Limit on the dark matter mass from its interaction with photons

Zhihuan Zhou, Gang Liu, Yuhao Mu, Lixin Xu
2022 Physical Review D  
In this work, we explore the phenomenology of generalized dark matter (GDM) which interacts with photons (γ). We assume that DM establishes elastic scattering with γ when it has already become nonrelativistic, otherwise the abundance of DM today is disfavored by current observations. Within this scenario, the equation of state (EoS) of DM is determined by its mass (m_χ) and the DM-γ scattering cross-section. The distinctive imprints of a nonzero EoS of DM on CMB angular power spectrum allow us
more » ... o set a lower limit on m_χ with Planck 2018 data alone, i.e., m_χ > 8.7 keV at 95% C.L. In the study of cosmic concordance problems, we find that the GDM scenario preserves the sound horizon (r_s(z_*)) predicted in the fiducial ΛCDM model, and thus does not solve the H_0 tension. When performing the joint analysis of Planck+LSS datasets, the best-fit S_8= 0.785± 0.017 closely matches the given S_8 prior. This suggests that the GDM scenario can be counted as a viable candidate to restore the S_8 (σ_8) tension.
doi:10.1103/physrevd.105.103509 fatcat:pc56vzkrqfeg7pka7wuxlfmhjy