{"paper":{"title":"Measurement of the Helicity Asymmetry $E$ for the reaction $ \\gamma p\\to \\pi^0 p$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Gridnev, A. Sarantsev, A. Thiel, A.V. Anisovich, A. Wilson, A. Winnebeck, B. Krusche, CBELSA/TAPS collaboration: M. Gottschall, Ch. Hammann, Ch. Honisch, Ch. Schmidt, Ch. Wendel, D. Bayadilov, D. Elsner, D. Piontek, D. Walther, D. Werthm\\\"uller, E. Gutz, E. Klempt, F. Afzal, F. Dietz, F. Frommberger, F. Klein, G. Reicherz, H. Dutz, H. Eberhardt, H. Kalinowsky, H. Schmieden, H. van Pee, I. Keshelashvili, I. Lopatin, J. Hannappel, J. Hartmann, J. M\\\"uller, J. M\\\"ullers, K. Fornet-Ponse, K. Koop, K. Makonyi, K. Spieker, K.-Th. Brinkmann, L. Witthauer, M. Bichow, M. Dieterle, M. Gr\\\"uner, M. Kube, M. Lang, M. Nanova, M. Urban, Ph. Hoffmeister, P. Klassen, P. Mahlberg, R. Beck, R. Ewald, R. Novotny, S. Kammer, St. Friedrich, T. Jude, T. Rostomyan, T. Seifen, U. Thoma, U. Wiedner, V. Crede, V. Metag, V. Nikonov, V. Sokhoyan, W. Hillert, W. Meyer, Y. Wunderlich","submitted_at":"2019-04-29T11:24:00Z","abstract_excerpt":"A measurement of the double-polarization observable $E$ for the reaction $\\gamma p\\to \\pi^0 p$ is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from $E_\\gamma =600$~MeV to $E_\\gamma =2310$~MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave an"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.12560","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"}