UC Irvine

Using 2.92 fb-1 of electron-positron annihilation data collected at s=3.773 GeV with the BESIII detector, we obtain the first measurements of the absolute branching fraction B(D+→KL0e+νe)=(4.481±0.027(stat)±0.103(sys))% and the CP asymmetry ACPD+→KL0e+νe=(-0.59±0.60(stat)±1.48(sys))%. From the D+→KL0e+νe differential decay rate distribution, the product of the hadronic form factor and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, f+K(0)|Vcs|, is determined to be 0.728±0.006(stat)±0.011(sys). Using |Vcs| from the SM constrained fit with the measured f+K(0)|Vcs|, f+K(0)=0.748±0.007(stat)±0.012(sys) is obtained, and utilizing the unquenched Lattice QCD (LQCD) calculation for f+K(0), |Vcs|=0.975±0.008(stat)±0.015(sys)±0.025(LQCD).