{"paper":{"title":"First observation of 20B and 21B","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["nucl-th"],"primary_cat":"nucl-ex","authors_text":"A.G. Tuff, A. Navin, D. Kameda, D. Kanno, D. Murai, F. Delaunay, F.M. Marqu\\'es, H. Baba, H. Otsu, H. Sato, H. Suzuki, H. Takeda, J. Bonnard, J. Gibelin, J. Lee, J.W. Hwang, K. Muto, K. Takahashi, K. Yoneda, M. Vandebrouck, N.A. Orr, N. Fukuda, N. Inabe, N. Kobayashi, N.L. Achouri, N. Michel, N. Nakatsuka, P. Doornenbal, Q. Deshayes, R. Minakata, R. Tanaka, S. Kim, S. Leblond, S. Nishi, S. Ogoshi, S. Takeuchi, T. Aumann, T. Isobe, T. Kobayashi, T. Kubo, T. Motobayashi, T. Murakami, T. Nakamura, T. Nakashima, Y. Kondo, Y. Satou, Y. Shimizu, Y. Togano","submitted_at":"2019-01-02T17:33:51Z","abstract_excerpt":"The most neutron-rich boron isotopes 20B and 21B have been observed for the first time following proton removal from 22N and 22C at energies around 230 MeV/nucleon. Both nuclei were found to exist as resonances which were detected through their decay into 19B and one or two neutrons. Two-proton removal from 22N populated a prominent resonance-like structure in 20B 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 22C, the 19B plus one- and t"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1901.00455","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}