Study of Z Boson Production in PbPb Collisions at √S(NN)=2.76 TeV.

A search for Z bosons in the µ + µ - decay channel has been performed in PbPb collisions at √s NN =2.76 TeV with the CMS detector at the LHC, in a 7.2 µb −1 data sample. The number of opposite-sign muon pairs observed in the 60-120 GeV/c 2 invariant mass range is 39, corresponding to a yield per unit of rapidity (Υ) and per minimum bias event of [33.8±5.5(stat)±4.4(syst)]×10 −8 , in the |Υ|<2.0 range. Rapidity, transverse momentum, and centrality dependencies are also measured. The results agree with next-to-leading order QCD calculations, scaled by the number of incoherent nucleon-nucleon collisions.