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Indications of Suppression of Excited Upsilon States in Pb-Pb Collisions at root(s)NN=2.76 TeV
(2011)Physical Review LettersA comparison of the relative yields of Υ resonances in the μ+μ− decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4 GeV/c and pseudorapidity below 2.4, the double ratio of the Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)]Pb−Pb/[ ...Journal Article -
Upsilon production cross section in pp collisions at √s=7 TeV
(2011)Physical Review DThe Υ(1S), Υ(2S), and Υ(3S) production cross sections in proton-proton collisions at √s=7 TeV are measured using a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 3.1±0.3 pb−1. Integrated over the rapidity range |y|<2, we find the product of the Υ(1S) production cross section and branching fraction to dimuons to be σ(pp→Υ(1S)X)⋅B(Υ(1S)→μ+μ−)=7.37±0.13+0.61−0.42±0.81 nb, where the ...Journal Article -
Measurement of Dijet Angular Distributions and Search for Quark Compositeness in pp Collisions √s=7 TeV
(2011)Physical Review LettersDijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at √s=7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb−1. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction ...Journal Article -
Measurement of the B+ Production Cross Section in pp Collisions at √s=7 TeV
(2011)Physical Review LettersMeasurements of the total and differential cross sections dσ/dpBT and dσ/dyB for B+ mesons produced in pp collisions at √s=7 TeV are presented. The data correspond to an integrated luminosity of 5.8 pb−1 collected by the CMS experiment operating at the LHC. The exclusive decay B+→J/ψK+, with J/ψ→μ+μ−, is used to detect B+ mesons and to measure the production cross section as a function of pBT and yB. The total cross section for pBT>5 GeV ...Journal Article