Semileptonic meson decays in the quark model: An update

We present the predictions of the ISGW2 model, an update of the ISGW quark model for semileptonic meson decays. The updated model incorporates a number of features which should make it more reliable, including the constraints imposed by heavy quark symmetry, hyperfine distortions of wave functions, and form factors with more realistic high recoil behaviors.