Possible Excess in Charged Current Events with High-Q^2 at HERA from Stop and Sbottom Production

We investigate a production process $e^+p \to \st X \to \sb W^+ X$ at HERA, where we consider a decay mode $\sb \to \bar{\nu}_e d$ of the sbottom in the framework of an R-parity breaking supersymmetric standard model. Both processes of the stop production $e^+ d \to \st$ and the sbottom decay $\sb \to \bar{\nu}_e d$ are originated from an R-parity breaking superpotential $\lambda'_{131} \hat{L}_1 \hat{Q}_3 \hat{D^c}_1$. One of signatures of the process should be a large missing transverse momentum plus multijet events corresponding to hadronic decays of the $W$. It is shown that the signal could appear as an event excess in the charged current (CC) processes $e^+p \to \nu X$ with the high $Q^2$ at HERA. We compare expected event distributions with the CC data recently reported by the H1 and ZEUS groups at HERA. Methods for extracting the signal from the standard CC processes are also discussed.