oS(LATTICE 2007)365 High precision study of B¤Bpi coupling

The B¤Bpi coupling is a fundamental parameter of chiral effective Lagrangian with heavy-light mesons and can constrain the B! pilν form factor in the soft pion limit which will be useful for precise determination of jVubj. We compute the B¤Bpi coupling with the static heavy quark and the O(a)-improved Wilson light quark. Simulations are carried out with n f = 2 unquenched 123£24 lattices at β = 1:80 generated by CP-PACS collaboration. Following the quenched study by Negishi et al., we employ the all-to-all propagator with 200 low eigenmodes as well as HYP smeared link to improve the statistical accuracy