{"paper":{"title":"A two-neutron halo is unveiled in $^{29}$F","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["nucl-th"],"primary_cat":"nucl-ex","authors_text":"A. Estrad\\'e, A. O. Macchiavelli, A. Prochazka, C. Scheidenberger, D. S. Ahn, D. Steppenbeck, D. Suzuki, F. Browne, G. Hagen, G. R. Jansen, H. Baba, H. Geissel, H. J. Ong, H. Sakurai, H. Suzuki, H. Takeda, I. Murray, K. Behr, K. Itahashi, K. Wimmer, K. Yoshida, M. Holl, M. L. Cort\\'es, M. Takechi, N. Fukuda, N. Iwasa, N. Tsunoda, P. Doornenbal, P. Schrock, R. Kanungo, R. Taniuchi, S. Bagchi, S. Chen, S. J. Novario, S. Kaur, S. Momiyama, S. Paschalis, S. Takeuchi, S. Y. Matsumoto, T. Nakamura, T. Otsuka, T. Papenbrock, T. Suzuki, W. G. Jiang, W. Horiuchi, Y. K. Tanaka, Y. Shimizu","submitted_at":"2020-05-19T14:42:46Z","abstract_excerpt":"We report the measurement of reaction cross sections ($\\sigma_R^{\\rm ex}$) of $^{27,29}$F with a carbon target at RIKEN. The unexpectedly large $\\sigma_R^{\\rm ex}$ and derived matter radius identify $^{29}$F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the $2p_{3/2}$ orbital, thereby vanishing the shell closure associated with the neutron number $N = 20$. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2005.09492","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2005.09492/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}