Photoproduction of J/psi and high mass e+e- in ultra-peripheral Au + Au collisions at root s(NN) = GeV

We present the first measurement of photoproduction of J/Ψ and of two-photon production of high-mass e+e- pairs in electromagnetic (or ultra-peripheral) nucleus-nucleus interactions, using Au + Au data at √sNN. The events are tagged with forward neutrons emitted following Coulomb excitation of one or both Au* nuclei. The event sample consists of 28 events with me+e- > 2 GeV/c2 with zero like-sign background. The measured cross sections at midrapidity of dσ/dy (J/Ψ + Xn, y = 0) = 76 ± 33(stat) ± 11(syst) μb and d2σ/dm dy (e+e- + Xn, y = 0) = 86 ± 23(stat) ± 16(syst) μb/(GeV/c2) for me+e- (elementof) [2.0,2.8] GeV/c2 have been compared and found to be consistent with models for photoproduction of J/Ψ and QED based calculations of two-photon production of e+e- pairs.