The Glueball Superpotential for G_2

We perform a perturbative computation of the glueball superpotential for N=1 supersymmetric G_2 gauge theory with one adjoint matter multiplet. We find that the computation simplifies because the bosonic momentum integral cancels with the fermionic momentum integral. The effective glueball superpotential allows us to gain an insight into non-perturbative aspect of the supersymetric gauge theory.