11,616 research outputs found

    Autocorrelation of Hadrons in Jets Produced in Heavy-Ion Collisions

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    Autocorrelation of two pions produced in heavy-ion collisions at intermediate pTp_T is calculated in the framework of the recombination model. The differences of the pseudo-rapidities and azimuthal angles of the two pions are related to the angle between two shower partons in a jet. It is shown how the autocorrelation distribution reveals the properties of jet cone of the shower partons created by high-pTp_T partons in hard collisions.Comment: 24 pages in latex and 3 figures. This is an expanded version with more discussion and references without any change in the physical conten

    Effective models of two-flavor QCD: from small towards large mqm_q

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    We study effective models of chiral fields and Polyakov loop expected to describe the dynamics responsible for the phase structure of two-flavor QCD. We consider chiral sector described either using linear sigma model or Nambu-Jona-Lasinio model and study how these models, on the mean-field level when coupled with the Polyakov loop, behave as a function of increasing bare quark (or pion) mass. We find qualitatively similar behaviors for the cases of linear sigma model and Nambu-Jona-Lasinio model and, relating to existing lattice data, show that one cannot conclusively decide which or the two approximate symmetries drives the phase transitions near the physical point

    Securities Intermediaries in the Internet Age and the Traditional Principal-Agent Model of Regulation: Some Observations From the EU’s Markets in the Financial Instruments Directive

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    The regulation of securities intermediaries such as brokers and broker-dealers has hitherto been based onagency issues arising out of the client-intermediary relationship. This paper argues that, even in the Internetage where the interaction between clients and intermediaries take place over the Internet, the agency rationalefor regulation remains. However, the modalities of client-intermediary interaction take on certaincharacteristics that may affect the substantive regulation. As such, this paper examines the EU’s recentlyenacted Markets in Financial Instruments Directive to discern to what extent the Directive addresses newmodalities in client-intermediary interactions over the Internet

    Temporal Analysis of Language through Neural Language Models

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    We provide a method for automatically detecting change in language across time through a chronologically trained neural language model. We train the model on the Google Books Ngram corpus to obtain word vector representations specific to each year, and identify words that have changed significantly from 1900 to 2009. The model identifies words such as "cell" and "gay" as having changed during that time period. The model simultaneously identifies the specific years during which such words underwent change

    On computations of the integrated space shuttle flowfield using overset grids

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    Numerical simulations using the thin-layer Navier-Stokes equations and chimera (overset) grid approach were carried out for flows around the integrated space shuttle vehicle over a range of Mach numbers. Body-conforming grids were used for all the component grids. Testcases include a three-component overset grid - the external tank (ET), the solid rocket booster (SRB) and the orbiter (ORB), and a five-component overset grid - the ET, SRB, ORB, forward and aft attach hardware, configurations. The results were compared with the wind tunnel and flight data. In addition, a Poisson solution procedure (a special case of the vorticity-velocity formulation) using primitive variables was developed to solve three-dimensional, irrotational, inviscid flows for single as well as overset grids. The solutions were validated by comparisons with other analytical or numerical solution, and/or experimental results for various geometries. The Poisson solution was also used as an initial guess for the thin-layer Navier-Stokes solution procedure to improve the efficiency of the numerical flow simulations. It was found that this approach resulted in roughly a 30 percent CPU time savings as compared with the procedure solving the thin-layer Navier-Stokes equations from a uniform free stream flowfield