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17 results on '"D. Körper"'

1. Measurement of nuclear interaction cross sections towards neutron-skin thickness determination

Author

L. Ponnath, T. Aumann, C.A. Bertulani, R. Gernhäuser, M. Heil, T. Almusidi, H. Alvarez-Pol, L. Atar, L. Atkins, Y. Ayyad, J. Benlliure, K. Boretzky, M.J.G. Borge, L.T. Bott, G. Bruni, B. Brückner, P. Cabanelas, C. Caesar, E. Casarejos, J. Cederkall, A. Corsi, D. Cortina-Gil, J.A. Dueñas, M. Duer, Z. Elekes, S. Escribano Rodriguez, L. Fabbietti, A. Falduto, M. Feijoo, M. Feijoo Fontan, L.M. Fonseca, A. Frotscher, D. Galaviz, E. Galiana, G. García-Jiménez, I. Gašparic̀, E.I. Geraci, A. Gillibert, B. Gnoffo, D. González Caamaño, A. Graña González, K. Göbel, A.-L. Hartig, A. Heinz, T. Hensel, M. Holl, A. Horvat, A. Jedele, D. Jelavic̀ Malenica, T. Jenegger, H.T. Johansson, B. Jonson, N. Kalantar-Nayestanaki, A. Kelic-Heil, O.A. Kiselev, P. Klenze, D. Kresan, T. Kröll, E. Kudaibergenova, D. Kurtulgil, D. Körper, M. Labiche, C. Langer, I. Lihtar, Yu.A. Litvinov, B. Löher, J. Mayer, S. Murillo Morales, E. Nacher, T. Nilsson, A. Obertelli, V. Panin, J. Park, S. Paschalis, A. Perea, M. Petri, S. Pirrone, T. Pohl, R. Reifarth, H.-B. Rhee, J.L. Rodriguez-Sanchez, L. Rose, D.M. Rossi, P. Russotto, D. Savran, H. Scheit, H. Simon, S. Storck-Dutine, A.M. Stott, C. Sürder, R. Taniuchi, O. Tengblad, P. Teubig, L. Trache, M. Trimarchi, H.T. Törnqvist, L. Varga, V. Wagner, and F. Wamers

Subjects
Physics, QC1-999
Abstract

The accuracy of reaction theories used to extract properties of exotic nuclei from scattering experiments is often unknown or not quantified, but of utmost importance when, e.g., constraining the equation of state of asymmetric nuclear matter from observables as the neutron-skin thickness. In order to test the Glauber multiple-scattering model, the total interaction cross section of Image 1 on carbon targets was measured at initial beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The measurements were performed during the first experiment of the newly constructed R3B (Reaction with Relativistic Radioactive Beams) experiment after the start of FAIR Phase-0 at the GSI/FAIR facility with beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The combination of the large-acceptance dipole magnet GLAD and a newly designed and highly efficient Time-of-Flight detector enabled a precise transmission measurement with several target thicknesses for each initial beam energy with an experimental uncertainty of ±0.4%. A comparison with the Glauber model revealed a discrepancy of around 3.1% at higher beam energies, which will serve as a crucial baseline for the model-dependent uncertainty in future fragmentation experiments.

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

Author

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

Subjects
Unbound states, Knockout reaction, Single-particle strength, Shell evolution, Physics, QC1-999
Abstract

The calcium isotopes are an ideal system to investigate the evolution of shell structure and magic numbers. Although the properties of surface nucleons in calcium have been well studied, probing the structure of deeply bound nucleons remains a challenge. Here, we report on the first measurement of unbound states in 53Ca and 55Ca, populated from 54,56Ca(p,pn) reactions at a beam energy of around 216 MeV/nucleon at the RIKEN Radioactive Isotopes Beam Factory. The resonance properties, partial cross sections, and momentum distributions of these unbound states were analyzed. Orbital angular momentum l assignments were extracted from momentum distributions based on calculations using the distorted wave impulse approximation (DWIA) reaction model. The resonances at excitation energies of 5516(41)keV in 53Ca and 6000(250)keV in 55Ca indicate a significant l =3 component, providing the first experimental evidence for the ν0f7/2 single-particle strength of unbound hole states in the neutron-rich Ca isotopes. The observed excitation energies and cross-sections point towards extremely localized and well separated strength distributions, with some fragmentation for the ν0f7/2 orbital in 55Ca. These results are in good agreement with predictions from shell-model calculations using the effective GXPF1Bs interaction and ab initio calculations and diverge markedly from the experimental distributions in the nickel isotones at Z=28.

