%0 Journal Article %T String Theory on G_2 Manifolds Based on Gepner Construction %A Tohru Eguchi %A Yuji Sugawara %J Physics %D 2001 %I arXiv %R 10.1016/S0550-3213(02)00187-6 %X We study the type II string theories compactified on manifolds of $G_2$ holonomy of the type $({Calabi-Yau 3-fold} \times S^1)/\bz_2$ where $CY_3$ sectors realized by the Gepner models. We construct modular invariant partition functions for $G_2$ manifold for arbitrary Gepner models of the Calabi-Yau sector. We note that the conformal blocks contain the tricritical Ising model and find extra massless states in the twisted sectors of the theory when all the levels $k_i$ of minimal models in Gepner constructions are even. %U http://arxiv.org/abs/hep-th/0111012v3