Modified dark matter density evolution: a possible solution to hubble tension

Abstract

We study an alternative dark sector scenario of the

CDM type in which the dark matter density is modified due to an interaction with the quantum vacuum. The model is confronted with recent Type Ia supernovae samples (Pantheon+ &SH0ES, DES-Doviekie and Union3), combined with baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) distance priors. To assess the robustness of the results, an independent analysis employing a Big Bang nucleosynthesis (BBN) prior on the baryon density is also performed. Statistical model comparisons based on the Akaike, Bayesian, and Deviance information criteria indicate that

$$\Lambda (t)$$ Λ ( t )

CDM provides a better fit than the standard

$$\Lambda $$ Λ

CDM scenario, despite the introduction of one additional interaction parameter. We find values of the Hubble constant close to

$$H_0 \simeq 73\ \mathrm {km\,s^{-1}\,Mpc^{-1}}$$ H 0 ≃ 73 km s - 1 Mpc - 1

, consistent across the different supernova compilations. The dark sector interaction is driven by an

$$\alpha $$ α

parameter, which is positive in the case of decaying vacuum. The data favour a nonvanishing dark sector interaction, with

$$\alpha = 0.00203 \pm 0.00028$$ α = 0.00203 ± 0.00028

for Pantheon+ &SH0ES+BAO+CMB, while the remaining data combinations yield very similar and statistically consistent values of

$$\alpha $$ α

.