Published
2024
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3. 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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4. 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
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5. Pairing Forces Govern Population of Doubly Magic Ca54 from Direct Reactions

Author

J. M. Gheller, S. Y. Park, K. Yoneda, Masaki Sasano, P. A. Söderström, D. Sohler, D. Körper, H. Simon, A. Gillibert, K. Miki, Satoshi Takeuchi, Yasuhiro Togano, M. MacCormick, R.-B. Gerst, Duo Yan, Tomohiro Uesaka, Fabia Schindler, V. Wagner, B. D. Linh, M. Holl, A. Corsi, N. Paul, Igor Gašparić, H. N. Liu, P. Koseoglou, E. Sahin, Yosuke Kondo, T. Lokotko, T. Isobe, Victor Vaquero, M. L. Cortés, V. Werner, Takashi Nakamura, W. Rodriguez, Zaihong Yang, A. Delbart, S. Franchoo, F. Château, V. Lapoux, P. Doornenbal, K. I. Hahn, L. Stuhl, I. Murray, C. Caesar, Kazuyuki Ogata, C. Lehr, T. Kobayashi, X. X. Xu, C. Hilaire, Si-Ge Chen, Yutaka Utsuno, V. Panin, A. Giganon, Jenny Lee, N. L. Achouri, L. X. Chung, Y. L. Sun, K. Moschner, Yuya Kubota, D. M. Rossi, H. Baba, F. Flavigny, Masahiro Yasuda, L. Zanetti, Kathrin Wimmer, Dong-Wook Kim, O. Aktas, F. Browne, S. Wang, A. Obertelli, J. Kahlbow, Hiroyoshi Sakurai, T. Motobayashi, Julien Gibelin, K. Boretzky, D. Calvet, David Steppenbeck, H. Törnqvist, Thomas Aumann, Nobuyuki Chiga, T. Koiwai, Kazuki Yoshida, Hideaki Otsu, Hirofumi Yamada, and J. Tscheuschner

Subjects
Physics, education.field_of_study, Proton, 010308 nuclear & particles physics, Nuclear Theory, Population, Nuclear shell model, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Pairing, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Ground state, education
Abstract

Direct proton-knockout reactions of ^{55}Sc at ∼220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of ^{54}Ca were investigated through γ-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological internucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the ^{55}Sc ground state with states in ^{54}Ca. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of ^{55}Sc, valence proton removals populated predominantly the ground state of ^{54}Ca. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

Published
2021
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6. NeuLAND: The high-resolution neutron time-of-flight spectrometer for R3B at FAIR

