J/Psi and Z production in p+p and Pb+Pb collisions at the LHC measured with the ATLAS detector.

Measurements of the production of J/Ψ mesons and Z bosons at the LHC provides tests of the Standard Model in a new energy regime for proton-proton collisions, as well providing a probe of the matter produced in heavy ion collisions. Presented are measurements of the Z boson production cross section, both inclusive and in association with additional jets, observation of the Z through the decay to tau spp = 7 TeV. Good pairs, and J/Ψ production cross sections in proton-proton data at √ agreement is seen between the data and Standard Model predictions. Additionally, the production of J/Ψ mesons and Z bosons in lead-lead data at √ sNN =2.76TeV are measured. A decrease in the normalised J/Ψ yield with decreasing centrality is observed. However, no conclusions on the centrality dependence of the normalised Z yield may be drawn.