Possible modification to standard cosmological model to resolve tension with Hubble constant values

TL;DR

This paper explores modifications to the standard cosmological model to reconcile the discrepancy in Hubble constant measurements, considering dark matter with negative pressure or matter generation mechanisms, while maintaining consistency with observations.

Contribution

It proposes specific modifications to the {\

Findings

Dark matter with negative pressure could reconcile Hubble constant values.

Generation of new matter via dark energy decay offers a potential solution.

Limited options exist that satisfy both the Hubble tension and observational constraints.

Abstract

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model are considered, in which the Universe contains dark energy, cold baryonic matter and dark matter. They are based on general relativity and satisfy two requirements: (1) the value of the Hubble constant, calculated from the value of the Hubble parameter at the recombination by the formulas of flat {\Lambda}CDM model, should be equal to 92% of the one based on low-reshift observations; (2) deviations from the {\Lambda}CDM model should not lead to effects that contradict astronomical observations and estimations obtained thereof. The analysis showed that there are few opportunities for choice. Either we should consider DM with negative pressure -\r{ho}_{dm}c^2<<p_{dm}<0, which weakly affects the evolution of the Universe and the observed manifestations of DM, or we should admit the mechanism of generation of new matter, for example, by a decay of DE.