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Measurement of the differential cross section for isolated prompt photon production in pp collisions at 7 TeV
(2011)Physical Review DA measurement of the differential cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a center-of-mass energy of 7 TeV is presented. The data sample corresponds to an integrated luminosity of 36 pb−1 recorded by the CMS detector at the LHC. The measurement covers the pseudorapidity range |η|<2.5 and the transverse energy range 25<ET<400 GeV, corresponding to the kinematic region 0.007<xT<0.114. ...Journal Article -
Search for Three-Jet Resonances in pp Collisions at √s=7 TeVV
(2011)Physical Review LettersA search for three-jet hadronic resonance production in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 pb−1. Events with high jet multiplicity and a large scalar sum of jet transverse momenta are analyzed using a signature-based approach. The number of expected standard model background events is found to be in ...Journal Article -
Observation and studies of jet quenching in PbPb collisions at √sNN=2.76 TeV
(2011)Physical Review CJet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the Compact Muon Solenoid (CMS) detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7μb−1. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse ...Journal Article -
Measurement of the t-Channel Single Top Quark Production Cross Section in pp Collisions at √s=7 TeV
(2011)Physical Review LettersElectroweak production of the top quark is measured for the first time in pp collisions at √s=7 TeV, using a data set collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb−1. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from the data. ...Journal Article -
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 -
Measurement of the Polarization of W Bosons with Large Transverse Momenta in W plus jets Events at the LHC
(2011)Physical Review LettersA first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb−1 of data recorded at √s=7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (fL, fR, and f0, respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final ...Journal Article -
Measurement of the Inclusive Jet Cross Section in pp Collisions at √s=7 TeV
(2011)Physical Review LettersThe inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb−1. The measurement is made for jet transverse momenta in the range 18–1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet pT ever observed and, within ...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 -
Search for Pair Production of Second-Generation Scalar Leptoquarks in pp Collisions at √s=7 TeV
(2011)Physical Review LettersA search for pair production of second-generation scalar leptoquarks in the final state with two muons and two jets is performed using proton-proton collision data at √s=7 TeV collected by the CMS detector at the LHC. The data sample used corresponds to an integrated luminosity of 34 pb−1. The number of observed events is in good agreement with the predictions from the standard model processes. An upper limit is set on the second-generation ...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