{"paper":{"title":"The $Z_c$ structures in a coupled-channels model","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"David R. Entem, Francisco Fernandez, Jorge Segovia, Pablo G. Ortega","submitted_at":"2018-08-02T16:56:14Z","abstract_excerpt":"The $Z_{c}(3900)^\\pm/Z_c(3885)^\\pm$ and $Z_{c}(4020)^\\pm$ are two charmonium-like structures discovered in the $\\pi J/\\psi$ and $D^\\ast\\bar D^{(\\ast)}+h.c.$ invariant mass spectra. Their nature is puzzling due to their charge, which forces its minimal quark content to be $c\\bar c u\\bar d$ ($c\\bar c d\\bar u$). Thus, it is necessary to explore four-quark systems in order to understand their inner structure. Additionally, their strong coupling to channels such as $\\pi J/\\psi$ and the closeness of their mass to $D^\\ast\\bar D^{(\\ast)}$-thresholds stimulates both a molecular interpretation or a coup"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1808.00914","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"}