions and protons which are simultaneously produced in reactions motivated by studies of proton capture reactions of interest for nuclear astrophysics. The technical characteristics of the tracking array are described in detail as are its performance in two pilot experiments. The physics justification for such a system is also presented.

Published
2022

26. Analyzing Power Measurement for p-$$^3$$He Elastic Scattering at Intermediate Energies

Author

A. Watanabe, S. Nakai, Y. Wada, K. Sekiguchi, T. Akieda, D. Etoh, M. Inoue, Y. Inoue, K. Kawahara, H. Kon, K. Miki, T. Mukai, D. Sakai, S. Shibuya, Y. Shiokawa, T. Taguchi, H. Umetsu, Y. Utsuki, M. Watanabe, S. Goto, K. Hatanaka, Y. Hirai, Y. Ikeda, T. Ino, D. Inomoto, S. Ishikawa, M. Itoh, H. Kanda, H. Kasahara, Y. Maeda, S. Mitsumoto, K. Nonaka, H. J. Ong, H. Oshiro, Y. Otake, H. Sakai, A. Taketani, D. T. Tran, T. Uesaka, T. Wakasa, Y. Wakabayashi, and T. Wakui

Subjects
Atomic and Molecular Physics, and Optics
Published
2021

27. Search for $\alpha$ condensed states in $^{13}$C using $\alpha$ inelastic scattering

Author

Takahiro Kawabata, Yohei Shimizu, M. Uchida, Hiroshi Matsubara, Yasuro Funaki, Mamoru Fujiwara, K. Itoh, Yoshiko Sasamoto, K. Inaba, Yuji Tameshige, K. Hatanaka, T. Uesaka, Satoshi Sakaguchi, Taiichi Yamada, Yukie Maeda, Kenji Suda, Masatoshi Itoh, Atsushi Tamii, K. Kawase, and Hisataka Yoshida

Subjects
Physics, Dipole, Nuclear Theory, Excited state, Isoscalar, Magnetic monopole, General Physics and Astronomy, Parity (physics), State (functional analysis), Atomic physics, Inelastic scattering, Multipole expansion, Nuclear Experiment
Abstract

We searched for the $\alpha$ condensed state in $^{13}$C by measuring the $\alpha$ inelastic scattering at $E_{\alpha} = 388$ MeV at forward angles including 0 degrees. We performed the distorted-wave Born-approximation calculation with the single-folding potential and the multipole decomposition analysis to determine the isoscalar transition strengths in $^{13}$C. We found a bump structure around $E_x = 12.5$ MeV due to the isoscalar monopole ($IS0$) transition. A peak-fit analysis suggested that this bump consisted of several $1/2^-$ states. We propose that this bump is due to the mirror state of the 13.5 MeV-state in $^{13}$N, which dominantly decays to the $\alpha$ condensed state in $^{12}$C. It was speculated that the $1/2^-$ states around $E_x = 12.5$ MeV were candidates for the $\alpha$ condensed state, but the $3\alpha + n$ orthogonality condition model suggests that the $\alpha$ condensed state is unlikely to emerge as the negative parity states. We also found two $1/2^+$ or $3/2^+$ states at $E_x = 14.5$ and 16.1 MeV excited with the isoscalar dipole ($IS1$) strengths. We suggest that the 16.1-MeV state is a possible candidate for the $\alpha$ condensed state predicted by the cluster-model calculations on the basis of the good correspondence between the experimental and calculated level structures. However, the theoretical $IS1$ transition strength for this state is significantly smaller than the measured value. Further experimental information is strongly desired to establish the $\alpha$ condensed state in $^{13}$C., Comment: 24 pages, 12 figures, published in PTEP

Published
2021

28. Quasi-free Neutron Knockout Reaction Reveals a Small $s$-orbital Component in the Borromean Nucleus $^{17}$B

Author

Z H, Yang, Y, Kubota, A, Corsi, K, Yoshida, X-X, Sun, J G, Li, M, Kimura, N, Michel, K, Ogata, C X, Yuan, Q, Yuan, G, Authelet, H, Baba, C, Caesar, D, Calvet, A, Delbart, M, Dozono, J, Feng, F, Flavigny, J-M, Gheller, J, Gibelin, A, Giganon, A, Gillibert, K, Hasegawa, T, Isobe, Y, Kanaya, S, Kawakami, D, Kim, Y, Kiyokawa, M, Kobayashi, N, Kobayashi, T, Kobayashi, Y, Kondo, Z, Korkulu, S, Koyama, V, Lapoux, Y, Maeda, F M, Marqués, T, Motobayashi, T, Miyazaki, T, Nakamura, N, Nakatsuka, Y, Nishio, A, Obertelli, A, Ohkura, N A, Orr, S, Ota, H, Otsu, T, Ozaki, V, Panin, S, Paschalis, E C, Pollacco, S, Reichert, J-Y, Roussé, A T, Saito, S, Sakaguchi, M, Sako, C, Santamaria, M, Sasano, H, Sato, M, Shikata, Y, Shimizu, Y, Shindo, L, Stuhl, T, Sumikama, Y L, Sun, M, Tabata, Y, Togano, J, Tsubota, F R, Xu, J, Yasuda, K, Yoneda, J, Zenihiro, S-G, Zhou, W, Zuo, T, Uesaka, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Astrophysics::Galaxy Astrophysics, Nuclear Physics
Abstract

