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Compact Muon Solenoid
LHC, CERN

CMS-PAS-BPH-12-006
$\Upsilon$(1S), $\Upsilon$(2S) and $\Upsilon$(3S) cross section measurements in pp collisions at $\sqrt{s} =$ 7 TeV
Abstract: The differential cross section as a function of transverse momentum for the production of the $\Upsilon(nS)$ ($n$=1,2,3) states decaying into a pair of muons has been measured in pp collisions at $\sqrt{s}$ = 7 TeV using 4.9 fb$^{-1}$ of data collected by the CMS detector. The analysis selected events with dimuon rapidity $|y(\mu\mu)|$ 0.6, and the measurements cover dimuon transverse momentum in the range $p_T(\mu\mu)=$ 10-100 GeV. The data show a transition from exponential to power-law behavior in the neighborhood of 20 GeV, and the power-law exponents for all three states are consistent. The ratio of differential cross sections for higher-$n$ S-wave relative to lower-$n$ S-wave states rises at low $p_T(\mu\mu)$, then becomes flatter at higher $p_T(\mu\mu)$ where the power-law behavior dominates.
CMS Publications
Compact Muon Solenoid
LHC, CERN