A Reappraisal on Dark Matter Co-annihilating with a Top/Bottom Partner [CL]


We revisit the calculation of relic density of dark matter particles co-annihilating with a top or bottom partner, by properly including the QCD bound-states (onia) effects of the colored partners, as well as the relevant electroweak processes which become important in the low mass region. We carefully set up the complete framework that incorporates the relevant contributions and investigate their effects on the cosmologically preferred mass spectrum, which turn out to be comparable in size to those coming from the Sommerfeld enhancement. We apply the calculation to three scenarios: bino-stop and bino-sbottom co-annihilations in supersymmetry, and a vector dark matter co-annihilating with a fermionic top partner. In addition, we confront our analysis of the relic abundance with recent direct detection experiments and, in the case of bino-sbottom co-annihilation, collider searches at the LHC.

Read this paper on arXiv…

W. Keung, I. Low and Y. Zhang
Fri, 10 Mar 17

Comments: 19 pages, 6 figures