Form Factors for B→π and D→π Transitions
Armed with the information on the form factor f + (0) inferred from recent CLEO measurements of SU(3)-breaking effects in charmed meson decays, we have studied the form factor f + . In the heavy quark limit, f Bπ + (q ) is related to f + (q ) in the kinematic region close to zero recoil. Assuming pole dominance for its q dependence, f + (0) is estimated to be ≈ 0.39 . If the requirement of heavy quark symmetry is relaxed so that it applies only to soft pion emissions from the heavy meson, we find that f + (0) is more likely of order 0.55 ∼ 0.60 .