  The high-scale supersymmetry (SUSY) breaking scenario is now attracting many
attentions, because it is consistent with almost all experiments of particle
physics, astrophysics, and cosmology performed so far: e.g. it is possible to
explain the Higgs mass of about 126GeV and contains WIMP dark matter
candidates. In the scenario, gauginos are predicted to be around the TeV scale,
and thus within a kinematically accessible range of near future experiments.
Calculation of the thermal relic abundance for gaugino (bino or wino) dark
matter is then of particular importance in order to clarify its mass consistent
with cosmology and to determine future directions for exploring the high-scale
SUSY breaking scenario. In this article, we calculate the abundance of the
gaugino dark matter, with especially focusing on various coannihilations
between gauginos, which has not been extensively studied so far. Our
calculation involves the Sommerfeld effect on wino and gluino annihilations,
which is known to give significant contributions to their cross sections. Based
on obtained results, we discuss some implications to gaugino searches at
collider and indirect detection experiments of dark matter.
