中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

The precision cosmic microwave background (CMB) measurement and the anticipated observation of neutral hydrogen 21cm line tell us a lot about the CMB propagation during the dark and reionization epochs of the Universe. The CMB can be a powerful indirect test of energy deposition from beyond the Standard Model physics: Dark matter annihilation and decays, or the radiation from primordial black holes. I will discuss the ionization fraction and temperature corrections as two major imprints from new physics. The upcoming CMB polarization experiments and future 21cm measurement in early EoR will likely bring the prospective indirect dark matter search sensitivity to a whole new level.