Author

M.I. Cherciu, N.G. Kozlenko, Andreas Martin Heinz, P. Russotto, Christoph Langer, Z. Elekes, Nasser Kalantar-Nayestanaki, G. Ickert, Thomas Aumann, Thomas Nilsson, L. Zanetti, M. Volknandt, E. M. Orischin, Heiko Scheit, K. Koch, E.V. Pagano, V. Kuznetsov, S. Chakraborty, U. Datta, V. L. Golovtsov, N. Kurz, E. Hoemann, Tanja Heftrich, S. S. Volkov, J. Dreyer, M. Kempe, D. M. Rossi, T. Hensel, A. Horvat, C. Caesar, V. Wagner, G. Politi, I. Lihtar, F. Schindler, B. Löher, Ahibur Rahaman, Catherine Rigollet, J. Kahlbow, H. Törnqvist, A. Kelic-Heil, Herbert A. Simon, Daniel Stach, E. De Filippo, D. Galaviz, N. S. Martorana, Daniel Bemmerer, D. Gonzalez Diaz, D. Körper, Jorge Machado, E. Stan, B. Gnoffo, L. V. Chulkov, P. Teubig, N. Gruzinsky, J. Mayer, G. Alkhazov, J. Hehner, Rene Reifarth, S. Wranne, S. Pirrone, Håkan T Johansson, K. Miki, Lukas Bott, E. Geraci, K. Boretzky, I. Gašparić, H. Heggen, D. Kresan, M. Trimarchi, Kathrin Göbel, D. Jelavić Malenica, J. Stomvall Gill, S.V. Bondarev, M. Holl, Andreas Zilges, D. Yakorev, Joachim Enders, L. Atar, P.-M. Potlog, L. Uvarov, Björn Jonson, Andreas Wagner, Matthias Heil, M. Ciobanu, Á. Horváth, A.G. Krivshich, M. Röder, C.A. Douma, Y. Leifels, Deniz Savran, Kai Zuber, Research unit Nuclear & Hadron Physics, and Nuclear Energy

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, business.industry, High-energy neutron detection, Reactions with relativistic radioactive beams, Plastic scintillator array, Multi-neutron detection, Detector, Scintillator, Time of flight, Optics, Neutron detection, Facility for Antiproton and Ion Research, Neutron, ddc:530, Nuclear Experiment, business, Instrumentation, Image resolution
Abstract

Nuclear instruments & methods in physics research / A 1014, 165701 (2021). doi:10.1016/j.nima.2021.165701, Published by North-Holland Publ. Co., Amsterdam

Published
2021
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7. Extending the Southern Shore of the Island of Inversion to F28

Author

J. Mayer, Noritsugu Nakatsuka, Michael Thoennessen, A. Gillibert, Ákos Horváth, Q. Deshayes, Yosuke Kondo, J. Tscheuschner, Nasser Kalantar-Nayestanaki, J. M. Gheller, István Kuti, M. Shikata, Thomas Aumann, C. Caesar, J. Tsubota, A. Revel, N. L. Achouri, W. He, Z. Elekes, Calem Hoffman, Shoichiro Kawase, Heiko Scheit, J. Kahlbow, Masahiro Yasuda, H. Simon, H. Sato, K. Yoneda, A. Horvat, K. Nakano, Igor Gašparić, T. Ozaki, H. Chae, J. A. Tostevin, L. Stuhl, K. Miki, F. de Oliveira Santos, H. L. Crawford, D. Calvet, Stefanos Paschalis, S. Masuoka, T. Isobe, A. Obertelli, Tomoki Saito, Momoko Tanaka, N. A. Orr, Shoko Koyama, Nobuyuki Chiga, L. Atar, Y. Satou, P. Fallon, Atsumi Saito, Zsolt Dombrádi, H. Törnqvist, Jongwon Hwang, A. Corsi, Julien Gibelin, K. Boretzky, A. Delbart, D. M. Rossi, H. Baba, Masaki Sasano, D. Sohler, V. Lapoux, M. A. Najafi, S. K. Kim, A. Hirayama, H. Al Falou, K. Kisamori, T. Tomai, V. Panin, P. Schrock, Takashi Nakamura, Yasuhiro Togano, M.N. Harakeh, M. Holl, Zaihong Yang, F. Nowacki, T. Kobayashi, Cenxi Yuan, D. Körper, Tomohiro Uesaka, Thomas Nilsson, C. A. Douma, Simon Lindberg, Hideaki Otsu, O. Sorlin, T. Murakami, Yohei Shimizu, Fabia Schindler, Franck Delaunay, F. M. Marqués, and Satoshi Takeuchi

Subjects
Physics, Proton, Island of inversion, General Physics and Astronomy, 01 natural sciences, Spectral line, Momentum, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Nucleon, Spectroscopy, Ground state
Abstract

