Search for the rare decays $J/\psi \to D_s^{-}{\rho }^{+}$ and $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$

A search for the rare decays of $J/\psi \to D_s^{-}{\rho }^{+}+\mathrm{c}.\mathrm{c}.$ and $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}+\mathrm{c}.\mathrm{c}.$ is performed with a data sample of 225.3-million $J/\psi$ events collected with the Beijing Spectrometer III detector. No evident signal is observed. Upper limits on the branching fractions are determined to be $\mathcal{B}(J/\psi \to D_s^{-}{\rho }^{+}+\mathrm{c}.\mathrm{c}.)<1.3\times {10}^{-5}$ and $\mathcal{B}(J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}+\mathrm{c}.\mathrm{c}.)<2.5\times {10}^{-6}$ at the 90% confidence level.

Figure 1

Leading-order Feynman diagrams for (a) $J/\psi \to D_s^{-}{\rho }^{+}$ and (b) $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$.

Figure 2

The invariant mass distributions of resonance candidates for (a) ${\rho }^{+}$ from $J/\psi \to D_s^{-}{\rho }^{+}$, ${\rho }^{+}\to {\pi }^{+}{\pi }^0({\pi }^0\to \gamma \gamma )$ and (b) ${\overline{K}}^{*0}$ from $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$, ${\overline{K}}^{*0}\to K^{-}{\pi }^{+}$. The requirements of $M_{{\pi }^0{\pi }^{+}}\in (0.62,0.95)\mathrm{GeV}/c^2$ and $M_{K^{-}{\pi }^{+}}\in (0.82,0.98)\mathrm{GeV}/c^2$ are shown in the figures by vertical arrows. The dots with error bars are data, while the histograms represent distributions of the arbitrarily normalized exclusive signal MC events.

Figure 3

$P_{\text{miss}}$ distributions for the decay of (a) $J/\psi \to D_s^{-}{\rho }^{+}$ and (b) $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$. The requirement $P_{\text{mis}s}>0.1\mathrm{GeV}/c$ is shown in the figures by vertical arrows. The dots with error bars are data, while the histograms represent distributions of the arbitrarily normalized exclusive signal MC events.

Figure 4

$U_{\text{miss}}$ distributions for the decay of (a) $J/\psi \to D_s^{-}{\rho }^{+}$ and (b) $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$. The requirements $|U_{\text{miss}}|<0.05\mathrm{GeV}$ and $|U_{\text{miss}}|<0.02\mathrm{GeV}$ are shown in the figures by vertical arrows. The dots with error bars are data, while the histograms represent distributions of the arbitrarily normalized exclusive signal MC events.

Figure 5

Mass distributions recoiling against (a) ${\rho }^{+}$ from $J/\psi \to D_s^{-}{\rho }^{+}$ and (b) ${\overline{K}}^{*0}$ from $J/\psi \to {\overline{D}}^0{\overline{K}}^{*0}$. Data are shown by dots with error bars. The solid histograms are the unnormalized MC-simulated signal events, while the dashed histograms are background distributions from selected inclusive MC events.