{"paper":{"title":"Measurement of di-muons from 400 GeV/c protons interacting in a thick molybdenum/tungsten target","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Bμμ σ(J/ψ)/A = (1.18 ± 0.04 ± 0.10) nb/nucleon for 0.3 < y_cm < 0.6 in thick target, consistent with NA50 thin-target result within errors and limiting cascade contributions to <32%.","cross_cats":[],"primary_cat":"hep-ex","authors_text":"The SHiP Collaboration","submitted_at":"2026-04-04T09:28:09Z","abstract_excerpt":"Di-muon events emanating from a replica of the SHiP target at the CERN SPS (with a 400 GeV/c proton beam) contain a clear signal of \\jpsi production. The target consisted of 13 interaction lengths of molybdenum and tungsten, followed by a 2.4m iron hadron absorber. The di-muon rate is in reasonable agreement with \\MC based on Pythia v8. However, the $J/\\psi$ rate observed in the data is much lower than predicted by the Monte Carlo simulation, which is advantageous for SHiP since muons with a large $p_T$ are more difficult to deflect by the active muon shield. For the center of mass rapidity ($"},"claims":{"count":3,"items":[{"kind":"strongest_claim","text":"For 0.3 < y_cm < 0.6, Bμμ σ(J/ψ)/A = (1.18 ± 0.04 ± 0.10) nb/nucleon; within systematic errors no significant enhancement due to secondary production of J/ψ inside the target is observed, with upper limit of possible contributions from cascade collisions of <32%.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the Pythia v8 Monte Carlo accurately models both primary production and the effects of the thick target geometry, and that differences in target thickness and acceptance between this measurement and NA50 do not introduce unaccounted biases in the comparison.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Bμμ σ(J/ψ)/A = (1.18 ± 0.04 ± 0.10) nb/nucleon for 0.3 < y_cm < 0.6 in thick target, consistent with NA50 thin-target result within errors and limiting cascade contributions to <32%.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"}],"snapshot_sha256":"9082f25f01ffff6e5338806f76f3e15bc723b8e48436247652282f22c77fa6f8"},"source":{"id":"2604.03661","kind":"arxiv","version":2},"verdict":{"id":"3110481a-9a68-440b-a716-1e0e65e558a2","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-13T17:37:05.559432Z","strongest_claim":"For 0.3 < y_cm < 0.6, Bμμ σ(J/ψ)/A = (1.18 ± 0.04 ± 0.10) nb/nucleon; within systematic errors no significant enhancement due to secondary production of J/ψ inside the target is observed, with upper limit of possible contributions from cascade collisions of <32%.","one_line_summary":"Bμμ σ(J/ψ)/A = (1.18 ± 0.04 ± 0.10) nb/nucleon for 0.3 < y_cm < 0.6 in thick target, consistent with NA50 thin-target result within errors and limiting cascade contributions to <32%.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the Pythia v8 Monte Carlo accurately models both primary production and the effects of the thick target geometry, and that differences in target thickness and acceptance between this measurement and NA50 do not introduce unaccounted biases in the comparison.","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.03661/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"}