Sector-Resolved Bayesian Model Averaging for DESI-Era Cosmology
Abstract
We present a quotient-space Bayesian formulation for DESI-era anomaly interpretation. Given a pattern-labeled catalog with map i↦ Act(i), the induced posterior p(Act| D), sector inclusion probabilities Pα, co-activation probabilities Pαβ, and grouped Bayes factors Bα(D) are exact summaries over predeclared physical activation events. Pairwise comparisons such as lcdm versus wacdm 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.
Versions
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BibTeX
@misc{turyshev2026sectorresolved,
title = {{Sector-Resolved Bayesian Model Averaging for DESI-Era Cosmology}},
author = {Slava G. Turyshev},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.09045},
eprint = {2609.09045},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.09045},
}
RIS
TY - UNPB
TI - Sector-Resolved Bayesian Model Averaging for DESI-Era Cosmology
AU - Slava G. Turyshev
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.09045
UR - https://arxiv.org/abs/2609.09045
AB - We present a quotient-space Bayesian formulation for DESI-era anomaly interpretation. Given a pattern-labeled catalog with map i↦ Act(i), the induced posterior p(Act| D), sector inclusion probabilities P_α, co-activation probabilities P_αβ, and grouped Bayes factors B_α(D) are exact summaries over predeclared physical activation events. Pairwise comparisons such as lcdm versus wacdm 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.
ER -