Mainly axion cold dark matter from natural supersymmetry

Abstract

By eschewing fine-tuning from the electroweak and QCD sectors of supersymmetry (natural supersymmetry or SUSY), and by invoking the Kim-Nilles solution to the SUSY $\ensuremath{\mu}$ problem, one is lead to models wherein the dark matter is comprised of a mixture of axions and Higgsino-like WIMPs. Over a large range of Peccei-Quinn breaking scale ${f}_{a}\ensuremath{\sim}{10}^{9}--{10}^{12}\text{ }\text{ }\mathrm{GeV}$, one then expects about 90%--95% axion dark matter. In such a scenario, both axion and WIMP direct detection may be expected.