2003/11/30 by Filippo Vernizzi · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.69.083526
published as Phys.Rev. D69 (2004) 083526 · 21 pages, 4 figures, published version
openalex publication_date 2004/04/29 · arxiv created 2004/05/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the evolution of perturbations during the domination and decay of a massive particle species whose mass and decay rate are allowed to depend on the expectation value of a light scalar field. We specialize in the case where the light field is slow rolling, showing that during a phase of inhomogeneous mass domination and decay the isocurvature perturbation of the light field is converted into a curvature perturbation with an efficiency which is nine times larger than when the mass is fixed. We derive a condition on the annihilation cross section and on the decay rate for the domination of the massive particles and we show that standard model particles cannot dominate the universe before nucleosynthesis. We also compare this mechanism with the curvaton model. Finally, observational signatures are discussed. A cold dark matter isocurvature mode can be generated if the dark matter is produced out of equilibrium by both the inflaton and the massive particle species decay. Non-Gaussianities are present: they are chi-square deviations. However, they might be too small to be observable.