Interpreting the Hubble tension with a cascade decaying dark matter sector

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Hauptverfasser: Zhou, Quan, Xu, Zixuan, Zheng, Sibo
Format: Preprint
Veröffentlicht: 2025
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author Zhou, Quan
Xu, Zixuan
Zheng, Sibo
author_facet Zhou, Quan
Xu, Zixuan
Zheng, Sibo
contents Hubble tension can be alleviated by altering either early- or late-time $Λ$CDM. With only one of these effects introduced, early dark energy remains the only solution capable of reducing the tension to the $3σ$ level or below. In this work, we instead consider a modification of the dark matter sector that incorporates both the early- and late-time effects, with the goal of achieving the largest possible value of $H_0$ within this framework. As a realization of these two-fold effects, we study a cascade decaying dark matter model. By fitting the model to the latest datasets of Planck CMB+ DESI BAO+Pantheon (+SH0ES), we find that a 68$\%$ CL value of $H_{0}=68.76\pm0.35 (69.05^{+0.31}_{-0.27})$ km s$^{-1}$ Mpc$^{-1}$ with $Δχ^2=+16.0(12.4)$, and larger value of $H_0$ can be obtained by adjusting parameter priors but with a cost of significantly increased value of $Δχ^2$. Our findings suggest that the Hubble tension cannot be reduced below the $3σ$ level, revising the earlier results on the tension level in the literature. For completeness, we show that the parameter regions favored by the cosmological datasets are compatible with complementary limits arising from the Big Bang Nucleosynthesis, neutrino flux, and structure formation.
format Preprint
id arxiv_https___arxiv_org_abs_2507_08687
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Interpreting the Hubble tension with a cascade decaying dark matter sector
Zhou, Quan
Xu, Zixuan
Zheng, Sibo
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
Hubble tension can be alleviated by altering either early- or late-time $Λ$CDM. With only one of these effects introduced, early dark energy remains the only solution capable of reducing the tension to the $3σ$ level or below. In this work, we instead consider a modification of the dark matter sector that incorporates both the early- and late-time effects, with the goal of achieving the largest possible value of $H_0$ within this framework. As a realization of these two-fold effects, we study a cascade decaying dark matter model. By fitting the model to the latest datasets of Planck CMB+ DESI BAO+Pantheon (+SH0ES), we find that a 68$\%$ CL value of $H_{0}=68.76\pm0.35 (69.05^{+0.31}_{-0.27})$ km s$^{-1}$ Mpc$^{-1}$ with $Δχ^2=+16.0(12.4)$, and larger value of $H_0$ can be obtained by adjusting parameter priors but with a cost of significantly increased value of $Δχ^2$. Our findings suggest that the Hubble tension cannot be reduced below the $3σ$ level, revising the earlier results on the tension level in the literature. For completeness, we show that the parameter regions favored by the cosmological datasets are compatible with complementary limits arising from the Big Bang Nucleosynthesis, neutrino flux, and structure formation.
title Interpreting the Hubble tension with a cascade decaying dark matter sector
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2507.08687