{"paper":{"title":"Photoproduction of pi0pi0 and pi0pi+-pairs off the proton from threshold to the second resonance region","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Braghieri, A. Knezevic, A. Kulbardis, A. Nikolaev, A. Polonski, A. Starostin, A. Thomas, B. Boillat, B. Krusche, B. M. K. Nefkens, C. M. Tarbert, D. Branford, D. Hornidge, D. I. Glazier, D. Krambrich, D. Mekterovic, D. M. Manley, D. P. Watts, D. Sober, E. Heid, E. J. Downie, F. Pheron, F. Zehr, G. Rosner, H. J. Arends, I. Jaegle, I. J. D. MacGregor, I. Supek, J. Ahrens, J. Brudvik, J. C. McGeorge, J. R. M. Annand, J. W. Price, K. Livingston, L. V. Fil'kov, M. Korolija, M. Kotulla, M. Lang, M. Martinez, M. Ostrick, M. Rost, M. Unverzagt, O. Jahn, P. Aguar, P. Drexler, P. Pedroni, R. Beck, R. F. B. Codling, R. Gregor, R. Kondratiev, S. Cherepnya, S. Lugert, S. Prakhov, S. Schumann, Th. Walcher, T. Rostomyan, V. Bekrenev, V. Lisin, V. L. Kashevarov, V. Metag, W. J. Briscoe, Y. Maghrbi","submitted_at":"2012-07-10T14:17:39Z","abstract_excerpt":"Precise total cross-sections and invariant-mass distributions have been measured for photoproduction of pion pairs off the proton producing $p\\pi^0\\pi^0$ and $n\\pi^+\\pi^0$ final states from the threshold region up to 800 MeV incident photon energy. Additionally, beam helicity asymmetries have been measured in the second resonance region (550 MeV - 820 MeV). The experiment was performed at the tagged photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4$\\pi$ solid-angle electromagnetic calorimeter. The results are much more precise than "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.2361","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"}