Alleviating cosmological tensions with a hybrid dark sector
| Autor: | Teixeira, Elsa M., Poulot, Gaspard, van de Bruck, Carsten, Di Valentino, Eleonora, Poulin, Vivian |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We investigate a cosmological model inspired by hybrid inflation, where two scalar fields representing dark energy (DE) and dark matter (DM) interact through a coupling that is proportional to the DE scalar field $1/\phi$. The strength of the coupling is governed solely by the initial condition of the scalar field, $\phi_i$, which parametrises deviations from the standard $\Lambda$CDM model. In this model, the scalar field tracks the behaviour of DM during matter-domination until it transitions to DE while the DM component decays quicker than standard CDM during matter-domination, and is therefore different from some interacting DM-DE models which behaves like phantom dark energy. Using \textit{Planck} 2018 CMB data, DESI BAO measurements and Pantheon+ supernova observations, we find that the model allows for an increase in $H_0$ that can help reduce the Hubble tension. In addition, we find that higher values of the coupling parameter are correlated with lower values of $\omega_m$, and a mild decrease of the weak-lensing parameter $S_8$, potentially relevant to address the $S_8$ tension. Bayesian model comparison, however, reveals inconclusive results for most datasets, unless S$H_0$ES data are included, in which case a moderate evidence in favour of the hybrid model is found. Comment: V1: 17 pages, 9 figures, 6 tables |
| Databáze: | arXiv |
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