title: What mass are the smallest protohalos?
abstract: We calculate the kinetic-decoupling temperature for weakly interacting massive particles (WIMPs) in supersymmetric (SUSY) and extra dimensional models that can account for the cold-dark-matter abundance determined from cosmic microwave background measurements. Depending on the parameters of the particle-physics model, a wide variety of decoupling temperatures is possible, ranging from several MeV to a few GeV. These decoupling temperatures imply a range of masses for the smallest protohalos much larger than previously thought--ranging from 10(-6)M(+ in a circle) to 10(2)M(+ in a circle). We expect the range of protohalos masses derived here to be characteristic of most particle-physics models that can thermally accommodate the required relic abundance of WIMP dark matter, even beyond SUSY and extra dimensions.
authors.affiliation: California Institute of Technology, Mail Code 130-33, Pasadena, California 91125, USA. profumo@caltech.edu
authors.forename: Stefano
authors.initials: S
authors.lastname: Profumo
authors.forename: Kris
authors.initials: K
authors.lastname: Sigurdson
authors.forename: Marc
authors.initials: M
authors.lastname: Kamionkowski