What can future CMB experiments tell us about the dark sector interaction?

This paper explores the potential of future Cosmic Microwave Background (CMB) experiments, such as CMB-S4 and LiteBIRD, to constrain interactions within the dark sector. The forecast analysis demonstrates that future CMB data, with enhanced sensitivity to small-scale anisotropies and polarization, can significantly improve constraints on dark sector interaction parameters, potentially detecting even small interaction strengths and offering crucial insights into dark matter and dark energy.