  Many extensions of the SM contain hidden sectors which are uncharged under
the SM gauge group. The simplest model with an additional $U(1)$ group predicts
the existence of the new gauge boson, dark photon $Z_D$. In this work we
consider single production of dark photon $Z_D$ at the LHC and study its
discovery potential via the process $pp\rightarrow Z_D\gamma\rightarrow
ll\gamma$. After simulating the signal as well as the relevant backgrounds, the
numerical results show that the signal of $Z_D$ might be detected at the 14TeV
LHC.
