The power spectrum of SUSYCDM on subgalactic scales
Abstract
The formation of largescale structure is independent of the nature of the cold dark matter (CDM), however the fate of very smallscale inhomogeneities depends on the microphysics of the CDM particles. We investigate the matter power spectrum for scales that enter the Hubble radius well before matterradiation equality, and follow its evolution until the time when the first inhomogeneities become nonlinear. Our focus lies on weakly interacting massive particles (WIMPs), and as a concrete example we analyse the case when the lightest supersymmetric particle is a bino. We show that collisional damping and freestreaming of WIMPs lead to a matter power spectrum with a sharp cutoff at about 10^{6} M_{solar} and a maximum close to that cutoff. We also calculate the transfer function for the growth of the inhomogeneities in the linear regime. These three effects (collisional damping, freestreaming and gravitational growth) are combined to provide a WMAP normalized primordial CDM power spectrum, which could serve as an input for highresolution CDM simulations. The smallest inhomogeneities typically enter the nonlinear regime at a redshift of about 60.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 September 2004
 DOI:
 10.1111/j.13652966.2004.08232.x
 arXiv:
 arXiv:astroph/0309621
 Bibcode:
 2004MNRAS.353L..23G
 Keywords:

 cosmology: theory;
 dark matter;
 early Universe;
 Astrophysics;
 High Energy Physics  Phenomenology
 EPrint:
 5 pages, 2 figures