Quarkonia production in heavy ion collisions at TeV energies

The CMS experiment at the LHC has measured the production of several quarkonium S states in both PbPb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV. The various states are measured from the dimuon invariant mass spectra. The yields of quarkonia in PbPb collisions are lower than expected from the corresponding pp yields scaled by the number of nucleon-nucleon collisions. This suppression is stronger for more central collisions. For the $J/\psi$ at high $p_T$ the suppression is stronger than that observed at lower energies and high $p_T$ and stronger than at more forward rapidities and low $p_T$. The suppression is weakest for the $\Upsilon(1S)$ but increases as one moves to the $J/\psi$, $\psi(2S)$ the $\Upsilon(2S)$ and finally the $\Upsilon(3S)$.