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

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Date
2015-10-07Author
Khachatryan, Vardan
Sirunyan, A.M.
Tumasyan, A.
Adam, Wolfgang
Bergauer, T.
Dragicevic, M.
Baarmand, Marc M.
Hohlmann, Marcus
Kalakhety, Himali
Yumiceva, Francisco
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Show full item recordAbstract
Differential cross sections as a function of transverse momentum pT 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 fb−1 in pp collisions at √s = 7 TeV 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 10 <
pT < 100 GeV. The measurements show a transition from an exponential to a power-law behavior at
pT ≈ 20 GeV 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 pT increases at low pT, then become flatter at higher pT.