{"paper":{"title":"Chiral interactions and superfluidity in the calcium isotopic chain","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Bayesian calibration of third-order chiral interactions leaves neutron pairing gaps in calcium isotopes too small.","cross_cats":[],"primary_cat":"nucl-th","authors_text":"A. Ekstr\\\"om, A. Scalesi, C. Forss\\'en, G. Hagen","submitted_at":"2026-01-28T19:00:02Z","abstract_excerpt":"We perform ab initio calculations of three-point mass differences in the odd- and even-mass $^{39-49}$Ca isotopes to probe nuclear superfluidity via empirical neutron pairing gaps. We also quantify the sensitivity of those gaps to the parameters of the interaction at mean-field level. Recent studies employing accurate chiral nuclear interactions have found these gaps to be too small. We show that experimental values can be reproduced at mean-field level by substantially increasing the attraction of the singlet $S$-wave two-nucleon contact interaction, but doing so induces an unphysical bound s"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We find that pairing gaps remain largely unaffected, leaving the explanation of nuclear superfluidity as a future task for improved many-body modeling and refined interactions at higher chiral orders.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that mean-field level calculations combined with third-order chiral interactions and the chosen Bayesian posterior sampling are sufficient to conclude that the discrepancy originates outside the interaction calibration.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Neutron pairing gaps in calcium isotopes are insensitive to variations in third-order chiral interactions, indicating that nuclear superfluidity requires improved many-body modeling or higher-order terms.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Bayesian calibration of third-order chiral interactions leaves neutron pairing gaps in calcium isotopes too small.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"4c37e9561438729d617d00e08cf4c065056442eb85c33901ec7b1786be3eef72"},"source":{"id":"2601.20942","kind":"arxiv","version":2},"verdict":{"id":"0fd1a9c8-a30e-4735-84e4-4169c7d366af","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T09:41:30.505227Z","strongest_claim":"We find that pairing gaps remain largely unaffected, leaving the explanation of nuclear superfluidity as a future task for improved many-body modeling and refined interactions at higher chiral orders.","one_line_summary":"Neutron pairing gaps in calcium isotopes are insensitive to variations in third-order chiral interactions, indicating that nuclear superfluidity requires improved many-body modeling or higher-order terms.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that mean-field level calculations combined with third-order chiral interactions and the chosen Bayesian posterior sampling are sufficient to conclude that the discrepancy originates outside the interaction calibration.","pith_extraction_headline":"Bayesian calibration of third-order chiral interactions leaves neutron pairing gaps in calcium isotopes too small."},"references":{"count":54,"sample":[{"doi":"","year":1959,"title":"L. N. Cooper, R. L. Mills, and A. M. Sessler, Possible Su- perfluidity of a System of Strongly Interacting Fermions, Phys. Rev.114, 1377 (1959)","work_id":"ba012de4-bf66-4955-b491-dc09876020cd","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2003,"title":"D. J. Dean and M. Hjorth-Jensen, Pairing in nuclear sys- tems: from neutron stars to finite nuclei, Rev. Mod. Phys. 75, 607 (2003)","work_id":"1cd31d65-55a9-47b9-aab5-e5b909cb2faf","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2001,"title":"T. Duguet, P. Bonche, P.-H. Heenen, and J. Meyer, Pair- ing correlations. i. description of odd nuclei in mean-field theories, Phys. Rev. C65, 014310 (2001)","work_id":"c30e116a-9728-4d52-a870-5855ea6e2a61","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2001,"title":"T. Duguet, P. Bonche, P.-H. Heenen, and J. Meyer, Pair- ing correlations. ii. microscopic analysis of odd-even mass staggering in nuclei, Phys. Rev. C65, 014311 (2001)","work_id":"1e763a92-e684-4bf3-89ed-c0a862e833cb","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2020,"title":"T. Duguet, B. Bally, and A. Tichai, Zero-pairing limit of Hartree-Fock-Bogoliubov reference states, Phys. Rev. C 102, 054320 (2020)","work_id":"c49d03b1-70d2-4359-a846-6e95e15cd724","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":54,"snapshot_sha256":"4f9acfdb5e0e69e5826267a5d24212ea3be68cf1bf9a39755aca539259e04783","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"d2d0a4c4c1282ef749cb66c3ec743aaab168b2a89f7ba70f0489945772e44d10"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}