Measurement of charmonium production in PbPb collisions at image with CMS

The Compact Muon Solenoid (CMS) is fully equipped to measure hard probes in the di-muon decay channel in the high multiplicity environment of nucleus-nucleus collisions. Such probes are especially relevant for studying the quark–gluon plasma since they are produced at early times and propagate through the medium, mapping its evolution. CMS has measured the nuclear modification factors of non-prompt image (from b-hadron decays) and prompt image in PbPb collisions at image. For prompt image with relatively high image (image), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. In the same kinematic range, a suppression of non-prompt image, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Results from the 2010 data taking period are reported and an outlook on the 2011 data analysis will be given.