Detailed spectroscopy of the neutron-unbound nucleus 28 F has been performed for the first time following proton/neutron removal from 29 Ne / 29 F beams at energies around 230 MeV / nucleon . The invariant-mass spectra were reconstructed for both the 27 F ( * ) + n and 26 F ( * ) + 2 n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the 28 F ground state, with S n ( 28 F ) = − 199 ( 6 ) keV , while analysis of the 2 n decay channel allowed a considerably improved S n ( 27 F ) = 1620 ( 60 ) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of 28 F . Importantly, in the case of the ground state, the reconstructed 27 F + n momentum distribution following neutron removal from 29 F indicates that it arises mainly from the 1 p 3 / 2 neutron intruder configuration. This demonstrates that the island of inversion around N = 20 includes 28 F , and most probably 29 F , and suggests that 28 O is not doubly magic.

Published
2020
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8. Lifetime measurement of the $^{26}0 g.s.$ at SAMURAI

Author

Hiroyuki Takeda, Takashi Nakamura, Hideaki Otsu, Olivier Sorlin, Masaki Sasano, Zaihong Yang, I. Murray, D. M. Rossi, Yuya Kubota, A. Hirayama, Thomas Aumann, Makoto Yasuda, K. I. Hahn, L. Atar, H. Baba, Sonja Storck, S. Choi, Z. Halász, Yohei Shimizu, C. Caesar, L. Stuhl, H. Scheit, C. Lehr, Nobuyuki Chiga, Yasuhiro Togano, Thomas Nilsson, Hans Törnqvist, Z. Elekes, D. Körper, M. Matsumoto, M. L. Cortés, Naohito Inabe, Yosuke Kondo, T. Murakami, D. S. Ahn, K. Yoneda, Marina Petri, Atsumi Saito, T. Tomai, Tomohiro Uesaka, M. Parlog, Simon Lindberg, V. Panin, M. Marques, D. Cortina-Gil, T. Isobe, H. Chae, S. K. Kim, István Kuti, Jongwon Hwang, Herbert A. Simon, P. Schrock, Naoki Fukuda, T. Kobayashi, J. Kahlbow, H. Suzuki, D. Sohler, H. Yamada, I. Syndikus, K. Boretzky, Q. Deshayes, P. Doornenbal, I. Gaparic, Stefanos Paschalis, 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), 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), SAMURAI20, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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
Physics, Superconductivity, History, Radionuclide, Spectrum analyzer, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 010305 fluids & plasmas, Computer Science Applications, Education, Nuclear physics, Stack (abstract data type), 0103 physical sciences, Physics::Accelerator Physics, ddc:530, Neutron, Radio isotopes, 010306 general physics, Ground state, Nuclear Experiment, Beam (structure)
Abstract

27th International Nuclear Physics Conference, INPC2019, Glasgow, United Kingdom, 29 Jul 2019 - 2 Aug 2019; Journal of physics / Conference series 1643(1), 012106 (2020). doi:10.1088/1742-6596/1643/1/012106, Published by IOP Publ., Bristol

Published
2020
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9. Nuclear astrophysics with radioactive ions at FAIR

