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Search for supersymmetry with razor variables in pp collisions at √s=7 TeV
(2014)Physical Review DThe razor approach to search for R–parity conserving supersymmetric particles is described in detail. Two analyses are considered: an inclusive search for new heavy particle pairs decaying to final states with at least two jets and missing transverse energy, and a dedicated search for final states with at least one jet originating from a bottom quark. For both the inclusive study and the study requiring a bottom-quark jet, the data are ...Journal Article -
Measurement of differential cross sections for the production of a pair of isolated photons in pp collisions at √s=7 TeV
(2014)The European Physical Journal CA measurement of differential cross sections for the production of a pair of isolated photons in proton–proton collisions at √s=7TeV is presented. The data sample corresponds to an integrated luminosity of 5.0fb−1 collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25GeV respectively, ...Journal Article -
Measurement of pseudorapidity distributions of charged particles in proton-proton collisions at √s = 8 TeV by the CMS and TOTEM experiments
(2014)The European Physical Journal CPseudorapidity (η) distributions of charged particles produced in proton–proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges |η|<2.2 and 5.3<|η|<6.4 covered by the CMS and TOTEM detectors, respectively. The data correspond to an integrated luminosity of L=45 μb−1. Measurements are presented for three event categories. The most inclusive category is sensitive to 91–96 % of the total inelastic proton–proton ...Journal Article -
Study of hadronic event-shape variables in multijet final states in pp collisions at √s = 7 TeV
(2014)Journal of High Energy PhysicsEvent-shape variables, which are sensitive to perturbative and nonperturbative aspects of quantum chromodynamic (QCD) interactions, are studied in multijet events recorded in proton-proton collisions at s√=7 TeV. Events are selected with at least one jet with transverse momentum p T > 110 GeV and pseudorapidity |η| < 2.4, in a data sample corresponding to integrated luminosities of up to 5 fb−1. The distributions of five event-shape ...Journal Article -
Measurement of the ratio of inclusive jet cross sections using the anti-kT algorithm with radius parameters R=0.5 and 0.7 in pp collisions at √s=7 TeV
(2014)Physical Review DMeasurements of the inclusive jet cross section with the anti-kT clustering algorithm are presented for two radius parameters, R=0.5 and 0.7. They are based on data from LHC proton-proton collisions at √s=7 TeV corresponding to an integrated luminosity of 5.0 fb−1 collected with the CMS detector in 2011. The ratio of these two measurements is obtained as a function of the rapidity and transverse momentum of the jets. Significant ...Journal Article -
Description and performance of track and primary-vertex reconstruction with the CMS tracker akahashi
(2014)Journal of InstrumentationA description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events ...Journal Article -
Measurement of the ratio B(t→Wb)/B(t→Wq) in pp collisions at √s = 8 TeV
(2014)Physics Letters BThe ratio of the top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where the denominator includes the sum over all down-type quarks (q = b, s, d), is measured in the t (t) over bar dilepton final state with proton-proton collision data at root s = 8 TeV from an integrated luminosity of 19.7 fb(-1), collected with the CMS detector. In order to quantify the purity of the signal sample, the cross section is measured by fitting the ...Journal Article -
Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at √s=8 TeV
(2014)Physics Letters BA search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton–proton collisions at √s = 8TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb−1. The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant ...Journal Article -
Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
(2014)The European Physical Journal CSearches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and W, Z, and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy s√=8TeV with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 fb-1. The observed event rates are in agreement with expectations from ...Journal Article -
Evidence of b -Jet Quenching in PbPb Collisions at √sNN =2.76 TeV
(2014)Physical Review LettersThe production of jets associated to bottom quarks is measured for the first time in PbPb collisions at a center-of-mass energy of 2.76 TeV per nucleon pair. Jet spectra are reported in the transverse momentum (pT) range of 80-250GeV/c, and within pseudorapidity |η|<2. The nuclear modification factor (RAA) calculated from these spectra shows a strong suppression in the b-jet yield in PbPb collisions relative to the yield observed in pp ...Journal Article