Abundance of Cosmological Relics in Low-Temperature Scenarios

Mitsuru Kakizaki
2007 AIP Conference Proceedings  
We investigate the relic density n χ of non-relativistic long-lived or stable particles χ in cosmological scenarios in which the temperature T is too low for χ to achieve full chemical equilibrium. The case with a heavier particle decaying into χ is also investigated. We derive approximate solutions for n χ (T ) which accurately reproduce numerical results when full thermal equilibrium is not achieved. If full equilibrium is reached, our ansatz no longer reproduces the correct temperature
more » ... ence of the χ number density. However, it does give the correct final relic density, to an accuracy of about 3% or better, for all cross sections and initial temperatures. This talk is based on our work in Ref. [1] .
doi:10.1063/1.2735273 fatcat:dyxk4nlys5g2vkpbkwz4bcvwgq