Measurements of the ϒ(1S), ϒ(2S), and ϒ(3S) differential cross sections in pp collisions at √s = 7 TeV

Differential cross sections as a function of transverse momentum p_T are presented for the production of ϒ(nS) (n = 1, 2, 3) states decaying into a pair of muons. Data corresponding to an integrated luminosity of 4.9 in pp collisions at were collected with the CMS detector at the LHC. The analysis selects events with dimuon rapidity |y|<1.2 and dimuon transverse momentum in the range . The measurements show a transition from an exponential to a power-law behavior at for the three ϒ states. Above that transition, the ϒ(3S) spectrum is significantly harder than that of the ϒ(1S). The ratios of the ϒ(3S) and ϒ(2S)differential cross sections to the ϒ(1S) cross section show a rise as p_T increases at lowp_T, then become flatter at higher p_T.