Space-time Supersymmetry in Asymmetric Orbifold Models
  We study the condition for the appearance of space-time supercharges in twisted sectors of asymmetric orbifold models. We present a list of the asymmetric $Z_N$-orbifold models which satisfy a simple condition necessary for the appearance of space-time supercharges in twisted sectors. We investigate whether or not such asymmetric orbifold models possess $N=1$ space-time supersymmetry and obtain a new class of $N=1$ asymmetric orbifold models. It is pointed out that the result of space-time supersymmetry does not depend on any choice of a shift if the order of the left-moving degrees of freedom is preserved. 
Toshihiro Sasada