Minimal dark energy: Key to sterile neutrino and Hubble constant tensions?
Eleonora Di Valentino, Stefano Gariazzo, C. Giunti, Olga Mena, Supriya Pan, Weiqiang Yang
Abstract
Minimal dark energy models, described by the same number of free parameters of the standard cosmological model with cold dark matter plus a cosmological constant to parametrize the dark energy component, constitute very appealing scenarios which may solve long-standing, pending tensions. On the one hand, they alleviate significantly the tension between cosmological observations and the presence of one sterile neutrino motivated by the short-baseline anomalies: we obtain a 95% CL cosmological bound on the mass of a fully thermalized fourth sterile neutrino (${N}_{\mathrm{eff}}=4$) equal to ${m}_{s}<0.65(1.3)\text{ }\text{ }\mathrm{eV}$ within the Phenomenologically Emergent Dark Energy (PEDE) and Vacuum Metamorphosis (VM) scenarios under consideration. Interestingly, these limits are in agreement with the observations at short-baseline experiments, and the PEDE scenario is favored with respect to the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ case when the full data combination is considered. On the other hand, the Hubble tension is satisfactorily solved in almost all the minimal dark energy schemes explored here. These phenomenological scenarios may therefore shed light on differences arising from near and far Universe probes, and also on discrepancies between cosmological and laboratory sterile neutrino searches.