Title:Semileptonic D-decays at BESIII

Abstract:We present here three analyses of semileptonic $D$-meson decays based on the 2.92 fb$^{-1}$ of data collected by the BESIII experiment in 2010 and 2011 at the $\psi$(3770) peak. For the decay $D^{+}\to K^{-}\pi^{+}e^{+}\nu_{e}$, its branching fraction is measured over the whole $m_{K\pi}$ region and in the $\overline{K}^{*}(892)^{0}$ window, respectively. A partial wave analysis (PWA) is performed, indicating an \emph{S}-wave contribution of about 6\%. The \emph{S}-wave phase and the form factors are measured by the PWA and in a model-independent way. For the decay $D^{+}\to \omega e^{+}\nu_{e}$, an improved measurement of the branching fraction is performed and the form factors are determined for the first time. $D^{+}\to \phi e^{+}\nu_{e}$ is searched and an improved upper limit at 90\% confidence level is set. For the decay $D^{+}\to K_{L} e^{+}\nu_{e}$, its branching fraction is measured for the first time and the $CP$ asymmetry is presented. The product of the hadronic form factor and the CKM matrix element, $f_{+}^{K}(0)|V_{cs}|$, is also determined in this decay.