W and Z boson production in PbPb collisions at 2.76 TeV with CMS

Electroweak W and Z boson measurements in PbPb collisions at nucleon-nucleon center of mass energy $\sqrt{s} = 2.76$~TeV at the LHC using the CMS detector are presented. The W analysis is based on 2010 PbPb data corresponding to an integrated luminosity of 7.3 $\mu$b$^{-1}$ and also on 2011 pp data corresponding to an integrated luminosity of 231 nb$^{-1}$. The Z analysis is based on 2011 PbPb data with an integrated luminosity of 150 $\mu$b$^{-1}$ . The dependence of W and Z production as a function of PbPb collision centrality is studied and shown to scale with the number of NN binary collisions. $W^{+}$ and $W^{-}$ yields in PbPb and pp collisions are in agreement once we take into account the proton and neutron composition in Pb nuclei. The muon charge asymmetry is measured as a function of pseudo-rapidity and is in agreement with next-to-leading order perturbative QCD calculations.