Sector-resolved Bayesian model averaging for DESI-Era cosmology
Phys. Rev. D 114, 063505 – Published 3 September, 2026
DOI: https://doi.org/10.1103/1x24-4mrv
Abstract
We present a quotient-space Bayesian formulation for DESI-Era anomaly interpretation. Given a pattern-labeled catalog with map , the induced posterior , sector inclusion probabilities , coactivation probabilities , and grouped Bayes factors are exact summaries over predeclared physical activation events. Pairwise comparisons such as versus remain ordinary Bayes-factor tests between specified families; the quotient construction addresses the coarser question of which physical sector carries posterior support when different sectors are represented by unequal numbers of catalog elements. We derive a sector-resolved DESI-CMB-SN likelihood specification for late-time background, early-time ruler, supernova calibration, perturbation, and gravitational-wave propagation sectors. The construction includes an Alcock-Paczynski/isotropic-scale BAO decomposition, a pure-ruler projection, analytic marginalization of low-rank supernova calibration modes, Fisher-normalized sector priors, inactive-sector leakage tests, log-evidence uncertainty propagation, and prior/sector-partition diagnostics. The result is a quantitative procedure for reporting model-comparison support at the level of physically interpretable sectors.