2009/03/31 by Torsten Bringmann · 11 citations
Physics and Astronomy · #Astrophysics #Cold dark matter #Cosmology #Cosmology and Gravitation Theories #Cutoff #Dark Matter and Cosmic Phenomena #Dark energy #Dark matter #Decoupling (probability) #Formalism (music) #Massive particle #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum mechanics #Scalar field dark matter #WIMP #Weakly interacting massive particles #astro-ph.CO #hep-ph
paper · pdf · doi:10.1088/1367-2630/11/10/105027
published as New J.Phys.11:105027,2009 · 19 pages, 7 figures. Extended discussion, improved figures and corrected typos. Matches the published version (invited contribution to NJP Focus Issue on 'Dark Matter and Particle Physics')
arxiv created 2009/06/15 · openalex publication_date 2009/10/16 · arxiv updated 2014/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The kinetic decoupling of weakly interacting massive particles (WIMPs) in the early universe sets a scale that can directly be translated into a small-scale cutoff in the spectrum of matter density fluctuations. The formalism presented here allows a precise description of the decoupling process and thus the determination of this scale to a high accuracy from the details of the underlying WIMP microphysics. With decoupling temperatures of several MeV to a few GeV, the smallest protohalos to be formed range between 10 -11 and almost 10 -3 solar masses—a somewhat smaller range than what was found earlier using order-of-magnitude estimates for the decoupling temperature; for a given WIMP model, the actual cutoff mass is typically about a factor of 10 greater than derived in that way, though in some cases the difference may be as large as a factor of several hundreds. Observational consequences and prospects to probe this small-scale cutoff, which would provide a fascinating new window into the particle nature of dark matter, are discussed.