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1. 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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2. 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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3. Constraining nucleon effective masses with flow and stopping observables from the SπRIT experiment

Author

C.Y. Tsang, M. Kurata-Nishimura, M.B. Tsang, W.G. Lynch, Y.X. Zhang, J. Barney, J. Estee, G. Jhang, R. Wang, M. Kaneko, J.W. Lee, T. Isobe, T. Murakami, D.S. Ahn, L. Atar, T. Aumann, H. Baba, K. Boretzky, J. Brzychczyk, G. Cerizza, N. Chiga, N. Fukuda, I. Gasparic, B. Hong, A. Horvat, K. Ieki, N. Inabe, Y.J. Kim, T. Kobayashi, Y. Kondo, P. Lasko, H.S. Lee, Y. Leifels, J. Łukasik, J. Manfredi, A.B. McIntosh, P. Morfouace, T. Nakamura, N. Nakatsuka, S. Nishimura, H. Otsu, P. Pawłowski, K. Pelczar, D. Rossi, H. Sakurai, C. Santamaria, H. Sato, H. Scheit, R. Shane, Y. Shimizu, H. Simon, A. Snoch, A. Sochocka, T. Sumikama, H. Suzuki, D. Suzuki, H. Takeda, S. Tangwancharoen, H. Törnqvist, Y. Togano, Z.G. Xiao, S.J. Yennello, and Y. Zhang

Subjects
Physics, QC1-999
Abstract

Properties of the nuclear equation of state (EoS) can be probed by measuring the dynamical properties of nucleus-nucleus collisions. In this study, we present the directed flow (v1), elliptic flow (v2) and stopping (VarXZ) measured in fixed target Sn + Sn collisions at Image 1 with the SπRIT Time Projection Chamber. We perform Bayesian analyses in which EoS parameters are varied simultaneously within the Improved Quantum Molecular Dynamics-Skyrme (ImQMD-Sky) transport code to obtain a multivariate correlated constraint. The varied parameters include symmetry energy, S0, and slope of the symmetry energy, L, at saturation density, isoscalar effective mass, ms⁎/mN, isovector effective mass, mv⁎/mN and the in-medium cross-section enhancement factor η. We find that the flow and VarXZ observables are sensitive to the splitting of proton and neutron effective masses and the in-medium cross-section. Comparisons of ImQMD-Sky predictions to the SπRIT data suggest a narrow range of preferred values for ms⁎/mN, mv⁎/mN and η.

Published
2024
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4. 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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5. 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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6. 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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7. 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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8. Unbound states in 17C and p-sd shell-model interactions

Author

S. Kim, J.W. Hwang, Y. Satou, N.A. Orr, T. Nakamura, Y. Kondo, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
One-neutron removal reaction, Neutron-rich carbon isotopes, Cross-shell states, Shell-model Hamiltonian, Physics, QC1-999
Abstract

Unbound states in C17 were investigated via one-neutron removal from a C18 beam at an energy of 245 MeV/nucleon on a carbon target. The energy spectrum of C17, above the single-neutron decay threshold, was reconstructed using invariant mass spectroscopy from the measured momenta of the C16 fragment and neutron, and was found to exhibit resonances at Er=0.52(2), 0.77(2), 1.36(1), 1.91(1), 2.22(3) and 3.20(1) MeV. The resonance at Er=0.77(2) MeV [Ex=1.51(3) MeV] was provisionally assigned as the second 5/2+ state. The two resonances at Er=1.91(1) and 3.20(1) MeV [Ex=2.65(2) and 3.94(2) MeV] were identified, through comparison of the energies, cross sections and momentum distributions with shell-model and eikonal reaction calculations, as p-shell hole states with spin-parities 1/21− and 3/21−, respectively. A detailed comparison was made with the results obtained using a range of shell-model interactions. The YSOX shell-model Hamiltonian, the cross-shell part of which is based on the monopole-based universal interaction, was found to provide a very good description of the present results and those for the neighbouring odd-A carbon isotopes – in particular for the negative parity cross-shell states.

Published
2023
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9. 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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10. Rapidity distributions of Z = 1 isotopes and the nuclear symmetry energy from Sn+Sn collisions with radioactive beams at 270 MeV/nucleon

Author

M. Kaneko, T. Murakami, T. Isobe, M. Kurata-Nishimura, A. Ono, N. Ikeno, J. Barney, G. Cerizza, J. Estee, G. Jhang, J.W. Lee, W.G. Lynch, C. Santamaria, C.Y. Tsang, M.B. Tsang, R. Wang, D.S. Ahn, L. Atar, T. Aumann, H. Baba, K. Boretzky, J. Brzychczyk, N. Chiga, N. Fukuda, I. Gašparić, B. Hong, A. Horvat, T. Ichihara, K. Ieki, N. Inabe, Y.J. Kim, T. Kobayashi, Y. Kondo, P. Lasko, H.S. Lee, Y. Leifels, J. Łukasik, J. Manfredi, A.B. McIntosh, P. Morfouace, T. Nakamura, N. Nakatsuka, S. Nishimura, R. Olsen, H. Otsu, P. Pawłowski, K. Pelczar, D. Rossi, H. Sakurai, H. Sato, H. Scheit, R. Shane, Y. Shimizu, H. Simon, T. Sumikama, D. Suzuki, H. Suzuki, H. Takeda, S. Tangwancharoen, Y. Togano, H. Törnqvist, Z. Xiao, S.J. Yennello, J. Yurkon, and Y. Zhang

Subjects
Heavy radioactive isotope collisions, Cluster productions, Nuclear symmetry energy, Antisymmetrized molecular dynamics, Physics, QC1-999
Abstract

The rapidity distributions of hydrogen isotopes emitted from central collisions of neutron-rich 132Sn+124Sn and neutron-deficient 108Sn+112Sn systems at 270 MeV/nucleon were investigated at RIKEN-RIBF. The data are compared with antisymmetrized molecular dynamics (AMD) calculations and the rapidity distributions can be reproduced after adjusting the in-medium nucleon-nucleon cross sections. The double ratios between the two reaction systems taken for the relative yields of deuteron to proton (d/p) and triton to proton (t/p) are further examined in the midrapidity domain, where the adjustments in the AMD calculations do not affect much on them. The d/p and t/p double ratios at midrapidity agree well with the ratio of the system neutron numbers and its squared value, respectively, and the rapidity dependence of these double ratios is consistent with a picture of partial mixing of colliding nuclei. By comparing with the AMD model which shows a strong symmetry energy dependence of the t/p double ratio, the experimental result in the midrapidity domain favors the calculation with a symmetry-energy slope parameter around L=46 MeV rather than L=108 MeV.

Published
2021
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11. Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

Author

M. Holl, V. Panin, H. Alvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, J. Benlliure, C.A. Bertulani, J.M. Boillos, K. Boretzky, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, L. Chulkov, D. Cortina-Gil, E. Cravo, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, L.M. Fraile, D. Galaviz Redondo, R. Gernhäuser, P. Golubev, T. Heftrich, M. Heil, M. Heine, A. Heinz, A. Henriques, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, S. Lindberg, J. Machado, E. Nacher, M.A. Najafi, T. Nilsson, C. Nociforo, S. Paschalis, M. Petri, R. Reifarth, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, I. Syndikus, O. Tengblad, Y. Togano, M. Vandebrouck, P. Velho, F. Wamers, H. Weick, C. Wheldon, G.L. Wilson, J.S. Winfield, P. Woods, M. Zhukov, and K. Zuber

Subjects
Physics, QC1-999
Abstract

The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei. Keywords: Quasi-free scattering, Inverse kinematics, Shell model, Spectroscopic factors

Published
2019
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12. Three-body breakup of 6He and its halo structure

Author

Y.L. Sun, T. Nakamura, Y. Kondo, Y. Satou, J. Lee, T. Matsumoto, K. Ogata, Y. Kikuchi, N. Aoi, Y. Ichikawa, K. Ieki, M. Ishihara, T. Kobayshi, T. Motobayashi, H. Otsu, H. Sakurai, T. Shimamura, S. Shimoura, T. Shinohara, T. Sugimoto, S. Takeuchi, Y. Togano, and K. Yoneda

Subjects
Coulomb breakup, Nuclear breakup, Electric dipole response, Halo nuclei, 208Pb(6He, α+2n)X, 12C(6He, α+2n)X, Physics, QC1-999
Abstract

The Borromean halo nucleus 6He has been studied by a kinematically complete measurement of Coulomb and nuclear breakup into α + 2n on Pb and C targets at 70 MeV/nucleon. Fully quantum-mechanical four-body breakup calculations reproduce the energy and angular differential cross sections below Erel∼1 MeV for both targets. The model used here reproduces the 6He ground-state properties as well as α-n and n-n scattering data and predicts an average opening angle 〈θnn〉 of 68∘ between the two halo neutrons. However, the model underestimates the breakup cross sections for higher Erel, indicating a possible contribution from the inelastic breakup. Alternatively, we examine the empirically modified calculations that reproduce the energy-differential cross sections for a wide range of scattering angles for both targets. The extracted B(E1) peaks at Erel∼1.4 MeV and amounts to 1.6(2) e2fm2 for Erel ≤ 20 MeV, resulting 〈θnn〉 = 56−10+9 degrees. In either interpretation, the current results show evidence of the dineutron spatial correlation in 6He.

