Light quark dependence of the Isgur-Wise function

Abstract

Heavy quark spin flavor symmetry allows the form factors for B→ D and B→D ∗ semileptonic decay to be written in terms of a single universal function, the Isgur-Wise function. In the SU(3) v limit, the Isgur-Wise function is independent of light quark flavor. Leading SU(3) v violating corrections to the ratio of Isgur-Wise functions for B S versus B decay are computed in chiral perturbation theory. The correction is velocity dependent, but vanishes at zero recoil as required by heavy quark symmetry.