Dynamical dark sectors and neutrino masses and abundances

Abstract

We investigate generalized interacting dark matter-dark energy scenarios with a time-dependent coupling parameter, allowing also for freedom in the neutrino sector. The models are tested in the phantom and quintessence regimes, characterized by equations of state, w x < −1 and w x > −1, respectively. Our analyses show that for some of the scenarios, the existing tensions on the Hubble constant H 0 and on the clustering parameter S 8 can be significantly alleviated. The relief is either due to (a) a dark energy component which lies within the phantom region or (b) the presence of a dynamical coupling in quintessence scenarios. The inclusion of massive neutrinos into the interaction schemes does not affect either the constraints on the cosmological parameters or the bounds on the total number or relativistic degrees of freedom N eff , which are found to be extremely robust and, in general, strongly consistent with the canonical prediction N eff ¼ 3.045. The most stringent bound on the total neutrino mass M ν is M ν < 0.116 eV and it is obtained within a quintessence scenario in which the matter mass-energy density is only mildly affected by the presence of a dynamical dark sector coupling.

Constraining neutrino mass in dark energy dark matter interaction and comparison with 2018 Planck results

“…From the analyses of the Pantheon data alone, as shown in Table 3, we find that m ν < 0.45 eV 95%C L (32) Which in comparison of previous model, IDE+ m ν , with m ν < 0.253 eV have been changed significantly, however it is close to the result of [189] where using same model, interacting scenario IDE1p + m ν + N e f f and using Planck 2018 data, have been obtained m ν < 0.438 eV at 95% CL The interesting result of our analysis is that for this model, the most stringent upper limit we have on this parameter is obtained for the data set combination C M B + B AO + Pantheon + CC in which m ν < 0.125 eV 95%C L (33) This result is in good agreement with the results of Planck 2018 [185], where the limit of the total neutrino mass is m ν < 0.12 eV at (95% C.L. using TT, TE, EE + lowE + lensing + BAO data) and close to the result of [121], where they also find the most stringent upper limit on this parameter for the same model, IDE+ m ν and the same data (CMB + Pantheon + CC data) with m ν < 0.15 eV at 95% CL.…”

In the realm of the Hubble tension—a review of solutions *

“…However, the most general case is only realized when a time varying coupling parameter is considered, as there is no theoretical principle that can exclude this possibility. In references [662,663], the two following coupling functions were considered:…”

“…The above interaction models together with the variable coupling function were investigated for w DE = −1 (IVS), in reference [662], and for a constant value of w DE = −1 in reference [663] (IDE).…”

A structured analysis of Hubble tension

“…Both decaying (dark) matter solutions, as well as growing density-component solutions are very active areas of research. Because of this, we will not try to give an overview here of the candidates, but merely point to a number of recent papers [32,33,34,35,36,37,38,39] as a starting point for the interested reader, together with the more complete literature survey provided in [12]. By breaking Assumption 7, such solutions can increase H(0) relative to H(z) (where z > 0) more than would otherwise be possible.…”