Author

R Reifarth, S Altstadt, K Göbel, T Heftrich, M Heil, A Koloczek, C Langer, R Plag, M Pohl, K Sonnabend, M Weigand, T Adachi, F Aksouh, J Al-Khalili, M AlGarawi, S AlGhamdi, G Alkhazov, N Alkhomashi, H Alvarez-Pol, R Alvarez-Rodriguez, V Andreev, B Andrei, L Atar, T Aumann, V Avdeichikov, C Bacri, S Bagchi, C Barbieri, S Beceiro, C Beck, C Beinrucker, G Belier, D Bemmerer, M Bendel, J Benlliure, G Benzoni, R Berjillos, D Bertini, C Bertulani, S Bishop, N Blasi, T Bloch, Y Blumenfeld, A Bonaccorso, K Boretzky, A Botvina, A Boudard, P Boutachkov, I Boztosun, A Bracco, S Brambilla, J Briz Monago, M Caamano, C Caesar, F Camera, E Casarejos, W Catford, J Cederkall, B Cederwall, M Chartier, A Chatillon, M Cherciu, L Chulkov, P Coleman-Smith, D Cortina-Gil, F Crespi, R Crespo, J Cresswell, M Csatlós, F Déchery, B Davids, T Davinson, V Derya, P Detistov, P Diaz Fernandez, D DiJulio, S Dmitry, D Doré, J Dueñas, E Dupont, P Egelhof, I Egorova, Z Elekes, J Enders, J Endres, S Ershov, O Ershova, B Fernandez-Dominguez, A Fetisov, E Fiori, A Fomichev, M Fonseca, L Fraile, M Freer, J Friese, M G. Borge, D Galaviz Redondo, S Gannon, U Garg, I Gasparic, L Gasques, B Gastineau, H Geissel, R Gernhäuser, T Ghosh, M Gilbert, J Glorius, P Golubev, A Gorshkov, A Gourishetty, L Grigorenko, J Gulyas, M Haiduc, F Hammache, M Harakeh, M Hass, M Heine, A Hennig, A Henriques, R Herzberg, M Holl, A Ignatov, A Ignatyuk, S Ilieva, M Ivanov, N Iwasa, B Jakobsson, H Johansson, B Jonson, P Joshi, A Junghans, B Jurado, G Körner, N Kalantar, R Kanungo, A Kelic-Heil, K Kezzar, E Khan, A Khanzadeev, O Kiselev, M Kogimtzis, D Körper, S Kräckmann, T Kröll, R Krücken, A Krasznahorkay, J Kratz, D Kresan, T Krings, A Krumbholz, S Krupko, R Kulessa, S Kumar, N Kurz, E Kuzmin, M Labiche, K Langanke, I Lazarus, T Le Bleis, C Lederer, A Lemasson, R Lemmon, V Liberati, Y Litvinov, B Löher, J Lopez Herraiz, G Münzenberg, J Machado, E Maev, K Mahata, D Mancusi, J Marganiec, M Martinez Perez, V Marusov, D Mengoni, B Million, V Morcelle, O Moreno, A Movsesyan, E Nacher, M Najafi, T Nakamura, F Naqvi, E Nikolski, T Nilsson, C Nociforo, P Nolan, B Novatsky, G Nyman, A Ornelas, R Palit, S Pandit, V Panin, C Paradela, V Parkar, S Paschalis, P Pawłowski, A Perea, J Pereira, C Petrache, M Petri, S Pickstone, N Pietralla, S Pietri, Y Pivovarov, P Potlog, A Prokofiev, G Rastrepina, T Rauscher, G Ribeiro, M Ricciardi, A Richter, C Rigollet, K Riisager, A Rios, C Ritter, T Rodriguez Frutos, J Rodriguez Vignote, M Röder, C Romig, D Rossi, P Roussel-Chomaz, P Rout, S Roy, P Söderström, M Saha Sarkar, S Sakuta, M Salsac, J Sampson, J Sanchez, del Rio Saez, J Sanchez Rosado, S Sanjari, P Sarriguren, A Sauerwein, D Savran, C Scheidenberger, H Scheit, S Schmidt, C Schmitt, L Schnorrenberger, P Schrock, R Schwengner, D Seddon, B Sherrill, A Shrivastava, S Sidorchuk, J Silva, H Simon, E Simpson, P Singh, D Slobodan, D Sohler, M Spieker, D Stach, E Stan, M Stanoiu, S Stepantsov, P Stevenson, F Strieder, L Stuhl, T Suda, K Sümmerer, B Streicher, J Taieb, M Takechi, I Tanihata, J Taylor, O Tengblad, G Ter-Akopian, S Terashima, P Teubig, R Thies, M Thoennessen, T Thomas, J Thornhill, G Thungstrom, J Timar, Y Togano, U Tomohiro, T Tornyi, J Tostevin, C Townsley, W Trautmann, T Trivedi, S Typel, E Uberseder, J Udias, T Uesaka, L Uvarov, Z Vajta, P Velho, V Vikhrov, M Volknandt, V Volkov, P von Neumann-Cosel, M von Schmid, A Wagner, F Wamers, H Weick, D Wells, L Westerberg, O Wieland, M Wiescher, C Wimmer, K Wimmer, J S Winfield, M Winkel, P Woods, R Wyss, D Yakorev, M Yavor, J Zamora Cardona, I Zartova, T Zerguerras, M Zgura, A Zhdanov, M Zhukov, M Zieblinski, A Zilges, K Zuber, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Helmholtz International Center for FAIR, German Research Foundation, Helmholtz Association, SCOAP, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