A kinematically complete quasi-free $(p,pn)$ experiment in inverse kinematics was performed to study the structure of the Borromean nucleus $^{17}$B, which had long been considered to have neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $1s_{1/2}$ and $0d_{5/2}$ orbitals, and a surprisingly small percentage of 9(2)$\%$ was determined for $1s_{1/2}$. Our finding of such a small $1s_{1/2}$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $^{17}$B. The present work gives the smallest $s$- or $p$-orbital component among known nuclei exhibiting halo features, and implies that the dominant occupation of $s$ or $p$ orbitals is not a prerequisite for the occurrence of neutron halo., Accepted for publication in Physical Review Letters,8 pages, 4 figures

Published
2021

29. First application of mass measurement with the Rare-RI Ring reveals the solar r-process abundance trend at A=122 and A=123

Author

H F, Li, S, Naimi, T M, Sprouse, M R, Mumpower, Y, Abe, Y, Yamaguchi, D, Nagae, F, Suzaki, M, Wakasugi, H, Arakawa, W B, Dou, D, Hamakawa, S, Hosoi, Y, Inada, D, Kajiki, T, Kobayashi, M, Sakaue, Y, Yokoda, T, Yamaguchi, R, Kagesawa, D, Kamioka, T, Moriguchi, M, Mukai, A, Ozawa, S, Ota, N, Kitamura, S, Masuoka, S, Michimasa, H, Baba, N, Fukuda, Y, Shimizu, H, Suzuki, H, Takeda, D S, Ahn, M, Wang, C Y, Fu, Q, Wang, S, Suzuki, Z, Ge, Yu A, Litvinov, G, Lorusso, P M, Walker, Zs, Podolyak, and T, Uesaka

Subjects
Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The Rare-RI Ring (R3) is a recently commissioned cyclotron-like storage ring mass spectrometer dedicated to mass measurements of exotic nuclei far from stability at Radioactive Isotope Beam Factory (RIBF) in RIKEN. The first application of mass measurement using the R3 mass spectrometer at RIBF is reported. Rare isotopes produced at RIBF, $^{127}$Sn, $^{126}$In, $^{125}$Cd, $^{124}$Ag, $^{123}$Pd, were injected in R3. Masses of $^{126}$In, $^{125}$Cd, and $^{123}$Pd were measured whereby the mass uncertainty of $^{123}$Pd was improved. This is the first reported measurement with a new storage ring mass spectrometery technique realized at a heavy-ion cyclotron and employing individual injection of the pre-identified rare nuclei. The latter is essential for the future mass measurements of the rarest isotopes produced at RIBF. The impact of the new $^{123}$Pd result on the solar $r$-process abundances in a neutron star merger event is investigated by performing reaction network calculations of 20 trajectories with varying electron fraction $Y_e$. It is found that the neutron capture cross section on $^{123}$Pd increases by a factor of 2.2 and $\beta$-delayed neutron emission probability, $P_\mathrm{1n}$, of $^{123}$Rh increases by 14\%. The neutron capture cross section on $^{122}$Pd decreases by a factor of 2.6 leading to pileup of material at $A=122$, thus reproducing the trend of the solar $r$-process abundances. The trend of the two-neutron separation energies (S$_\mathrm{2n}$) was investigated for the Pd isotopic chain. The new mass measurement with improved uncertainty excludes large changes of the S$_\mathrm{2n}$ value at $N=77$. Such large increase of the S$_\mathrm{2n}$ values before $N=82$ was proposed as an alternative to the quenching of the $N=82$ shell gap to reproduce $r$-process abundances in the mass region of $A=112-124$.

Published
2021
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30. Quenching of single-particle strength from direct reactions with stable and rare-isotope beams

Author

A. M. Moro, Thomas Aumann, Daniel Bazin, Kazuyuki Ogata, Takashi Nakamura, Carlo Barbieri, M. Gómez-Ramos, Angela Bonaccorso, T. Uesaka, Carlos A. Bertulani, Alexandre Obertelli, Stefanos Paschalis, Alexandra Gade, W. H. Dickhoff, and B. P. Kay

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Quenching (fluorescence), Isotope, Nuclear Theory, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Nuclear structure, FOS: Physical sciences, 01 natural sciences, Asymmetry, 3. Good health, Nuclear Theory (nucl-th), Chemical physics, 0103 physical sciences, Particle, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common
Abstract

In this review article we discuss the present status of direct nuclear reactions and the nuclear structure aspects one can study with them. We discuss the spectroscopic information we can assess in experiments involving transfer reactions, heavy-ion-induced knockout reactions and quasifree scattering with (p,2p), (p,pn), and (e,e'p) reactions. In particular, we focus on the proton-to-neutron asymmetry of the quenching of the spectroscopic strength., 138 pages, 63 figures

