Speaker
BESIII Collaboration
Description
The BESIII experiment at BEPCII accumulated the world's largest $e^+e^-$ collision samples at 3.773 and 4.178 GeV. We have studied the purely leptonic decays $D^+_{(s) }\to l^+v$, and the semi-leptonic decays of $D^0\to K(\pi)^-e^+v_e$, $K(\pi)^-\mu^+v_\mu$, $D^+\to\bar K^0(\pi^0)e^+v_e$, $\bar K^0(\pi^0)\mu^+v_\mu$ and $D_s^+\to K^{(*)0}e^+v_e$. We will report the improved measurements of the branching fractions of these decays and the CKM matrix elements $|V_{cs(d)}|$, the $D_{(s)}^+$ decay constants, the form factors of $D_{(s)}^+$ semi-leptonic decays. These results are important to calibrate the LQCD calculations of $D_{(s)}^+$ decay constants and form factors and to test the CKM unitarity.
