Exotic nuclei with open heavy flavor mesons

We discuss stable exotic nuclei bound with $\bar{D}$ and $B$ mesons with respecting heavy quark symmetry. We indicate that an approximate degeneracy of $\bar{D}$($B$) and $\bar{D}^{*}$($B^{*}$) mesons plays an important role, and discuss the stability of $\bar{D}N$ and $BN$ bound states. We find the binding energies 1.4 MeV and 9.4 MeV for each state in the $J^{P}=1/2^{-}$ with $I=0$ channel, and no bound states with the other channels. These states are stable in the strong decay, and can be observed in the weak decay processes $\bar{D} N \rightarrow K^{+}\pi^{-} \pi^{-} + p$, and $B N \rightarrow D^{-}\pi^{+} + p$. We discuss also possible existence of exotic nuclei $\bar{D}NN$ and $BNN$. The existence of $\bar{D}N$ and $BN$ bound states would provide an opportunity to probe new exotic states near the thresholds, and, as well as strangeness nuclei, open a new way to investigate for exotic nuclei with variety of multi-flavor explored at future hadron facilities such as J- PARC (Japan Proton Accelerator Research Complex) and GSI (Gesellschaft f\"ur Schwerionenforschung).