547 research outputs found

    Fluctuation Results from PHENIX

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    The PHENIX Experiment at the Relativistic Heavy Ion Collider has made measurements of event-by-event fluctuations in the net charge, the mean transverse momentum, and the charged particle multiplicity as a function of collision energy, centrality, and transverse momentum in heavy ion collisions. The results of these measurements will be reviewed and discussed.Comment: Proceedings for the Workshop on Correlations and Fluctuations in Relativistic Nuclear Collisions, April 21-23, 2005; 10 pages, 17 figure

    Propagation of strangelets in the Earth's atmosphere

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    A new model for the description of the behaviour of strangelets in the Earth's atmosphere is presented. Strangelet fission induced by collision with air nuclei is included. It is shown that strangelets with certain parameters of initial mass and energy may reach depths near sea level, which can be examined by ground-based experiments.Comment: 10 pages, 6 figure

    Thermodynamic limit and semi--intensive quantities

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    The properties of statistical ensembles with abelian charges close to the thermodynamic limit are discussed. The finite volume corrections to the probability distributions and particle density moments are calculated. Results are obtained for statistical ensembles with both exact and average charge conservation. A new class of variables (semi--intensive variables) which differ in the thermodynamic limit depending on how charge conservation is implemented in the system is introduced. The thermodynamic limit behavior of these variables is calculated through the next to leading order finite volume corrections to the corresponding probability density distributions.Comment: 11 pages, 2 figures In v2 figures are added and corresponding editorial changes are done. Paper will be published in Journal of Physics

    Ascending aortic aneurysm and aortic valve dysfunction in bicuspid aortic valve disease

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    BACKGROUND: The relationship of aortic valve dysfunction and ascending aortic aneurysm is unclear in adults with bicuspid aortic valve disease. METHODS: We retrospectively studied 134 consecutive out-patients (98 men, 36 women aged 43+/-18years) with bicuspid aortic valve disease. To investigate the relationship of ascending aortic aneurysm and aortic valve dysfunction we exclusively considered severe pathologies that required treatment by surgical or percutaneous intervention. RESULTS: Of 134 patients, 39 had aortic valve dysfunction without concomitant ascending aortic aneurysm which had been treated previously with isolated valve surgery or percutaneous valvuloplasty comprising 25 patients with aortic stenosis (19%) and 14 patients with aortic regurgitation (10%). Conversely, 26 patients had ascending aortic aneurysm which had been treated previously with aortic surgery (19%). Of these, ascending aortic aneurysm was associated with severe aortic stenosis in 13 patients and with severe aortic regurgitation in 7 patients, whereas aneurysm was unrelated to severe aortic valve dysfunction in the remaining 6 patients including 2 without any degree of aortic valve dysfunction. The maximal aortic diameters were similar at the time of aortic surgery irrespective of presence of severe aortic valve dysfunction (P=.527). Other characteristics of patients with ascending aortic aneurysm were also similar irrespective of presence or type of aortic valve dysfunction. CONCLUSION: The majority of patients with bicuspid aortic valve disease exhibit ascending aortic aneurysm in conjunction with severe aortic valve dysfunction. However, in our study 6 of 134 (5%) of persons with bicuspid aortic valve disease developed ascending aortic aneurysm without aortic valve dysfunction

    System-size and centrality dependence of charged kaon and pion production in nucleus-nucleus collisions at 40A GeV and158A GeV beam energy

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    Measurements of charged pion and kaon production are presented in centrality selected Pb+Pb collisions at 40A GeV and 158A GeV beam energy as well as in semi-central C+C and Si+Si interactions at 40A GeV. Transverse mass spectra, rapidity spectra and total yields are determined as a function of centrality. The system-size and centrality dependence of relative strangeness production in nucleus-nucleus collisions at 40A GeV and 158A GeV beam energy are derived from the data presented here and published data for C+C and Si+Si collisions at 158A GeV beam energy. At both energies a steep increase with centrality is observed for small systems followed by a weak rise or even saturation for higher centralities. This behavior is compared to calculations using transport models (UrQMD and HSD), a percolation model and the core-corona approach.Comment: 32 pages, 14 figures, 4 tables, typo table II correcte

    Antideuteron and deuteron production in mid-central Pb+Pb collisions at 158AA GeV

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    Production of deuterons and antideuterons was studied by the NA49 experiment in the 23.5% most central Pb+Pb collisions at the top SPS energy of sNN\sqrt{s_{NN}}=17.3 GeV. Invariant yields for dˉ\bar{d} and dd were measured as a function of centrality in the center-of-mass rapidity range 1.2<y<0.6-1.2<y<-0.6. Results for dˉ(d)\bar{d}(d) together with previously published pˉ(p)\bar{p}(p) measurements are discussed in the context of the coalescence model. The coalescence parameters B2B_2 were deduced as a function of transverse momentum ptp_t and collision centrality.Comment: 9 figure

    Measurement of event-by-event transverse momentum and multiplicity fluctuations using strongly intensive measures Δ[PT,N]\Delta[P_T, N] and Σ[PT,N]\Sigma[P_T, N] in nucleus-nucleus collisions at the CERN Super Proton Synchrotron

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    Results from the NA49 experiment at the CERN SPS are presented on event-by-event transverse momentum and multiplicity fluctuations of charged particles, produced at forward rapidities in central Pb+Pb interactions at beam momenta 20AA, 30AA, 40AA, 80AA, and 158AA GeV/c, as well as in systems of different size (p+pp+p, C+C, Si+Si, and Pb+Pb) at 158AA GeV/c. This publication extends the previous NA49 measurements of the strongly intensive measure ΦpT\Phi_{p_T} by a study of the recently proposed strongly intensive measures of fluctuations Δ[PT,N]\Delta[P_T, N] and Σ[PT,N]\Sigma[P_T, N]. In the explored kinematic region transverse momentum and multiplicity fluctuations show no significant energy dependence in the SPS energy range. However, a remarkable system size dependence is observed for both Δ[PT,N]\Delta[P_T, N] and Σ[PT,N]\Sigma[P_T, N], with the largest values measured in peripheral Pb+Pb interactions. The results are compared with NA61/SHINE measurements in p+pp+p collisions, as well as with predictions of the UrQMD and EPOS models.Comment: 12 pages, 14 figures, to be submitted to PR

    Conformal oxide coating of Carbon Nanotubes

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    The International Roadmap for Ferroelectric Memories requires three-dimensional integration of high-dielectric materials onto metal interconnects or bottom electrodes by 2010. We report the first integration of high-dielectric oxide films onto carbon nanotube electrodes with an aim of ultra-high integration density of FeRAMs (Tb/in2).Comment: 4 pages, 3 figure
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