Upsilon measurements in pp, pPb abd PbPb collisions

The CMS experiment enables the measurement of the three Upsilon states Υ ( 1 S ) , Υ ( 2 S ) , Υ ( 3 S ) in pp, pPb and PbPb collisions. The PbPb measurements at 2.76 TeV as a function of event centrality shows that less stable excited states are more suppressed than ground state, a phenomenon termed as sequential suppression. The measurements in pPb collisions, at 5.02 TeV shows that the ratio of the excited to the ground state varies as a function of the global event activity. The three states are also observed to be individually more produced in events with more activity, for the three collision systems. How these CMS measurements compare with other experiments at RHIC and LHC and have improved the understanding of quarkonia physics in heavy ion collisions has been discussed.