Note on helicity amplitudes inD→Vsemileptonic decays

Abstract

Motivated by the recent extraction of the helicity amplitudes for the ${D}^{+}\ensuremath{\rightarrow}{\overline{K}}^{*0}\ensuremath{\mu}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ decay, done by the FOCUS collaboration, we determine helicity amplitudes for the ${D}^{+}\ensuremath{\rightarrow}{\overline{K}}^{*0}l{\ensuremath{\nu}}_{l}$, ${D}^{+}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}l{\ensuremath{\nu}}_{l}$ and ${D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\phi}l{\ensuremath{\nu}}_{l}$ semileptonic decays using the knowledge of the relevant form factors. The vector and axial form factors for $D\ensuremath{\rightarrow}Vl{\ensuremath{\nu}}_{l}$ decays are parametrized by including contributions of charm meson resonances and using the HQET and SCET limits. In the case that the vector form factor receives contributions from two poles while axial form factors are dominated by a single pole for ${D}^{+}\ensuremath{\rightarrow}{\overline{K}}^{*0}l{\ensuremath{\nu}}_{l}$, we obtain better agreement with the experimental result then when all of them are dominated by single poles.