{"paper":{"title":"Measurement of the two-photon exchange contribution in elastic $ep$ scattering at VEPP-3","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","hep-ph"],"primary_cat":"nucl-ex","authors_text":"A. V. Gramolin, B. A. Lazarenko, D. K. Toporkov, D. M. Nikolenko, H. de Vries, I. A. Rachek, J. Arrington, L. M. Barkov, N. Yu. Muchnoi, R. A. Golovin, R. J. Holt, R. Sh. Sadykov, S. A. Zevakov, S. I. Mishnev, V. F. Dmitriev, V. N. Stibunov, V. N. Zhilich, V. V. Gauzshtein, V. V. Kaminsky, V. V. Neufeld, Yu. V. Shestakov","submitted_at":"2011-12-22T16:34:13Z","abstract_excerpt":"We report on the status of the Novosibirsk experiment on a precision measurement of the ratio $R$ of the elastic $e^+ p$ and $e^- p$ scattering cross sections. Such measurements determine the two-photon exchange effect in elastic electron-proton scattering. The experiment is conducted at the VEPP-3 storage ring using a hydrogen internal gas target. The ratio $R$ is measured with a beam energy of 1.6 GeV (electron/positron scattering angles are $\\theta = 55 \\div 75^{\\circ}$ and $\\theta = 15 \\div 25^{\\circ}$) and 1 GeV ($\\theta = 65 \\div 105^{\\circ}$). We briefly describe the experimental method"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1112.5369","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"}