X(3872) as a molecular $D{\bar{D}}^{\ast }$ state in the Bethe-Salpeter equation approach

We discuss the possibility that the X(3872) can be a $D{\bar{D}}^{\ast }$ molecular bound state in the Bethe-Salpeter equation approach in the ladder and instantaneous approximations. We show that the $D{\bar{D}}^{\ast }$ bound state with quantum numbers $J^{PC}=1^{++}$ exists. We also calculate the decay width of $X(3872)\to \gamma J\mathrm{/}\psi$ channel and compare our result with those from previous calculations.