Secondary-vertex pointing conventions and an exploratory displaced-muon quarkonium sample in CMS Open Data

Independent CMS Open Data validation study of public Run-2016 data. Five complete files with 423,326 secondary-vertex rows demonstrate that the stored legacy SV_pAngle uses the inward PV-SV vector, opposite to the branch documentation. Geometry, producer source and 688 full-precision CMS vertex comparisons support a documentation-only correction. A separate scan of 57 DoubleMuon G/H files (94,148,416 raw entries) retains 444 displaced-muon quarkonium candidates, including 135 with exact MiniAOD vertex-daughter membership checks. Known Upsilon structures are observed, but the frozen final mass model fails its adequacy check (bootstrap p = 0.018), and purity, production origin and efficiency-corrected rates remain unresolved. No new particle, Standard Model discrepancy or new production measurement is claimed. Prepared with substantial OpenAI Codex assistance under Friedrich Otto Krone’s direction. No independent specialist review is claimed. This is an independent preprint, not an official CMS Collaboration result or a CERN-endorsed publication. Files include the manuscript, editable source and evidence ledger, and the complete retained reproduction archive. Original CMS data are credited through their CERN Open Data DOIs. Third-party data and software retain their original rights and license terms.