Multiverse Dark Matter: SUSY or Axions

Understand

The observed values of the cosmological constant {\it and} the abundance of Dark Matter (DM) can be successfully understood, using certain measures, by imposing the anthropic requirement that density perturbations go non-linear and virialize to form halos.

• This requires a probability distribution favoring low amounts of DM, i.e.
• low values of the PQ scale $f$ for the QCD axion and low values of the superpartner mass scale $\tilde{m}$ for LSP thermal relics.
• In theories with independent scanning of multiple DM components, there is a high probability for DM to be dominated by a single component.