The Missing Link Between Dark Matter And Structure Formation

Abstract

Weakly interacting massive particles (WIMPs) are excellent candidates for cold dark matter. After the first millisecond, WIMPs have decoupled from standard model matter, both chemically and kinetically, they enter the free streaming regime and the formation of cosmic structure begins. Another 40 million years pass before the typical first structures enter the nonlinear regime and collapse to the first WIMPy halos. Therefore, it has been assumed that structure formation is insensitive to the WIMP field theory and can be neglected. However, this leads to a monotonically increasing power of structure formation on small scales and some kind of regularization procedure would be required to make the hierarchical picture of structure formation well defined. It will be shown that nonequilibrium processes give rise to a physical regularization of hierarchical structure formation. This has important consequences for indirect and direct dark matter searches which are sensitive to sub-galactic and sub-milli-parsec scales. Furthermore, due the existence of a physical regulator, the problem of structure formation can consistently be solved using N-body simulations.