Thermally Producing and Weakly Freezing-out Dark Matter in Bouncing   Universe
  We investigate the production and freeze-out of dark matter with a constant thermally averaged cross-section in a generic bouncing universe framework. Our result shows that, there is a novel avenue that dark matter is produced thermally and take a weakly freezing-out process, besides two previously known cases, the thermally production & strongly freezing-out case and the non-thermally production & weakly freezing-out case, in which the relic abundance of dark matter are inverse and proportional to its cross-section respectively. We calculated the relic abundance of dark matter for this new case, and find its relic abundance is independent of its cross-section. We also present the cosmological constraints on the cross-section and mass relation of dark matter for this new case. 
Changhong Li
astro-ph.CO