Form Factors in D Meson Decays

Abstract

We study the $d\Gamma /d{q}^2$ spectra and the branching fractions of the $D$ meson exclusive semileptonic decays with the lepton mass effects into consideration. We investigate their sensitivity to form factor models, and find that the decays to a pseudoscalar meson and a lepton pair are sensitive to the property of the form factor $F_1(q^2)$, and those to a vector meson and a lepton pair to the form factor $A_1(q^2)$. We also analyze the experimental results of the branching fractions $\mathcal{B}({\mathcal{D}}^0\to {\mathcal{K}}^{-}(or{\pi }^{-}){\pi }^{+})$ and $\mathcal{B}({\mathcal{D}}^0\to {\mathcal{K}}^{-}(or{\pi }^{-})e^{+}\nu )$, and show that it is implied that $F_1(q^2)$ is of dipole type, instead of simple pole type which is commonly assumed.

18 pages, 8 postscript figures. We corrected a mistake in computer program for the numerical calculation, and modified the title and contents