Renormalization in gravitational leptogenesis with pseudo-scalar-tensor
  coupling
  We consider the renormalization in the pseudo-scalar inflation models with
the gravitational Chern-Simons term. In this model, lepton asymmetry is
generated from the chiral gravitational waves produced due to the Chern-Simons
term through the gravitational chiral anomaly. However, it is known that the
naive estimate of the expectation value of the gravitational Chern-Pontryagin
density as well as the resultant lepton number density depend on the UV-cutoff
scale, which raises a question on their validity. In this paper, we propose a
way to renormalize the expectation value of the Chern-Pontryagin density to
remove the UV-cutoff dependence. We also discuss the renormalized lepton number
density when we adopt the minimal subtraction scheme and the viability of the
gravitational leptogenesis scenario.
