Chiral symmetry and exclusive B decays in the SCET

We construct a chiral formalism for processes involving both energetic hadrons and soft Goldstone bosons, which extends the application of soft-collinear effective theory to multibody B decays. The nonfactorizable helicity amplitudes for heavy meson decays into multibody final states satisfy symmetry relations analogous to the large energy form factor relations, which are broken at leading order in Λ/mb by calculable factorizable terms. We use the chiral effective theory to compute the leading corrections to these symmetry relations in B→Mnπℓν¯ and B→Mnπℓ+ℓ− decays, with one energetic meson Mn and one soft pion.