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

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

Published
2016
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10. Performance of timing resistive plate chambers with relativistic neutrons from 300 to 1500 MeV

Author

M. Pohl, Rene Reifarth, B. Löher, L. Lopes, Daniel Stach, G. Rastrepina, M. Holl, M. Heine, J. Marganiec, D. M. Rossi, Daniel Bemmerer, J. Fruehauf, A. Kelic-Heil, P. Schrock, J. Silva, Deniz Savran, D. Galaviz, Stefanos Paschalis, Andreas Martin Heinz, Mario Weigand, M. Traxler, P. Teubig, Z. Elekes, P. Velho, Marek Palka, R. Thies, Jorge Machado, Marina Petri, L. Cartegni, D. Körper, Tanja Heftrich, C. Caesar, V. Panin, J. Isaak, A. Henriques, Simon Lindberg, C. Lederer, A. Blanco, A. Pereira, P. Fonte, Thomas Nilsson, S. Altstadt, Kathrin Göbel, F. Wamers, T. P. Reinhardt, Thomas Aumann, J. Gerbig, G. Ickert, Heiko Scheit, Mikael Mårtensson, A. Ignatov, Igor Gašparić, Håkan T Johansson, Fredrik Strannerdahl, Ralf Plag, E. Fiori, K. Boretzky, R. Ferreira Marques, L. Atar, J. Adamczewski-Musch, P. Cabanelas, H. Simon, Matthias Heil, M. Röder, Andreas Wagner, and Alexandre Charpy

Subjects
Resistive touchscreen, Materials science, business.industry, Aucun, Float glass, Glass electrode, Neutron temperature, law.invention, Time of flight, Nuclear magnetic resonance, Optics, law, Electrode, Neutron, business, Instrumentation, Mathematical Physics, Beam (structure)
Abstract

A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic neutrons produced from a deuteron beam of varying energy (300 to 1500 AMeV) in experiment S406 at GSI, Darmstad, Germany. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Measurements of the time of flight jitter of neutrons, in the mentioned energy range, point to a contribution of the resistive plate chamber in the order of 150 ps, independent of the neutron energy.

Published
2015
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11. Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV

Author

D. M. Rossi, Mario Weigand, Simon Lindberg, Rene Reifarth, T. P. Reinhardt, J. Isaak, M. Heine, Z. Elekes, A. Henriques, R. Thies, Daniel Bemmerer, Jorge Machado, Thomas Nilsson, J. Marganiec, Marina Petri, G. Ickert, B. Löher, L. Lopes, L. Cartegni, D. Körper, A. Blanco, P. Fonte, Stefanos Paschalis, Heiko Scheit, F. Wamers, Daniel Stach, M. Traxler, E. Fiori, A. Ignatov, Thomas Aumann, Håkan T Johansson, J. Gerbig, G. Rastrepina, J. Silva, Fredrik Strannerdahl, J. Fruehauf, Mikael Mårtensson, Ralf Plag, Andreas Martin Heinz, A. Kelic-Heil, Tanja Heftrich, A. Pereira, D. Galaviz, K. Boretzky, P. Teubig, Kathrin Göbel, Igor Gašparić, P. Schrock, V. Panin, S. Altstadt, H. Simon, M. Pohl, L. Atar, P. Velho, P. Cabanelas, Matthias Heil, J. Adamczewski-Musch, M. Röder, Andreas Wagner, Alexandre Charpy, M. Holl, Deniz Savran, R. Ferreira Marques, Marek Palka, C. Lederer, and C. Caesar

Subjects
Range (particle radiation), Resistive touchscreen, Materials science, business.industry, Electrical engineering, Float glass, STRIPS, 7. Clean energy, Glass electrode, Particle detector, law.invention, Optics, law, Electrode, business, Instrumentation, Mathematical Physics, Beam (structure)
Abstract

A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm2 area.

