Search for the charmonium weak decay $\psi (2S)\to D_s^{-}{\pi }^{+}+c.c.$ and $\psi (2S)\to D_s^{-}{\rho }^{+}+c.c.$

Abstract

Using the data sample of $(2712.4\pm 14.3)\times 10^6$ $\psi (2S)$ events collected with the BESIII detector at the center-of-mass energy $\sqrt{s}=3.686\mathrm{GeV}$, we search for the weak decays $\psi (2S)\to D_s^{-}{\pi }^{+}+c.c.$ and $\psi (2S)\to D_s^{-}{\rho }^{+}+c.c.$ for the first time. Since no signal excess above the background is observed, the upper limits on the branching fractions at the 90\% confidence level are set to be $1.4\times 10^{-6}$ and $7.0\times 10^{-6}$ for $\psi (2S)\to D_s^{-}{\pi }^{+}+c.c.$ and $\psi (2S)\to D_s^{-}{\rho }^{+}+c.c.$, respectively.