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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 -
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 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 -
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 -
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 -
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 -
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 -
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 -
Search for WWγ and WZγ production and constraints on anomalous quartic gauge couplings in pp collisions at √s=8 TeV
(2014)Physical Review DA search for WVγ triple vector boson production is presented based on events containing a W boson decaying to a muon or an electron and a neutrino, a second V (W or Z) boson, and a photon. The data correspond to an integrated luminosity of 19.3 fb−1 collected in 2012 with the CMS detector at the LHC in pp collisions at √s=8 TeV. An upper limit of 311 fb on the cross section for the WVγ production process is obtained at 95% confidence ...Journal Article -
Evidence for the direct decay of the 125 GeV Higgs boson to fermions
(2014)Nature PhysicsThe discovery of a new boson with a mass of approximately 125 GeV in 2012 at the Large Hadron Collider1,2,3 has heralded a new era in understanding the nature of electroweak symmetry breaking and possibly completing the standard model of particle physics4,5,6,7,8,9. Since the first observation in decays to γγ, WW and ZZ boson pairs, an extensive set of measurements of the mass10,11 and couplings to W and Z bosons11,12,13, as well as ...Journal Article