Published
2015
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12. Magicity versus Superfluidity around ^{28}O viewed from the Study of ^{30}F.

Author

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

Abstract

The neutron-rich unbound fluorine isotope ^{30}F_{21} has been observed for the first time by measuring its neutron decay at the SAMURAI spectrometer (RIBF, RIKEN) in the quasifree proton knockout reaction of ^{31}Ne nuclei at 235  MeV/nucleon. The mass and thus one-neutron-separation energy of ^{30}F has been determined to be S_{n}=-472±58(stat)±33(sys)  keV from the measurement of its invariant-mass spectrum. The absence of a sharp drop in S_{n}(^{30}F) shows that the "magic" N=20 shell gap is not restored close to ^{28}O, which is in agreement with our shell-model calculations that predict a near degeneracy between the neutron d and fp orbitals, with the 1p_{3/2} and 1p_{1/2} orbitals becoming more bound than the 0f_{7/2} one. This degeneracy and reordering of orbitals has two potential consequences: ^{28}O behaves like a strongly superfluid nucleus with neutron pairs scattering across shells, and both ^{29,31}F appear to be good two-neutron halo-nucleus candidates.

Published
2024
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13. Publisher Correction: First observation of 28 O.

Author

Kondo Y, Achouri NL, Falou HA, Atar L, Aumann T, Baba H, Boretzky K, Caesar C, Calvet D, Chae H, Chiga N, Corsi A, Delaunay F, Delbart A, Deshayes Q, Dombrádi Z, Douma CA, Ekström A, Elekes Z, Forssén C, Gašparić I, Gheller JM, Gibelin J, Gillibert A, Hagen G, Harakeh MN, Hirayama A, Hoffman CR, Holl M, Horvat A, Horváth Á, Hwang JW, Isobe T, Jiang WG, Kahlbow J, Kalantar-Nayestanaki N, Kawase S, Kim S, Kisamori K, Kobayashi T, Körper D, Koyama S, Kuti I, Lapoux V, Lindberg S, Marqués FM, Masuoka S, Mayer J, Miki K, Murakami T, Najafi M, Nakamura T, Nakano K, Nakatsuka N, Nilsson T, Obertelli A, Ogata K, de Oliveira Santos F, Orr NA, Otsu H, Otsuka T, Ozaki T, Panin V, Papenbrock T, Paschalis S, Revel A, Rossi D, Saito AT, Saito TY, Sasano M, Sato H, Satou Y, Scheit H, Schindler F, Schrock P, Shikata M, Shimizu N, Shimizu Y, Simon H, Sohler D, Sorlin O, Stuhl L, Sun ZH, Takeuchi S, Tanaka M, Thoennessen M, Törnqvist H, Togano Y, Tomai T, Tscheuschner J, Tsubota J, Tsunoda N, Uesaka T, Utsuno Y, Vernon I, Wang H, Yang Z, Yasuda M, Yoneda K, and Yoshida S

Published
2023
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14. First observation of 28 O.

Author

Kondo Y, Achouri NL, Falou HA, Atar L, Aumann T, Baba H, Boretzky K, Caesar C, Calvet D, Chae H, Chiga N, Corsi A, Delaunay F, Delbart A, Deshayes Q, Dombrádi Z, Douma CA, Ekström A, Elekes Z, Forssén C, Gašparić I, Gheller JM, Gibelin J, Gillibert A, Hagen G, Harakeh MN, Hirayama A, Hoffman CR, Holl M, Horvat A, Horváth Á, Hwang JW, Isobe T, Jiang WG, Kahlbow J, Kalantar-Nayestanaki N, Kawase S, Kim S, Kisamori K, Kobayashi T, Körper D, Koyama S, Kuti I, Lapoux V, Lindberg S, Marqués FM, Masuoka S, Mayer J, Miki K, Murakami T, Najafi M, Nakamura T, Nakano K, Nakatsuka N, Nilsson T, Obertelli A, Ogata K, de Oliveira Santos F, Orr NA, Otsu H, Otsuka T, Ozaki T, Panin V, Papenbrock T, Paschalis S, Revel A, Rossi D, Saito AT, Saito TY, Sasano M, Sato H, Satou Y, Scheit H, Schindler F, Schrock P, Shikata M, Shimizu N, Shimizu Y, Simon H, Sohler D, Sorlin O, Stuhl L, Sun ZH, Takeuchi S, Tanaka M, Thoennessen M, Törnqvist H, Togano Y, Tomai T, Tscheuschner J, Tsubota J, Tsunoda N, Uesaka T, Utsuno Y, Vernon I, Wang H, Yang Z, Yasuda M, Yoneda K, and Yoshida S