Published
2021
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13. 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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14. Symmetry energy investigation with pion production from Sn+Sn systems

Author

G. Jhang, J. Estee, J. Barney, G. Cerizza, M. Kaneko, J.W. Lee, W.G. Lynch, T. Isobe, M. Kurata-Nishimura, T. Murakami, C.Y. Tsang, M.B. Tsang, R. Wang, D.S. Ahn, L. Atar, T. Aumann, H. Baba, K. Boretzky, J. Brzychczyk, N. Chiga, N. Fukuda, I. Gasparic, B. Hong, A. Horvat, K. Ieki, N. Inabe, Y.J. Kim, T. Kobayashi, Y. Kondo, P. Lasko, H.S. Lee, Y. Leifels, J. Łukasik, J. Manfredi, A.B. McIntosh, P. Morfouace, T. Nakamura, N. Nakatsuka, S. Nishimura, R. Olsen, H. Otsu, P. Pawłowski, K. Pelczar, D. Rossi, H. Sakurai, C. Santamaria, H. Sato, H. Scheit, R. Shane, Y. Shimizu, H. Simon, A. Snoch, A. Sochocka, Z. Sosin, T. Sumikama, H. Suzuki, D. Suzuki, H. Takeda, S. Tangwancharoen, H. Toernqvist, Y. Togano, Z.G. Xiao, S.J. Yennello, J. Yurkon, Y. Zhang, Maria Colonna, Dan Cozma, Paweł Danielewicz, Hannah Elfner, Natsumi Ikeno, Che Ming Ko, Justin Mohs, Dmytro Oliinychenko, Akira Ono, Jun Su, Yong Jia Wang, Hermann Wolter, Jun Xu, Ying-Xun Zhang, and Zhen Zhang

Subjects
Physics, QC1-999
Abstract

In the past two decades, pions created in the high density regions of heavy ion collisions have been predicted to be sensitive at high densities to the symmetry energy term in the nuclear equation of state, a property that is key to our understanding of neutron stars. In a new experiment designed to study the symmetry energy, the multiplicities of negatively and positively charged pions have been measured with high accuracy for central 132Sn+124Sn, 112Sn+124Sn, and 108Sn+112Sn collisions at E/A=270 MeV with the SπRIT Time Projection Chamber. While individual pion multiplicities are measured to 4% accuracy, those of the charged pion multiplicity ratios are measured to 2% accuracy. We compare these data to predictions from seven major transport models. The calculations reproduce qualitatively the dependence of the multiplicities and their ratios on the total neutron and proton number in the colliding systems. However, the predictions of the transport models from different codes differ too much to allow extraction of reliable constraints on the symmetry energy from the data. This finding may explain previous contradictory conclusions on symmetry energy constraints obtained from pion data in Au+Au system. These new results call for still better understanding of the differences among transport codes, and new observables that are more sensitive to the density dependence of the symmetry energy.

Published
2021
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15. Evolution of the dipole polarizability in the stable tin isotope chain

Author

S. Bassauer, P. von Neumann-Cosel, P.-G. Reinhard, A. Tamii, S. Adachi, C.A. Bertulani, P.Y. Chan, G. Colò, A. D'Alessio, H. Fujioka, H. Fujita, Y. Fujita, G. Gey, M. Hilcker, T.H. Hoang, A. Inoue, J. Isaak, C. Iwamoto, T. Klaus, N. Kobayashi, Y. Maeda, M. Matsuda, N. Nakatsuka, S. Noji, H.J. Ong, I. Ou, N. Paar, N. Pietralla, V.Yu. Ponomarev, M.S. Reen, A. Richter, X. Roca-Maza, M. Singer, G. Steinhilber, T. Sudo, Y. Togano, M. Tsumura, Y. Watanabe, and V. Werner

Subjects
112,114,116,118,120,124Sn(p,p′), Ep=295MeV, θlab=0°−6°, Relativistic Coulomb excitation, Photoabsorption cross sections, Dipole polarizability, Physics, QC1-999
Abstract

The dipole polarizability of stable even-mass tin isotopes 112,114,116,118,120,124Sn was extracted from inelastic proton scattering experiments at 295MeV under very forward angles performed at RCNP. Predictions from energy density functionals cannot account for the present data and the polarizability of 208Pb simultaneously. The evolution of the polarizabilities in neighboring isotopes indicates a kink at 120Sn while all model results show a nearly linear increase with mass number after inclusion of pairing corrections.

Published
2020
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16. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author

I. Syndikus, M. Petri, A.O. Macchiavelli, S. Paschalis, C.A. Bertulani, T. Aumann, H. Alvarez-Pol, L. Atar, S. Beceiro-Novo, J. Benlliure, J.M. Boillos, K. Boretzky, M.J.G. Borge, B.A. Brown, M. Caamaño, C. Caesar, E. Casarejos, W. Catford, J. Cederkall, S. Chakraborty, L.V. Chulkov, D. Cortina-Gil, E. Cravo, R. Crespo, U. Datta Pramanik, I. Dillmann, P. Díaz Fernández, Z. Elekes, J. Enders, F. Farinon, L.M. Fraile, D. Galaviz, H. Geissel, R. Gernhäuser, P. Golubev, K. Göbel, M. Heil, M. Heine, A. Heinz, A. Henriques, M. Holl, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, T. Kröll, N. Kurz, C. Langer, T. Le Bleis, J. Machado, J. Marganiec-Gałązka, E. Nacher, T. Nilsson, C. Nociforo, V. Panin, A. Perea, S.B. Pietri, R. Plag, A. Rahaman, R. Reifarth, A. Revel, G. Ribeiro, C. Rigollet, D.M. Rossi, D. Savran, H. Scheit, H. Simon, O. Sorlin, O. Tengblad, Y. Togano, M. Vandebrouck, V. Volkov, F. Wamers, C. Wheldon, G.L. Wilson, J.S. Winfield, H. Weick, P. Woods, D. Yakorev, M. Zhukov, A. Zilges, and K. Zuber

Subjects
Quasi-free scattering reactions, Magic numbers, Spin-orbit splitting, Tensor force, Shell evolution, Exotic nuclei, Physics, QC1-999
Abstract

The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 21+ state of 16,18,20C. The experimental findings support the notion of a moderate reduction of the proton 1p1/2−1p3/2 spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline.

Published
2020
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17. 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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18. 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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19. 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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20. Single-neutron knockout from 20C and the structure of 19C

Author

J.W. Hwang, S. Kim, Y. Satou, N.A. Orr, Y. Kondo, T. Nakamura, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Heavy-ion knockout, Invariant mass spectroscopy, Shell evolution, Physics, QC1-999
Abstract

The low-lying unbound level structure of the halo nucleus 19C has been investigated using single-neutron knockout from 20C on a carbon target at 280 MeV/nucleon. The invariant mass spectrum, derived from the momenta of the forward going beam velocity 18C fragment and neutrons, was found to be dominated by a very narrow near threshold (Erel=0.036(1) MeV) peak. Two less strongly populated resonance-like features were also observed at Erel=0.84(4) and 2.31(3) MeV, both of which exhibit characteristics consistent with neutron p-shell hole states. Comparisons of the energies, measured cross sections and parallel momentum distributions to the results of shell-model and eikonal reaction calculations lead to spin-parity assignments of 5/21+ and 1/21− for the levels at Ex=0.62(9) and 2.89(10) MeV with Sn=0.58(9) MeV. Spectroscopic factors were also deduced and found to be in reasonable accord with shell-model calculations. The valence neutron configuration of the 20C ground state is thus seen to include, in addition to the known 1s1/22 component, a significant 0d5/22 contribution. The level scheme of 19C, including significantly the 1/21− cross-shell state, is well accounted for by the YSOX shell-model interaction developed from the monopole-based universal interaction.

Published
2017
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21. Observation of isoscalar and isovector dipole excitations in neutron-rich 20O

Author

N. Nakatsuka, H. Baba, T. Aumann, R. Avigo, S.R. Banerjee, A. Bracco, C. Caesar, F. Camera, S. Ceruti, S. Chen, V. Derya, P. Doornenbal, A. Giaz, A. Horvat, K. Ieki, T. Inakura, N. Imai, T. Kawabata, N. Kobayashi, Y. Kondo, S. Koyama, M. Kurata-Nishimura, S. Masuoka, M. Matsushita, S. Michimasa, B. Million, T. Motobayashi, T. Murakami, T. Nakamura, T. Ohnishi, H.J. Ong, S. Ota, H. Otsu, T. Ozaki, A. Saito, H. Sakurai, H. Scheit, F. Schindler, P. Schrock, Y. Shiga, M. Shikata, S. Shimoura, D. Steppenbeck, T. Sumikama, I. Syndikus, H. Takeda, S. Takeuchi, A. Tamii, R. Taniuchi, Y. Togano, J. Tscheuschner, J. Tsubota, H. Wang, O. Wieland, K. Wimmer, Y. Yamaguchi, K. Yoneda, and J. Zenihiro

Subjects
O20, Low-energy dipole excitation, Inelastic α scattering, Virtual-photon excitation, Physics, QC1-999
Abstract

The isospin characters of low-energy dipole excitations in neutron-rich unstable nucleus 20O were investigated, for the first time in unstable nuclei. Two spectra obtained from a dominant isovector probe (O20+Au) and a dominant isoscalar probe (O20+α) were compared and analyzed by the distorted-wave Born approximation to extract independently the isovector and isoscalar dipole strengths. Two known 1− states with large isovector dipole strengths at energies of 5.36(5) MeV (11−) and 6.84(7) MeV (12−) were also excited by the isoscalar probe. These two states were found to have different isoscalar dipole strengths, 2.70(32)% (11−) and 0.67(12)% (12−), respectively, in exhaustion of the isoscalar dipole-energy-weighted sum rule. The difference in isoscalar strength indicated that they have different underlying structures.

