(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in ...proton-proton collision data at a centre-of-mass energy of ... corresponding to an integrated luminosity of 38 pb^sup -1^. Jets are reconstructed with the anti-k ^sub t^ algorithm with distance parameters R=0.4 or R=0.6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta p ^sub T^greater than or equal to20 GeV and pseudorapidities |eta|<4.5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2.5 % in the central calorimeter region (|eta|<0.8) for jets with 60less than or equal top ^sub T^<800 GeV, and is maximally 14 % for p ^sub T^<30 GeV in the most forward region 3.2less than or equal to|eta|<4.5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon p ^sub T^, the sum of the transverse momenta of tracks associated to the jet, or a system of low-p ^sub T^ jets recoiling against a high-p ^sub T^ jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-p ^sub T^ jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The dependence of the rate of proton-proton interactions on the centre-of-mass collision energy, √s, is of fundamental importance for both hadron collider physics and particle astrophysics. The ...dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurement of the inelastic proton-proton interaction cross-section at a centre-of-mass energy, √s, of 7 TeV using the ATLAS detector at the Large Hadron Collider. Events are selected by requiring hits on scintillation counters mounted in the forward region of the detector. An inelastic cross-section of 60.3 ± 2.1 mb is measured for ξ > 5×10⁻⁶, where ξ is calculated from the invariant mass, M(X), of hadrons selected using the largest rapidity gap in the event. For diffractive events, this corresponds to requiring at least one of the dissociation masses to be larger than 15.7 GeV.
This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from √s=7 TeV proton-proton collisions at the ...LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35 pb(-1). No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. Within this framework, for A(0)=0 GeV, tanβ=3, and μ>0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidence level.
A measurement of the multi-strange Ξ− and Ω− baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton–proton collisions at a ...centre-of-mass energy of 7 TeV. The transverse momentum (pT) distributions were studied at mid-rapidity (|y|<0.5) in the range of 0.6<pT<8.5 GeV/c for Ξ− and Ξ¯+ baryons, and in the range of 0.8<pT<5 GeV/c for Ω− and Ω¯+. Baryons and antibaryons were measured as separate particles and we find that the baryon to antibaryon ratio of both particle species is consistent with unity over the entire range of the measurement. The statistical precision of the current data has allowed us to measure a difference between the mean pT of Ξ− (Ξ¯+) and Ω− (Ω¯+). Particle yields, mean pT, and the spectra in the intermediate pT range are not well described by the PYTHIA Perugia 2011 tune Monte Carlo event generator, which has been tuned to reproduce the early LHC data. The discrepancy is largest for Ω− (Ω¯+). This PYTHIA tune approaches the pT spectra of Ξ− and Ξ¯+ baryons below pT<0.85 GeV/c and describes the Ξ− and Ξ¯+ spectra above pT>6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω−+Ω¯+)/(Ξ−+Ξ¯+) as a function of transverse mass.
This Letter reports on a search for narrow high-mass resonances decaying into dilepton final states. The data were recorded by the ATLAS experiment in pp collisions at √s=7 TeV at the Large Hadron ...Collider and correspond to a total integrated luminosity of 1.08 (1.21) fb(-1) in the e(+)e(-) (μ(+)μ(-)) channel. No statistically significant excess above the standard model expectation is observed and upper limits are set at the 95% C.L. on the cross section times branching fraction of Z' resonances and Randall-Sundrum gravitons decaying into dileptons as a function of the resonance mass. A lower mass limit of 1.83 TeV on the sequential standard model Z' boson is set. A Randall-Sundrum graviton with coupling k/M(Pl)=0.1 is excluded at 95% C.L. for masses below 1.63 TeV.
The production of muons from heavy flavour decays is measured at forward rapidity in proton–proton collisions at s=7 TeV collected with the ALICE experiment at the LHC. The analysis is carried out on ...a data sample corresponding to an integrated luminosity Lint=16.5 nb−1. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5<y<4, over the transverse momentum range 2<pt<12 GeV/c. The results are compared to predictions based on perturbative QCD calculations.
•Pectin edible coatings with lemon essential oil and reuterin were developed.•Edible coatings decreased color changes in cold-stored strawberries.•Reuterin reduced Penicillium conidia more than two ...logarithmic cycles.•This is the first report of the development of a coating with reuterin as a food preserver.
The effect of reuterin in pectin-based edible coatings with lemon essential oil (LEO) on the quality of cold-stored strawberries was investigated. Pectin was extracted from orange peels and pectin-based solutions (3 %, w/v) were prepared (T1). T2 formulation was added with LEO (2 %, v/v), while T3 incorporated LEO and reuterin (10 mM). Strawberries were inoculated with Penicillium sp. conidia (3.36 × 107 CFU/mL) and coated with the formulated solutions. Physicochemical and microbiological parameters were assessed during 31 days of storage. Physicochemical properties were not significantly influenced by coatings. Coated samples showed a more intense, redder color than control samples. T2 coatings kept up to 3.5 % more moisture than control samples. Reuterin in T3 decreased viable Penicillium spp. conidia more than two logarithmic cycles in comparison to the other treatments. Edible coatings elaborated with pectin and added with LEO and reuterin show great potential to be employed in strawberries preservation, because these coatings are able to avoid fungal spoilage without quality reduction.
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