403 research outputs found

    Effect of Pulp Protection Technique on the Clinical Performance of Amalgam Restorations: Three-Year Results

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    This study evaluated the influence of the pulp protection technique on clinical performance of amalgam restorations after three years, with particular reference to post-operative sensitivity and secondary caries. One hundred and twenty (120) Class II amalgam restorations (68 premolars, 52 molars; 78 MOD, 42 OD/MO) were placed in 30 participants (four restorations per participant).The restorations were divided into four groups according to the pulp protection technique used: copal varnish; 2% neutral sodium fluoride; adhesive resin and no pulp protection. The parameters evaluated were post-operative sensitivity, staining of the dental structure, tooth vitality, partial or total loss of the restoration and secondary caries. One hundred and eight (108)restorations were available for evaluation after three years. No partial or total loss of restorations had occurred; all teeth were vital, no tooth structure staining or secondary caries was detected in any of the restored teeth. Post-operative sensitivity was observed only in two restorations at baseline and at seven-days. The three year clinical performance of teeth restored with a high copper dispersed phase amalgam was not affected by the choice of pulp protection technique

    Dipole model for double meson production in two-photon interactions at high energies

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    In this work the double vector meson production in two-photon interactions at high energies is investigated considering saturation physics. We extend the color dipole picture for this process and study the energy and virtuality dependence of the forward differential cross section. Comparison with previous results is presented and the contribution of the different photon polarizations is estimated.Comment: 20 pages, 8 figures, 1 table. Version to be published in European Physical Jornal

    Non-linear QCD dynamics and exclusive production in epep collisions

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    The exclusive processes in electron-proton (epep) interactions are an important tool to investigate the QCD dynamics at high energies as they are in general driven by the gluon content of proton which is strongly subject to parton saturation effects. In this paper we compute the cross sections for the exclusive vector meson production as well as the deeply virtual Compton scattering (DVCS) relying on the color dipole approach and considering the numerical solution of the Balitsky-Kovchegov equation including running coupling corrections. We show that the small-xx evolution given by this evolution equation is able to describe the DESY-HERA data and is relevant for the physics of the exclusive observables in future electron-proton colliders and in photoproduction processes to be measured in coherent interactions at the LHC.Comment: 6 pages, 4 figure

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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