Non-SUSY Gepner Models with Vanishing Cosmological Constant

In this article we discuss a construction of non-SUSY type II string vacua with the vanishing cosmological constant at the one loop level based on the generic Gepner models for Calabi-Yau 3-folds. We make an orbifolding of the Gepner models by $Z_2 \times Z_4$, which asymmetrically acts with some discrete torsions incorporated. We demonstrate that the obtained type II string vacua indeed lead to the vanishing cosmological constant at the one loop, whereas any space-time supercharges cannot be constructed as long as assuming the chiral forms such as '$Q^{\alpha}_L \equiv \oint dz J_L^{\alpha}(z)$'. We further discuss possible generalizations of the models described above.