Physical Review Letters
A search for Z bosons in the þ decay channel has been performed in PbPb collisions at √sNN = 2:76 TeV with the CMS detector at the LHC, in a 7:2 b 1 data sample. The number of opposite-sign muon pairs observed in the 60–120 GeV=c2 invariant mass range is 39, corresponding to a yield per unit of rapidity (y) and per minimum bias event of ½33:8 5:5ðstatÞ 4:4ðsystÞ 10 8, in the jyj < 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.
Chatrchyan, S., Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Bergauer, T., . . . Weinberg, M. (2011). Study of Z boson production in PbPb collisions at √s NN=2.76TeV. Physical Review Letters, 106(21)