{"paper":{"title":"Observation of $Z_c(3900)$ both by BESIII and Belle","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"Zhiqing Liu","submitted_at":"2013-11-04T16:39:57Z","abstract_excerpt":"Using $525$ pb$^{-1}$ data collected with the BESIII detector at $e^+e^-$ central-of-mass energy 4.26 GeV, the BESIII Collaboration observed a charged charmoniumlike state $Z_c(3900)\\to\\pi^{\\pm}J/\\psi$ with mass $M[Z_c(3900)]=3899.0\\pm 3.6 \\pm 4.9$ MeV/c$^2$, and width $\\Gamma[Z_c(3900)]=46\\pm 10 \\pm 20$ MeV. The significance of this state was estimated to be $>8\\sigma$ in all kinds of systematic tests. Using $967$ fb$^{-1}$ data recorded by the Belle detector on or near $\\Upsilon(nS)$, n=1, 2, $\\cdots$, 5 resonances, the $e^+e^- \\to \\pi^+\\pi^-J/\\psi$ process has been studied through initial-s"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1311.0762","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"}