{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2020:EEPWFL52WJKGWIL7IUQ7D5BKWX","short_pith_number":"pith:EEPWFL52","canonical_record":{"source":{"id":"2007.06079","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"nucl-ex","submitted_at":"2020-07-12T20:04:32Z","cross_cats_sorted":[],"title_canon_sha256":"faffd4eed9e05d5a54585fb5294541a1c49eef74f3dbc8ad73e250928aae49d4","abstract_canon_sha256":"ffbc6b9eb04ea3b4ab67c72613f9ee8659646ddd681644b07f4b94334776b660"},"schema_version":"1.0"},"canonical_sha256":"211f62afbab2546b217f4521f1f42ab5c3367c69570b831be0659fb776c0b058","source":{"kind":"arxiv","id":"2007.06079","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2007.06079","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"arxiv_version","alias_value":"2007.06079v1","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2007.06079","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_12","alias_value":"EEPWFL52WJKG","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_16","alias_value":"EEPWFL52WJKGWIL7","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_8","alias_value":"EEPWFL52","created_at":"2026-07-05T01:26:21Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2020:EEPWFL52WJKGWIL7IUQ7D5BKWX","target":"record","payload":{"canonical_record":{"source":{"id":"2007.06079","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"nucl-ex","submitted_at":"2020-07-12T20:04:32Z","cross_cats_sorted":[],"title_canon_sha256":"faffd4eed9e05d5a54585fb5294541a1c49eef74f3dbc8ad73e250928aae49d4","abstract_canon_sha256":"ffbc6b9eb04ea3b4ab67c72613f9ee8659646ddd681644b07f4b94334776b660"},"schema_version":"1.0"},"canonical_sha256":"211f62afbab2546b217f4521f1f42ab5c3367c69570b831be0659fb776c0b058","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T01:26:21.508754Z","signature_b64":"pbw+Xa2ZaG2Jv3TU+NiJM6d4ZE6Znxxy69H07NJ33+hhKj+KEtkXhC08ld/cOUnaQSha4D2oh7g01h7v4UuxDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"211f62afbab2546b217f4521f1f42ab5c3367c69570b831be0659fb776c0b058","last_reissued_at":"2026-07-05T01:26:21.508284Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T01:26:21.508284Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2007.06079","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T01:26:21Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"S1//eRM/amlDJEWcw/PlDCEBqYgZ0W81l7pILoIquhyDCcz1R/yXG/2m9FPHRgds8Bob0TXKiadKffBQhge9Ag==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-20T19:06:02.518030Z"},"content_sha256":"648bcdbd4dbc8663bb7f1c268dd3428b314e96b23da281f0524b3f7ea88cc18b","schema_version":"1.0","event_id":"sha256:648bcdbd4dbc8663bb7f1c268dd3428b314e96b23da281f0524b3f7ea88cc18b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2020:EEPWFL52WJKGWIL7IUQ7D5BKWX","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Helicity-dependent cross sections for the photoproduction of $\\pi^0$ pairs from nucleons","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Braghieri, A. Denig, A. Fix, A. K{\\\"a, A. Lazarev, A. Mushkarenkov, A. Neganov, A. Neiser, A. Polonski, A. Powell, A. Sarty, A.S. Dolzhikov, A. Thiel, A. Thomas, B. Krusche, C. Collicott, C. Mullen, C. Sfienti, D. Ghosal, D.G. Middleton, D. Gurevich, 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. Huber, G. Reicherz, G. Ron, H.J. Arends, I. Gorodnov, I.I. Strakovsky, I.J.D. MacGregor, I. Keshelashvili, I. Supek, J.R.M. Annand, J. Wettig, K. Livingston, K. Spieker, L.A. Zana, ld, L. Heijkenskj{\\\"o, L. Witthauer, M. Bashkanov, M. Biroth, M. Dieterle, M. G{\\\"u, M. Korolija, M. Oberle, M. Ostrick, M. Thiel, M. Unverzagt, M. Wolfes, N. Borisov, N.K. Walford, nther, O. Steffen, P. Achenbach, P. Adlarson, P. Aguar Bartolome, P.B. Otte, P. Drexler, P. Pedroni, P.P. Martel, R. Beck, R. Kondratiev, R. Miskimen, S. Abt, S. Costanza, ser, S. Gardner, S. Kay, S. Lutterer, S.N. Prakhov, S. Wagner, T. Rostomyan, T. Strub, V. Lisin, V.L. Kashevarov, V. Metag, V. Sokhoyan, W. Gradl, W.J. Briscoe, W. Meyer, Yu.A. Usov, Z. Ahmed","submitted_at":"2020-07-12T20:04:32Z","abstract_excerpt":"The double-polarization observable $E$ and helicity-dependent cross sections $\\sigma_{1/2}$, $\\sigma_{3/2}$ have been measured for the photoproduction of $\\pi^0$ pairs off quasi-free protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost $4\\pi$ covering calorimeter. The results reveal for the first time the helicity- and isospin-dependent