Published
2017
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22. Intruder configurations in the ground state of 30Ne

Author

H.N. Liu, J. Lee, P. Doornenbal, H. Scheit, S. Takeuchi, N. Aoi, K.A. Li, M. Matsushita, D. Steppenbeck, H. Wang, H. Baba, E. Ideguchi, N. Kobayashi, Y. Kondo, G. Lee, S. Michimasa, T. Motobayashi, A. Poves, H. Sakurai, M. Takechi, Y. Togano, J.A. Tostevin, and Y. Utsuno

Subjects
Intruder configurations, One-neutron knockout reactions 12C(30Ne, 29Ne+γ)X, Physics, QC1-999
Abstract

We report on the first detailed study of intruder configurations in the ground state of 30Ne by means of the 12C(30Ne, 29Ne+γ)X one-neutron knockout reaction at 228 MeV/nucleon. Using a combined analysis of individual parallel momentum distributions and partial cross sections we find: (a) comparable p- and d-wave removal strength to 29Ne final states with excitation energies below 200 keV, and (b) significant p-wave removal strength to the 620 keV state of 29Ne, and (c) no evidence for f-wave intruder strength leading to bound 29Ne final states. The SDPF-U-MIX shell model calculation in the sd–pf model space provides a better overall agreement with the measured energy levels of 29Ne and the fp-intruder amplitudes in 30Ne than the SDPF-M prediction, suggesting that the refinement of the sd–pf cross shell interaction and extension of the model space to include the 2p1/2 and 1f5/2 levels are important for understanding the island of inversion.

Published
2017
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23. Interaction cross section study of the two-neutron halo nucleus 22C

Author

Y. Togano, T. Nakamura, Y. Kondo, J.A. Tostevin, A.T. Saito, J. Gibelin, N.A. Orr, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, J.W. Hwang, N. Inabe, T. Isobe, D. Kameda, D. Kanno, S. Kim, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Satou, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Interaction cross section, Matter radius, Two-neutron halo nucleus 22C, Physics, QC1-999
Abstract

The interaction cross sections (σI) of the very neutron-rich carbon isotopes 19C, 20C and 22C have been measured on a carbon target at 307, 280, and 235 MeV/nucleon, respectively. A σI of 1.280±0.023 b was obtained for 22C, significantly larger than for 19,20C, supporting the halo character of 22C. A 22C root-mean-squared matter radius of 3.44±0.08 fm was deduced using a four-body Glauber reaction model. This value is smaller than an earlier estimate (of 5.4±0.9 fm) derived from a σI measurement on a hydrogen target at 40 MeV/nucleon. These new, higher-precision σI data provide stronger constraints for assessing the consistency of theories describing weakly bound nuclei.

Published
2016
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24. Different mechanism of two-proton emission from proton-rich nuclei 23Al and 22Mg

Author

Y.G. Ma, D.Q. Fang, X.Y. Sun, P. Zhou, Y. Togano, N. Aoi, H. Baba, X.Z. Cai, X.G. Cao, J.G. Chen, Y. Fu, W. Guo, Y. Hara, T. Honda, Z.G. Hu, K. Ieki, Y. Ishibashi, Y. Ito, N. Iwasa, S. Kanno, T. Kawabata, H. Kimura, Y. Kondo, K. Kurita, M. Kurokawa, T. Moriguchi, H. Murakami, H. Ooishi, K. Okada, S. Ota, A. Ozawa, H. Sakurai, S. Shimoura, R. Shioda, E. Takeshita, S. Takeuchi, W.D. Tian, H.W. Wang, J.S. Wang, M. Wang, K. Yamada, Y. Yamada, Y. Yasuda, K. Yoneda, G.Q. Zhang, and T. Motobayashi

Subjects
Physics, QC1-999
Abstract

Two-proton relative momentum (qpp) and opening angle (θpp) distributions from the three-body decay of two excited proton-rich nuclei, namely Al23→p+p+Na21 and Mg22→p+p+Ne20, have been measured with the projectile fragment separator (RIPS) at the RIKEN RI Beam Factory. An evident peak at qpp∼20 MeV/c as well as a peak in θpp around 30° are seen in the two-proton break-up channel from a highly-excited 22Mg. In contrast, such peaks are absent for the 23Al case. It is concluded that the two-proton emission mechanism of excited 22Mg is quite different from the 23Al case, with the former having a favorable diproton emission component at a highly excited state and the latter dominated by the sequential decay process.

Published
2015
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25. Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O

Author

K. Tshoo, Y. Satou, C.A. Bertulani, H. Bhang, S. Choi, T. Nakamura, Y. Kondo, S. Deguchi, Y. Kawada, Y. Nakayama, K.N. Tanaka, N. Tanaka, Y. Togano, N. Kobayashi, N. Aoi, M. Ishihara, T. Motobayashi, H. Otsu, H. Sakurai, S. Takeuchi, K. Yoneda, F. Delaunay, J. Gibelin, F.M. Marqués, N.A. Orr, T. Honda, T. Kobayashi, T. Sumikama, Y. Miyashita, K. Yoshinaga, M. Matsushita, S. Shimoura, D. Sohler, J.W. Hwang, T. Zheng, Z.H. Li, and Z.X. Cao

Subjects
Physics, QC1-999
Abstract

One-neutron knockout from 24O leading to the first excited state in 23O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of 23O was reconstructed from the measured four momenta of the 22O fragment and emitted neutron. A sharp peak was found at Edecay=50±3 keV, corresponding to an excited state in 23O at 2.78±0.11 MeV, as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d-wave neutron knockout, providing support for a Jπ assignment of 5/2+. The associated spectroscopic factor was deduced to be C2S(0d5/2)=4.1±0.4 by comparing the measured cross section (σ−1nexp=61±6 mb) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0d5/2 orbital is in line with the N=16 shell closure in 24O.

Published
2014
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26. Corrigendum to 'Single-neutron knockout from 20C and the structure of 19C' [Phys. Lett. B 769 (2017) 503–508]

Author

J.W. Hwang, S. Kim, Y. Satou, N.A. Orr, Y. Kondo, T. Nakamura, J. Gibelin, N.L. Achouri, T. Aumann, H. Baba, F. Delaunay, P. Doornenbal, N. Fukuda, N. Inabe, T. Isobe, D. Kameda, D. Kanno, N. Kobayashi, T. Kobayashi, T. Kubo, S. Leblond, J. Lee, F.M. Marqués, R. Minakata, T. Motobayashi, D. Murai, T. Murakami, K. Muto, T. Nakashima, N. Nakatsuka, A. Navin, S. Nishi, S. Ogoshi, H. Otsu, H. Sato, Y. Shimizu, H. Suzuki, K. Takahashi, H. Takeda, S. Takeuchi, R. Tanaka, Y. Togano, A.G. Tuff, M. Vandebrouck, and K. Yoneda

Subjects
Physics, QC1-999
Published
2017
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27. 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

28. Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author

A. Henriques, J. S. Winfield, Thomas Nilsson, Rene Reifarth, M. Heine, E. Cravo, L. M. Fraile, Håkan T Johansson, O. Sorlin, L. Chulkov, W. N. Catford, A. Revel, J. Marganiec-Gałązka, Pavel Golubev, H. Scheit, S. Beceiro-Novo, Joakim Cederkäll, R. Gernhäuser, Carlos A. Bertulani, Y. Togano, T. Le Bleis, D. Cortina-Gil, L. Atar, G. L. Wilson, S. Pietri, F. Farinon, Kai Zuber, N. Kurz, Andreas Zilges, V. Volkov, M. Heil, C. Langer, A. Kelic-Heil, R. Plag, Catherine Rigollet, J. Enders, Iris Dillmann, U. Datta Pramanik, Jorge Machado, H. Alvarez-Pol, I. Syndikus, A. O. Macchiavelli, Marina Petri, D. Yakorev, M. Holl, Enrique Casarejos, G. Ribeiro, Mikhail V. Zhukov, Stefanos Paschalis, María José García Borge, Marine Vandebrouck, Deniz Savran, V. Panin, Björn Jonson, Nasser Kalantar-Nayestanaki, Philip Woods, Ángel Perea, C. Wheldon, R. Crespo, Thomas Aumann, Hans Geissel, Z. Elekes, Andreas Martin Heinz, J. M. Boillos, B. A. Brown, D. Galaviz, T. Kröll, S. Chakraborty, K. Göbel, Enrique Nácher, H. Weick, Rituparna Kanungo, P. Díaz Fernández, K. Boretzky, M. Caamaño, Anisur Rahaman, C. Caesar, J. Benlliure, F. Wamers, D. Rossi, Haik Simon, Olof Tengblad, C. Nociforo, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), R$^3$B, Energy and Sustainability Research Institute Groni, Research unit Nuclear & Hadron Physics, Royal Society (UK), Department of Energy (US), Federal Ministry of Education and Research (Germany), State of Hesse, Technische Universität Darmstadt, Helmholtz Association, European Young Investigator Awards, Swedish Research Council, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Xunta de Galicia, German Research Foundation, National Science Foundation (US), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Quasi-free scattering reactions, Field (physics), Proton, Nuclear Theory, Shell (structure), FOS: Physical sciences, Shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Atomic, Nuclear physics, Magic number (programming), Particle and Plasma Physics, 0103 physical sciences, Neutron, Nuclear, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Mathematical Physics, Spin-½, Physics, 010308 nuclear & particles physics, Scattering, Molecular, Spin-orbit splitting, Nuclear & Particles Physics, lcsh:QC1-999, 3. Good health, Valley of stability, Tensor force, Magic numbers, Física nuclear, lcsh:Physics, Astronomical and Space Sciences, Exotic nuclei
Abstract

