CHRONON-1 (Stage 00): Loop-closure null tests and an endpoint-only constraint from the ROCIT campaign (March 2022)

CHRONON-1 — Stage 00 is a fully reproducible, integrity-first analysis of public optical-clock comparisons from the ROCIT campaign (March 2022), conducted in a preregistration-style framework. The objective is deliberately narrow and conservative:(1) stress-test the internal consistency of the network using loop-closure (triangle) null tests, and(2) report a single conservative bound from an endpoint-only residual, without model fitting or speculative interpretation. What this release contains Network integrity (primary result):Loop-closure / triangle non-closure null tests on Ntri = 10 independent triangles. Robustness matrix:Nruns = 32 analysis variants (aggregation, trimming, HAC lag choices, veto gates) to ensure the verdict is not a fragile pipeline artefact. Endpoint-only prototype (exploratory):Post-GR residual defined on an inter-laboratory same-species baseline, included for operational definition only. Main Stage 00 result (locked endpoint) No statistically significant non-closure is observed on the tested loops(primary verdict: Run 00; multiplicity control: Bonferroni, m = 10). Conservative global integrity bound:BoundStage00 (UB) = 4.613 × 10⁻¹⁷ Worst-case informative triangle:INRIM_ITYb1 – PTB_In_CombKnoten – SYRTE_Sr2(worst run: Run 21) Limits / non-claims (explicit) Stage 00 does not claim a detection.Public geodesy (U, sigma_U) is not standardized across sites in the ROCIT archive; therefore any physical “signal” interpretation is intentionally out of scope at this stage. Data & attribution Input data: ROCIT Consortium public archive (Zenodo; see Related Works / References).This work is an independent analysis and is not affiliated with the ROCIT consortium. Reproducibility Every reported number is traceable to a machine-generated artifact (report.pdf) and a pinned public input archive.Cryptographic checksums, a reproduction manifest (MANIFEST.json), and all generated figures and tables are provided as replication artifacts.