$Λ_{\rm s}$CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties

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Autori principali: Yadav, Anita, Kumar, Suresh, Kibris, Cihad, Akarsu, Ozgur
Natura: Preprint
Pubblicazione: 2024
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author Yadav, Anita
Kumar, Suresh
Kibris, Cihad
Akarsu, Ozgur
author_facet Yadav, Anita
Kumar, Suresh
Kibris, Cihad
Akarsu, Ozgur
contents We investigate a two-parameter extension of the $Λ_{\rm s}$CDM model by allowing variations in the effective number of neutrino species $N_{\rm eff}$ and their total mass $\sum m_ν$. Our motivation is twofold: (i) to examine whether $Λ_{\rm s}$CDM retains its success in fitting the data and addressing major cosmological tensions, without suggesting a need for a deviation from the standard model of particle physics, and (ii) to determine whether the data indicate new physics that could potentially address cosmological tensions, either in the post-recombination universe through the late-time mirror AdS-dS transition, or in the pre-recombination universe through modifications in the standard values of $N_{\rm eff}$ and $\sum m_ν$, or both. Within the extended $Λ_{\rm s}$CDM model, referred to as $Λ_{\rm s}$CDM+$N_{\rm eff}$+$\sum m_{\rm ν}$, we find no significant tension when considering the Planck-alone analysis. We observe that incorporating BAO data limits the further success of the $Λ_{\rm s}$CDM extension. However, the weakly model-dependent BAOtr data, along with Planck and Planck+PP\&SH0ES, favor $H_0\sim 73\,{\rm km\, s^{-1}\, Mpc^{-1}}$. In cases where BAOtr dataset is used, the mirror AdS-dS transition is very effective in providing enhanced $H_0$ values, and thus the model requires no significant deviation from the standard value of $N_{\rm eff} = 3.044$. Both the $H_0$ and $S_8$ tensions are effectively addressed, with some compromise in the case of the Planck+BAO dataset. Finally, the upper bounds obtained on $\sum m_ν\lesssim 0.5$~eV are fully compatible with neutrino oscillation experiments. Our findings provide evidence that late-time physics beyond $Λ$CDM, such as $Λ_{\rm s}$CDM, without altering the standard pre-recombination universe, can suffice to alleviate the major cosmological tensions.
format Preprint
id arxiv_https___arxiv_org_abs_2406_18496
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle $Λ_{\rm s}$CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties
Yadav, Anita
Kumar, Suresh
Kibris, Cihad
Akarsu, Ozgur
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
We investigate a two-parameter extension of the $Λ_{\rm s}$CDM model by allowing variations in the effective number of neutrino species $N_{\rm eff}$ and their total mass $\sum m_ν$. Our motivation is twofold: (i) to examine whether $Λ_{\rm s}$CDM retains its success in fitting the data and addressing major cosmological tensions, without suggesting a need for a deviation from the standard model of particle physics, and (ii) to determine whether the data indicate new physics that could potentially address cosmological tensions, either in the post-recombination universe through the late-time mirror AdS-dS transition, or in the pre-recombination universe through modifications in the standard values of $N_{\rm eff}$ and $\sum m_ν$, or both. Within the extended $Λ_{\rm s}$CDM model, referred to as $Λ_{\rm s}$CDM+$N_{\rm eff}$+$\sum m_{\rm ν}$, we find no significant tension when considering the Planck-alone analysis. We observe that incorporating BAO data limits the further success of the $Λ_{\rm s}$CDM extension. However, the weakly model-dependent BAOtr data, along with Planck and Planck+PP\&SH0ES, favor $H_0\sim 73\,{\rm km\, s^{-1}\, Mpc^{-1}}$. In cases where BAOtr dataset is used, the mirror AdS-dS transition is very effective in providing enhanced $H_0$ values, and thus the model requires no significant deviation from the standard value of $N_{\rm eff} = 3.044$. Both the $H_0$ and $S_8$ tensions are effectively addressed, with some compromise in the case of the Planck+BAO dataset. Finally, the upper bounds obtained on $\sum m_ν\lesssim 0.5$~eV are fully compatible with neutrino oscillation experiments. Our findings provide evidence that late-time physics beyond $Λ$CDM, such as $Λ_{\rm s}$CDM, without altering the standard pre-recombination universe, can suffice to alleviate the major cosmological tensions.
title $Λ_{\rm s}$CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2406.18496