Published
2020

31. 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

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

Abstract

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

Published
2020

32. Mass measurements for the T z = − 2 f p -shell nuclei Ti

Author

C. Y. Fu, Y. H. Zhang, M. Wang, X. H. Zhou, Yu. A. Litvinov, K. Blaum, H. S. Xu, X. Xu, P. Shuai, Y. H. Lam, R. J. Chen, X. L. Yan, X. C. Chen, J. J. He, S. Kubono, M. Z. Sun, X. L. Tu, Y. M. Xing, Q. Zeng, X. Zhou, W. L. Zhan, S. Litvinov, G. Audi, T. Uesaka, T. Yamaguchi, A. Ozawa, B. H. Sun, Y. Sun, F. R. Xu

Published
2020
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33. Spectroscopy of $^{16}$B from quasi-free ($p,pn$) reaction with $^{17}$B

Author

T. Kobayashi, Yosuke Kondo, J. Yasuda, Alessandra Corsi, D. Calvet, T. Isobe, Y. Kanaya, H. Sato, K. Hasegawa, Atsumi Saito, C. Santamaria, Tsuyoshi Miyazaki, Toshiyuki Sumikama, Satoshi Sakaguchi, Y. Shindo, T. Ozaki, M. Shikata, G. Authelet, J. M. Gheller, J. Tsubota, M. Tabata, S. Kawakami, Noritsugu Nakatsuka, D. Kim, T. Motobayashi, Motoki Kobayashi, Shoko Koyama, K. Yoneda, Z. Korkulu, H. Baba, Y. Nishio, T. Uesaka, A. Ohkura, Juzo Zenihiro, V. Lapoux, Masaki Sasano, J.-Y. Roussé, Y. Kiyokawa, A. Giganon, Yasuhiro Togano, A. Gillibert, Yuya Kubota, A. Obertelli, S. Reichert, Takashi Nakamura, Ji Feng, N. A. Orr, Y. L. Sun, S. Ota, J. Gibelin, C. Caesar, M. Sako, V. Panin, Yohei Shimizu, Zaihong Yang, L. Stuhl, F. M. Marqués, Yukie Maeda, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, A. Delbart, Masanori Dozono, E. C. Pollacco, Hideaki Otsu, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Paper, History, 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Molecular physics, 3. Good health, Computer Science Applications, Education, ddc, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, 0103 physical sciences, Halo, 010306 general physics, Spectroscopy
Abstract

Spectroscopy of 16B plays an essential role in understanding the halo structure in 17B, but very limited knowledge has so far been obtained. We have carried out a kinematically complete measurement on the spectroscopy of 16B by using quasi-free (p,pn) reaction on 17B. The level scheme of 16B up to 5 MeV was made clear for the first time.

Published
2020

34. How Different is the Core of 25F from 24Og.s. ?

Author

T., L. Tang (Univ. Tokyo, CNS), T., Uesaka (RIKEN), S., Kawase (Univ. Tokyo, CNS), D., Beaumel (Inst. Phys. Nucl. Orsay), M., Dozono (RIKEN), T., Fujii (Univ. Tokyo CNS), N., Fukuda (RIKEN), T., Fukunaga (Kyushu Univ.), A., Galindo-Uribarri (Oak Ridge Natl. Lab.), S., H. Hwang (Kyungpook Natl. Univ.), N., Inabe (RIKEN), D., Kameda (RIKEN), T., Kawahara (Toho Univ.), W., Kim ( Kyungpook Natl. Univ. ), K., Kisamori (Univ. Tokyo, CNS), M., Kobayashi (Univ. Tokyo, CNS), T., Kubo (RIKEN), Y., Kubota (Univ. Tokyo, CNS), K., Kusaka (RIKEN), C., S. Lee (Univ. Tokyo, CNS), Y., Maeda (Univ. Miyazaki), Wakui, Takashi, al., et, Takashi, Wakui, T., L. Tang (Univ. Tokyo, CNS), T., Uesaka (RIKEN), S., Kawase (Univ. Tokyo, CNS), D., Beaumel (Inst. Phys. Nucl. Orsay), M., Dozono (RIKEN), T., Fujii (Univ. Tokyo CNS), N., Fukuda (RIKEN), T., Fukunaga (Kyushu Univ.), A., Galindo-Uribarri (Oak Ridge Natl. Lab.), S., H. Hwang (Kyungpook Natl. Univ.), N., Inabe (RIKEN), D., Kameda (RIKEN), T., Kawahara (Toho Univ.), W., Kim ( Kyungpook Natl. Univ. ), K., Kisamori (Univ. Tokyo, CNS), M., Kobayashi (Univ. Tokyo, CNS), T., Kubo (RIKEN), Y., Kubota (Univ. Tokyo, CNS), K., Kusaka (RIKEN), C., S. Lee (Univ. Tokyo, CNS), Y., Maeda (Univ. Miyazaki), Wakui, Takashi, al., et, and Takashi, Wakui

Abstract

The structure of a neutron-rich F-25 nucleus is investigated by a quasifree (p, 2p) knockout reaction at 270A MeV in inverse kinematics. The sum of spectroscopic factors of pi 0d(5/2) orbital is found to be 1.0 +/- 0.3. However, the spectroscopic factor with residual O-24 nucleus being in the ground state is found to be only 0.36 +/- 0.13, while those in the excited state is 0.65 +/- 0.25. The result shows that the O-24 core of F-25 nucleus significantly differs from a free O-24 nucleus, and the core consists of similar to 35% O-24(g.s.). and similar to 65% excited O-24. The result may infer that the addition of the 0d(5/2) proton considerably changes neutron structure in F-25 from that in O-24, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Published
2020

