We investigate the observational constraints on an interacting vacuum energy scenario with two different neutrino schemes (with and without a sterile neutrino) using the most recent data from cosmic microwave background (CMB) temperature and polarization anisotropy, baryon acoustic oscillations (BAO), type Ia supernovae from JLA sample and structure growth inferred from cluster counts. We find that inclusion of the galaxy clusters data with the minimal data combination $\mathrm{CMB}+\mathrm{BAO}+\mathrm{JLA}$ suggests an interaction in the dark sector, implying the decay of dark matter particles into dark energy, since the constraints obtained by including the galaxy clusters data yield a non-null and negative coupling parameter between the dark components at 99% confidence level. We deduce that the current tensions on the parameters $H_0$ and ${\sigma }_8$ can be alleviated within the framework of the interacting as well as noninteracting vacuum energy models with sterile neutrinos.

We consider the possibility of an interaction in the dark sector in the presence of massive neutrinos and study the observational constraints on three different scenarios of massive neutrinos using the most recent cosmic microwave background anisotropy data in combination with type Ia supernovae, baryon acoustic oscillations, and Hubble parameter measurements. When a sterile neutrino is introduced into the interacting dark sector scenario in addition to the standard model prediction of neutrinos, we find that the coupling parameter is nonzero at a $2\sigma$ confidence level. The interaction model with a sterile neutrino is also found to be a promising one to alleviate the current tension on the Hubble constant. We do not find the evidence for a coupling in the dark sector when the possibility of a sterile neutrino is discarded.

The well-known tensions on the cosmological parameters [equation] and [equation] within the [equation]CDM cosmology shown by the Planck-CMB and LSS data are possibly due to the systematics in the...

Inspired by the recent conjecture originated from graduated dark energy that the Universe has recently transitioned from anti–de Sitter vacua to de Sitter vacua, we extend the standard $\mathrm{\Lambda }\mathrm{CDM}$ model by a cosmological constant (${\mathrm{\Lambda }}_s$) that switches sign at a certain redshift $z_{†}$, and we call this model ${\mathrm{\Lambda }}_s\mathrm{CDM}$. We discuss the construction and theoretical features of this model in detail and find out that, when the consistency of the ${\mathrm{\Lambda }}_s\mathrm{CDM}$ model with the cosmic microwave background (CMB) data is ensured, (i) $z_{†}\gtrsim 1.1$ is implied by the condition that the Universe monotonically expands, (ii) $H_0$ and $M_B$ (type Ia supernovae absolute magnitude) values are inversely correlated with $z_{†}$ and reach $H_0\approx 74.5\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ and $M_B\approx -19.2\mathrm{mag}$ for $z_{†}=1.5$, in agreement with the SH0ES measurements, and (iii) $H(z)$ presents an excellent fit to the Ly-$\alpha$ measurements provided that $z_{†}\lesssim 2.34$. We further investigate the model constraints by using the full Planck CMB data set, with and without baryon acoustic oscillation (BAO) data. We find that the CMB data alone does not constrain $z_{†}$, but the $\mathrm{CMB}+\mathrm{BAO}$ data set favors the sign switch of ${\mathrm{\Lambda }}_s$, providing the constraint $z_{†}=2.44\pm 0.29$ (68% C.L.). Our analysis reveals that the lower and upper limits of $z_{†}$ are controlled by the Galaxy and Ly-$\alpha$ BAO measurements, respectively, and the larger $z_{†}$ values imposed by the Galaxy BAO data prevent the model from achieving the highest local $H_0$ measurements. In general, the ${\mathrm{\Lambda }}_s\mathrm{CDM}$ model (i) relaxes the $H_0$ tension while being fully consistent with the tip of the red giant branch measurements, (ii) relaxes the $M_B$ tension, (iii) removes the discrepancy with the Ly-$\alpha$ measurements, (iv) relaxes the $S_8$ tension, and (v) finds a better agreement with the big bang nucleosynthesis constraints on the physical baryon density. We find no strong statistical evidence to discriminate between the ${\mathrm{\Lambda }}_s\mathrm{CDM}$ and $\mathrm{\Lambda }\mathrm{CDM}$ models. However, interesting and promising features of the ${\mathrm{\Lambda }}_s\mathrm{CDM}$ model, which we describe in our study, provide an advantage over $\mathrm{\Lambda }\mathrm{CDM}$.

We explore the role of redshift-space galaxy clustering data in constraining nongravitational interactions between dark energy (DE) and dark matter (DM), for which state-of-the-art limits have so far been obtained from late-time background measurements. We use the joint likelihood for prereconstruction full-shape (FS) galaxy power spectrum and postreconstruction Baryon Acoustic Oscillation (BAO) measurements from the BOSS DR12 sample, alongside Cosmic Microwave Background (CMB) data from Planck: from this dataset combination we infer $H_0=68.02_{-0.60}^{+0.49}\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ and the $2\sigma$ lower limit $\xi >-0.12$, among the strongest limits ever reported on the DM-DE coupling strength $\xi$ for the particular model considered. Contrary to what has been observed for the $\mathrm{\Lambda }\mathrm{CDM}$ model and simple extensions thereof, we find that the $\mathrm{CMB}+\mathrm{FS}$ combination returns tighter constraints compared to the $\mathrm{CMB}+\mathrm{BAO}$ one, suggesting that there is valuable additional information contained in the broadband of the power spectrum. We test this finding by running additional CMB-free analyses and removing sound horizon information, and discuss the important role of the equality scale in setting constraints on DM-DE interactions. Our results reinforce the critical role played by redshift-space galaxy clustering measurements in the epoch of precision cosmology, particularly in relation to tests of nonminimal dark sector extensions of the $\mathrm{\Lambda }\mathrm{CDM}$ model.

We use 28 measurements of the Hubble parameter, H(z), at intermediate redshifts to determine the present-day Hubble constant H ₀ in four cosmological models. We measure , and Mpc⁻¹ (1σ errors) in the ΛCDM (spatially flat and non-flat), ωCDM, and ϕCDM models, respectively. These measured H ₀ values are more consistent with the lower values determined from recent data on the cosmic microwave background and baryon acoustic oscillations, as well as with the value found from a median statistical analysis of Huchra’s compilation of H ₀ measurements, but include the higher local measurements of H ₀ within the 2σ confidence limits.