9 pags., 5 figs., 2 tabs., The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 2 state of C. The experimental findings support the notion of a moderate reduction of the proton 1p−1p spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline., This work was supported by the Royal Society award UF150476, UK STFC awards ST/M006433/1 and ST/P003885/1, U.S. Department of Energy, Office of Nuclear Physics, contract No. DE-AC02- 05CH11231 (LBNL), the German Federal Ministry of Education and Research (BMBF projects 05P15RDFN1, 05P15WOFNA and 05P19RDFN1), the GSI-TU Darmstadt cooperation agreement, the State of Hesse through the LOEWE center HIC for FAIR, the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe and Young Investigators Grants, and the Swedish Research Council under contract number 621-2011-5324. This work was also supported by the Spanish research grants (Ministerio Ciencia e Innovación), FPA2015-64969-P, FPA2015-69640-C2-1-P, FPA2017- 87568-P, PGC2018-099746-B-C21, RTI2018-098868-B-I00, Undidad de Excelencia María de Maeztu under project MDM-2016.0692, and the Xunta de Galicia research grant GRC ED431C 2017/54. This work was partly supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245. C.A.B. acknowledges support from the U.S. NSF Grant No. 1415656, and U.S. DOE Grant No. DE-FG02-08ER41533.

Published
2020

29. Interplay between nuclear shell evolution and shape deformation revealed by the magnetic moment of $^{75}$Cu

Author

Y. Ichikawa, H. Nishibata, Y. Tsunoda, A. Takamine, K. Imamura, T. Fujita, T. Sato, S. Momiyama, Y. Shimizu, D. S. Ahn, K. Asahi, H. Baba, D. L. Balabanski, F. Boulay, J. M. Daugas, T. Egami, N. Fukuda, C. Funayama, T. Furukawa, G. Georgiev, A. Gladkov, N. Inabe, Y. Ishibashi, T. Kawaguchi, T. Kawamura, Y. Kobayashi, S. Kojima, A. Kusoglu, I. Mukul, M. Niikura, T. Nishizaka, A. Odahara, Y. Ohtomo, T. Otsuka, D. Ralet, G. S. Simpson, T. Sumikama, H. Suzuki, H. Takeda, L. C. Tao, Y. Togano, D. Tominaga, H. Ueno, H. Yamazaki, X. F. Yang, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre 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)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Physics, Magnetic moment, Nuclear Theory, Shell (structure), General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Molecular physics, 010305 fluids & plasmas, medicine.anatomical_structure, Nucleosynthesis, 0103 physical sciences, medicine, Nuclear force, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Spin (physics), Nuclear Experiment, Nucleus
Abstract

Exotic nuclei are characterized by a number of neutrons (or protons) in excess relative to stable nuclei. Their shell structure, which represents single-particle motion in a nucleus, may vary due to nuclear force and excess neutrons, in a phenomenon called shell evolution. This effect could be counterbalanced by collective modes causing deformations of the nuclear surface. Here, we study the interplay between shell evolution and shape deformation by focusing on the magnetic moment of an isomeric state of the neutron-rich nucleus 75Cu. We measure the magnetic moment using highly spin-controlled rare-isotope beams and achieving large spin alignment via a two-step reaction scheme that incorporates an angular-momentum-selecting nucleon removal. By combining our experiments with numerical simulations of many-fermion correlations, we find that the low-lying states in 75Cu are, to a large extent, of single-particle nature on top of a correlated 74Ni core. We elucidate the crucial role of shell evolution even in the presence of the collective mode, and within the same framework, we consider whether and how the double magicity of the 78Ni nucleus is restored, which is also of keen interest from the perspective of nucleosynthesis in explosive stellar processes., 10 pages, 4 figures

Published
2019

30. Cross-Shell States in 17,19C Populated via One-Neutron Knockout Reactions

Author

Jongmin Lee, Yosuke Kondo, T. Kubo, N. L. Achouri, T. Kobayashi, Nagao Kobayashi, Hiroshi Suzuki, Satoshi Takeuchi, H. Baba, S. K. Kim, H. Sato, Noritsugu Nakatsuka, Ryuki Tanaka, Jongwon Hwang, Marine Vandebrouck, Naoki Fukuda, Kenichiro Yoneda, T. Motobayashi, D. Kanno, Hideaki Otsu, A. G. Tuff, T. Isobe, H. Takeda, S. Nishi, Takashi Nakamura, Thomas Aumann, K. Muto, T. Murakami, Julien Gibelin, Daichi Murai, K. Takahashi, D. Kameda, S. Ogoshi, S. Leblond, T. Nakashima, N. A. Orr, Franck Delaunay, F. M. Marqués, Y. Shimizu, Y. Satou, R. Minakata, A. Navin, Pieter Doornenbal, N. Inabe, Y. Togano, 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), 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), Normandie Université (NU)-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
Physics, Experiment-Nucl, 010308 nuclear & particles physics, Nuclear Theory, 0103 physical sciences, Shell (structure), Neutron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, 010306 general physics, 01 natural sciences, Molecular physics
Abstract

International audience; Theoretical description of cross-shell states, whose parity is opposite to that of the ground state, in light neutron-rich nuclei represents a difficult task, since they involve transitions encompassing two major shells on a proton-neutron asymmetric system. More specifically obtaining reliable effective interactions in the nuclear shell model for such transitions is a challenge. Scarcity of experimental constraints may be additionally responsible to this. An experimental attempt to furnish new spectroscopic information on cross-shell states in neutron-rich carbon isotopes, ^17C and ^19C, is described, and the applicability of modern shell-model interactions in describing relevant spectroscopy is discussed. Brief description of the experiment utilizing RIKEN-RIBF, SAMURAI spectrometer is provided.

Published
2018

31. Observation of New Neutron Resonances in $^{17,19}\mathrm{C}$

Author

T. Kubo, Yosuke Kondo, Noritsugu Nakatsuka, A. Navin, T. Nakashima, T. Murakami, Kenichiro Yoneda, N. Inabe, Y. Togano, Jongwon Hwang, A. G. Tuff, T. Isobe, Naoki Fukuda, H. Baba, Jongmin Lee, N. L. Achouri, Hideaki Otsu, S. K. Kim, T. Motobayashi, H. Sato, Thomas Aumann, Nagao Kobayashi, Daichi Murai, Hiroshi Suzuki, Ryuki Tanaka, N. A. Orr, S. Nishi, Pieter Doornenbal, Satoshi Takeuchi, Takashi Nakamura, Franck Delaunay, Y. Satou, F. M. Marqués, D. Kanno, S. Ogoshi, Y. Shimizu, K. Takahashi, D. Kameda, S. Leblond, K. Muto, T. Kobayashi, Julien Gibelin, H. Takeda, Marine Vandebrouck, R. Minakata, 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), 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), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université 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, Proton, Spins, 010308 nuclear & particles physics, Nuclear Theory, State (functional analysis), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Coupling (probability), 01 natural sciences, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

International audience; High-lying isolated neutron resonances have been observed in$^{17,19}\mathrm{C}$. Analyses of the decay properties utilizing shell-model calculations suggest that they could be interpreted as possible variants of proton core excited states. The spins of these states are likely to be originating from anti-parallel coupling of spins of the $d_{5/2}$ neutron and the proton $2^+$ state in the assumed respective core nuclei,$^{16,18}\mathrm{C}$.

Published
2018

32. Strong neutron pairing in core+4n nuclei

Author

S. Beceiro-Novo, R. Thies, Jorge Machado, Andreas Martin Heinz, Tanja Heftrich, L. M. Fraile, A. Estrade, Marina Petri, T. Le Bleis, D. Cortina-Gil, L. Atar, T. Kröll, A. Knyazev, M. A. Najafi, G. L. Wilson, D. Rossi, Kai Zuber, A. Movsesyan, Z. Elekes, Simon Lindberg, I. Syndikus, P. Díaz Fernández, K. Göbel, Catherine Rigollet, Ángel Perea, R. Crespo, F. Farinon, J. Kahlbow, V. Volkov, M. Caamaño, W. N. Catford, A. Ignatov, S. Pietri, Carlos A. Bertulani, V. Panin, C. Langer, A. Kelic-Heil, O. Sorlin, Stefanos Paschalis, J. M. Boillos, Enrique Casarejos, J. Hagdahl, Iris Dillmann, M Vandebrouck, O. Ershova, K. Boretzky, A. Henriques, Roy Crawford Lemmon, J. S. Winfield, J. Benlliure, M. Labiche, Vladimir Avdeichikov, Enrique Nácher, H. Weick, Thomas Nilsson, F. Wamers, Rituparna Kanungo, M. Holl, C. Caesar, P. Velho, Håkan T Johansson, G. Ribeiro, Pavel Golubev, F. M. Marqués, M. Heine, Andreas Zilges, Hans Geissel, J. Enders, D. Galaviz, Daniel Bemmerer, Deniz Savran, Marielle Chartier, María José García Borge, Haik Simon, M. Freer, J. Taylor, Nasser Kalantar-Nayestanaki, Olof Tengblad, C. Wheldon, C. Nociforo, A. Revel, H. Alvarez-Pol, Joakim Cederkäll, Thomas Aumann, Rene Reifarth, L. Chulkov, J. Marganiec, Mikhail V. Zhukov, D. Yakorev, Björn Jonson, M. Röder, Philip Woods, R. Plag, U. Datta Pramanik, Andreas Wagner, R. Gernhäuser, E. Cravo, Y. Togano, H. Scheit, N. Kurz, M. Heil, 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 ), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole 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, Institut Pluridisciplinaire Hubert Curien ( IPHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), R3B, Technische Universität Darmstadt, Federal Ministry of Education and Research (Germany), National Science Foundation (US), Department of Energy (US), 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), 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, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Valence (chemistry), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Aucun, General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Molecular physics, Pairing, 0103 physical sciences, Neutron, Física nuclear, Nuclear Experiment (nucl-ex), [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nucleon, Nuclear Experiment, R3B radioactive beams nuclear structure neutron-rich Coulomb dissociation
Abstract

