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Measurement of the underlying event activity in pp collisions at √s=0.9 and 7 TeV with the novel jet-area/median approach
(2012)Journal of High Energy PhysicsThe first measurement of the charged component of the underlying event using the novel “jet-area/median” approach is presented for proton-proton collisions at centre-of-mass energies of 0.9 and 7 TeV. The data were recorded in 2010 with the CMS experiment at the LHC. A new observable, sensitive to soft particle production, is introduced and investigated inclusively and as a function of the event scale defined by the transverse momentum ...Journal Article -
Search for leptonic decays of W′ bosons in pp collisions at sqrt(s)=7 TeV
(2012)Journal of High Energy PhysicsA search for a new heavy gauge boson W′ decaying to an electron or muon, plus a low mass neutrino, is presented. This study uses data corresponding to an integrated luminosity of 5.0 fb−1, collected using the CMS detector in pp collisions at a centre-of-mass energy of 7 TeV at the LHC. Events containing a single electron or muon and missing transverse momentum are analyzed. No significant excess of events above the standard model expectation ...Journal Article -
Search for new physics in events with same-sign dileptons and b-tagged jets in pp collisions at sqrt(s) = 7 TeV
(2012)Journal of High Energy PhysicsA search for new physics is performed using isolated same-sign dileptons with at least two b-quark jets in the final state. Results are based on a 4.98 fb−1 sample of proton-proton collisions at a centre-of-mass energy of 7 TeV collected by the CMS detector. No excess above the standard model background is observed. Upper limits at 95% confidence level are set on the number of events from non-standard-model sources. These limits are used ...Journal Article -
Azimuthal Anisotropy of Charged Particles at High Transverse Momenta in Pb-Pb Collisions at √sNN=2.76 TeV
(2012)Physical Review LettersThe azimuthal anisotropy of charged particles in Pb-Pb collisions at √sNN=2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pT) range up to approximately 60 GeV/c. The data cover both the low-pT region associated with hydrodynamic flow phenomena and the high-pT region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter ...Journal Article -
Search for heavy long-lived charged particles in pp collisions at sqrt(s)=7 TeV
(2012)Physics Letters BThe result of a search for heavy long-lived charged particles produced in pp collisions at √s=7 TeV at the LHC is described. The data sample has been collected using the CMS detector and corresponds to an integrated luminosity of 5.0 fb-1. The inner tracking detectors are used to define a sample of events containing tracks with high momentum and high ionization energy loss. A second sample of events, which have high-momentum tracks ...Journal Article -
Search for a light charged Higgs boson in top quark decays in pp collisions at √s=7TeV
(2012)Journal of High Energy PhysicsResults are presented on a search for a light charged Higgs boson that can be produced in the decay of the top quark t → H+b and which, in turn, decays into τ +ν τ . The analysed data correspond to an integrated luminosity of about 2 fb−1 recorded in protonproton collisions at s√=7TeV by the CMS experiment at the LHC. The search is sensitive to the decays of the top quark pairs tt¯ → H± W ∓ bb¯¯¯ and tt¯ → H±H∓ bb¯¯¯. Various final states ...Journal Article -
Observation of a new Xi(b) baryon
(2012)Physical Review LettersThe observation of a new b baryon via its strong decay into Ξ−bπ+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at √s=7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 fb−1. The known Ξ−b baryon is reconstructed via the decay chain Ξ−b→J/ψΞ−→μ+μ−Λ0π−, with Λ0→pπ−. A peak is observed in the distribution of the difference between the mass of the ...Journal Article -
Search for neutral Higgs bosons decaying to tau pairs in pp collisions at sqrt(s)=7 TeV
(2012)Physics Letters BA search for neutral Higgs bosons decaying to tau pairs at a center-of-mass energy of 7 TeV is performed using a dataset corresponding to an integrated luminosity of 4.6 fb−1 recorded by the CMS experiment at the LHC. The search is sensitive to both the standard model Higgs boson and to the neutral Higgs bosons predicted by the minimal supersymmetric extension of the standard model (MSSM). No excess of events is observed in the tau-pair ...Journal Article -
Jet momentum dependence of jet quenching in PbPb collisions at root s(NN)=2.76 TeV
(2012)Physics Letters BDijet production in PbPb collisions at a nucleon–nucleon center-of-mass energy of 2.76 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 150 μb−1 is analyzed. Jets are reconstructed using combined information from tracking and calorimetry, using the anti-kT algorithm with R = 0.3. The dijet momentum balance and angular correlations are studied as a function of collision centrality ...Journal Article -
Search for Dark Matter and Large Extra Dimensions in pp Collisions Yielding a Photon and Missing Transverse Energy
(2012)Physical Review LettersResults are presented from a search for new physics in the final state containing a photon (γ) and missing transverse energy (E̸T). The data correspond to an integrated luminosity of 5.0 fb−1 collected in pp collisions at √s=7 TeV by the CMS experiment. The observed event yield agrees with standard-model expectations for the γ+E̸T events. Using models for the production of dark-matter particles (χ), we set 90% confidence level (C.L.) ...Journal Article