| Abstract: |
Three main mechanisms have been investigated for Axion-Like-Particle (ALP) production in the early universe: misalignment, thermal production in the plasma, and decay of cosmic strings. Recently, a new production mechanism has been advocated, axion fragmentation, that can arise if the axion field rolls through many wiggles during its early evolution, before it gets trapped in one minimum. In this context, axions are produced relativistically and then cool down to make cold dark matter. I’ll discuss the impact of axion fragmentation on the allowed parameter space for ALP dark matter and show that axion fragmentation largely opens the region of parameter space for ALP dark matter towards higher values for the axion-photon coupling, which can be probed by the whole set of next decade’s upcoming experiments. |