6 pags., 4 figs., The emission of neutron pairs from the neutron-rich N = 12 isotones C-18 and O-20 has been studied by high-energy nucleon knockout from N-19 and O-21 secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay N-19(-1p)18C*-> C-16 + n + n is clearly dominated by direct pair emission. The two- neutron correlation strength, the largest ever observed, suggests the predominance of a C-14 core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay O-21(-1n)O-20*-> O-18 + n + n, attributed to its formation through the knockout of a deeply bound neutron that breaks the O-16 core and reduces the number of pairs., This work was supported by the German Federal Ministry for Education and Research (BMBF Project No. 05P15RDFN1), and through the GSI-TU Darmstadt cooperation agreement. C. A. Bertulani acknowledges support by U.S. Department of Energy Grant No. DE-FG02-08ER41533 and U.S. National Science Foundation Grant No. 1415656.

Published
2018

33. Quasifree ( p,pN ) scattering of light neutron-rich nuclei near N=14

Author

Roy Crawford Lemmon, M. Röder, Rituparna Kanungo, P. Cabanelas, M. Heil, S. Pietri, Hans Geissel, E. Y. Nikolskii, A. Movsesyan, J. Marganiec, O. Ershova, J. Enders, N. Kurz, V. Volkov, K. Boretzky, Iris Dillmann, Stefanos Paschalis, H. Scheit, F. Farinon, A. Estrade, Vladimir Avdeichikov, R. Plag, G. L. Wilson, A. Najafi, L. M. Fraile, V. Panin, A. M. Moro, D. Jurčiukonis, Simon Lindberg, Catherine Rigollet, Kai Zuber, U. Datta Pramanik, A. Henriques, J. Benlliure, F. Wamers, D. Yakorev, Carlos A. Bertulani, María José García Borge, J. S. Winfield, C. Langer, Andreas Zilges, I. Syndikus, A. Kelic-Heil, A. Deltuva, Thomas Nilsson, T. Le Bleis, M. Heine, G. Ribeiro, E. Cravo, D. Cortina-Gil, L. Atar, Nasser Kalantar-Nayestanaki, Mikhail V. Zhukov, Daniel Bemmerer, C. Wheldon, Marine Vandebrouck, D. Galaviz, Thomas Aumann, Y. Togano, Andreas Martin Heinz, O. Sorlin, Björn Jonson, M. Holl, T. Kröll, Andreas Wagner, Joakim Cederkäll, S. Beceiro-Novo, Ángel Perea, Enrique Nácher, Z. Elekes, H. Weick, B. Fernández-Domínguez, Philip Woods, Håkan T Johansson, K. Göbel, R. Gernhäuser, B. Pietras, Deniz Savran, Pavel Golubev, Haik Simon, M. Freer, Olof Tengblad, Rene Reifarth, Tanja Heftrich, C. Nociforo, W. N. Catford, D. Rossi, H. Alvarez-Pol, A. Ignatov, L. Chulkov, C. Caesar, J. Taylor, P. Velho, R. Crespo, A. Knyazev, R. Thies, Jorge Machado, Marina Petri, J. M. Boillos, J. Hagdahl, A. Hufnagel, M. Labiche, P. Díaz Fernández, Marielle Chartier, M. Caamaño, and Enrique Casarejos

Subjects
Physics, Proton, Inverse kinematics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Inverse, 01 natural sciences, Light scattering, Nuclear physics, Momentum, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The (RB)-B-3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C-12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p, pn) and (p, 2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N = 14 to N = 15. Method: The structure of the projectiles O-23, O-22, and N-21 has been studied simultaneously via (p, pn) and (p, 2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the (RB)-B-3-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p, pn) and (p, 2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p, pn) channels, indications of a change in the structure of these nuclei moving from N = 14 to N = 15 have been observed, i.e., from the 0d(5/2) shell to the 1s(1/2). This supports previous observations of a subshell closure at N = 14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.

Published
2018

34. Quasifree ( p , 2p ) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength

Author

Rene Reifarth, J. Kahlbow, E. Y. Nikolskii, R. Thies, Jorge Machado, M. Heine, A. Estrade, Marina Petri, G. Ribeiro, J. Taylor, Daniel Bemmerer, M. A. Najafi, Haik Simon, M. Freer, Olof Tengblad, Enrique Casarejos, H. Alvarez-Pol, Kai Zuber, F. Farinon, C. Nociforo, D. Rossi, Nasser Kalantar-Nayestanaki, C. Wheldon, Thomas Aumann, K. Boretzky, L. Chulkov, Andreas Martin Heinz, C. Caesar, Vladimir Avdeichikov, Tanja Heftrich, J. M. Boillos, J. Hagdahl, V. Panin, D. Galaviz Redondo, Ángel Perea, T. Kröll, Joakim Cederkäll, A. Ignatov, Carlos A. Bertulani, N. Kurz, A. Hufnagel, M. Labiche, S. Pietri, V. Volkov, P. Díaz Fernández, Mikhail V. Zhukov, G. L. Wilson, Simon Lindberg, Carlo Barbieri, I. Syndikus, J. Benlliure, F. Wamers, M. Heil, Marine Vandebrouck, Catherine Rigollet, M. Caamaño, Enrique Nácher, H. Weick, S. Beceiro-Novo, C. Langer, O. Ershova, A. Kelic-Heil, P. Velho, A. Henriques, J. S. Winfield, Thomas Nilsson, A. Knyazev, E. Cravo, Håkan T Johansson, R. Crespo, María José García Borge, Pavel Golubev, O. Sorlin, H. Scheit, Marielle Chartier, M. Holl, Deniz Savran, I. Dillmann, Stefanos Paschalis, D. Yakorev, Y. Togano, J. Marganiec-Gałązka, T. Le Bleis, D. Cortina-Gil, Rituparna Kanungo, Hans Geissel, L. Atar, A. Movsesyan, L. M. Fraile, Björn Jonson, Philip Woods, Andreas Wagner, R. Gernhäuser, Andreas Zilges, J. Enders, R. Lemmon, M. Röder, Z. Elekes, K. Göbel, R. Plag, and W. N. Catford

Subjects
Physics, Range (particle radiation), 010308 nuclear & particles physics, Eikonal equation, media_common.quotation_subject, Nuclear Theory, Ab initio, General Physics and Astronomy, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Asymmetry, Oxygen, Isotopes of oxygen, Nuclear physics, chemistry, Isospin, 0103 physical sciences, Particle, Nuclear Experiment, 010306 general physics, media_common
Abstract

Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B/LAND setup with incident beam energies in the range of 300-450 MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type OA(p,2p)NA-1 have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.

Published
2018

35. Corrigendum to 'Single-neutron knockout from 20 C and the structure of 19 C' [Phys. Lett. B 769 (2017) 503–508]

Author

T. Nakashima, S. Ogoshi, Shuichi Takeuchi, T. Murakami, Takashi Nakamura, Nagao Kobayashi, N.A. Orr, Jongwon Hwang, S. K. Kim, Noritsugu Nakatsuka, K. Yoneda, T. Isobe, Y. Togano, S. Leblond, N.L. Achouri, A. Navin, Naoki Fukuda, Takashi Kubo, Thomas Aumann, Jenny Lee, D. Kanno, Hiroshi Sato, Naohito Inabe, Hiroshi Suzuki, H. Takeda, S. Nishi, Daichi Murai, Hideaki Otsu, D. Kameda, K. Muto, Yosuke Kondo, K. Takahashi, Y. Satou, F. M. Marqués, P. Doornenbal, T. Motobayashi, A. G. Tuff, Y. Shimizu, J. Gibelin, F. Delaunay, T. Kobayashi, Marine Vandebrouck, H. Baba, Ryuki Tanaka, and R. Minakata

Subjects
Physics, Nuclear and High Energy Physics, Structure (category theory), Neutron, Atomic physics, lcsh:Physics, lcsh:QC1-999
Published
2017

36. Spectroscopy of Fe61 via the neutron transfer reaction H2(Fe60,p)Fe*61

Author

S. Giron, F. Hammache, N. de Séréville, P. Roussel, J. Burgunder, M. Moukaddam, D. Beaumel, L. Caceres, G. Duchêne, E. Clément, B. Fernandez-Dominguez, F. Flavigny, G. de France, S. Franchoo, D. Galaviz-Redondo, L. Gasques, J. Gibelin, A. Gillibert, S. Grevy, J. Guillot, M. Heil, J. Kiener, V. Lapoux, F. Maréchal, A. Matta, I. Matea, L. Nalpas, J. Pancin, L. Perrot, A. Obertelli, R. Raabe, J. A. Scarpaci, K. Sieja, O. Sorlin, I. Stefan, C. Stodel, M. Takechi, J. C. Thomas, and Y. Togano

Subjects
Physics, Photon, Silicon, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Charged particle, Cross section (physics), chemistry, 0103 physical sciences, Bound state, Neutron, Atomic physics, 010306 general physics, Adiabatic process, Spectroscopy
Abstract

The direct component of the 60Fe(n,γ)61Fe cross section was investigated by populating the bound states of the 61Fe nucleus through the (d,pγ) transfer reaction in inverse kinematics using a radioactive beam of 60Fe at 27A MeV. The experiment was performed at GANIL using the MUST2 array and an annular double-sided silicon strip detector for the detection of the light charged particle in coincidence with the photons measured in the EXOGAM γ-ray detectors. For the first time, the spectroscopic factors of the first 3/2−, 5/2−, 1/2−, and 9/2+ states of 61Fe were deduced experimentally from an adiabatic distorted wave approximation analysis of the data. The obtained results show a very good agreement with the shell-model predictions. The calculated direct component of the (n,γ) cross section was found negligible and of about 2% of the total, indicating a dominant resonant component.

