First study of B → π semileptonic decay form factors using NRQCD

Abstract

We present a quenched calculation of the form factors of the semileptonic weak decay B → πl ν with O(1/ m Q ) NRQCD heavy quark and Wilson light quark on a 16 3 × 32 lattice at β = 5.8. The form factors are evaluated at six heavy quark masses, in the range of m Q ∼ 1.5 – 8 GeV. 1/ m Q dependence of matrix elements are investigated and compared with HQET predictions. We observed clear signal for the form factors near q max 2, even at the b-quark mass range. f 0( q max 2) is compared with f B f π based on the soft poin theorem and significant difference is observed.