Yukawa cosmology and intersecting brane models

In string theory, stabilization of moduli fields and their cosmological implications have been discussed by many authors. In this paper we do not consider conventional modulus, nor relative distance between two branes. We focus our attention to a relative position of three branes and discuss its cosmological problem. In general, stabilization of the relative position of three intersecting branes is much more difficult than the stabilization of conventional moduli fields. We will show that the area of the corresponding triangle is not a free parameter. Effective potential is generated from loop corrections in the low energy effective theory, which involves Yukawa couplings. Any model of intersecting brane world that utilizes finely tuned relative position of three branes requires another mechanism that keeps triangles at their desirable value. We consider a simplest model and discuss how relative positions of intersecting three branes affect cosmology.