2010/01/31 by Annika H. G. Peter · 1 citation
Physics and Astronomy · #astro-ph.CO #hep-ph
paper · pdf · doi:10.1103/physrevd.81.083511
published as Phys.Rev.D81:083511,2010 · 14 pages, 5 figures, references added, replaced to match version published in Phys. Rev. D
arxiv created 2010/04/12 · arxiv updated 2010/04/22
I consider constraints on a phenomenological decaying-dark-matter model, in which two weakly-interacting massive particle (WIMP) species have a small mass splitting, and in which the heavier particle decays to the lighter particle and a massless particle on cosmological timescales. The decay parameter space is parameterized by vk, the speed of the lighter particle in the center-of-mass frame of the heavier particle prior to decay, and the decay time τ. Since I consider the case in which dark-matter halos have formed before there has been significant decay, I focus on the effects of decay in already-formed halos. I show that the vk-τ parameter space may be constrained by observed properties of dark-matter halos. I highlight which set of observations is likely to yield the cleanest constraints on vk-τ parameter space, and calculate the constraints in those cases in which the effect of decay on the observables can be calculated without N-body simulations of decaying dark matter. I show that for vk \gtrsim 5× 103 km s-1, the z=0 galaxy cluster mass function and halo mass-concentration relation constrain τ\gtrsim 40 Gyr, and that precise constraints on τ for smaller vk will require N-body simulations.