J/$\psi $ photo-production at the Relativistic Heavy Ion Collider with STAR.

Ultra-peripheral collision events are effectively photo-production on nuclear targets. Relativistic heavy ions carry strong transverse electromagnetic fields that can be treated as sources of quasi-real virtual photons. The ions interact through photon-pomeron and photon-photon collisions at impact parameters more than twice the nuclear radius, so hadronic interactions are suppressed. These events also provide an ideal proving ground for new programs in e$+$A physics. We present recent results from the J/$\psi $ photo-production measurement using 200GeV Au$+$Au collisions in the STAR experiment at RHIC. The p$_{\mathrm{T}}$ distribution of the J/$\psi $ mesons peaks at very low p$_{\mathrm{T}}$, consistent with expectations for coherent photo-production. Because of its heavy mass, the J/$\psi $ meson has sufficient virtuality to probe the Au wave function deeply enough to discern the possible presence of gluon shadowing. We will present the measurement of J/$\psi $ cross section in 200GeV Au$+$Au collisions, as well as a distribution of J/$\psi $ rapidity within $|y| < 1$. Possible theory comparisons are also discussed.