1,306 research outputs found
ALICE physics: Theoretical overview
No full textAlessandro B, Aurenche P, Baier R, Becattini F, Botje M. ALICE physics: Theoretical overview. CERN-Alice-Internal-Note. 2002;2002-025
Measurements of R(d) - R(p) and R(Ca) - R(C) in deep inelastic muon scattering
No full textAmaudruz P, Arneodo M, Arvidson A, et al. Measurements of R(d) - R(p) and R(Ca) - R(C) in deep inelastic muon scattering. Phys.Lett. B. 1992;294(1):120-126
Search for resonances decaying into top-quark pairs using fully hadronic decays in pp collisions with ATLAS at root s=7 TeV
No full textContains fulltext :
111244.pdf (Publisher’s version ) (Open Access
Measurements of top quark pair relative differential cross-sections with ATLAS in pp collisions at root s=7 TeV
No full textATLAS Collaboration Contributor: Paul Douglas Jackson of SLAC National Accelerator Laboratory, Stanford CA, United States of AmericaMeasurements are presented of differential cross-sections for top quark pair production in pp collisions at √s = 7 TeV relative to the total inclusive top quark pair production cross-section. A data sample of 2.05 fb⁻¹ recorded by the ATLAS detector at the Large Hadron Collider is used. Relative differential cross-sections are derived as a function of the invariant mass, the transverse momentum and the rapidity of the top quark pair system. Events are selected in the lepton (electron or muon) + jets channel. The background-subtracted differential distributions are corrected for detector effects, normalized to the total inclusive top quark pair production cross-section and compared to theoretical predictions. The measurement uncertainties range typically between 10 % and 20 % and are generally dominated by systematic effects. No significant deviations from the Standard Model expectations are observed.The ATLAS Collaboratio
Search for a heavy top-quark partner in final states with two leptons with the ATLAS detector at the LHC
No full textContains fulltext :
103720.pdf (Publisher’s version ) (Open Access
A QCD analysis of HERA and fixed target structure function data
No full textThe parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and down anti-quark distributions. The uncertainties in the parton densities, structure functions and related cross sections are estimated from the experimental errors and those on the input parameters of the fit. Several QCD predictions obtained from this analysis are calculated and compared to data. The parton densites including the full error information is made available on a computer readable file
Search for R-parity-violating supersymmetry in events with four or more leptons in root s=7 TeV pp collisions with the ATLAS detector
No full textATLAS Contributors: Paul Douglas Jackson and Nitesh Soni of School of Chemistry and Physics, University of Adelaide, Adelaide, Australia. Extent: 36p.A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb⁻¹ of √s=7TeV proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m₁₍₂ up to 820 GeV are excluded for 10 < tan β < 40.The ATLAS collaboratio
Search for top quark decays t → qH with H → γγ using the ATLAS detector
No full textA search is performed for flavour-changing neutral currents in the decay of a top quark to an up-type (c, u) quark and a Higgs boson, where the Higgs boson decays to two photons. The proton-proton collision data set used corresponds to 4.7 fb-1 at √ = 7TeV and 20.3fb-1 at √ = 8TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for in which one top quark decays to qH and the other decays to bW. Both the hadronic and the leptonic decay modes of the W boson are used. No significant signal is observed and an upper limit is set on the t → qH branching ratio of 0.79 at the 95% confidence level. The corresponding limit on the tqH coupling combination λtcH 2 + λtuH 2 is 0.17
Measurement of the top quark pair production charge asymmetry in proton-proton collisions at root s=7 TeV using the ATLAS detector
No full textContains fulltext :
127828.pdf (Publisher’s version ) (Open Access)
Contains fulltext :
127828.pdf (Author’s version preprint ) (Open Access
NA49 Energy Scan Results for Central Lead-Lead Collisions at the CERN SPS
No full textThe energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi.The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the ratio exhibits a sharp peak located at about 30 AGeV. The ratio also shows a pronounced maximum which is weaker in and absent in .The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi.The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi.The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi.The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi
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