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

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. CorsiH. 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, M. Holl, A. Horvat, Horváth, T. Isobe, J. Kahlbow, N. Kalantar-Nayestanaki, S. Kawase, K. Kisamori, T. Kobayashi, D. Körper, S. Koyama, I. Kuti, V. Lapoux, 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, K. Yoneda

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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.

Original languageEnglish
Article number138038
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume843
Early online date27 Jun 2023
DOIs
Publication statusPublished - 10 Aug 2023

Bibliographical note

Funding Information:
We express our gratitude to the RIKEN Nishina accelerator staff for providing the 48 Ca beam and to the BigRIPS team for tuning the secondary beams. H.W acknowledges the support by MEXT KAKENHI Grant Nos. JP21H04465 and JP18H05404 . This work was supported partially by MEXT KAKENHI Grant No. JP16H02179 . J.A.T acknowledges the support of the United Kingdom Science and Technology Facilities Council (STFC) Grant No. ST/V001108/1 . A.P. is supported by grants CEX2020-001007-S funded by MCIN/AEI/10.13039/501100011033 and PID2021-127890NB-I00 . K.O acknowledges the support by MEXT KAKENHI Grant Nos. JP21H00125 and JP21H04975 . The LPC-Caen group wished to acknowledge support from the Franco-Japanese LIA-International Associated Laboratory for Nuclear Structure Problems as well as the French ANR-14-CE33-0022-02 EXPAND. This material is in part based upon work supported by the U.S. Department of Energy Office of Science , Office of Nuclear Physics, under Contracts No. DE-AC02-06CH11357 (Argonne). This work was in part supported by the Institute for Basic Science ( IBS-R031-D1 ) in Republic of Korea. This work is partly supported from the National Research, Development and Innovation Fund of Hungary via Project No. K128947 and TKP2021-NKTA-42 . This work was supported by the National Science Foundation , USA under Grants No. PHY-1102511 .

Publisher Copyright:
© 2023 The Author(s)

Keywords

  • In-beam γ-ray spectroscopy
  • Island of inversion
  • Shell evolution

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