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

Author

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

Subjects
Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment
Abstract

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

Published
2019

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

Author

M. Gómez-Ramos, Yuya Kubota, Takashi Nakamura, Tsuyoshi Miyazaki, Yukie Maeda, J. Casal, H. Sato, J. Tsubota, A. Gillibert, Michikazu Kobayashi, J. Gibelin, C. Caesar, V. Lapoux, Y. Shindo, M. Sako, K. Hasegawa, Y. Nishio, A. Ohkura, K. Yoneda, S. Kawakami, V. Panin, A. M. Moro, A. Obertelli, T. Uesaka, G. Authelet, Yosuke Kondo, Masanori Dozono, J.-Y. Roussé, J. M. Gheller, T. Ozaki, C. Santamaria, Yohei Shimizu, S. Reichert, Y. Kiyokawa, Zaihong Yang, Hidetada Baba, Y. Kanaya, T. Isobe, D. Kim, Yasuhiro Togano, E. C. Pollacco, A. Giganon, M. Shikata, F. M. Marqués, M. Tabata, Hideaki Otsu, T. Motobayashi, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, Shoko Koyama, A. Delbart, L. Stuhl, Z. Korkulu, Satoshi Sakaguchi, Masaki Sasano, A. Corsi, S. Ota, Y.L. Sun, D. Calvet, Atsumi Saito, Toshiyuki Sumikama, Toshio Kobayashi, Noritsugu Nakatsuka, Juzo Zenihiro, J. Feng, N.A. Orr, J. Yasuda, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Département des Accélérateurs, de Cryogénie et de Magnétisme (ex SACM) (DACM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

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

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

Published
2019

37. Masses of neutron-rich Sc 52 – 54 and Ti

Author

X. Xu, M. Wang, K. Blaum, J. D. Holt, Yu. A. Litvinov, A. Schwenk, J. Simonis, S. R. Stroberg, Y. H. Zhang, H. S. Xu, P. Shuai, X. L. Tu, X. H. Zhou, F. R. Xu, G. Audi, R. J. Chen, X. C. Chen, C. Y. Fu, Z. Ge, W. J. Huang, S. Litvinov, D. W. Liu, Y. H. Lam, X. W. Ma, R. S. Mao, A. Ozawa, B. H. Sun, Y. Sun, T. Uesaka, G. Q. Xiao, Y. M. Xing, T. Yamaguchi, Y. Yamaguchi, X. L. Yan, Q. Zeng, H. W. Zha

Published
2019
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38. Masses of ground and isomeric states of In 101 and configuration-dependent shell evolution in odd- A indium isotopes

Author

X. Xu, J. H. Liu, C. X. Yuan, Y. M. Xing, M. Wang, Y. H. Zhang, X. H. Zhou, Yu. A. Litvinov, K. Blaum, R. J. Chen, X. C. Chen, C. Y. Fu, B. S. Gao, J. J. He, S. Kubono, Y. H. Lam, H. F. Li, M. L. Liu, X. W. Ma, P. Shuai, M. Si, M. Z. Sun, X. L. Tu, Q. Wang, H. S. Xu, X. L. Yan, J. C. Yang, Y. J. Yuan, Q. Zeng, P. Zhang, X. Zhou, W. L. Zhan, S. Litvinov, G. Audi, S. Naimi, T. Uesaka, Y. Yamaguchi

Published
2019
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39. Nuclear Breakup and Coulomb Dissociation of $^{9}$C Nucleus Studied at RIBF RIKEN

Author

Livius Trache, H. Baba, M.N. Harakeh, H. N. Liu, H. Takeda, F. M. Marques, Zoltán Halász, T. Isobe, H. Murakami, H. Otsu, J. Zenihiro, D. H. Kim, M. Sasano, S. Y. Park, Z. Yang, I. C. Stefanescu, D. Tudor, T. Motobayashi, Masahiro Yasuda, A. E. Spiridon, A. N. Petrovici, Y. L. Sun, Takashi Nakamura, Naoki Fukuda, Y. Kubota, K. Yoneda, Masanori Nishimura, Y. Shimizu, T. Uesaka, Yasuhiro Togano, P. J. Li, A. Kurihara, K. Y. Chae, H. Suzuki, D. S. Ahn, A. I. Chilug, T. Kobayashi, J. Gibelin, Shuichi Ota, I. S. Hahn, L. Stuhl, F. Carstoiu, N. T. Zhang, Z. Elekes, Antti Saastamoinen, H. Sato, G. G. Kiss, T. Harada, V. Panin, 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), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Hydrogen, Explosive material, 010308 nuclear & particles physics, chemistry.chemical_element, Inverse, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, 7. Clean energy, Dissociation (chemistry), Nuclear physics, chemistry, 0103 physical sciences, Radiative transfer, Coulomb, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mass gap
Abstract

