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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. The distribution and orientation of energy inside jets is predicted to be an experimental handle on colour connections between the hard--scatter quarks and gluons initiating the jets. This Letter presents a measurement of the distribution of one such variable, the jet pull angle.
CERN-LHC. Double-differential three-jet cross-sections have been measured in proton-proton collisions at a centre-of-mass energy of sqrt(s)=7 TeV using the ATLAS detector at the Large Hadron Collider. The measurements are presented as functions of the three-jet invariant mass (m_jjj) and the sum of absolute rapidity separations between the three leading jets (|Y*|). Invariant masses extending up to 5 TeV are reached for 8<|Y*|<10. These measurements use the sample of proton-proton collision data recorded using the ATLAS detector in 2011, which corresponds to an integrated luminosity of 4.51 fb^-1. Jets are identified using the anti-kt algorithm with two different jet radius parameters, R=0.4 and R=0.6. The dominant uncertainty in this measurement comes from the jet energy scale. Next-to-leading-order QCD calculations corrected to account for non-perturbative effects are compared to the measurements. Good agreement is found between the data and the theoretical predictions based on most of the available sets of parton distribution functions, over the full kinematic range, covering almost seven orders of magnitude in the measured cross-section values.
CERN-LHC. Results are reported of a search for new phenomena, such as supersymmetric particle production, that could be observed in high-energy proton--proton collisions. Events with large numbers of jets, together with missing transverse momentum from unobserved particles, are selected.
CERN-LHC. Measurements of the average charged particle multiplicity inside jets in dijet events in proton-proton collisions at a centre-of-mass energy of 8 TeV with 20.3 fb^-1 of data collected in 2012. Measurements are reported separately for the more forward and more central jets (in pseudo-rapidity) as well as combined and as a difference between the two selected jets. The event selection is minimal, with only a requirement that the magnitude of the transverse momenta of the two leading jets be above 50 GeV and that these momenta be within 50% of each other.
CERN-LHC. Measurements of charged particle distributions in proton-proton collisions at a centre-of-mass energy of 13 TeV. A data sample of nearly 9 million events recorded by the ATLAS detector during a special LHC fill with low beam currents, and thus giving a low expected mean number of interactions, is used. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on the charged-particle multiplicity are presented. The measurements are performed with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 2.5, in events with at least one charged particle satisfying these kinematic requirements. Events with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 0.8 are also measured. The results are corrected for detector effects, presented as particle-level distributions and are compared to various Monte Carlo event generator models.
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 Large Hadron Collider are reported.
CERN-LHC, ATLAS. Measurements of the fiducial and total cross sections and ratios for W+/-, Z production using the electron and muon final states in proton-proton collisions at a centre-of-mass energy of 13 TeV with 81 pb^-1 of data collected in 2015. Where there are two systematic uncertainties, the first is experimental (omitting luminosity) and the second uncertainty is that of luminosity.
CERN-LHC. Measurements of distributions of charged particles with transverse momentum greater than 100 MeV and absolute pseudorapidity less than 2.5 produced in proton--proton collisions at the LHC with a centre-of-mass energy of 13 TeV are presented. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on multiplicity are measured in events containing at least two charged particles satisfying the above kinematic criteria.
CERN-LHC. Event-shape observables measured using charged particles in inclusive Z-Boson events are presented, using the electron and muon decay modes of the Z-bosons.
CERN-LHC. The results of a search for the stop, the supersymmetric partner of the top quark, in final states with one isolated electron or muon, jets, and missing transverse momentum are reported.
CERN-LHC. A search for squarks and gluinos in final states containing hadronic jets, missing transverse momentum but no electrons or muons is presented.
CERN-LHC. Measurement of the inelastic proton-proton cross section at a centre-of-mass energy of 13 TeV.
CERN-LHC. Measurement of the dijet production cross section for jets containing a b-hadron (b-jets) in proton proton collisions at a centre-of-mass energy of 7 TeV, with 4.2 fb^-1 of data collected by the ATLAS detector in 2011. The cross section is measured for events with two identified b-jets with a transverse momentum pT > 20 GeV and a minimum separation in the eta-phi plane of Delta R = 0.4. At least one of the jets in the event is required to have pT > 270 GeV. The cross section is measured differentially as a function of the dijet invariant mass, dijet transverse momentum, boost of the dijet system, and of the rapidity difference, azimuthal angle and angular distance between the b-jets.
CERN-LHC, ATLAS. Measurements of the fiducial and total cross sections for Z production using the electron and muon final states in proton-proton collisions at a centre-of-mass energy of 13 TeV with 3.2 fb^-1 of data collected in 2015. Measurements of single and double fiducial and total cross-section ratios for ttbar and Z production at 13, 8, and 7TeV.
CERN-LHC. Measurements on the triboson W+-W+-W-+ production cross-section using two decay channels fully-leptonic W+-W+-W-+ -> l+-nu l+-nu l-+nu and semi-leptonic W+-W+-W-+ -> l+-nu l+-nu jj (with l=e,mu) in proton-proton collision data corresponding to an integrated luminosity of 20.3 fb-1 at a centre of-mass energy of 8 TeV with the ATLAS detector at the Large Hadron Collider. Limits are also sets on WWWW anomalous quartic gauge couplings.
CERN-LHC. Measurements of the cross section for ZZ production using the 4l and 2l2nu decay channels in proton-proton collisions at a centre-of-mass energy of 8 TeV with 20.3 fb^-1 of data collected in 2012. The final states used are 4 electrons, 4 muons, 2 electrons and 2 muons, 2 electrons and missing transverse momentum, and 2 muons and missing transverse momentum (MET).
CERN-LHC. Measurement of the inclusive isolated prompt photon cross section in pp collisions at 8 TeV with the ATLAS detector.
CERN-LHC. Measurement of the angular coefficients of the Z-boson in the Collins-Soper rest frame using dielectron and dimuon pairs in proton-proton collisions at a centre-of-mass energy of 8 TeV with 20.3 fb^-1 of data collected in 2012. The measurement is performed in a narrow window of the Z-mass pole between 80-100 GeV, in fine bins of Z-boson momenta, and both integrated in rapidity as well as in coarse rapidity bins. The measurements are performed in the full phase space of the lepton kinematics, where the leptons are defined at Born-level.