The H0 Olympics: A fair ranking of proposed models

Jul 21, 2021
77 pages
Published in:
  • Phys.Rept. 984 (2022) 1-55
  • Published: Oct 26, 2022
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Abstract: (Elsevier B.V.)
Despite the remarkable success of the Λ Cold Dark Matter (ΛCDM) cosmological model, a growing discrepancy has emerged (currently measured at the level of 46σ) between the value of the Hubble constant H0 measured using the local distance ladder and the value inferred using the cosmic microwave background and galaxy surveys. While a vast array of ΛCDM extensions have been proposed to explain these discordant observations, understanding the (relative) success of these models in resolving the tension has proven difficult — this is a direct consequence of the fact that each model has been subjected to differing, and typically incomplete, compilations of cosmological data. In this review, we attempt to make a systematic comparison of seventeen different models which have been proposed to resolve the H0 tension (spanning both early- and late-Universe solutions), and quantify the relative success of each using a series of metrics and a vast array of data combinations. Owing to the timely appearance of this article, we refer to this contest as the “H0 Olympics”; the goal being to identify which of the proposed solutions, and more broadly which underlying mechanisms, are most likely to be responsible for explaining the observed discrepancy (should unaccounted for systematics not be the culprit). This work also establishes a foundation of tests which will allow the success of novel proposals to be meaningfully “benchmarked”.
Note:
  • 77 pages, 39 figures, 11 tables ; V2 - updated results with improved minimization scheme; expanded discussion about the role of cosmic chronometers and the impact of halofit; additional model considered [early modified gravity] (subject to potential small changes by final publication). Submitted to Physics Report
  • Hubble tension
  • Dark energy
  • Dark matter phenomenology
  • Dark radiation
  • Early dark energy
  • Varying fundamental constants
  • cosmological model: parameter space
  • tension
  • dark matter: density
  • cosmic background radiation