Heavy quark mass dependence of semileptonic form factors for B decays

We present our study of the dependence of the heavy-to-light semileptonic B decay form factors on the heavy-light meson mass M_PS. Simulations are made over a range of the heavy quark mass covering both the charm and bottom quarks using the O(a)-improved clover action at β = 5.9 on a 16 ³ × 40 and 24 ³ × 64 lattice. We find that a weak dependence of form factors on M_PS observed in previous studies in the region of charm quark persists up to the region of b quark. The soft relation f ⁰(q ²_max)= {f _B}/{f _π} is examined and found to be largely violated.