Yields of prompt and non-prompt J/psi, as well as Y(1S) mesons, are measured by the CMS experiment via their dimuon decays in PbPb and pp collisions at sqrt(sNN) = 2.76 TeV for quarkonium rapidity |y|<2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum pt, as well as collision centrality. For prompt J/psi with relatively high pt (6.5<pt<30 GeV/c), 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 J/psi, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Also the low-pt Y(1S) mesons are suppressed in PbPb collisions.

— The Large Hadron Collider (LHC), which is scheduled to begin operation in summer 2008, will collide pro-ton beams at a center of mass energy of 14 TeV. The Compact Muon Solenoid (CMS) detector is one of the two general-purpose experiments at the LHC, which will probe the TeV frontier of energies to search for new phenomena. One of the most promising early discoveries can be achieved by checking the dimuon signature. Dimuon events can be explored by CMS with high precision up to very high invariant masses. We present a strategy to measure the inclusive dimuon cross section with the first available data, and discuss possible discovery scenarios of high-mass dimuon resonances by searching for deviations in the invariant mass differential cross section spectrum and the forward-backward asymmetry. These measurements re-quire the development of dedicated methods to determine trigger, reconstruction, and selection efficiencies from data, which are discussed in detail.