7,023 research outputs found

    Trends in multiparticle production and some "predictions" for pp and PbPb collisions at LHC

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    Based on trends seen at lower energies we "predict" the multiplicities and pseudorapidity distributions of particle density and elliptic flow that will be seen in PbPb and pp collisions at the LHC. We argue that, if these predictions turn out to be correct, either these quantities are insensitive to the state of matter created in high energy heavy ion collisions or the observed simplicity and universality of the data must be telling us something profound about the mechanism of particle production, which to this date is not well understood.Comment: Invited Talk at SQM2007 Conferenc

    Kaon and Φ\Phi production vs Participants in Nuclear Collisions

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    Data on kaon and Φ\Phi production in nuclear collisions as a function of centrality are analysed both at AGS and SPS energy range. We compare the results of several experiments, looking for common trend in `participant scaling' of production yields. We find a smooth description of scaled kaon and Φ\Phi yields as a function of participant density. We also show a participant density dependence of kaons and Φ\Phi produced in the forward hemisphere for proton-nucleus collisions.Comment: Proceedings of the International Conference on Strangeness in Quark Matter, 20-25 July 2000, Berkeley, CA. To appear in Journal of Physics G: Nuclear and Particle Physic

    Where Is Your Farm Today?

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    The typical farm business is different from most nonfarm businesses. In farming, there\u27s a close interdependence between the farm household and the farm business- they can\u27t be separated into two distinct units as in most other industries

    Interdependence between the farm business and the farm household with implications on economic efficiency

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    In no other industry is the interdependence between the consuming household and the business firm so strong as in agriculture. The farm is a complete economic unit by itself. The business and household units are intertwined in the farm with production and consumption taking place in one central spot. Hence limited resources are allocated between the two in accordance with the preferences of the family. The economic problems of a farm exactly parallel those of a national economy and include the three major areas of choice and decision: (1) the allocation of resources or income between current and future consumption, (2) the allocation of limited resources or income in current production and (3) the distribution of current consumption income between different individuals. In reality, the first decision is largely one of allocation in production over time. Problems of production and consumption allocation at the farm level have received little attention in the general body of economic principIes. In general, the economic principles applicable to the business firm have been developed independently of the consumption unit, and the logic of the consuming unit has been developed independently of the business firm. A more realistic approach for agriculture is to consider production and consumption as interdependent units

    Possible glueball production in relativistic heavy-ion collisions

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    Within a thermal model we estimate possible multiplicities of scalar glueballs in central Au+Au collisions at AGS, SPS, RHIC and LHC energies. For the glueball mass in the region 1.5-1.7 GeV, the model predicts on average (per event) 0.5-1.5 glueballs at RHIC and 1.5-4 glueballs at LHC energies. Possible enhancement mechanisms are discussed.Comment: 8 pages, 2 figure

    Studies of multiplicity in relativistic heavy-ion collisions

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    In this talk I'll review the present status of charged particle multiplicity measurements from heavy-ion collisions. The characteristic features of multiplicity distributions obtained in Au+Au collisions will be discussed in terms of collision centrality and energy and compared to those of p+p collisions. Multiplicity measurements of d+Au collisions at 200 GeV nucleon-nucleon center-of-mass energy will also be discussed. The results will be compared to various theoretical models and simple scaling properties of the data will be identified.Comment: "Focus on Multiplicity" Internationsl Workshop on Particle Multiplicity in Relativistic Heavy Ion Collisions, Bari, Italy, June 17-19, 2003, 16 pages, 15 figure

    Silicon Pad Detectors for the PHOBOS Experiment at RHIC

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    The PHOBOS experiment is well positioned to obtain crucial information about relativistic heavy ion collisions at RHIC, combining a multiplicity counter with a multi-particle spectrometer. The multiplicity arrays will measure the charged particle multiplicity over the full solid angle. The spectrometer will be able to identify particles at mid-rapidity. The experiment is constructed almost exclusively of silicon pad detectors. Detectors of nine different types are configured in the multiplicity and vertex detector (22,000 channels) and two multi-particle spectrometers (120,000 channels). The overall layout of the experiment, testing of the silicon sensors and the performance of the detectors during the engineering run at RHIC in 1999 are discussed.Comment: 7 pages, 7 figures, 1 table, Late

    Global polarization of QGP in non-central heavy ion collisions at high energies

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    Due to the presence of a large orbital angular momentum of the parton system produced at the early stage of non-central heavy-ion collisions, quarks and anti-quarks are shown to be polarized in the direction opposite to the reaction plane which is determined by the impact-parameter and the beam momentum. The global quark polarization via elastic scattering was first calculated in an effective static potential model, then using QCD at finite temperature with the hard-thermal-loop re-summed gluon propagator. The measurable consequences are discussed. Global hyperon polarization from the hadronization of polarized quarks are predicted independent of the hadronization scenarios. It has also been shown that the global polarization of quarks and anti-quarks leads also to spin alignment of vector mesons. Dedicated measurements at RHIC are underway and some of the preliminary results are obtained. In this presentation, the basic idea and main results of global quark polarization are presented. The direct consequences such as global hyperon polarization and spin alignment are summarized.Comment: plenary talk at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2006), Shanghai, China, November 14-20, 200
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