Updated constraints on interacting dark energy: A comprehensive analysis using multiple CMB probes, DESI DR2, and supernovae observations

Abstract

Recent DESI baryon acoustic oscillation (BAO) measurements, combined with Planck cosmic microwave background (CMB) data and DESY5 type Ia supernova (SN) data, indicate a significant deviation from $\Lambda$CDM, which seems to suggest that this deviation can be explained by an interaction between dark energy and dark matter. In this work, we perform a comprehensive analysis by utilizing the latest DESI DR2 BAO data in conjunction with CMB data from ACT, SPT, Planck, and WMAP, along with SN data from PantheonPlus and DESY5. We consider four interacting dark energy (IDE) models with different forms of the interaction term $Q$. Our analysis indicates that CMB experiments other than Planck enhance the evidence for an interaction in the IDE models with $Q \propto \rho_{\rm de}$. In particular, when using the SPT+DESI+DESY5 data, the IDE model with $Q = \beta H_0 \rho_{\rm de}$ gives $\beta = -0.4170 \pm 0.1220$, with a deviation from zero reaching $3.4\sigma$ level. When replacing DESY5 with PantheonPlus, this deviation weakens to $2.1\sigma$ level, but remains relatively significant. Furthermore, the Bayes factors of the IDE model with $Q = \beta H_0 \rho_{\rm de}$ are positive in all cases, providing a moderate-to-strong preference over $\Lambda$CDM. Overall, our comprehensive analysis clearly suggests that the IDE models with $Q \propto \rho_{\rm de}$ (especially, $Q = \beta H_0 \rho_{\rm de}$) provide strong evidence supporting the existence of interaction and are more preferred by the current cosmological data.