{"paper":{"title":"Systematic Study of Two-Pion Production in NN Collisions -- from Single-Baryon to Di-Baryon Excitations","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Pricking, E. Doroshkevich, F. Kren, G. J. Wagner (for the CELSIUS/WASA Collaboration), H. Clement, M. Bashkanov, O. Khakimova, T. Skorodko","submitted_at":"2010-01-29T17:51:47Z","abstract_excerpt":"The two-pion production in nucleon-nucleon collisions has been studied by exclusive and kinematically complete experiments from threshold up to $T_p$ = 1.36 GeV at CELSIUS-WASA. At near-threshold energies the total and differential distributions for the $\\pi^+\\pi^-$ and $\\pi^0\\pi^0$ channels are dominated by Roper excitation and its decay into $N\\sigma$ and $\\Delta\\pi$ channels. At beam energies $T_p >$ 1.1 GeV the $\\Delta\\Delta$ excitation governs the two-pion production process. In the $\\pi^+\\pi^+$ channel evidence is found for the excitation of a higher-lying I=3/2 resonance, favorably the "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1001.5446","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"}