International audience; The 9C breakup was studied during the SAMURAI29R1 experiment through inclusive and exclusive measurements at energies around 160 AMeV for 9C, in order to evaluate the astrophysical S18 factor for the inverse process 8B(p,γ)9C at energies in the region of astrophysical interest. The radiative proton capture on 8B is important in the hot pp chains, in explosive Hydrogen burning (ppIV and rapI), at temperatures between 0.05 < T9 < 1 K, as possible alternative paths across the A = 8 mass gap. Another goal of this experiment was a detailed study of the breakup reaction mechanism. During the experiment the nuclear breakup process was studied using a natural C target with 425 µm thickness and the Coulomb dissociation by using a natural Pb target with 150 µm thickness. The reaction products were tracked simultaneously using a system of position sensitive Si detectors and in total 1024 output channels were read out by using new dual gain preamplifiers (DGP) specially designed for the experiments of the HI-p collaboration. The SAMURAI29R1 experiment was carried out during the SAMURAI 18Oxygen 2018 Spring campaign and it is part of the HI-p collaboration together with another three experiments. Performances of the setup used and first results of the analysis are presented.

Published
2018

40. Extraction of the Landau-Migdal Parameter from the Gamow-Teller Giant Resonance in ^{132}Sn

Author

J, Yasuda, M, Sasano, R G T, Zegers, H, Baba, D, Bazin, W, Chao, M, Dozono, N, Fukuda, N, Inabe, T, Isobe, G, Jhang, D, Kameda, M, Kaneko, K, Kisamori, M, Kobayashi, N, Kobayashi, T, Kobayashi, S, Koyama, Y, Kondo, A J, Krasznahorkay, T, Kubo, Y, Kubota, M, Kurata-Nishimura, C S, Lee, J W, Lee, Y, Matsuda, E, Milman, S, Michimasa, T, Motobayashi, D, Muecher, T, Murakami, T, Nakamura, N, Nakatsuka, S, Ota, H, Otsu, V, Panin, W, Powell, S, Reichert, S, Sakaguchi, H, Sakai, M, Sako, H, Sato, Y, Shimizu, M, Shikata, S, Shimoura, L, Stuhl, T, Sumikama, H, Suzuki, S, Tangwancharoen, M, Takaki, H, Takeda, T, Tako, Y, Togano, H, Tokieda, J, Tsubota, T, Uesaka, T, Wakasa, K, Yako, K, Yoneda, and J, Zenihiro

Abstract

The key parameter to discuss the possibility of the pion condensation in nuclear matter, i.e., the so-called Landau-Migdal parameter g^{'}, was extracted by measuring the double-differential cross sections for the (p,n) reaction at 216 MeV/u on a neutron-rich doubly magic unstable nucleus, ^{132}Sn with the quality comparable to data taken with stable nuclei. The extracted strengths for Gamow-Teller (GT) transitions from ^{132}Sn leading to ^{132}Sb exhibit the GT giant resonance (GTR) at the excitation energy of 16.3±0.4(stat)±0.4(syst) MeV with the width of Γ=4.7±0.8 MeV. The integrated GT strength up to E_{x}=25 MeV is S_{GT}^{-}=53±5(stat)_{-10}^{+11}(syst), corresponding to 56% of Ikeda's sum rule of 3(N-Z)=96. The present result accurately constrains the Landau-Migdal parameter as g^{'}=0.68±0.07, thanks to the high sensitivity of the GTR energy to g^{'}. In combination with previous studies on the GTR for ^{90}Zr and ^{208}Pb, the result of this work shows the constancy of this parameter in the nuclear chart region with (N-Z)/A=0.11 to 0.24 and A=90 to 208.

Published
2018

41. Erratum: Persistence of the Z=28 Shell Gap Around ^{78}Ni: First Spectroscopy of ^{79}Cu [Phys. Rev. Lett. 119, 192501 (2017)]

Author

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

Abstract

This corrects the article DOI: 10.1103/PhysRevLett.119.192501.

Published
2018

42. Structure of Beryllium Isotopes Beyond the Neutron Dripline

Author

V. Panin, Tsuyoshi Miyazaki, K. Yoneda, T. Isobe, S. Reichert, T. Uesaka, K. Hasegawa, Y. Shindo, Nagao Kobayashi, Stefanos Paschalis, F. Flavigny, J. Gibelin, C. Caesar, T. Ozaki, D. Kim, J.-Y. Roussé, Yuya Kubota, Yasuhiro Togano, F. M. Marqués, Yohei Shimizu, Takashi Nakamura, Zaihong Yang, Ji Feng, M. Sako, G. Authelet, J. M. Gheller, T. Kobayashi, E. C. Pollacco, Hideaki Otsu, Masanori Dozono, Yukie Maeda, Atsumi Saito, V. Lapoux, L. Stuhl, D. Calvet, M. Shikata, Toshiyuki Sumikama, Satoshi Sakaguchi, Noritsugu Nakatsuka, Juzo Zenihiro, A. Corsi, A. Delbart, Masaki Sasano, A. Ohkura, J. Yasuda, Motoki Kobayashi, Shoko Koyama, Z. Korkulu, Y. Kanaya, H. Sato, Yosuke Kondo, A. Gillibert, Y. Kiyokawa, A. Obertelli, Y. Nishio, A. Giganon, M. Tabata, T. Motobayashi, S. Kawakami, H. Baba, B. Monteagudo, J. Tsubota, C. Santamaria, N. A. Orr, S. Ota, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

