Search for Color-Suppressed B Hadronic Decay Processes with CLEO

Using 3.1 fb$^{-1}$ of data accumulated at the $\Upsilon$(4S) by the CLEO-II detector, corresponding to 3.3 million $B\bar{B}$ pairs, we have searched for the color-suppressed $B$ hadronic decay processes: $\bar{B}^0 \to D^0 (D^{*0}) X^0$, where $X^0$ is a light neutral meson $\pi^0$, $\rho^0$, $\eta$, $\eta'$ or $\omega$. No obvious signal is observed. We set 90 % C.L. upper limits on these modes, varying from $1.2 \times 10^{-4}$ for $\bar{B}^0 \to D^0 \pi^0$ to $1.9 \times 10^{-3}$ for $\bar{B}^0 \to D^{*0} \eta'$.