  A Dirac fermion carrying an integral weak isospin and the vanishing
hypercharge is considered as its neutral component can be a promising dark
matter candidate (called the minimal dark matter) whose mass is of order 100
GeV. While the symmetric population annihilates away due to a rapid gauge
interaction, its asymmetric abundance is supposed to be produced by the decay
of a right-handed neutrino superfield in the supersymmetric type I seesaw
mechanism. The efficiencies for generating the dark matter and lepton
asymmetries are calculated by solving a set of approximate Boltzmann equations.
A spectacular feature of this scenario is the existence of a long-lived singly-
or multiply-charged scalar and a shorter-lived singly-charged fermion whose
tracks can be readily looked for at the LHC.
