Study of the decay $D^0\to \rho (770{)}^{-}{e}^{+}{\nu }_e$

Abstract

We present a study of the semileptonic decay $D^0\to {\pi }^{-}{\pi }^0{e}^{+}{\nu }_e$ using an $e^{+}{e}^{-}$ annihilation data sample of $7.93{\mathrm{fb}}^{-1}$ collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The branching fraction of $D^0\to \rho (770{)}^{-}{e}^{+}{\nu }_e$ is measured to be $(1.439\pm 0.033(stat.)\pm 0.027(syst.))\times 10^{-3}$, which is a factor 1.6 more precise than previous measurements. By performing an amplitude analysis, we measure the hadronic form-factor ratios of $D^0\to \rho (770{)}^{-}{e}^{+}{\nu }_e$ at $q^2=0$ assuming the single-pole-dominance parametrization: $r_V=V(0)/A_1(0)=1.548\pm 0.079(stat.)\pm 0.041(syst.)$ and $r_2=A_2(0)/A_1(0)=0.823\pm 0.056(stat.)\pm 0.026(syst.)$.

12 pages, 3 figures