What Is the Damping Tail in the CMB Power Spectrum?
The damping tail is the high-multipole region of the cosmic microwave background power spectrum where temperature fluctuations are exponentially suppressed by photon diffusion and Silk damping. It provides a precise probe of the baryon density, the epoch of recombination, and the physics of the early universe, and has been measured by COBE, WMAP, and Planck.
