Study of the decay ${D}^{0}\to {\overline{K}}^{0}{\pi }^{-}{e}^{+}{\nu }_{e}$

We report a study of the decay ${D}^{0}\to {\overline{K}}^{0}{\pi }^{-}{e}^{+}{\nu }_{e}$ based on a sample of $2.93\text{}\text{}{\mathrm{fb}}^{-1}$ ${e}^{+}{e}^{-}$ annihilation data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. The total branching fraction is determined to be $B\left({D}^{0}\to {\overline{K}}^{0}{\pi }^{-}{e}^{+}{\nu }_{e}\right)=\left(1.434±0.029\left(\mathrm{stat}.\right)±0.032\left(\mathrm{syst}.\right)\right)%$, which is the most precise to date. According to a detailed analysis of the involved dynamics, we find this decay is dominated with the ${K}^{*}\left(892{\right)}^{-}$ contribution and present an improved measurement of its branching fraction to be $B\left({D}^{0}\to {K}^{*}\left(892{\right)}^{-}{e}^{+}{\nu }_{e}\right)=\left(2.033±0.046\left(\mathrm{stat}.\right)±0.047\left(\mathrm{syst}.\right)\right)%$. We further access their hadronic form-factor ratios for the first time as ${r}_{V}=V\left(0\right)/{A}_{1}\left(0\right)=1.46±0.07\left(\mathrm{stat}.\right)±0.02\left(\mathrm{syst}.\right)$ and ${r}_{2}={A}_{2}\left(0\right)/{A}_{1}\left(0\right)=0.67±0.06\left(\mathrm{stat}.\right)±0.01\left(\mathrm{syst}.\right)$. In addition, we observe a significant ${\overline{K}}^{0}{\pi }^{-}\text{}\text{}S$-wave component accounting for $\left(5.51±0.97\left(\mathrm{stat}.\right)±0.62\left(\mathrm{syst}.\right)\right)%$ of the total decay rate.