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

Published
2018

43. Magic Nature of Neutrons in ^{54}Ca: First Mass Measurements of ^{55-57}Ca

Author

S, Michimasa, M, Kobayashi, Y, Kiyokawa, S, Ota, D S, Ahn, H, Baba, G P A, Berg, M, Dozono, N, Fukuda, T, Furuno, E, Ideguchi, N, Inabe, T, Kawabata, S, Kawase, K, Kisamori, K, Kobayashi, T, Kubo, Y, Kubota, C S, Lee, M, Matsushita, H, Miya, A, Mizukami, H, Nagakura, D, Nishimura, H, Oikawa, H, Sakai, Y, Shimizu, A, Stolz, H, Suzuki, M, Takaki, H, Takeda, S, Takeuchi, H, Tokieda, T, Uesaka, K, Yako, Y, Yamaguchi, Y, Yanagisawa, R, Yokoyama, K, Yoshida, and S, Shimoura

Abstract

We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.

Published
2018

44. Excitation of the Isovector Spin Monopole Resonance via the Exothermic ^{90}Zr(^{12}N,^{12}C) Reaction at 175 MeV/u

Author

S, Noji, H, Sakai, N, Aoi, H, Baba, G P A, Berg, P, Doornenbal, M, Dozono, N, Fukuda, N, Inabe, D, Kameda, T, Kawabata, S, Kawase, Y, Kikuchi, K, Kisamori, T, Kubo, Y, Maeda, H, Matsubara, S, Michimasa, K, Miki, H, Miya, H, Miyasako, S, Sakaguchi, Y, Sasamoto, S, Shimoura, M, Takaki, H, Takeda, S, Takeuchi, H, Tokieda, T, Ohnishi, S, Ota, T, Uesaka, H, Wang, K, Yako, Y, Yanagisawa, N, Yokota, K, Yoshida, and R G T, Zegers

Abstract

The (^{12}N, ^{12}C) charge-exchange reaction at 175 MeV/u was developed as a novel probe for studying the isovector spin giant monopole resonance (IVSMR), whose properties are important for better understanding the bulk properties of nuclei and asymmetric nuclear matter. This probe, now available through the production of ^{12}N as a secondary rare-isotope beam, is exothermic, is strongly absorbed at the surface of the target nucleus, and provides selectivity for spin-transfer excitations. All three properties enhance the excitation of the IVSMR compared to other, primarily light-ion, probes, which have been used to study the IVSMR thus far. The ^{90}Zr(^{12}N,^{12}C) reaction was measured and the excitation energy spectra up to about 70 MeV for both the spin-transfer and non-spin-transfer channels were deduced separately by tagging the decay by γ emission from the ^{12}C ejectile. Besides the well-known Gamow-Teller and isobaric analog transitions, a clear signature of the IVSMR was identified. By comparing with the results from light-ion reactions on the same target nucleus and theoretical predictions, the suitability of this new probe for studying the IVSMR was confirmed.

Published
2018

45. Spectroscopy of Pionic Atoms in ^{122}Sn(d,^{3}He) Reaction and Angular Dependence of the Formation Cross Sections

Author

T, Nishi, K, Itahashi, G P A, Berg, H, Fujioka, N, Fukuda, N, Fukunishi, H, Geissel, R S, Hayano, S, Hirenzaki, K, Ichikawa, N, Ikeno, N, Inabe, S, Itoh, M, Iwasaki, D, Kameda, S, Kawase, T, Kubo, K, Kusaka, H, Matsubara, S, Michimasa, K, Miki, G, Mishima, H, Miya, H, Nagahiro, M, Nakamura, S, Noji, K, Okochi, S, Ota, N, Sakamoto, K, Suzuki, H, Takeda, Y K, Tanaka, K, Todoroki, K, Tsukada, T, Uesaka, Y N, Watanabe, H, Weick, H, Yamakami, and K, Yoshida

Abstract

We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.

Published
2018

46. Spectroscopy of2565,67Mn: Strong coupling in the N = 40 'island of inversion'

Author

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

Subjects
In-beam γ-ray spectroscopy, Strong coupling, Nuclear and High Energy Physics, Structure evolution, “Island of inversion” around N=40, lcsh:Physics, lcsh:QC1-999
Abstract

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

Published
2018

47. Isochronous mass measurements of T z = − 1 f p -shell nuclei from projectile fragmentation of

Author

Y. H. Zhang, P. Zhang, X. H. Zhou, M. Wang, Yu. A. Litvinov, H. S. Xu, X. Xu, P. Shuai, Y. H. Lam, R. J. Chen, X. L. Yan, T. Bao, X. C. Chen, H. Chen, C. Y. Fu, J. J. He, S. Kubono, D. W. Liu, R. S. Mao, X. W. Ma, M. Z. Sun, X. L. Tu, Y. M. Xing, Q. Zeng, X. Zhou, W. L. Zhan, S. Litvinov, K. Blaum, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, B. H. Sun, Y. Sun, and F. R. Xu

