First Observation of B20 and B21

Autor: T. Murakami, Tomio Kubo, Hiroshi Suzuki, Yosuke Kondo, Y. Shimizu, D. Kameda, K. Takahashi, Thomas Aumann, Q. Deshayes, Yasuhiro Togano, M Vandebrouck, P. Doornenbal, K. Muto, T. Isobe, T. Motobayashi, A. Navin, Hiroshi Sato, T. Kobayashi, Jongwon Hwang, S. K. Kim, J. Bonnard, N. A. Orr, D. Kanno, Hideaki Otsu, Y. Satou, A. G. Tuff, Naoki Fukuda, R. Minakata, Nagao Kobayashi, Julien Gibelin, Nicolas Michel, K. Yoneda, Franck Delaunay, Takashi Nakamura, F. M. Marqués, H. Baba, Ryuki Tanaka, S. Ogoshi, Satoshi Takeuchi, S. Nishi, N. L. Achouri, Noritsugu Nakatsuka, J.H. Lee, Daichi Murai, Naohito Inabe, H. Takeda, S. Leblond, T. Nakashima
Rok vydání: 2018
Předmět:
Zdroj: Physical Review Letters. 121
ISSN: 1079-7114
0031-9007
Popis: The most neutron-rich boron isotopes ^{20}B and ^{21}B have been observed for the first time following proton removal from ^{22}N and ^{22}C at energies around 230 MeV/nucleon. Both nuclei were found to exist as resonances which were detected through their decay into ^{19}B and one or two neutrons. Two-proton removal from ^{22}N populated a prominent resonancelike structure in ^{20}B at around 2.5 MeV above the one-neutron decay threshold, which is interpreted as arising from the closely spaced 1^{-},2^{-} ground-state doublet predicted by the shell model. In the case of proton removal from ^{22}C, the ^{19}B plus one- and two-neutron channels were consistent with the population of a resonance in ^{21}B 2.47±0.19 MeV above the two-neutron decay threshold, which is found to exhibit direct two-neutron decay. The ground-state mass excesses determined for ^{20,21}B are found to be in agreement with mass surface extrapolations derived within the latest atomic-mass evaluations.
Databáze: OpenAIRE
Externí odkaz: