{"paper":{"title":"Spin polarizabilities of the proton by measurement of Compton double-polarization observables","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A.B. Lazarev, A.B. Neganov, A. Braghieri, A. Denig, A. K\\\"aser, A. Mushkarenkov, A. Neiser, A. Polonski, A. Powell, A. Rajabi, A. Sarty, A. Thiel, A. Thomas, B. Krusche, C. Collicott, C. Mullen, C.S. Akondi, C. Sfienti, D. Glowa, D. Hamilton, D. Hornidge, D.I. Glazier, D.M. Manley, D. Paudyal, D.P. Watts, D. Werthm\\\"uller, E.J. Downie, E. Mornacchi, F. Afzal, F. Cividini, G.M. Gurevich, G.M. Huber, G. Reicherz, G. Ron, H.J. Arends, I. Gorodnov, I.I. Strakovsky, I.J.D. MacGregor, I. Keshelashvili, I. Supek, J. Mancell, J.M. Linturi, J.R.M. Annand, J. Wettig, K. Livingston, K. Spieker, L. Heijkenskj\\\"old, L. Witthauer, L. Zana (A2 Collaboration), M. Bashkanov, M. Biroth, M. Dieterle, M.H. Sikora, M.I. Ferretti-Bondy, M. Korolija, M. Oberle, M. Ostrick, M. Thiel, M. Unverzagt, M. Wolfes, N.K. Walford, N.S. Borisov, O. Steffen, P. Achenbach, P. Adlarson, P.B. Otte, P. Drexler, P. Pedroni, P.P. Martel, R. Beck, R. Kondratiev, R. MacRae, R. Miskimen, S. Abt, S. Costanza, S. Gardner, S. Garni, S. G\\\"unther, S. Kay, S. Lutterer, S.N. Prakhov, S. Wagner, Th. Strub, T. Rostomyan, V. Lisin, V.L. Kashevarov, V. Metag, V. Sokhoyan, W. Gradl, W.J. Briscoe, W. Meyer, Yu.A. Usov, Z. Ahmed","submitted_at":"2019-09-04T18:09:50Z","abstract_excerpt":"The Compton double-polarization observable $\\Sigma_{2z}$ has been measured for the first time in the $\\Delta(1232)$ resonance region using a circularly polarized photon beam incident on a longitudinally polarized target at the Mainz Microtron. This paper reports these results, together with the model-dependent extraction of four proton spin polarizabilities from fits to additional asymmetry data using dispersion relation and chiral perturbation theory calculations, with the former resulting in: $\\gamma_{E1E1} = -3.18 \\pm 0.52$, $\\gamma_{M1M1} = 2.98 \\pm 0.43$, $\\gamma_{E1M2} = -0.44 \\pm 0.67$ "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1909.02032","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/1909.02032/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}