{"paper":{"title":"Backward spin polarizability $\\gamma_\\pi$ of the proton","license":"","headline":"","cross_cats":["hep-ex","hep-ph"],"primary_cat":"nucl-ex","authors_text":"A.I. L'vov, A. Natter, A. Thomas, B. Seitz, F. Smend, F. Wissmann, F. Zapadtka, G. Caselotti, H.-J. Arends, J. Ahrens, J.C. McGeorge, K. Kossert, M. Camen, M.I. Levchuk, M. Schumacher, O. Jahn, P.D. Harty, P. Grabmayr, P. Jennenwein, R. Beck, R. Kondratiev, V. Lisin, V. Olmos de Le\\'on, W. Weihofen","submitted_at":"2001-12-28T11:45:24Z","abstract_excerpt":"Using the Mainz $48 cm {\\O}\\times 64 cm$ NaI(Tl) detector and the segmented G\\\"ottingen recoil detector SENECA in coincidence, Compton scattering by the proton at $\\theta^{lab}_\\gamma = 136^\\circ$ has been measured at MAMI (Mainz) in the energy range from 200 to 470 MeV. The new data confirm the previous observation that there is a systematic discrepancy between MAMI and LEGS (Brookhaven) data leading to different spin polarizabilities $\\gamma_\\pi = - 38.7 \\pm 1.8$ and $-27.2 \\pm 3.1$ $(\\times 10^{-4}fm^4)$, respectively."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"nucl-ex/0112015","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"}