Dependence on BAO tracer families
Individual run · T-f293cd83d197
Public summary of an internal test, not yet independently validated or published.
Question investigated
Does the preference for evolving dark energy in Pantheon+ and Union3 persist when the low- and high-redshift BAO groups are excluded?
Test conditions
For each supernova compilation (Pantheon+ and Union3), the fit is repeated with one BAO group excluded at a time. The groups contain measurements at z = (0.295, 0.51, 0.706); (0.934, 1.321, 1.484, 2.33). The supernova data and comparison criteria are held fixed. The comparison tracks fit quality and the direction of the preference in dark-energy parameters.
Result
A large share of the fit improvement was concentrated in one tracer group for the data and grouping examined. This concentration does not identify its cause or demonstrate a specific systematic effect.
Physical interpretation
Excluding tracer groups reveals where the fit improvement is concentrated. The test does not determine the cause of that concentration.