ALP Dark Matter from Kinetic Fragmentation: Opening up the Parameter Window

Understand

The main mechanism responsible for Axion-Like-Particle (ALP) production in the early universe is the so-called misalignment mechanism.

• Three regimes have been investigated in this context: standard misalignment, large misalignment and kinetic misalignment.
• The latter applies if the axion inherits a large initial velocity in the early universe, such that the field rolls through many wiggles during its evolution, before it gets trapped in one minimum.
• This 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.