{"paper":{"title":"Production of the excited charm mesons D_1 and D^*_2 at HERA","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"ZEUS Collaboration","submitted_at":"2012-08-22T10:30:33Z","abstract_excerpt":"The production of the excited charm mesons D_1(2420) and D^*_2(2460) in ep collisions has been measured with the ZEUS detector at HERA using an integrated luminosity of 373 pb^{-1}. The masses of the neutral and charged states, the widths of the neutral states, and the helicity parameter of D_1(2420)^{0} were determined and compared with other measurements and with theoretical expectations. The measured helicity parameter of the D^0_1 allows for some mixing of S- and D-waves in its decay to D^{*\\pm}\\pi^{\\mp}. The result is also consistent with a pure D-wave decay. Ratios of branching fractions"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1208.4468","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"}