Published
2017

37. Determination of the neutron-capture rate of C17 for r -process nucleosynthesis

Author

Håkan T Johansson, Pavel Golubev, Enrique Casarejos, T. Adachi, J. Van de Walle, Ethan Uberseder, G. L. Wilson, Y. Aksyutina, S. Beceiro-Novo, J. Enders, Ángel Perea, F. Farinon, C. Langer, R. Knöbel, J. Benlliure, O. Lepyoshkina, Marielle Chartier, A. Kelic-Heil, F. Wamers, N. I. Ashwood, A. Najafi, M. Barr, Kai Zuber, J. Alcantara, Tanja Heftrich, T. Le Bleis, A. Henriques, G. Ickert, J. S. Winfield, D. Cortina-Gil, Thomas Nilsson, G. Ribeiro, Hans Geissel, S. Pietri, Haik Simon, M. Freer, Anisur Rahaman, C. Caesar, Olof Tengblad, C. Nociforo, Stefanos Paschalis, O. Ershova, D. Rossi, Y. Togano, Stefan Typel, S. Chakraborty, A. Movsesyan, O. Sorlin, K. Boretzky, K. Riisager, P. Díaz Fernández, Andreas Zilges, A. Ignatov, Meng-Ru Wu, P. Velho, Vladimir Avdeichikov, Simon Lindberg, A. Prochazka, Catherine Rigollet, Mario Weigand, M. Caamaño, B. Streicher, J. Taylor, Z. Elekes, W. N. Catford, S. Terashima, K. Göbel, V. Panin, Bo Jakobsson, M. Heil, J. Hagdahl, Carlos A. Bertulani, M. V. Ricciardi, Björn Jonson, Philip Woods, M. Labiche, M. Freudenberger, L. M. Fraile, R. Plag, U. Datta Pramanik, S. Altstadt, Gabriel Martínez-Pinedo, R. Thies, Jorge Machado, T. Neff, Marina Petri, R. Crespo, H. Weick, M. Holl, J. Kurcewicz, Andreas Wagner, H. Scheit, H. Alvarez-Pol, R. Gernhäuser, H. O. U. Fynbo, Nasser Kalantar-Nayestanaki, G. Rastrepina, J. Sanchez del Rio, D. Galaviz, C. Wheldon, Thomas Aumann, Deniz Savran, N. Kurz, Andreas Martin Heinz, M. Röder, T. Kröll, V. Stoica, M. Mostazo, V. Volkov, M. Heine, Daniel Bemmerer, I. Dillmann, Joakim Cederkäll, D. Yakorev, Mikhail V. Zhukov, V. Maroussov, A. Estrade, J. Marganiec, Rene Reifarth, G. Burgunder, Roy Crawford Lemmon, C. Wimmer, Rituparna Kanungo, L. Chulkov, R. Krücken, D. Gonzalez Diaz, and María José García Borge

Subjects
Physics, education.field_of_study, 010308 nuclear & particles physics, Population, 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Neutron capture, Nucleosynthesis, Excited state, 0103 physical sciences, Coulomb, r-process, Atomic physics, Nuclear Experiment, 010306 general physics, education, Ground state
Abstract

With the R$^{3}$B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile energy around 425~AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of $^{17}$C into the ground state of $^{18}$C. Those data have been used to constrain theoretical calculations for transitions populating excited states in $^{18}$C. This allowed to derive the astrophysical cross section $\sigma^{*}_{\mathrm{n}\gamma}$ accounting for the thermal population of $^{17}$C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures $T_{9}\leq{}1$~GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of $^{17}$C on the production of second- and third-peak elements in contrast to earlier sensitivity studies.

Published
2017

38. Direct experimental evidence for a multiparticle-hole ground state configuration of deformedMg33

Author

Ushasi Datta, A. Rahaman, T. Aumann, S. Beceiro-Novo, K. Boretzky, C. Caesar, B. V. Carlson, W. N. Catford, S. Chakraborty, M. Chartier, D. Cortina-Gil, G. de Angelis, P. Diaz Fernandez, H. Emling, O. Ershova, L. M. Fraile, H. Geissel, D. Gonzalez-Diaz, B. Jonson, H. Johansson, N. Kalantar-Nayestanaki, T. Kröll, R. Krücken, J. Kurcewicz, C. Langer, T. Le Bleis, Y. Leifels, J. Marganiec, G. Münzenberg, M. A. Najafi, T. Nilsson, C. Nociforo, V. Panin, S. Paschalis, R. Plag, R. Reifarth, V. Ricciardi, D. Rossi, H. Scheit, C. Scheidenberger, H. Simon, J. T. Taylor, Y. Togano, S. Typel, V. Volkov, A. Wagner, F. Wamers, H. Weick, M. Weigand, J. S. Winfield, D. Yakorev, and M. Zoric

Subjects
Physics, Valence (chemistry), 010308 nuclear & particles physics, Monte Carlo method, 01 natural sciences, Dissociation (chemistry), Atomic orbital, Excited state, 0103 physical sciences, Coulomb, Neutron, Atomic physics, 010306 general physics, Ground state
Abstract

The first direct experimental evidence of a multiparticle-hole ground state configuration of the neutron-rich Mg-33 isotope has been obtained via intermediate energy (400 A MeV) Coulomb dissociation measurement. The major part similar to(70 +/- 13)% of the cross section is observed to populate the excited states of Mg-32 after the Coulomb breakup of Mg-33. The shapes of the differential Coulomb dissociation cross sections in coincidence with different core excited states favor that the valence neutron occupies both the s(1/2) and p(3/2) orbitals. These experimental findings suggest a significant reduction and merging of sd-pf shell gaps at N similar to 20 and 28. The ground state configuration of Mg-33 is predominantly a combination of Mg-32(3.0,3.5MeV; 2(-), 1(-)) circle times nu(s1/2), Mg-32(2.5MeV; 2(+)) circle times nu(p3/2), and Mg-32(0; 0(+)) circle times nu(p3/2). The experimentally obtained quantitative spectroscopic information for the valence neutron occupation of the s and p orbitals, coupled with different core states, is in agreement with Monte Carlo shell model (MCSM) calculation using 3 MeV as the shell gap at N = 20.

Published
2016

39. 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

40. EXPERIMENTAL INVESTIGATION OF THE STELLAR REACTION S-30(p, gamma)(31) Cl VIA COULOMB DISSOCIATION

Author

K. Yoneda, Y. Matsuo, Nagao Kobayashi, T. Kuboki, N. Aoi, H. W. Wang, D. Q. Fang, K. Tanaka, Y. Satou, N. Kume, J. S. Wang, H. Murakami, P. Doornenbal, Shuichi Ota, K. Kurita, K. Okada, Y. Yamada, Meiko Kurokawa, Satoshi Takeuchi, T. Motobayashi, X. Z. Cai, Masafumi Matsushita, Naohito Iwasa, Y. Togano, Wendong Tian, Susumu Shimoura, Shawn Bishop, Takeo Kawabata, Y. Kondo, R. Shioda, Takeshi Furukawa, S. Kanno, Y. G. Ma, Takashi Nakamura, Kazunari Yamada, Kazuo Ieki, and H. Baba

Subjects
Elastic scattering, Physics, History, Nuclear and High Energy Physics, Nuclear Theory, General Physics and Astronomy, Astronomy and Astrophysics, Coulomb excitation, Coincidence, Dissociation (chemistry), Computer Science Applications, Education, Excited state, Coulomb, Invariant mass, 30S, Atomic physics, Nuclear Experiment, Nucleon, P system, Relative energy
Abstract

The Coulomb dissociation of the proton-rich nuclei 31 Cl was studied experimentally using 31 Cl beams at 58 MeV/nucleon with a lead target. The relative energy between the reaction products, 30 S and proton, was obtained. The first excited state in 31 Cl was observed which is relevant to the resonant capture of stellar 30 S (p,γ)31 Cl reaction.

Published
2010

41. Probing the Structure of Unstable Nuclei Through the Recoiled Proton Tagged Knockout Reaction

Author

Y. Ye, Z. Cao, D. Jiang, T. Zheng, H. Hua, Y. Ge, X. Li, J. Lou, J. Xiao, Q. Li, L. Lv, R. Qiao, H. You, R. Chen, H. Sakurai, H. Otsu, Z. Li, M. Nishimura, S. Sakaguchi, H. Baba, Y. Togano, K. Yoneda, C. Li, S. Wang, H. Wang, K. Li, H. Xu, Z. Hu, J. Wang, L. Duan, X. Zhang, Z. Guo, Z. Sun, X. Lei, Z. Xu, T. Nakamura, Y. Nakayama, Y. Kondo, S. Deguchi, Y. Satou, and K.H. Tshoo

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Reaction mechanism, Proton, Nuclear Theory, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment
Abstract

Recoiled proton tagged knockout reaction experiments were carried-out for He-8 at 82.5 MeV/u in RIKEN and for He-6 at 65 MeV/u in Lanzhou. The very preliminary results for the distinguish of the reaction mechanism are presented and compared to the kinematics calculation.

