A novel model-marginalized cosmological bound on the QCD axion mass ...

We present model-marginalized limits on mixed hot dark matter scenarios, which consider both thermal neutrinos and thermal QCD axions. A novel aspect of our analyses is the inclusion of small-scale Cosmic Microwave Background (CMB) observations from the Atacama Cosmology Telescope (ACT) and the Sout...

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Bibliographic Details
Main Authors: Di Valentino, Eleonora, Gariazzo, Stefano, Giarè, William, Melchiorri, Alessandro, Mena, Olga, Renzi, Fabrizio
Format: Text
Language:unknown
Published: arXiv 2022
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Online Access:https://dx.doi.org/10.48550/arxiv.2212.11926
https://arxiv.org/abs/2212.11926
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Summary:We present model-marginalized limits on mixed hot dark matter scenarios, which consider both thermal neutrinos and thermal QCD axions. A novel aspect of our analyses is the inclusion of small-scale Cosmic Microwave Background (CMB) observations from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), together with those from the Planck satellite and Baryon Acoustic Oscillation (BAO) data. After marginalizing over a number of well-motivated non-minimal background cosmologies, the tightest $95\%$ CL upper bound we obtain is $0.21$ eV, both for $\sum m_ν$ and $m_{\rm a}$, from the combination of ACT, Planck and BAO measurements. Restricting the analyses to the standard $Λ$CDM picture, we find $\sum m_ν<0.16$ eV and $m_{\rm a}<0.18$ eV, both at $95\%$ CL. Interestingly, the best background cosmology is never found within the minimal $Λ$CDM plus hot relics, regardless of the data sets exploited in the analyses. The combination of Planck with either BAO, SPT or ACT prefers a universe ... : 17 pages, 5 figures, 9 tables. V2:updated to match the PRD published version ...