Weak coupling expansion of a chiral gauge theory on a lattice in the overlap formulation

Weak coupling expansion of a chiral gauge theory on a lattice is discussed in the overlap formulation. We analyze the fermion propagator and the fermion-fermion-gauge boson vertex in the one loop level. The chiral properties of the propagator and vertex are correctly preserved without tuning the parameters involved even after the one-loop renormalization, and the ultraviolet divergent parts agree with the continuum theory. Our analysis, together with the existing studies on the vacuum polarization and the gauge boson n-point functions, completes the proof of the renormalizability of this formulation to the one loop level. On leave of absence from: Department of Physics, University of Tokyo, Tokyo, 113 Japan.