Published
2010

42. 13,14B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process

Author

Rene Reifarth, S. Chakraborty, D. Rossi, Ethan Uberseder, Enrique Casarejos, Håkan T Johansson, Pavel Golubev, H. Alvarez-Pol, L. Chulkov, Y. Aksyutina, F. Farinon, J. Alcantara, V. Volkov, P. Velho, J. Van de Walle, G. L. Wilson, K. Boretzky, J. Sanchez del Rio, A. Ignatov, R. Krücken, Mikhail V. Zhukov, Achim Schwenk, V. Maroussov, C. Langer, A. Kelic-Heil, M. A. Najafi, D. Gonzalez Diaz, Tanja Heftrich, Vladimir Avdeichikov, Kerstin Sonnabend, H. Weick, J. Kurcewicz, Kai Zuber, S. Terashima, James Taylor, J. Enders, Tatuya Adachi, María José García Borge, G. Ickert, N. Kurz, A. Henriques, R. Knöbel, J. Marganiec, D. Galaviz, J. Benlliure, O. Lepyoshkina, L. Atar, J. S. Winfield, S. Pietri, J.D. Holt, F. Wamers, Thomas Nilsson, M. Zoric, O. Sorlin, Nasser Kalantar-Nayestanaki, C. Wheldon, Catherine Rigollet, G. Rastrepina, Hans Geissel, Carlos A. Bertulani, M. Holl, Thomas Aumann, Andreas Martin Heinz, M. Freudenberger, M. Mostazo, O. Ershova, H. Scheit, C. Caesar, S.G. Altstadt, Deniz Savran, B. Streicher, M. Heine, T. Kröll, V. Stoica, Daniel Bemmerer, D. Yakorev, J. Simonis, J. Hagdahl, I. Dillmann, Haik Simon, H. O. U. Fynbo, M. Freer, M. Labiche, Olof Tengblad, Ahibur Rahaman, A. Prochazka, P. Díaz Fernández, C. Nociforo, Joakim Cederkäll, Z. Elekes, V. Panin, Y. Togano, Mario Weigand, M. Caamaño, Andreas Zilges, K. Riisager, R. Thies, Jorge Machado, K. Göbel, S. Beceiro, W. N. Catford, M. V. Ricciardi, A. Estrade, G. Burgunder, Bo Jakobsson, Björn Jonson, Philip Woods, M. Röder, Andreas Wagner, Javier Fernandez Menendez, R. Gernhäuser, R. Plag, U. Datta Pramanik, Roy Crawford Lemmon, C. Wimmer, Rituparna Kanungo, L. M. Fraile, M. Heil, Marielle Chartier, N. I. Ashwood, T. Le Bleis, D. Cortina-Gil, A. Movsesyan, G. Ribeiro, Ángel Perea, M. Barr, 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), 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
Physics, Nuclear and High Energy Physics, Photon, Coulomb breakup, r-process, Aucun, Nuclear data, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Dissociation (chemistry), Nuclear physics, Fragmentation (mass spectrometry), Nucleosynthesis, Coulomb, Physics::Accelerator Physics, r-process, Neutron, Atomic physics, Nuclear Experiment
Abstract

Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented. © 2014 Elsevier Inc., This project was supported by the Helmholtz International Center for FAIR, the Helmholtz Young Investigator Group VH-NG-327 and the Helmholtz Alliance Program of the Helmholtz Association, Contract No. HA216/EMMI.

Published
2014

43. Beyond the neutron drip line: The unbound oxygen isotopes25O and26O

Author

Heiko Scheit, Roy Crawford Lemmon, C. Wimmer, Rene Reifarth, A. Ignatov, Z. Elekes, G. Rastrepina, W. N. Catford, Hans Geissel, Jason D. Holt, Kai Zuber, A. Kelic-Heil, S. Terashima, U. Datta Pramanik, L. Chulkov, O. Sorlin, M. Heine, M. V. Ricciardi, D. Galaviz, Ethan Uberseder, T. Kröll, P. Díaz Fernández, C. Nociforo, Daniel Bemmerer, M. Caamaño, R. Krücken, Enrique Casarejos, I. Dillmann, Andreas Wagner, Mikhail V. Zhukov, V. Maroussov, J. Sanchez del Rio, F. Farinon, R. Gernhäuser, Ralf Plag, J. Benlliure, O. Lepyoshkina, L. M. Fraile, R. Knöbel, D. Gonzalez Diaz, Deniz Savran, O. Ershova, A. Najafi, Vladimir Avdeichikov, C. Caesar, J. Alcantara, Tatuya Adachi, María José García Borge, J. Marganiec, Y. Togano, Ángel Perea, Joakim Cederkäll, Mario Weigand, A. Prochazka, B. Streicher, James Taylor, M. Barr, A. Henriques, V. Volkov, Javier Fernandez Menendez, S. Chakraborty, K. Riisager, Helmut Weick, G. Ickert, A. Estrade, V. Panin, M. Zoric, Andreas Zilges, A. Movsesyan, J. Van de Walle, G. L. Wilson, Haik Simon, S. Altstadt, S. Beceiro, H. O. U. Fynbo, M. Freer, M. Holl, Thomas Nilsson, G. Burgunder, S. Pietri, J. Simonis, Olof Tengblad, Marielle Chartier, N. I. Ashwood, H. Alvarez-Pol, J. Hagdahl, K. Boretzky, Bo Jakobsson, G. Ribeiro, R. Kanungo, Christoph Langer, M. Labiche, T. Le Bleis, Björn Jonson, Michael Heil, Philip Woods, D. Cortina-Gil, Nasser Kalantar-Nayestanaki, F. Wamers, M. Mostazo, J. S. Winfield, R. Thies, C. Wheldon, Jorge Machado, P. Velho, D. Yakorev, Joachim Enders, Thomas Aumann, Andreas Martin Heinz, V. Stoica, Y. Aksyutina, Ahibur Rahaman, M. Röder, Simon Lindberg, Catherine Rigollet, Achim Schwenk, Tanja Heftrich, Carlos A. Bertulani, M. Freudenberger, J. Kurcewicz, Håkan T Johansson, Pavel Golubev, and D. Rossi

Subjects
Physics, Nuclear and High Energy Physics, Valence (chemistry), 010308 nuclear & particles physics, Nuclear Theory, Particle stability, 01 natural sciences, 7. Clean energy, Isotopes of oxygen, Neutron spectroscopy, Nuclear physics, Excited state, 0103 physical sciences, Neutron, Nuclear drip line, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.

Published
2013

44. Well Developed Deformation inSi42

Author

Richard Hughes, M. Takechi, S. Michimasa, Hiroyoshi Sakurai, Y. Togano, Julien Gibelin, K. Steiger, Nagao Kobayashi, Eiji Ideguchi, D. G. Jenkins, Roman Gernhäuser, T. Sako, K. Yoneda, G Lee, L. Caceres, Yosuke Kondo, C. Hinke, H. L. Crawford, Masafumi Matsushita, A. Matta, Hao Wang, Calem Hoffman, Tohru Motobayashi, P. Doornenbal, Marina Petri, Jongmin Lee, Heiko Scheit, H. Baba, Shuichi Ota, K. Li, T. Le Bleis, D. Bazin, Takashi Nakamura, Shintaro Go, S. Grévy, Nori Aoi, Susumu Shimoura, P. Fallon, R. Winkler, David Steppenbeck, Kazutaka Takahashi, Satoshi Takeuchi, and R. Krücken

Subjects
Physics, Silicon, Isotope, 010308 nuclear & particles physics, Yrast, Cyclotron, Gamma ray, General Physics and Astronomy, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, law.invention, Time of flight, chemistry, law, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy
Abstract

Excited states in (38,40,42) Si nuclei have been studied via in-beam γ-ray spectroscopy with multinucleon removal reactions. Intense radioactive beams of ^{40}S and (44)S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled γ-γ coincidence measurements. A prominent γ line observed with an energy of 742(8) keV in (42) Si confirms the 2(+) state reported in an earlier study. Among the γ lines observed in coincidence with the 2^{+} → 0+ transition, the most probable candidate for the transition from the yrast 4(+) state was identified, leading to a 4(1)+) energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2(1)+ and 4(1)(+) states indicates well-developed deformation in (42) Si at N = 28 and Z = 14. Also for 38,40)Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for (42)Si, the results show a rapid deformation development of Si isotopes from N = 24 to N = 28.