Published
2018
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48. SHARAQ spectrometer for high-resolution studies for RI-induced reactions

Author

Hiromi Sato, C. S. Lee, Yuki Kubota, K. Miki, S. Ota, Y. Yanagisawa, Toshiyuki Kubo, Shoichiro Kawase, Hiroshi Suzuki, T. Uesaka, Naoki Fukuda, T. Fujii, T. Baba, Naohito Inabe, Masanori Dozono, Hiroyuki Takeda, Susumu Shimoura, Shumpei Noji, Andreas Stolz, Y. Kikuchi, Takeo Kawabata, Shin'ichiro Michimasa, T. Ichihara, Hiroaki Matsubara, Remco Zegers, Hiroyuki Miya, H. Baba, Hideyuki Sakai, Yuji Shimizu, Kentaro Yako, Motoki Kobayashi, Hiroshi Tokieda, Daisuke Kameda, Rin Yokoyama, Yoshiko Sasamoto, Takahiro Nishi, K. Kisamori, Motonobu Takaki, M. Tsumura, and Shintaro Go

Subjects
Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Chemistry, business.industry, Resolution (electron density), Detector, Tracking (particle physics), law.invention, Nuclear physics, Momentum, Optics, Beamline, Achromatic lens, law, Physics::Accelerator Physics, business, Instrumentation, Beam (structure)
Abstract

The SHARAQ spectrometer and High-Resolution Beamline, which began operation in March 2009, have been put into use for six experiments using charge exchange reactions with radioactive isotope beams. For experiments at SHARAQ, detector developments and ion optics studies continue to improve performance in high-resolution nuclear spectroscopy. We have introduced improved timing resolution with CVD diamond detectors, high count-rate beamline tracking detectors and development of multi-particle detection by cathode-readout drift chambers. Ion-optics studies for the high-resolution achromatic (HA) and dispersion-matching (DM) transport modes are also reported here. Momentum tagging in the HA mode demonstrated an improvement in spectroscopic resolution with respect to the momentum spread of the radioactive beam. For the DM transportation mode, a momentum resolution of 1 / 8100 (FWHM) was achieved by taking into account the positions and angles of the beam at the third focal plane of BigRIPS.

Published
2013

49. Sum rule study for Double Gamow-Teller states

Author

Hiroyuki Sagawa and T. Uesaka

Subjects
Physics, Nuclear Theory, 010308 nuclear & particles physics, Operator (physics), Sigma, FOS: Physical sciences, State (functional analysis), 01 natural sciences, Nuclear Theory (nucl-th), Transition strength, Isospin, 0103 physical sciences, Sum rule in quantum mechanics, Atomic physics, 010306 general physics, Unit (ring theory), Excitation
Abstract

We study the sum rules of double Gamow-Teller (DGT) excitations through double spin-isospin operator $(\sigma t_-)^2$. In general, $2^+$ states in the granddaughter nuclei have dominant transition strength in DGT excitations and $0^+$ states are weak, except in $T=1$ mother nuclei in which $0^+$ strength is competitive with 2$^+$ strength. The isospin selection of DGT is also discussed among 5 possible isospin states in granddaughter nuclei. A possibility to extract the unit cross section for the DGT transition strength is pointed out in the $(\sigma t_-)^2$ excitation of double isobaric analog state (DIAS) in $T=1$ nuclei., Comment: 4pages, Physical Review C, in press(2016)

Published
2016
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50. Nuclear astrophysics with radioactive ions at FAIR

