Semileptonic and rare B meson decays into a light pseudoscalar meson

In the framework of a QCD relativistic potential model we evaluate the form factors describing the exclusive decays B --> pi l nu and B --> Kl(+)l(-). The present calculation extends a previous analysis of B meson decays into light vector mesons. We find results in agreement with the data, when avai lable, and with the theoretical constraints imposed by the Callan-Treiman r elation and the infinite heavy quark mass limit. (C) 1999 Published by Else vier Science B.V. All rights reserved.