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Search Results: 1 - 10 of 20854 matches for " Jean Letessier "
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Some results on co-recursive associated Laguerre and Jacobi polynomials
Jean Letessier
Mathematics , 1993,
Abstract: We present results on co-recursive associated Laguerre and Jacobi polynomials which are of interest for the solution of the Chapman-Kolmogorov equations of some birth and death processes with or without absorption. Explicit forms, generating functions, and absolutely continuous part of the spectral measures are given. We derive fourth-order differential equations satisfied by the polynomials with a special attention to some simple limiting cases.
Quark-Gluon Plasma in Pb--Pb 158 A GeV collisions: Evidence from strange particle abundances and the Coulomb effect
Jean Letessier,Johann Rafelski
Physics , 1998,
Abstract: The hadronic particle production data from relativistic nuclear Pb--Pb 158 A GeV collisions are successfully described within the chemical non-equilibrium model, provided that the analysis treats Omega and anti-Omega abundances with care. We further show that there is a subtle influence of the Coulomb potential on strange quarks in quark matter which is also seen in our data analysis, and this Coulomb effect confirms the finding made by chemical analysis in the S--Au/W/Pb 200 A GeV collisions that the hadron particle source is deconfined with respect to strange quark propagation. Physical freeze-out conditions (pressure, specific energy, entropy, and strangeness) are evaluated and considerable universality of hadron freeze-out between the two different collision systems is established.
Strangeness Excitation Function in Heavy Ion Collisions
Johann Rafelski,Jean Letessier
Physics , 2003, DOI: 10.1063/1.1843597
Abstract: We study as function of energy strangeness created in relativistic heavy ion collisions. We consider statistical hadronization with chemical freeze-out in both equilibrium and nonequilibrium. We obtain strangeness per baryon and per entropy in the energy range $8.75\lessim\sqrt{s_{NN}}\lessim 200 A$ GeV. A baryon density independent evaluation of the kaon to pion ratio is presented.
Chemical Nonequilibrium in High Energy Nuclear Collisions
Jean Letessier,Johann Rafelski
Physics , 1998, DOI: 10.1088/0954-3899/25/2/018
Abstract: Strange particles produced in S-Au/W/Pb 200 A GeV and Pb-Pb 158 A GeV reactions are described invoking final hadronic phase space in thermal equilibrium, but allowing chemical non-equilibrium. Several sets of statistical freeze-out parameters are obtained for each system, invoking different models of dense matter. We show that only when allowing for strange and non-strange flavor abundance non-equilibrium, a statistically significant description of the experimental results is obtained. Physical properties of the fireball at chemical freeze-out condition are evaluated and considerable universality of hadron freeze-out between the two different collision systems is established. The relevance of the Coulomb effect in the highly charged Pb-Pb fireballs for the chemical analysis are discussed. The influence of explosive collective matter flow is also described.
Strangeness enhancement at LHC
Johann Rafelski,Jean Letessier
Physics , 2008, DOI: 10.1088/0954-3899/35/4/044042
Abstract: We study production of strangeness in the hot QGP fireball in conditions achieved at LHC, and use these results to obtain soft (strange) hadron multiplicities. We compare the chemical equilibrium and non-equilibrium conditions and identify characteristic experimental observables.
Sudden Hadronization in Relativistic Nuclear Collisions
Johann Rafelski,Jean Letessier
Physics , 2000, DOI: 10.1103/PhysRevLett.85.4695
Abstract: We formulate and study a mechanical instability criterion for sudden hadronization of dense matter fireballs formed in 158A GeV Pb--Pb collisions. Considering properties of quark-gluon matter and hadron gas we obtain the phase boundary between these two phases and demonstrate that the required deep QGP supercooling prior to sudden hadronization has occurred.
Observing Quark-Gluon Plasma with Strange Hadrons
Jean Letessier,Johann Rafelski
Physics , 2000, DOI: 10.1142/S0218301300000076
Abstract: We review the methods and results obtained in an analysis of the experimental heavy ion collision research program at nuclear beam energy of 160-200A GeV. We study strange, and more generally, hadronic particle production experimental data. We discuss present expectations concerning how these observables will perform at other collision energies. We also present the dynamical theory of strangeness production and apply it to show that it agrees with available experimental results. We describe strange hadron production from the baryon-poor quark-gluon phase formed at much higher reaction energies, where the abundance of strange baryons and antibaryons exceeds that of nonstrange baryons and antibaryons.
Critical Hadronization Pressure
Johann Rafelski,Jean Letessier
Physics , 2009, DOI: 10.1088/0954-3899/36/6/064017
Abstract: We discuss the bulk properties of QGP produced at RHIC obtained at time of hadronization. We argue that hadronization of quark--gluon plasma occurs at a critical pressure of 82 MeV/fm3, obtained for SPS energy range.
Non-equilibrium Hadrochemistry in QGP Hadronization
Johann Rafelski,Jean Letessier
Physics , 2002, DOI: 10.1063/1.1513695
Abstract: This survey offers an introductory tutorial for students of any age of the currently thriving field of hadrochemistry. We discuss the different chemical potentials, how the hadronic phase space is described and how one evaluates the abundance of hadrons at time of hadronization. We show that a rather accurate description of experimental data arises and we present results of fits to hadron yields at SPS and RHIC. We show that introduction of chemical non-equilibrium originating in a sudden hadronization of a QGP is favored strongly at SPS and is presently also emerging at RHIC. The low chemical freeze-out temperatures are consistent with the picture of single freeze-out scenario (chemical and thermal freeze-out coincide).
Hadron Production and Phase Changes in Relativistic Heavy Ion Collisions
Jean Letessier,Johann Rafelski
Physics , 2005, DOI: 10.1140/epja/i2007-10546-7
Abstract: We study soft hadron production in relativistic heavy ion collisions in a wide range of reaction energy, 4.8 GeV sqrt{s_NN} \ge 200 GeV, we use continuity of particle yields and statistical parameters to predict the hadron production at sqrt{s_NN}=62.4 GeV, and obtain total yields of hadrons at sqrt{s_NN}=130 GeV. We consider, in depth, the pattern we uncover within the hadronization condition, and discuss possible mechanisms associated with the identified rapid change in system properties at sqrt{s_NN ^cr}. We propose that the chemically over-saturated 2+1 flavor hadron matter system undergoes a 1st order phase transition.
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