4,255 research outputs found

    Baryon anomaly and strong color fields in Pb+Pb collisions at 2.76A TeV at the CERN Large Hadron Collider

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    With the HIJING/BBbar v2.0 heavy ion event generator, we explore the phenomenological consequences of several high parton density dynamical effects predicted in central Pb+Pb collisions at the Large Hadron Collider (LHC) energies. These include (1) jet quenching due to parton energy loss (dE/dx), (2) strangeness and hyperon enhancement due to strong longitudinal color field (SCF), and (3) enhancement of baryon-to-meson ratios due to baryon-anti-baryon junctions (JJbar) loops and SCF effects. The saturation/minijet cutoff scale p0(s)and effective string tension kappa(s,A) are constrained by our previous analysis of LHC p+p data and recent data on the charged multiplicity for Pb+Pb collisions reported by the ALICE collaboration. We predict the hadron flavor dependence (mesons and baryons) of the nuclear modification factor RAA(pT)$ and emphasize the possibility that the baryon anomaly could persist at the LHC up to pT=10 GeV, well beyond the range observed in central Au+Au collisions at RHIC energies.Comment: 25 pages, 8 figures, revtex4, text modifications, added references, accepted for publication Phys. Rev. C (2011

    BANKING EFFICIENCY AND EUROPEAN INTEGRATION. IMPLICATIONS OF THE BANKING REFORM IN ROMANIA

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    The aim of this study is to analyze the influence that the European integrationprocess has had over the banking efficiency levels in those countries which have recentlyexperienced more intensely the European integration process. For this purpose we haveanalyzed, using stochastic frontier models (SFA), applied to panel data, bank efficiency levelsof a sample of 240 banks from 12 countries during the period 2000 to 2008. The resultssustain the hypothesis that the European integration process has significantly improved theefficiency levels in these countries. However, the improvements haven‘t appeared simply bythe accession to the EU, but have appeared during the process. In order to illustrate the results, we have analyzed the banking system in Romania inthe context of the European integration, a country which because of the delay in the initiationof the reforms, despite belonging to the EU, it hasn‘t still recorded the essential improvementsin banking efficiency associated to this process that the other new members have alreadyexperienced.banking efficiency, European integration, stochastic models, banking reform.

    Experimental demonstration of Aharonov-Casher interference in a Josephson junction circuit

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    A neutral quantum particle with magnetic moment encircling a static electric charge acquires a quantum mechanical phase (Aharonov-Casher effect). In superconducting electronics the neutral particle becomes a fluxon that moves around superconducting islands connected by Josephson junctions. The full understanding of this effect in systems of many junctions is crucial for the design of novel quantum circuits. Here we present measurements and quantitative analysis of fluxon interference patterns in a six Josephson junction chain. In this multi-junction circuit the fluxon can encircle any combination of charges on five superconducting islands, resulting in a complex pattern. We compare the experimental results with predictions of a simplified model that treats fluxons as independent excitations and with the results of the full diagonalization of the quantum problem. Our results demonstrate the accuracy of the fluxon interference description and the quantum coherence of these arrays

    Charge transfer complexes and radical cation salts of chiral methylated organosulfur donors

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    The single crystal X-ray structure of the all-axial conformer of the (R,R,R,R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S,S,S,S)-Tetramethyl-BEDT-TTF formed crystalline 1 : 1 complexes with TCNQ and TCNQ-F4, as well as a THF solvate of the TCNQ complex. Donors bis((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene and (ethylenedithio)((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)2XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting
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