{"paper":{"title":"A blind spot in transverse BAO calibration","arxiv_id":"2608.20296","primary_cat":"astro-ph.CO","submitted_at":"2026-08-20T17:36:09+00:00","version_compiled":"v1"},"notice":"Every quoted sentence is the authors' text from the arXiv listing abstract. Labels and probabilities are the outputs of classifier-1.13.0 on the question bank abstract-p1-20260923, exactly as returned. No sentence in this record was written by a language model.","schema":"pith.compiled-record/v0","status":"compiled","abstract":{"source":"arXiv listing abstract v1","sentences":[{"i":0,"p":0.78,"id":"s0","own":false,"role":"background","text":"Transverse baryon acoustic oscillation (BAO) measurements are increasingly used for cosmological inference, and carry a calibration that no such inference can constrain.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.09,"main_claim_p":0.26,"quantitative":false,"quantitative_p":0.06,"role_probabilities":{"gap":0.21,"method":0.0,"result":0.0,"background":0.78,"limitation":0.01,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":1,"p":0.56,"id":"s1","own":false,"role":"background","text":"A constant error in the transverse BAO scale is exactly degenerate with the combination $r_{\\rm d} h$: it leaves the goodness of fit unchanged and the recovered parameters plausible, and is therefore invisible to any analysis that uses these measurements alone.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.21,"main_claim_p":0.39,"quantitative":false,"quantitative_p":0.11,"role_probabilities":{"gap":0.35,"method":0.0,"result":0.01,"background":0.56,"limitation":0.03,"future_work":0.0,"contribution":0.0,"interpretation":0.05}},{"i":2,"p":0.56,"id":"s2","own":false,"role":"method","text":"The radial BAO sector removes this degeneracy, supplying $D_{\\rm M}/r_{\\rm d}$ by integration without reference to $H_0$ or to any model for the expansion rate.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.16,"main_claim_p":0.11,"quantitative":false,"quantitative_p":0.06,"role_probabilities":{"gap":0.02,"method":0.56,"result":0.0,"background":0.33,"limitation":0.0,"future_work":0.0,"contribution":0.05,"interpretation":0.04}},{"i":3,"p":0.57,"id":"s3","own":false,"role":"method","text":"In flat Friedmann--Lema\\^itre--Robertson--Walker (FLRW) geometry the relation between the two sectors is an identity, so the sound horizon and the dark-energy equation of state cancel as well.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.22,"main_claim_p":0.08,"quantitative":false,"quantitative_p":0.08,"role_probabilities":{"gap":0.0,"method":0.57,"result":0.0,"background":0.25,"limitation":0.0,"future_work":0.0,"contribution":0.03,"interpretation":0.15}},{"i":4,"p":0.87,"id":"s4","own":true,"role":"method","text":"An integrated form of this identity reduces the consistency test to a straight line, whose slope measures a relative transverse calibration $\\varepsilon$.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.52,"main_claim_p":0.11,"quantitative":false,"quantitative_p":0.11,"role_probabilities":{"gap":0.0,"method":0.87,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.13,"interpretation":0.0}},{"i":5,"p":0.95,"id":"s5","own":false,"role":"interpretation","text":"A departure from $\\varepsilon = 1$ cannot be produced by any dark-energy model, nor by spatial curvature: it indicates an inconsistency in the measurement chain rather than in the cosmology.","hedge":{"p":0.95,"label":"asserted"},"own_p":0.28,"main_claim_p":0.36,"quantitative":true,"quantitative_p":0.7,"role_probabilities":{"gap":0.0,"method":0.02,"result":0.01,"background":0.01,"limitation":0.0,"future_work":0.0,"contribution":0.01,"interpretation":0.95}},{"i":6,"p":0.83,"id":"s6","own":true,"role":"result","text":"We apply the test to the two main SDSS transverse BAO compilations, which give $\\varepsilon = 1.073 \\pm 0.021$ and $1.021 \\pm 0.029$.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.93,"main_claim_p":0.14,"quantitative":true,"quantitative_p":0.98,"role_probabilities":{"gap":0.0,"method":0.02,"result":0.83,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.15,"interpretation":0.0}},{"i":7,"p":0.98,"id":"s7","own":true,"role":"result","text":"The first differs from unity at $3.8\\sigma$ using the published independent errors, while the second is consistent with unity.","hedge":{"p":0.96,"label":"asserted"},"own_p":0.85,"main_claim_p":0.15,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.98,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.02}},{"i":8,"p":1.0,"id":"s8","own":true,"role":"result","text":"The two compilations themselves differ by $(5.4 \\pm 1.4)\\%$, or $3.9\\sigma$, and the offset is constant in redshift.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.89,"main_claim_p":0.19,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":1.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":9,"p":0.65,"id":"s9","own":false,"role":"interpretation","text":"The test provides a direct diagnostic for current and future angular BAO measurements.","hedge":{"p":0.99,"label":"asserted"},"own_p":0.37,"main_claim_p":0.13,"quantitative":false,"quantitative_p":0.04,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.27,"contribution":0.08,"interpretation":0.65}}]},"compiled":{"main_claim":{"p":0.37,"text":"The two compilations themselves differ by $(5.4 \\pm 1.4)\\%$, or $3.9\\sigma$, and the offset is constant in redshift.","location":"abstract s8","hedge_strength":{"p":1.0,"label":"asserted"}},"provenance":{"route":{"via":"TypeSafe API","model":"classifier-1.13.0","endpoint":"https://api.typesafe.ai/v1/systemone","provider":"TypeSafe"},"packing":"one request per 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