Speaker
Description
The cosmic microwave background (CMB) is a powerful probe of physics beyond the standard model (BSM). While BSM searches using the CMB have traditionally focused on the primary anisotropies imprinted at the surface of last scattering, secondary anisotropies – arising from the interaction of CMB photons with intervening large-scale structure (LSS) – can also encode subtle signatures of new physics. In this talk, I will discuss how CMB secondary anisotropies can be used to probe the dark sector via “dark screening” processes, whereby CMB photons can resonantly convert into axions or dark photons as they propagate through the plasma in galactic halos. These conversions introduce frequency-dependent spectral distortions in the intensity and polarization of the CMB that are spatially correlated with the locations of galaxies. I will outline the theoretical and observational challenges in searching for such signals and present new constraints on the axion-photon coupling and dark photon kinetic mixing parameter using the state-of-the-art CMB and galaxy survey observations. These results highlight the power of combining CMB and LSS data to probe the dark sector.
