SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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CERN-LHC. A generic search for anomalous production of events with at least three charged leptons is presented.
CERN-LHC. A low-background inclusive search for new physics in events with same-sign dileptons is presented.
CERN-LHC. The transverse polarization of LAMBDA and LAMBDABAR hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured.
CERN-LHC. This paper reports a measurement of the jets production cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC.
CERN-LHC. The production of a W boson decaying to (e nu) or (mu nu) in association with a W or Z boson decaying to two jets is studied using 4.6 fb-1 of proton-proton collision data at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC. The combined WW+WZ cross section is measured with a significance of 3.4 sigma. Two cross sections are measured, a fiducial and a total cross section. The cross sections are measured assuming the SM ratio between the WW and WZ cross sections.
CERN-LHC. A measurement of the cross section for the production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The results are based on an integrated luminosity of 4.6 fb-1 collected with the ATLAS detector at the LHC. The cross section is measured as a function of photon pseudorapidity and transverse energy in the kinematic range between 100 GeV and 1000 GeV and in the regions of pseudorapidity less than 1.37 and between 1.52 and 2.37. The results are compared to leading-order parton-shower Monte Carlo models and next-to-leading-order perturbative QCD calculations. Next-to-leading-order perturbative QCD calculations agree well with the measured cross sections as a function of transverse energy and pseudorapidity
CERN-LHC. Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton--proton collisions at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 20.3 fb-1. The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of such events is 6.1 (5.3) fb at 95% confidence level. Exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates.
CERN-LHC. The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider (LHC) are reported.
CERN-LHC. The results of a dedicated search for pair production of scalar partners of charm quarks are reported.
CERN-LHC. Measurements of normalized differential cross-sections for top-quark pair production as a function of the top-quark transverse momentum, and of the mass, transverse momentum, and rapidity of the ttbar system, in proton--proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV.
CERN-LHC. A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC.
CERN-LHC. Two searches for supersymmetric particles in final states containing a same-flavour opposite-sign lepton pair, jets and large missing transverse momentum are presented.
CERN-LHC. Measurements of cross sections for the production of jets in association with a Z0 boson in proton-proton collisions at a centre of mass energy of 7 TeV. The 2011 data sample used has an integrated luminosity of 4.6 fb^{-1}. Inclusive cross sections for Z0 decaying into either electron or muon pairs with jets of transverse momentum above 30 GeV and |rapidity| less than 4.4 are presented along with a detailed breakdown of the systematic errors in the measurements. Data are given here for the individual electron and muon channels as well as for the combined data as shown in the paper. The combined cross section has been extrapolated to the common phase space |eta|<2.5 and pT>20 GeV, similar to the 2010 analysis.
CERN-LHC. Using inelastic proton-proton interactions at sqrt(s) = 900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a selected kinematic region of the event. The results are compared with predictions from tunes of the PYTHIA and HERWIG++ Monte Carlo generators, which in most cases are found to provide a reasonable description of the data. Data taken from the RIVET analysis code.
CERN-LHC. The b-hadron production cross section is measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV, using 3.3 pb^-1 of integrated luminosity, collected during the 2010 LHC run. The b-hadrons are selected by partially reconstructing D*muX final states. Differential cross sections are measured as functions of the transverse momentum and pseudorapidity. The measured production cross section for a b-hadron with pT>9 GeV and |eta|<2.5 is 32.7 pm 0.8 (stat) ^{+4.5}_{-6.8} (syst) ub, higher than the next-to-leading-order QCD predictions but consistent within the experimental and theoretical uncertainties. Data taken from the RIVET analysis code.
CERN-LHC. This paper describes measurements of the sum of the transverse energy of particles as a function of particle pseudorapidity, eta, in proton-proton collisions at a centre-of-mass energy, sqrt(s) = 7 TeV using the ATLAS detector at the Large Hadron Collider. The measurements are performed in the region |eta| < 4.8 for two event classes: those requiring the presence of particles with a low transverse momentum and those requiring particles with a significant transverse momentum. In the second dataset measurements are made in the region transverse to the hard scatter. The distributions are compared to the predictions of various Monte Carlo event generators, which generally tend to underestimate the amount of transverse energy at high |eta|. Data taken from the RIVET analysis code.
CERN-LHC. This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at sqrt{s}=7 TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb^-1. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity |y| < 2.1. The fit results agree with the predictions of leading- and next-to-leading-order calculations, with the exception of the dijet fraction composed of bottom and light flavour jets, which is underestimated by all models at large transverse jet momenta. The ability to identify jets containing two b-hadrons, originating from e.g. gluon splitting, is demonstrated. The difference between bottom jet production rates in leading and subleading jets is consistent with the next-to-leading-order predictions. Data taken from the RIVET analysis code.
CERN-LHC. The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported.