On dataset tensions and signatures of new cosmological physics

Fuente: arXiv
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Autores principales: Cortês, Marina, Liddle, Andrew R.
Formato: Preprint
Publicado: 2023
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author Cortês, Marina
Liddle, Andrew R.
author_facet Cortês, Marina
Liddle, Andrew R.
contents Can new cosmic physics be uncovered through tensions amongst datasets? Tensions in parameter determinations amongst different types of cosmological observation, especially the `Hubble tension' between probes of the expansion rate, have been invoked as possible indicators of new physics, requiring extension of the $Λ$CDM paradigm to resolve. Within a fully Bayesian framework, we show that the standard tension metric gives only part of the updating of model probabilities, supplying a data co-dependence term that must be combined with the Bayes factors of individual datasets. This shows that, on its own, a reduction of dataset tension under an extension to $Λ$CDM is insufficient to demonstrate that the extended model is favoured. Any analysis that claims evidence for new physics {\it solely} on the basis of alleviating dataset tensions should be considered incomplete and suspect. We describe the implications of our results for the interpretation of the Hubble tension.
format Preprint
id arxiv_https___arxiv_org_abs_2309_03286
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On dataset tensions and signatures of new cosmological physics
Cortês, Marina
Liddle, Andrew R.
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Can new cosmic physics be uncovered through tensions amongst datasets? Tensions in parameter determinations amongst different types of cosmological observation, especially the `Hubble tension' between probes of the expansion rate, have been invoked as possible indicators of new physics, requiring extension of the $Λ$CDM paradigm to resolve. Within a fully Bayesian framework, we show that the standard tension metric gives only part of the updating of model probabilities, supplying a data co-dependence term that must be combined with the Bayes factors of individual datasets. This shows that, on its own, a reduction of dataset tension under an extension to $Λ$CDM is insufficient to demonstrate that the extended model is favoured. Any analysis that claims evidence for new physics {\it solely} on the basis of alleviating dataset tensions should be considered incomplete and suspect. We describe the implications of our results for the interpretation of the Hubble tension.
title On dataset tensions and signatures of new cosmological physics
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2309.03286