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Measurement of Prompt ψ(2S) to J/ψ Yield Ratios in Pb-Pb and p-p Collisions at √sNN = 2.76 TeV
(2014)Physical Review LettersThe ratio between the prompt ψ(2S) and J/ψ yields, reconstructed via their decays into μ+μ−, is measured in Pb-Pb and p-p collisions at √sNN=2.76 TeV. The analysis is based on Pb-Pb and p-p data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150 μb−1 and 5.4 pb−1, respectively. The double ratio of measured yields (Nψ(2S)/NJ/ψ)Pb−Pb/(Nψ(2S)/NJ/ψ)p−p is computed in three Pb-Pb collision ...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 four-jet production in proton-proton collisions at √s =7TeV
(2014)Physical Review DMeasurements of the differential cross sections for the production of exactly four jets in proton-proton collisions are presented as a function of the transverse momentum pT and pseudorapidity η, together with the correlations in azimuthal angle and the pT balance among the jets. The data sample was collected in 2010 at a center-of-mass energy of 7 TeV with the CMS detector at the LHC, with an integrated luminosity of 36 pb−1. The cross ...Journal Article -
Measurements of t¯t Spin Correlations and Top-Quark Polarization Using Dilepton Final States in pp Collisions at √s=7 TeV
(2014)Physical Review LettersSpin correlations and polarization in the top quark–antiquark system are measured using dilepton final states produced in pp collisions at the LHC at √s=7 TeV. The data correspond to an integrated luminosity of 5.0 fb−1 collected with the CMS detector. The measurements are performed using events with two oppositely charged leptons (electrons or muons), a significant imbalance in transverse momentum, and two or more jets, where at least ...Journal Article -
First Measurement of Bose-Einstein Correlations in Proton-Proton Collisions at √s=0.9 and 2.36 TeV at the LHC
(2010)Physical Review LettersBose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed in the form of an enhancement of pairs of same-sign charged particles with small relative four-momentum. The size of the correlated particle emission region is seen to increase significantly with the particle multiplicity ...Journal Article -
Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up
(2008)Journal of InstrumentationJournal Article -
Azimuthal decorrelation of jets widely separated in rapidity in pp collisions at √s = 7 TeV
(2016)Journal of High Energy PhysicsThe decorrelation in the azimuthal angle between the most forward and the most backward jets (Mueller-Navelet jets) is measured in data collected in pp collisions with the CMS detector at the LHC at s√=7 TeV. The measurement is presented in the form of distributions of azimuthal-angle differences, Δϕ, between the Mueller-Navelet jets, the average cosines of (π − Δϕ), 2(π − Δϕ), and 3(π − Δϕ), and ratios of these cosines. The jets are ...Journal Article -
Search for physics beyond the standard model in dilepton mass spectra in proton-proton collisions at √s=8 TeV
(2015)Journal of High Energy PhysicsDimuon and dielectron mass spectra, obtained from data resulting from proton-proton collisions at 8 TeV and recorded by the CMS experiment, are used to search for both narrow resonances and broad deviations from standard model predictions. The data correspond to an integrated luminosity of 20.6 (19.7) fb−1 for the dimuon (dielectron) channel. No evidence for non-standard-model physics is observed and 95% confidence level limits are set ...Journal Article -
Identification techniques for highly boosted W bosons that decay into hadrons
(2014)Journal of High Energy PhysicsIn searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that ...Journal Article -
Combined search for electroweak production of charginos and neutralinos in proton-proton collisions at √s=13 TeV
(2018)Journal of High Energy PhysicsA statistical combination of several searches for the electroweak production of charginos and neutralinos is presented. All searches use proton-proton collision data at s√=13 TeV, recorded with the CMS detector at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb−1. In addition to the combination of previous searches, a targeted analysis requiring three or more charged leptons (electrons or muons) is presented, ...Journal Article