Published
2012

45. Resonance states in27P using Coulomb dissociation and their effect on the stellar reaction26Si(p,γ) 27P

Author

H. Murakami, Ken Ishikawa, Zsolt Fülöp, N. Aoi, Satoshi Takeuchi, K. Demichi, Tomoko Gomi, Kazunari Yamada, Naohito Iwasa, Hiroyoshi Sakurai, Y. Yanagisawa, A. Saito, Yoshihide Higurashi, Masamichi Ishihara, Y. U. Matsuyama, Y. Togano, M. Serata, H. Hasegawa, Toshiyuki Minemura, Shigeru Kubono, S. Michimasa, Takashi Sugimoto, Yoshiaki Ando, N. Imai, Shuichi Ota, H. Baba, Kazuo Ieki, Z. Elekes, K. Kurita, U. Futakami, T. Motobayashi, E. Takeshita, Naoki Fukuda, M. Miura, Takashi Nakamura, Y. Kondo, Masahiro Notani, Susumu Shimoura, A. Yoshida, T. Kubo, K. Yoneda, S. Kanno, M. Kunibu, Hironori Iwasaki, and K. Ue

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Excited state, Coulomb excitation, Mirror nuclei, Isotopes of silicon, Atomic physics, Isotopes of magnesium, Omega, Resonance (particle physics)
Abstract

The stellar reaction ${}^{26}$Si($p,\phantom{\rule{-0.16em}{0ex}}\ensuremath{\gamma}$)${}^{27}$P was studied in the Coulomb dissociation of ${}^{27}$P. Two known resonance levels in ${}^{27}$P were excited and a candidate for the third excited state was found in the ${}^{26}$Si $p$ relative energy spectrum. The $E$2 resonance strengths $\ensuremath{\omega}\ensuremath{\gamma}$ were obtained to be $(6.5\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$, $(6.0\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, and $(1.10\ifmmode\pm\else\textpm\fi{}0.27)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ MeV. The total ($E2+M$1) $\ensuremath{\omega}\ensuremath{\gamma}$ value for the first excited state was evaluated to be $1.{9}_{\ensuremath{-}1.1}^{+1.9}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ MeV with the help of the shell model. The error was estimated from the deviation of theoretical predictions with the same shell model from experimental strengths obtained in the present study for ${}^{27}$P and earlier ones for the mirror nucleus ${}^{27}$Mg. The astrophysical reaction rate for the ${}^{26}$Si($p,\phantom{\rule{-0.16em}{0ex}}\ensuremath{\gamma}$)${}^{27}$P reaction was also calculated and compared with previous estimations.

Published
2011

46. SIGNALS OF DIPROTON EMISSION FROM THE THREEBODY BREAKUP CHANNEL OF 23<font>AL</font> AND 22<font>MG</font>

Author

P. Zhou, H. Oishi, Kazuo Ieki, Guoqiang Zhang, Wendong Tian, Xia-Yin Sun, Zheng-Guo Hu, Y. Ishibashi, T. Motobayashi, A. Ozawa, H. Murakami, Jian-Song Wang, S. Kanno, Takeo Kawabata, Y. Yasuda, Meiko Kurokawa, K. Yamada, Meng Wang, Shuichi Ota, Xi-Guang Cao, S. Takeuchi, Xiangzhou Cai, Y. Itou, T. Honda, K. Okada, Y. Kondo, K. Kurita, K. Yoneda, H. Baba, E. Takeshita, H. Kimura, Naohito Iwasa, Susumu Shimoura, T. Moriguchi, Y. Togano, R. Shioda, N. Aoi, Hiroyoshi Sakurai, Y. Hara, Yukiko Yamada, Jingen Chen, De-Qing Fang, Hongwei Wang, Wei Guo, Yu-Gang Ma, and Y. Fu

Subjects
Physics, Channel (broadcasting), Atomic physics, Breakup
Published
2011

47. Astrophysical reaction rate of 30S(p,\gamma )31Cl studied by Coulomb dissociation

Author

T. Kuboki, Takashi Nakamura, Takahiro Kawabata, Xiangzhou Cai, K. Yoneda, Kana Tanaka, Y. Togano, Wendong Tian, Masafumi Matsushita, Yu-Gang Ma, Pieter Doornenbal, Nobuyuki Kobayashi, Yusuke Yamada, S. Bishop, N. Aoi, Y. Satou, Kazuo Ieki, Shoko Kanno, N. Kume, Satoshi Takeuchi, Kensuke Okada, R. Shioda, Takeshi Furukawa, Jian-Song Wang, Yukari Matsuo, K. Kurita, Meiko Kurokawa, Kazunari Yamada, Y. Kondo, T. Motobayashi, H. Baba, Hiroshi Murakami, Shinsuke Ota, Susumu Shimoura, Naohito Iwasa, De-Qing Fang, and Hongwei Wang

Subjects
Physics, Reaction rate, Coulomb, Atomic physics, Dissociation (chemistry)
Published
2011

48. Search for [sup 7]H at RIKEN

Author

E. Yu. Nikolskii, A. A. Korsheninnikov, H. Otsu, H. Suzuki, K. Yoneda, H. Baba, K. Yamada, Y. Kondo, N. Aoi, M. S. Golovkov, A. S. Fomichev, S. A. Krupko, M. Kurokawa, E. A. Kuzmin, I. Martel, W. Mittig, T. Motobayashi, T. Nakamura, M. Niikura, S. Nishimura, A. A. Ogloblin, P. Roussel-Chomaz, A. Sanchez-Benitez, Y. Satou, S. I. Sidorchuk, T. Suda, S. Takeuchi, K. Tanaka, G. M. Ter-Akopian, Y. Togano, M. Yamaguchi, Yu. E. Penionzhkevich, and S. M. Lukyanov

Subjects
Physics, Nuclear reaction, Nuclear physics, education.field_of_study, Helium-3, Population, Atomic physics, Isotopes of beryllium, Ground state, education, Isotopes of helium, Resonance (particle physics), Spectral line
Abstract

Experimental search for the low‐lying 7H resonance was performed in the d(8He,3He)7H reaction with a 8He beam at 42A MeV. No well‐pronounced peak of 7H was observed, but the spectrum has some peculiarities at ∼2 MeV and ∼10.5 MeV above the t+4 n threshold. The d(12Be,3He)11Li reaction simultaneously measured at 71A MeV showed the population of 11Li ground state with the c.m.s. cross section of ≈1 mb/sr.

Published
2010

49. Measurement on proton-proton correlation of the excited [sup 23]Al

Author

Y. G. Ma, D. Q. Fang, P. Zhou, X. Z. Cai, J. G. Chen, W. Guo, X. Y. Sun, W. D. Tian, H. W. Wang, G. Q. Zhang, X. G. Cao, Y. Fu, Z. G. Hu, J. S. Wang, M. Wang, Y. Togano, N. Aoi, H. Baba, T. Honda, K. Okada, Y. Hara, K. Ieki, Y. Ishibashi, Y. Itou, N. Iwasa, S. Kanno, T. Kawabata, H. Kimura, Y. Konda, K. Kurita, M. Kurokawa, T. Moriguchi, H. Murakami, H. Oishi, S. Ota, A. Ozawa, H. Sakurai, S. Shimoura, R. Shioda, E. Takeshita, S. Takeuchi, K. Yamada, Y. Yamada, Y. Yasuda, K. Yoneda, T. Motobayashi, Akira Ozawa, and Weiping Lu

Subjects
Physics, Proton, Nuclear Theory, Hadron, Cyclotron, Rest frame, law.invention, Nuclear physics, law, Excited state, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Nucleon, Isotopes of helium, Radioactive decay
Abstract

We have measured two‐proton momentum and angular correlations for the 23Al excited states from the 23Al radioactive beam on a 12C target at an energy of 60∼70 A MeV at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The decay products, namely 21Na+p+p from 23Al are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels demonstrate that there are some diproton emission components from 2He cluster for the excited 23Al.

Published
2010

50. Study of [sup 60]Fe(n,γ)[sup 61]Fe reaction of astrophysical interest via d([sup 60]Fe,pγ) indirect reaction

Author

S. Giron, F. Hammache, N. de Séréville, D. Beaumel, J. Burgunder, L. Caceres, E. Clement, G. Duchene, F. Flavigny, G. De France, S. Franchoo, B. Fernandez, D. Galaviz-Redondo, L. Gasques, J. Gibelin, A. Gillibert, S. Grevy, J. Guillot, M. Heil, J. Kiener, V. Lapoux, F. Maréchal, A. Matta, Y. Matea, M. Moukaddam, L. Nalpas, A. Obertelli, L. Perrot, R. Raabe, J. A. Scarpaci, O. Sorlin, I. Stefan, C. Stoedel, M. Takechi, J. C. Thomas, Y. Togano, Claudi Spitaleri, Claus Rolfs, and Rosario G. Pizzone

Subjects
Nuclear reaction, Physics, Angular momentum, 010308 nuclear & particles physics, Context (language use), 7. Clean energy, 01 natural sciences, Nuclear physics, Supernova, Nucleosynthesis, Excited state, 0103 physical sciences, Atomic physics, Radioactive decay, Excitation
Abstract

INTEGRAL and RHESSI spacecrafts recently detected the 1.173 and 1.333 MeV γ‐ray lines coming from the 60Fe—60Co—60Ni radioactive decay chain. The long lived isotope 60Fe (T1/2 = 1.5 106y) is believed to be primarily produced in core‐collapse supernovae. However the interpretation of the observations is difficult because of the large uncertainties concerning 59Fe(n,γ)60Fe and 60Fe(n,γ)61Fe cross sections, involved in 60Fe nucleosynthesis.The direct component of the 60Fe(n,γ)61Fe reaction was studied indirectly via the d(60Fe,pγ)61Fe transfer reaction. The experiment performed in GANIL in spring 2009 will allow to determine the excitation energies of the populated excited states of 61Fe and for the first time their spectroscopic factors as well as their transfer angular momentum.I will first give an overview of the astrophysical context, then I will describe the experimental setup and finally present some preliminary results of the ongoing analysis.

Published
2010

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