Anatomy of Coannihilation with a Scalar Top Partner
  We investigate a simplified model of dark matter where a Majorana fermion
$\chi$ coannihilates with a colored scalar top partner $\tilde{t}$. We explore
the cosmological history, with particular emphasis on the most relevant
low-energy parameters: the mass splitting between the dark matter and the
coannihilator, and the Yukawa coupling $y_\chi$ that connects these fields to
the Standard Model top quarks. We also allow a free quartic coupling
$\lambda_h$ between a pair of Higgs bosons and $\tilde{t}$ pairs. We pay
special attention to the case where the values take on those expected where
$\tilde{t}$ corresponds to the superpartner of the right-handed top, and $\chi$
is a bino. Direct detection, indirect detection, and colliders are
complementary probes of this simple model.
