Can decaying vacuum solve the H_0 Tension?

TL;DR

This paper investigates vacuum decay models where dark energy interacts with dark matter, finding they can reconcile the H_0 tension by fitting higher H_0 values consistent with SH0ES data and excluding noninteracting models at high confidence.

Contribution

The study demonstrates that vacuum decay models can effectively address the H_0 tension and provides constraints on decay parameters, showing their potential as viable solutions.

Findings

H_0=73.1±0.86 km/s/Mpc with combined data

Decay parameter ε≈0.02 in both models

Noninteracting models excluded at >6σ confidence

Abstract

In the present work we analyze two different models of interaction between dark energy and dark matter, also known as vacuum decay models or $\Lambda(t)$CDM models. In both models, when the $H_0$ parameter is constrained by the Planck distance priors, its value is compatible with a higher value of $H_0$, in agreement with SH0ES data, while simultaneously reducing the values of $\Omega_m$ and $\Omega_b$. In both models, we find $H_0=73.1\pm0.86$ at 68\% c.l. by combining Planck+SH0ES data. We also find the decay parameter to be $\varepsilon=0.0197^{+0.0032}_{-0.0027}$ for one model and $\varepsilon=0.0203\pm0.0034$ for the other one. From these analyses, a noninteracting model is excluded at least at $6\sigma$ c.l.! This shows that these types of models are promising in solving or at least alleviating the $H_0$ tension problem. Our analysis also shows a preference for the decay of vacuum into dark matter, in agreement to thermodynamic analyses.