Measurement of charged particle RAA at high pT in PbPb collisions at sNN=2.76TeV with CMS

Charged particle transverse momentum (pT) spectra have been measured by CMS for pp and PbPb collisions at the same sNN=2.76 TeV collision energy per nucleon pairs. Calorimeter-based jet triggers are employed to enhance the statistical reach of the high-pT measurements. The nuclear modification factor (RAA) is obtained in bins of collision centrality for the PbPb data sample dividing by the measured pp reference spectrum. In the range pT=5 - 10 GeV/c, the charged particle yield in the most central PbPb collisions is suppressed by up to a factor of 7. At higher pT, this suppression is significantly reduced, approaching a factor of 2 for particles with pT=40 - 100 GeV/c.