Refitting cosmological data with neutrino mass and degeneracy
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| Format: | Preprint |
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2024
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| _version_ | 1866912564264304640 |
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| author | Yeung, Shek Zhang, Wangzheng Chu, Ming-chung |
| author_facet | Yeung, Shek Zhang, Wangzheng Chu, Ming-chung |
| contents | A simple and natural extension of the standard Lambda cold dark matter ($Λ$CDM) model is to allow relic neutrinos to have finite chemical potentials. We confront this $Λ$CDM$ξ$ model, a $Λ$CDM with neutrino mass $M_ν$ and degeneracy $ξ_3$ as additional parameters, with various cosmological data sets. We find that the $H_0$ and $S_8$ tensions become significant only in the presence of the cosmic microwave background (CMB) polarization data. Specifically, the global and local measurements agree to within 0.8$σ$ and 1.6$σ$ for the $H_0$ and $S_8$ tensions, respectively, when the CMB polarization data are not included. Therefore, the $H_0$ and $S_8$ tensions exist between CMB temperature and polarization data, both being global measurements. Fitting the $Λ$CDM$ξ$ model to the CMB temperature data, we find 3$σ$ evidence for nonzero neutrino mass ($M_ν=0.57^{+0.17}_{-0.13}\,\mathrm{eV}$) and degeneracy ($ξ_3=1.13^{+0.41}_{-0.19}$), and the O(1) neutrino degeneracy parameter is compatible with Big Bang nucleosynthesis data. The scalar index $n_s$ exceeds 1 slightly, which is compatible with some hybrid inflation models. Furthermore, the recent DESI baryon acoustic oscillation data prefer the $Λ$CDM$ξ$ model to the Planck $Λ$CDM model. Similar results are obtained when including additional supernova data, while the inclusion of the Atacama Cosmology Telescope $τ$ prior shifts the preferred $M_ν$ and $ξ_3$ values closer to zero and brings $n_s$ back to the values favored when the polarization data are included. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2403_11499 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Refitting cosmological data with neutrino mass and degeneracy Yeung, Shek Zhang, Wangzheng Chu, Ming-chung High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics A simple and natural extension of the standard Lambda cold dark matter ($Λ$CDM) model is to allow relic neutrinos to have finite chemical potentials. We confront this $Λ$CDM$ξ$ model, a $Λ$CDM with neutrino mass $M_ν$ and degeneracy $ξ_3$ as additional parameters, with various cosmological data sets. We find that the $H_0$ and $S_8$ tensions become significant only in the presence of the cosmic microwave background (CMB) polarization data. Specifically, the global and local measurements agree to within 0.8$σ$ and 1.6$σ$ for the $H_0$ and $S_8$ tensions, respectively, when the CMB polarization data are not included. Therefore, the $H_0$ and $S_8$ tensions exist between CMB temperature and polarization data, both being global measurements. Fitting the $Λ$CDM$ξ$ model to the CMB temperature data, we find 3$σ$ evidence for nonzero neutrino mass ($M_ν=0.57^{+0.17}_{-0.13}\,\mathrm{eV}$) and degeneracy ($ξ_3=1.13^{+0.41}_{-0.19}$), and the O(1) neutrino degeneracy parameter is compatible with Big Bang nucleosynthesis data. The scalar index $n_s$ exceeds 1 slightly, which is compatible with some hybrid inflation models. Furthermore, the recent DESI baryon acoustic oscillation data prefer the $Λ$CDM$ξ$ model to the Planck $Λ$CDM model. Similar results are obtained when including additional supernova data, while the inclusion of the Atacama Cosmology Telescope $τ$ prior shifts the preferred $M_ν$ and $ξ_3$ values closer to zero and brings $n_s$ back to the values favored when the polarization data are included. |
| title | Refitting cosmological data with neutrino mass and degeneracy |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2403.11499 |