  We consider the complex inflaton field with a CP asymmetric term for its
potential. This CP asymmetric term produces the global charge of the inflaton
after inflation. With the assignment of the baryon number to the inflaton, the
baryon asymmetry of the universe is produced by inflaton's decay. In addition
to this, the $U(1)$ breaking term modulates the curvature of the inflaton
radial direction depending on its phase, which affects the tensor to scalar
ratio. In this paper, we have studied the relation between the baryon asymmetry
and the tensor to scalar ratio, then verified that the future CMB observation
could test this baryogenesis scenario with large tensor mode.
