English

The $H_0$ world cup. II. A comprehensive competition between proposed Hubble tension solutions

Cosmology and Nongalactic Astrophysics 2026-07-14 v1 High Energy Physics - Phenomenology

Abstract

Cosmology stands at a crossroads. The Hubble tension has reached a nominal significance above 7σ7\sigma, while analyses combining DESI BAO and Type Ia supernova data show emerging hints of departures from Λ\LambdaCDM. Meanwhile, high-precision CMB measurements from ACT and SPT enable a timely and more stringent reassessment of proposed solutions to the tension. In this paper, we revisit the H0H_0 Olympics, a systematic contest comparing proposed alternatives to Λ\LambdaCDM using common datasets, likelihoods, and statistical criteria. In this updated edition, the H0H_0 World Cup, we subject fourteen representative solutions to a common analysis of current CMB, BAO, and SN data. The contenders span four broad mechanisms: late-time modifications of the expansion history, modified recombination, additional pre-recombination radiation, and early non-radiative energy injection. Relative to the original analysis, the present competition includes models and mechanisms proposed in the intervening years and evaluates all contenders using both Bayesian and Frequentist tests of tension and model performance, letting the neutrino mass sum vary. We further test if late-time extensions through curvature or the Chevallier-Polarski-Linder (CPL) dark energy parametrization can aid the success of the models. Finally, we subject the leading contenders to dedicated robustness tests involving alternative CMB likelihoods and multipole cuts, supernova samples, large-scale-structure information, and big-bang nucleosynthesis constraints. This framework assesses both the ability of each mechanism to ease the Hubble tension and the robustness of our conclusions to datasets and analysis choices.

Keywords

Cite

@article{arxiv.2607.13283,
  title  = {The $H_0$ world cup. II. A comprehensive competition between proposed Hubble tension solutions},
  author = {Nils Schöneberg and Vivian Poulin and Angelo G. Ferrari and Fabio Finelli and Julien Lesgourgues and Luca Morelli and Markus R. Mosbech and Ravi Kumar Sharma and Théo Simon},
  journal= {arXiv preprint arXiv:2607.13283},
  year   = {2026}
}

Comments

69 pages, 31figures, 16tables