  The BB-mode correlation angular power spectrum of CMB is studied for
primordial massive gravitational waves for several inflation models. The
comparative study of the angular power spectrum with the joint BICEP2/Keck
Array and Planck data suggests further constraint on the lower and upper bounds
on the mass of primordial gravitons. Assuming a modified dispersion relation,
the mass of primordial graviton is also calculated. The resulting constraint
also agrees with other theoretical estimates.
