Resonant and nonresonant D+→K-π+l+νl semileptonic decays

We analyze the semileptonic decay D+→K-π+l+νl using an effective Lagrangian developed previously to describe the decays D→Plνl and D→Vlνl. Light vector mesons are included in the model which combines the heavy quark effective Lagrangian and chiral perturbation theory approach. The nonresonant and resonant contributions are compared. With no new parameters the model correctly reproduces the measured ratio Γnres/Γnresthinsp+thinspres. We also present useful nonresonant decay distributions. Finally, a similar model, but with a modified current which satisfies the soft pion theorems at the expense of introducing another parameter, is analyzed and the results of the models are compared. copyright 1998 The American Physical Society