{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2011:OCXUG3E4EFWHXTL62J7V7U2JXY","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":"f99416c826a38a1fba919bce0ef2d08bffe1bafb3706b58fecc6955934b3ba79","cross_cats_sorted":["hep-ph","nucl-ex"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-ex","submitted_at":"2011-08-13T02:32:01Z","title_canon_sha256":"159b44fecbbc38efb5abaeed15db27b113844fd16f9270851e869fe413837c80"},"schema_version":"1.0","source":{"id":"1108.2750","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1108.2750","created_at":"2026-05-18T02:00:54Z"},{"alias_kind":"arxiv_version","alias_value":"1108.2750v2","created_at":"2026-05-18T02:00:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1108.2750","created_at":"2026-05-18T02:00:54Z"},{"alias_kind":"pith_short_12","alias_value":"OCXUG3E4EFWH","created_at":"2026-05-18T12:26:37Z"},{"alias_kind":"pith_short_16","alias_value":"OCXUG3E4EFWHXTL6","created_at":"2026-05-18T12:26:37Z"},{"alias_kind":"pith_short_8","alias_value":"OCXUG3E4","created_at":"2026-05-18T12:26:37Z"}],"graph_snapshots":[{"event_id":"sha256:f5bc5ed1a0950f2a96b56a120e5ea7d3ed00509d5c9d83186791d72f960f1250","target":"graph","created_at":"2026-05-18T02:00:54Z","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"},"paper":{"abstract_excerpt":"We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $\\alpha'$ to electrons. Such a particle $A'$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $A'\\to e^+e^-$ reaction, and set an upper limit of $\\alpha'/\\alpha \\simeq 10^{-6}$. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and","authors_text":"A.Barbieri, A.Camsonne, A.Gasparian, A.Kelleher, A.Odian, A.Shahinyan, B.Sawatzky, B.Wojtsekhowski, C.Field, C.W.deJager, D.Anez, D.Walz, D.W.Higinbotham, E.Folts, E.Jensen, E.Long, E.Piasetzky, I.Pomerantz, J.Beacham, J.Bono, J.Donaghy, J.Gomez, J.Huang, J.Jaros, J.J.LeRose, J.Mammei, J.McDonald, J.-O.Hansen, J.R.Boyce, J.Segal, J.Zhang, K.Allada, K.Bartlett, K.Cranmer, K.Moffeit, L.Selvy, M.Graham, M.Khandaker, M.M.Dalton, M.Oriunno, M.Paolone, N.Goeckner-Wald, N.Liyanage, N.Toro, P.Brindza, P.Markowitz, P.Schuster, R.Essig, R.Lindgren, R.Michaels, R.Partridge, R.Subedi, S.Abrahamyan, S.Iqbal, S.Mayilyan, S.Riordan, S.Stepanyan, T.Averett, T.Holmstrom, T.Maruyama, V.Maxwell, V.Nelyubin, V.Sulkosky, Y.Qiang, Y.Roblin, Z.Ahmed","cross_cats":["hep-ph","nucl-ex"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-ex","submitted_at":"2011-08-13T02:32:01Z","title":"Search for a new gauge boson in the $A'$ Experiment (APEX)"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1108.2750","kind":"arxiv","version":2},"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":"sha256:100cff68cde1354566d0a7a8f20b876e705a6af95c615e3a2a2e8e131f1cda7a","target":"record","created_at":"2026-05-18T02:00:54Z","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":"f99416c826a38a1fba919bce0ef2d08bffe1bafb3706b58fecc6955934b3ba79","cross_cats_sorted":["hep-ph","nucl-ex"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-ex","submitted_at":"2011-08-13T02:32:01Z","title_canon_sha256":"159b44fecbbc38efb5abaeed15db27b113844fd16f9270851e869fe413837c80"},"schema_version":"1.0","source":{"id":"1108.2750","kind":"arxiv","version":2}},"canonical_sha256":"70af436c9c216c7bcd7ed27f5fd349be1e0b904cf927c5640f632c5f2cde9542","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"70af436c9c216c7bcd7ed27f5fd349be1e0b904cf927c5640f632c5f2cde9542","first_computed_at":"2026-05-18T02:00:54.401255Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:00:54.401255Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"gegX5i3n7YQ17iJL7eJMY0J711r1jQnyuSVR+mE5/srAg/+j+/5DCbbFUBCWVyG41N+L/HtgPQkCqaXuX9R5BQ==","signature_status":"signed_v1","signed_at":"2026-05-18T02:00:54.401924Z","signed_message":"canonical_sha256_bytes"},"source_id":"1108.2750","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:100cff68cde1354566d0a7a8f20b876e705a6af95c615e3a2a2e8e131f1cda7a","sha256:f5bc5ed1a0950f2a96b56a120e5ea7d3ed00509d5c9d83186791d72f960f1250"],"state_sha256":"843106933605aad3bef41950bc13aee1240df9c5ee21ecc298be796981eca83d"}