Author

R Reifarth, S Altstadt, K Göbel, T Heftrich, M Heil, A Koloczek, C Langer, R Plag, M Pohl, K Sonnabend, M Weigand, T Adachi, F Aksouh, J Al-Khalili, M AlGarawi, S AlGhamdi, G Alkhazov, N Alkhomashi, H Alvarez-Pol, R Alvarez-Rodriguez, V Andreev, B Andrei, L Atar, T Aumann, V Avdeichikov, C Bacri, S Bagchi, C Barbieri, S Beceiro, C Beck, C Beinrucker, G Belier, D Bemmerer, M Bendel, J Benlliure, G Benzoni, R Berjillos, D Bertini, C Bertulani, S Bishop, N Blasi, T Bloch, Y Blumenfeld, A Bonaccorso, K Boretzky, A Botvina, A Boudard, P Boutachkov, I Boztosun, A Bracco, S Brambilla, J Briz Monago, M Caamano, C Caesar, F Camera, E Casarejos, W Catford, J Cederkall, B Cederwall, M Chartier, A Chatillon, M Cherciu, L Chulkov, P Coleman-Smith, D Cortina-Gil, F Crespi, R Crespo, J Cresswell, M Csatlós, F Déchery, B Davids, T Davinson, V Derya, P Detistov, P Diaz Fernandez, D DiJulio, S Dmitry, D Doré, J Dueñas, E Dupont, P Egelhof, I Egorova, Z Elekes, J Enders, J Endres, S Ershov, O Ershova, B Fernandez-Dominguez, A Fetisov, E Fiori, A Fomichev, M Fonseca, L Fraile, M Freer, J Friese, M G. Borge, D Galaviz Redondo, S Gannon, U Garg, I Gasparic, L Gasques, B Gastineau, H Geissel, R Gernhäuser, T Ghosh, M Gilbert, J Glorius, P Golubev, A Gorshkov, A Gourishetty, L Grigorenko, J Gulyas, M Haiduc, F Hammache, M Harakeh, M Hass, M Heine, A Hennig, A Henriques, R Herzberg, M Holl, A Ignatov, A Ignatyuk, S Ilieva, M Ivanov, N Iwasa, B Jakobsson, H Johansson, B Jonson, P Joshi, A Junghans, B Jurado, G Körner, N Kalantar, R Kanungo, A Kelic-Heil, K Kezzar, E Khan, A Khanzadeev, O Kiselev, M Kogimtzis, D Körper, S Kräckmann, T Kröll, R Krücken, A Krasznahorkay, J Kratz, D Kresan, T Krings, A Krumbholz, S Krupko, R Kulessa, S Kumar, N Kurz, E Kuzmin, M Labiche, K Langanke, I Lazarus, T Le Bleis, C Lederer, A Lemasson, R Lemmon, V Liberati, Y Litvinov, B Löher, J Lopez Herraiz, G Münzenberg, J Machado, E Maev, K Mahata, D Mancusi, J Marganiec, M Martinez Perez, V Marusov, D Mengoni, B Million, V Morcelle, O Moreno, A Movsesyan, E Nacher, M Najafi, T Nakamura, F Naqvi, E Nikolski, T Nilsson, C Nociforo, P Nolan, B Novatsky, G Nyman, A Ornelas, R Palit, S Pandit, V Panin, C Paradela, V Parkar, S Paschalis, P Pawłowski, A Perea, J Pereira, C Petrache, M Petri, S Pickstone, N Pietralla, S Pietri, Y Pivovarov, P Potlog, A Prokofiev, G Rastrepina, T Rauscher, G Ribeiro, M Ricciardi, A Richter, C Rigollet, K Riisager, A Rios, C Ritter, T Rodriguez Frutos, J Rodriguez Vignote, M Röder, C Romig, D Rossi, P Roussel-Chomaz, P Rout, S Roy, P Söderström, M Saha Sarkar, S Sakuta, M Salsac, J Sampson, J Sanchez, del Rio Saez, J Sanchez Rosado, S Sanjari, P Sarriguren, A Sauerwein, D Savran, C Scheidenberger, H Scheit, S Schmidt, C Schmitt, L Schnorrenberger, P Schrock, R Schwengner, D Seddon, B Sherrill, A Shrivastava, S Sidorchuk, J Silva, H Simon, E Simpson, P Singh, D Slobodan, D Sohler, M Spieker, D Stach, E Stan, M Stanoiu, S Stepantsov, P Stevenson, F Strieder, L Stuhl, T Suda, K Sümmerer, B Streicher, J Taieb, M Takechi, I Tanihata, J Taylor, O Tengblad, G Ter-Akopian, S Terashima, P Teubig, R Thies, M Thoennessen, T Thomas, J Thornhill, G Thungstrom, J Timar, Y Togano, U Tomohiro, T Tornyi, J Tostevin, C Townsley, W Trautmann, T Trivedi, S Typel, E Uberseder, J Udias, T Uesaka, L Uvarov, Z Vajta, P Velho, V Vikhrov, M Volknandt, V Volkov, P von Neumann-Cosel, M von Schmid, A Wagner, F Wamers, H Weick, D Wells, L Westerberg, O Wieland, M Wiescher, C Wimmer, K Wimmer, J S Winfield, M Winkel, P Woods, R Wyss, D Yakorev, M Yavor, J Zamora Cardona, I Zartova, T Zerguerras, M Zgura, A Zhdanov, M Zhukov, M Zieblinski, A Zilges, K Zuber, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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 de Sciences Nucléaires et de Sciences de la Matière (CSNSM), 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), 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), Helmholtz International Center for FAIR, German Research Foundation, Helmholtz Association, SCOAP, 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), 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), and 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)

Subjects
History, Astrophysics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 01 natural sciences, Education, Nuclear physics, Subatomär fysik, Nucleosynthesis, 0103 physical sciences, Subatomic Physics, Nuclear astrophysics, Fysik, Neutron, Nuclear Physics - Experiment, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, Radionuclide, Isotope, rp-process, Computer Science Applications, FAIR nuclear astrophysics radioactive ion beams, Valley of stability, r-process nucleosynthesis, weak-interaction rates, s-process, stars, supernovae, light, Physical Sciences, Facility for Antiproton and Ion Research, Física nuclear, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], astro-ph.IM
Abstract

R. Reifarth et al: ; 12 págs.; 9 figs.; Open Access funded by Creative Commons Atribution Licence 3.0 ; Nuclear Physics in Astrophysics VI (NPA6), The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process ow and r-process -decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will oer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes., This project was supported by the HGF Young Investigators Project VH-NG-327, EMMI, H4F, HGS-HIRe, JINA, NAVI, DFG and ATHENA.

Published
2016

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