{"paper":{"title":"Cross section of the reaction $e^+ e^- \\to \\pi^+\\pi^-\\pi^+\\pi^- $ below 1 GeV at CMD-2","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"CMD-2 collaboration","submitted_at":"1999-12-10T09:24:37Z","abstract_excerpt":"Using 3.07 ${pb}^{-1}$ of data collected in the energy range 0.60-0.97 GeV by CMD-2, about 150 events of the process $\\epm \\to \\pch$ have been selected. The energy dependence of the cross section agrees with the assumption of the $a_1(1260) \\pi$ intermediate state which is dominant above 1 GeV. For the first time \\fourpi events are observed at the $\\rho$ meson energy. Under the assumption that all these events come from the $\\rho$ meson decay, the value of the cross section at the $\\rho$ meson peak corresponds to the following decay width:\n  \\Gamma(\\rho^0 \\to \\fourpi) = (2.8 \\pm 1.4 \\pm 0.5) {"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ex/9912020","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"}