Abstract

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10 -21  s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28 O and 27 O through their decay into 24 O and four and three neutrons, respectively. The 28 O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers 1,2 , it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27 O and 28 O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28 O from a 29 F beam is consistent with it not exhibiting a closed N = 20 shell structure., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2023
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15. Observation of a correlated free four-neutron system.

Author

Duer M, Aumann T, Gernhäuser R, Panin V, Paschalis S, Rossi DM, Achouri NL, Ahn D, Baba H, Bertulani CA, Böhmer M, Boretzky K, Caesar C, Chiga N, Corsi A, Cortina-Gil D, Douma CA, Dufter F, Elekes Z, Feng J, Fernández-Domínguez B, Forsberg U, Fukuda N, Gasparic I, Ge Z, Gheller JM, Gibelin J, Gillibert A, Hahn KI, Halász Z, Harakeh MN, Hirayama A, Holl M, Inabe N, Isobe T, Kahlbow J, Kalantar-Nayestanaki N, Kim D, Kim S, Kobayashi T, Kondo Y, Körper D, Koseoglou P, Kubota Y, Kuti I, Li PJ, Lehr C, Lindberg S, Liu Y, Marqués FM, Masuoka S, Matsumoto M, Mayer J, Miki K, Monteagudo B, Nakamura T, Nilsson T, Obertelli A, Orr NA, Otsu H, Park SY, Parlog M, Potlog PM, Reichert S, Revel A, Saito AT, Sasano M, Scheit H, Schindler F, Shimoura S, Simon H, Stuhl L, Suzuki H, Symochko D, Takeda H, Tanaka J, Togano Y, Tomai T, Törnqvist HT, Tscheuschner J, Uesaka T, Wagner V, Yamada H, Yang B, Yang L, Yang ZH, Yasuda M, Yoneda K, Zanetti L, Zenihiro J, and Zhukov MV

Abstract

A long-standing question in nuclear physics is whether chargeless nuclear systems can exist. To our knowledge, only neutron stars represent near-pure neutron systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron systems has been an ongoing quest for several decades 1 , with a particular focus on the four-neutron system called the tetraneutron, resulting in only a few indications of its existence so far 2-4 , leaving the tetraneutron an elusive nuclear system for six decades. Here we report on the observation of a resonance-like structure near threshold in the four-neutron system that is consistent with a quasi-bound tetraneutron state existing for a very short time. The measured energy and width of this state provide a key benchmark for our understanding of the nuclear force. The use of an experimental approach based on a knockout reaction at large momentum transfer with a radioactive high-energy 8 He beam was key., (© 2022. The Author(s).)

Published
2022
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16. Pairing Forces Govern Population of Doubly Magic ^{54}Ca from Direct Reactions.

Author

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

Abstract

Direct proton-knockout reactions of ^{55}Sc at ∼220  MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of ^{54}Ca were investigated through γ-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological internucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the ^{55}Sc ground state with states in ^{54}Ca. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of ^{55}Sc, valence proton removals populated predominantly the ground state of ^{54}Ca. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.

Published
2021
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17. Extending the Southern Shore of the Island of Inversion to ^{28}F.

Author

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

Abstract

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230  MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6)  keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60)  keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

Published
2020
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