Mixed (Cold+Warm) Dark Matter in the Bino-Wino co-annihilation scenario
  We study phenomenological aspects of the bino-wino co-annihilation scenario
in high-scale supersymmetry breaking models. High-scale SUSY breaking scenarios
are considered to be promising possibility after the discovery of the Higgs
boson with a mass around 126 GeV. In this paper, we discuss the bino lightest
supersymmetric particle (LSP) accompanied by the at most around 30 GeV heavier
wino. With the suitable mass splitting between the bino and the wino, the bino
LSP has the correct relic abundance of dark matter. For the smaller mass
splitting, the late-time decay of the gravitino can provide the correct
abundance of the bino dark matter. It is extremely challenging to find signals
from the bino dark matter in direct and indirect detections. By utilizing
multi-jets plus missing transverse momentum events at the LHC, we can
constraint the gluino mass and thus probe the bino-wino co-annihilation
scenario indirectly. The collider experiment, however, can not search the bino
dark matter directly. In this paper, we suggest the direct probe of the bino
dark matter. We show that the bino dark matter leaves imprints on the
small-scale matter power spectrum when the bino dark matter is produced by the
decay of the gravitino. The non-thermal bino dark matter behaves as mixed
(cold+warm) dark matter.
