{"paper":{"title":"$a_1(1420)$ resonance as a tetraquark state and its isospin partner","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","nucl-ex"],"primary_cat":"hep-ph","authors_text":"Er-Liang Cui, Hua-Xing Chen, Shi-Lin Zhu, T. G. Steele, Wei Chen, Xiang Liu","submitted_at":"2015-03-09T18:14:30Z","abstract_excerpt":"We systematically construct tetraquark currents of $I^GJ^{PC}=1^-1^{++}$ and classify them into types $\\mathbf{A}$ (antisymmetric), $\\mathbf{S}$ (symmetric) and $\\mathbf{M}$ (mixed), based on flavor symmetries of diquarks and antidiquarks composing the tetra quark currents. We use tetraquark currents of type $\\mathbf{M}$ to perform QCD sum rule analyses, and find a tetraquark current $\\eta^M_{5\\mu}$ with quark contents $q s\\bar q \\bar s$($q=u$ or $d$) leading to a mass of $1.44 \\pm 0.08$ GeV consistent with the $a_1(1420)$ state recently observed by the COMPASS collaboration. Our results suppo"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1503.02597","kind":"arxiv","version":2},"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"}