  In this work, we suggest that hard-pion chiral perturbation theory may be
applicable to the real parts of nonleptonic B^{+} to D^{0}P^{+} and B^{+} to
Dbar^{0}P^{+} (P=K,pi) decay amplitudes. These amplitudes play an important
role in the extraction of the angle gamma in the b-d unitarity triangle of the
CKM matrix, and their real parts can be computed using lattice QCD. We
construct the leading-order operator in the chiral expansion for these
nonleptonic decays, and discuss the generic features of the
next-to-leading-order terms.
