Feasibility study of CP Violation in τ-→ΚSπ-ντ decays at Super Tau Charm Facility

We report a feasibility study for violation in \begin{document}$\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$\end{document} decays at a Super Tau Charm Facility (STCF). With an expected luminosity of 1 ab \begin{document}$^{-1}$\end{document} collected by STCF per year at a center-of-mass energy of 4.26 GeV, the statistical sensitivity for CP violation is determined to be of order \begin{document}$9.7\times10^{-4}$\end{document} by measuring the decay-rate difference between \begin{document}$\tau^{+}\rightarrow K_{S}\pi^{+}\bar{\nu}_{\tau}$\end{document} and \begin{document}$\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$\end{document} . The analysis is performed using a reliable fast simulation software package, which can describe the detector responses properly and vary the responses flexibly for further optimization. Moreover, the energy-dependent efficiencies for reconstructing \begin{document}$\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$\end{document} are presented. The expected CP sensitivity is proportional to \begin{document}$1/\sqrt{\cal{L}}$\end{document} in the energy region from 4.0 to 5.0 GeV. The sensitivity of CP violation is of order \begin{document}$3.1\times10^{-4}$\end{document} with 10 ab \begin{document}$^{-1}$\end{document} integrated luminosity, which is equivalent to ten years' data taking in this energy region at STCF.