A New Mechanism For Baryogenesis Living Through Electroweak Era
  We present a new mechanism for baryogenesis by introducing a heavy vector-like SU(2)_W singlet quark(s) with Q_{em}=2/3 quark U or Q_{em}=-1/3 quark D. The lifetime of the heavy quark is assumed to be in the range 2 \times 10^{-11}s < t < 1s. Being SU(2)_W singlet, it survives the electroweak phase transition era. It mixes with SU(2)_W doublet quarks with tiny mixing angles to satisfy the FCNC constraints, where a simple Z_2 symmetry is suggested for realizing this scheme. The heavy quark asymmetry is generated in analogy with the old GUT scenario. 
Hyung Do Kim, Jihn E. Kim and Takuya Morozumi