Extended Wess-Zumino Dark Radiation Model with Interacting Scalar Field Dark Matter and Stepped Dark Radiation

Abstract

This paper investigates the interaction between scalar field dark matter and stepped dark radiation as an extension of the Wess-Zumino dark radiation (WZDR) model. The WZDR framework, based on supersymmetry, shows promise in alleviating the Hubble tension. Previous studies have explored the interaction between stepped dark radiation and cold dark matter to address both the Hubble and $S_8$ tensions. In this work, we replace cold dark matter with scalar field dark matter, introducing its interaction with stepped dark radiation via pure momentum coupling, creating a novel model. We constrain the model parameters using a range of cosmological datasets, including the Cosmic Microwave Background, Baryon Acoustic Oscillations, Type Ia Supernovae, $H_0$ measurement from SH0ES, $S_8$ data from the Dark Energy Survey Year 3, and Atacama Cosmology Telescope data. Our analysis shows that the new model performs similarly to the original WZDR model, with only a marginal improvement. The best-fit $H_0$ values for the coupled model and WZDR model are $70.89$ km/s/Mpc and $70.68$ km/s/Mpc, respectively. The $S_8$ parameter decreases from $0.8136$ in the original model to $0.8113$ in the new model. Compared to the $\Lambda$CDM model, the new model improves the $\chi^2_{\min}$ statistic by $-8.34$, while the WZDR model improves it by $-7.49$. The coupling signal remains weak, with the coupling parameter constrained to $\log_{10}(\xi)<4.56$. Although the coupling model provides some improvement, it does not fully resolve the cosmological tensions, suggesting the need for further investigation.