DRAKE: Dark matter Relic Abundance beyond Kinetic Equilibrium
Abstract
We introduce DRAKE, a numerical precision tool for predicting the dark matter relic abundance also in situations where the standard assumption of kinetic equilibrium during the freezeout process may not be satisfied. DRAKE comes with a set of three dedicated Boltzmann equation solvers that implement, respectively, the traditionally adopted equation for the dark matter number density, fluidlike equations that couple the evolution of number density and velocity dispersion, and a full numerical evolution of the phasespace distribution. We review the general motivation for these approaches and, for illustration, highlight three concrete classes of models where kinetic and chemical decoupling are intertwined in a way that quantitatively impacts the relic density: i) dark matter annihilation via a narrow resonance, ii) Sommerfeldenhanced annihilation and iii) `forbidden' annihilation to final states that are kinematically inaccessible at threshold. We discuss all these cases in some detail, demonstrating that the commonly adopted, traditional treatment can result in an estimate of the relic density that is wrong by up to an order of magnitude. The public release of DRAKE, along with several examples of how to calculate the relic density in concrete models, is provided at drake.hepforge.org
 Publication:

arXiv eprints
 Pub Date:
 March 2021
 arXiv:
 arXiv:2103.01944
 Bibcode:
 2021arXiv210301944B
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 23 pages, 12 figures