st"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2007.06079","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2007.06079/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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T01:26:21Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"0jGqsxfMz3Epz/SMTnIWhSGrJ3bwnnXr3vohpFFCUZyNa2jDLu9dR8CBUoq+26NjMp7CZHuc2oLimU9v9R+kCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-20T19:06:02.518546Z"},"content_sha256":"705e3e0ecab1500b1ad048433223938a62493d4c50df66a8e8ae1d656eb9d9de","schema_version":"1.0","event_id":"sha256:705e3e0ecab1500b1ad048433223938a62493d4c50df66a8e8ae1d656eb9d9de"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/bundle.json","state_url":"https://pith.science/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-20T19:06:02Z","links":{"resolver":"https://pith.science/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX","bundle":"https://pith.science/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/bundle.json","state":"https://pith.science/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/state.json","well_known_bundle":"https://pith.science/.well-known/pith/EEPWFL52WJKGWIL7IUQ7D5BKWX/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:EEPWFL52WJKGWIL7IUQ7D5BKWX","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"ffbc6b9eb04ea3b4ab67c72613f9ee8659646ddd681644b07f4b94334776b660","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"nucl-ex","submitted_at":"2020-07-12T20:04:32Z","title_canon_sha256":"faffd4eed9e05d5a54585fb5294541a1c49eef74f3dbc8ad73e250928aae49d4"},"schema_version":"1.0","source":{"id":"2007.06079","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2007.06079","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"arxiv_version","alias_value":"2007.06079v1","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2007.06079","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_12","alias_value":"EEPWFL52WJKG","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_16","alias_value":"EEPWFL52WJKGWIL7","created_at":"2026-07-05T01:26:21Z"},{"alias_kind":"pith_short_8","alias_value":"EEPWFL52","created_at":"2026-07-05T01:26:21Z"}],"graph_snapshots":[{"event_id":"sha256:705e3e0ecab1500b1ad048433223938a62493d4c50df66a8e8ae1d656eb9d9de","target":"graph","created_at":"2026-07-05T01:26:21Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2007.06079/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"The double-polarization observable $E$ and helicity-dependent cross sections $\\sigma_{1/2}$, $\\sigma_{3/2}$ have been measured for the photoproduction of $\\pi^0$ pairs off quasi-free protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost $4\\pi$ covering calorimeter. The results reveal for the first time the helicity- and isospin-dependent st","authors_text":"A. Braghieri, A. Denig, A. Fix, A. K{\\\"a, A. Lazarev, A. Mushkarenkov, A. Neganov, A. Neiser, A. Polonski, A. Powell, A. Sarty, A.S. Dolzhikov, A. Thiel, A. Thomas, B. Krusche, C. Collicott, C. Mullen, C. Sfienti, D. Ghosal, D.G. Middleton, D. Gurevich, 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. Huber, G. Reicherz, G. Ron, H.J. Arends, I. Gorodnov, I.I. Strakovsky, I.J.D. MacGregor, I. Keshelashvili, I. Supek, J.R.M. Annand, J. Wettig, K. Livingston, K. Spieker, L.A. Zana, ld, L. Heijkenskj{\\\"o, L. Witthauer, M. Bashkanov, M. Biroth, M. Dieterle, M. G{\\\"u, M. Korolija, M. Oberle, M. Ostrick, M. Thiel, M. Unverzagt, M. Wolfes, N. Borisov, N.K. Walford, nther, O. Steffen, P. Achenbach, P. Adlarson, P. Aguar Bartolome, P.B. Otte, P. Drexler, P. Pedroni, P.P. Martel, R. Beck, R. Kondratiev, R. Miskimen, S. Abt, S. Costanza, ser, S. Gardner, S. Kay, S. Lutterer, S.N. Prakhov, S. Wagner, T. Rostomyan, T. Strub, V. Lisin, V.L. Kashevarov, V. Metag, V. Sokhoyan, W. Gradl, W.J. Briscoe, W. Meyer, Yu.A. Usov, Z. Ahmed","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"nucl-ex","submitted_at":"2020-07-12T20:04:32Z","title":"Helicity-dependent cross sections for the photoproduction of $\\pi^0$ pairs from nucleons"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2007.06079","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:648bcdbd4dbc8663bb7f1c268dd3428b314e96b23da281f0524b3f7ea88cc18b","target":"record","created_at":"2026-07-05T01:26:21Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"ffbc6b9eb04ea3b4ab67c72613f9ee8659646ddd681644b07f4b94334776b660","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"nucl-ex","submitted_at":"2020-07-12T20:04:32Z","title_canon_sha256":"faffd4eed9e05d5a54585fb5294541a1c49eef74f3dbc8ad73e250928aae49d4"},"schema_version":"1.0","source":{"id":"2007.06079","kind":"arxiv","version":1}},"canonical_sha256":"211f62afbab2546b217f4521f1f42ab5c3367c69570b831be0659fb776c0b058","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"211f62afbab2546b217f4521f1f42ab5c3367c69570b831be0659fb776c0b058","first_computed_at":"2026-07-05T01:26:21.508284Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T01:26:21.508284Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"pbw+Xa2ZaG2Jv3TU+NiJM6d4ZE6Znxxy69H07NJ33+hhKj+KEtkXhC08ld/cOUnaQSha4D2oh7g01h7v4UuxDQ==","signature_status":"signed_v1","signed_at":"2026-07-05T01:26:21.508754Z","signed_message":"canonical_sha256_bytes"},"source_id":"2007.06079","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:648bcdbd4dbc8663bb7f1c268dd3428b314e96b23da281f0524b3f7ea88cc18b","sha256:705e3e0ecab1500b1ad048433223938a62493d4c50df66a8e8ae1d656eb9d9de"],"state_sha256":"cf5f1ca661ecf6ce5b2512478692f6d8e36f68d5b452c5538df1e9aab7d5c751"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ug1goYdw4HZwU775C/uBiYAzR2SlrNcElKkorFNNhHaBNLiyGV4FPfiexC7/vias7FBfXr4BXEabcTLurl0aBA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-20T19:06:02.522624Z","bundle_sha256":"17d52410643c87598e85f16b282b7c9f12dcd0db6b252474e54441a490c847a5"}}