Probing Particle Physics with the Global 21-cm Signal

Observations of the 21-cm line of the atomic hydrogen at the early universe has the potential to probe the unexplored period between the so-called dark ages and the reionization epoch of the Universe, and to significantly improve the constraints on the cosmological parameters. Here we summarize briefly the physics behind the 21-cm sky averaged (global) signal and how it can be used to place limits on particle physics properties, in particular constraints on the mass and self-annihilation cross-section of the dark matter particles.