{"paper":{"title":"Unambiguous Identification of the Second 2+ State in 12C and the Structure of the Hoyle State","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR","nucl-th","physics.ins-det"],"primary_cat":"nucl-ex","authors_text":"A. Breskin, B. Bromberger, C. Sun, H.R. Weller, J.M. Mueller, K. Tittelmeier, M. Gai, M.W. Ahmed, NCCU, PTB, S.C. Stave, S.S. Henshaw, Th. Delbar, TUNL, UCL, V. Dangendorf, Weizmann, W.R. Zimmerman, Yale), Y.K. Wu (UConn","submitted_at":"2013-03-18T17:25:31Z","abstract_excerpt":"The second 2+ state of 12C, predicted over fifty years ago as an excitation of the Hoyle state, has been unambiguously identified using the 12C(g,a_0)8Be reaction. The alpha particles produced by the photodisintegration of 12C were detected using an Optical Time Projection Chamber (O-TPC). Data were collected at beam energies between 9.1 and 10.7 MeV using the intense nearly mono-energetic gamma-ray beams at the HIgS facility. The measured angular distributions determine the cross section and the E1-E2 relative phases as a function of energy leading to an unambiguous identification of the seco"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1303.4326","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"}