{"paper":{"title":"Mass Measurements Demonstrate a Strong N =28 Shell Gap in Argon","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Estrad\\'e, A. Gade, B. A. Brown, C. Langer, D. Bazin, D. J. Morrissey, D. Shapira, F. Montes, H. Chung, H. Schatz, J. Browne, J. F. Carpino, J. Pereira, J. R. Winkelbauer, J. Schatz, J. Stevens, J. Yurkon, K. Smith, K. Wimmer, M. Famiano, M. Mato\\v{s}, M. Scott, O. Tarasov, R. G. T. Zegers, R. H. Cyburt, S. Ahn, S. George, S. Towers, W. Mittig, W. Tan, Z. Meisel","submitted_at":"2015-10-06T09:42:13Z","abstract_excerpt":"We present results from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. We report the first mass measurements of 48Ar and 49Ar and find atomic mass excesses of -22.28(31) MeV and -17.8(1.1) MeV, respectively. These masses provide strong evidence for the closed shell nature of neutron number N=28 in argon, which is therefore the lowest even-Z element exhibiting the N=28 closed shell. The resulting trend in binding-energy differences, which probes the strength of the N=28 shell, compares favorably with shellmodel "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1510.01501","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"}