685 research outputs found

    Buda-Lund hydro model for ellipsoidally symmetric fireballs and the elliptic flow at RHIC

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    The ellipsoidally symmetric extension of Buda-Lund hydrodynamic model is shown here to yield a natural description of the pseudorapidity dependence of the elliptic flow v2(η)v_2(\eta), as determined recently by the PHOBOS experiment for Au+Au collisions at sNN=130\sqrt{s_{NN}} = 130 and 200 GeV. With the same set of parameters, the Buda-Lund model describes also the transverse momentum dependence of v2v_2 of identified particles at mid-rapidity. The results confirm the indication for quark deconfinement in Au+Au collisions at RHIC, obtained from a successful Buda-Lund hydro model fit to the single particle spectra and two-particle correlation data, as measured by the BRAHMS, PHOBOS, PHENIX and STAR collaborations.Comment: 16 pages, 2 figures, 1 table added, discussion extended and an important misprint in the caption of Fig. 1 is correcte

    Simple analytic solution of fireball hydrodynamics

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    A new family of simple analytic solutions of hydrodynamics is found for non-relativistic, rotationally symmetric fireballs assuming an ideal gas equation of state. The solution features linear flow profile and a non-trivial transverse temperature profile. The radial temperature gradient vanishes only in the collisionless gas limit. The Zimanyi-Bondorf-Garpman solution and the Buda-Lund parameterization of expanding hydrodynamical sources are recovered as special cases. The results are applied to predict new features of proton-proton correlations and spectra data at 1.93 AGeV Ni + Ni reactions.Comment: Latex, Revte

    Weak convergence of Vervaat and Vervaat Error processes of long-range dependent sequences

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    Following Cs\"{o}rg\H{o}, Szyszkowicz and Wang (Ann. Statist. {\bf 34}, (2006), 1013--1044) we consider a long range dependent linear sequence. We prove weak convergence of the uniform Vervaat and the uniform Vervaat error processes, extending their results to distributions with unbounded support and removing normality assumption

    A new family of exact and rotating solutions of fireball hydrodynamics

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    A new class of analytic, exact, rotating, self-similar and surprisingly simple solutions of non-relativistic hydrodynamics are presented for a three-dimensionally expanding, spheroidally symmetric fireball. These results generalize earlier, non-rotating solutions for ellipsoidally symmetric fireballs with directional, three-dimensional Hubble flows. The solutions are presented for a general class of equations of state that includes the lattice QCD equations of state and may feature inhomogeneous temperature and corresponding density profiles.Comment: Dedicated to T. Kodama on the occasion of his 70th birthday. 15 pages, no figures. Accepted for publication at Phys. Rev. C. Minor rewritings from previous versio

    Simple solutions of fireball hydrodynamics for rotating and expanding triaxial ellipsoids and final state observables

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    We present a class of analytic solutions of non-relativistic fireball hydrodynamics for a fairly general class of equation of state. The presented solution describes the expansion of a triaxial ellipsoid that rotates around one of the principal axes. We calculate the hadronic final state observables such as single-particle spectra, directed, elliptic and third flows, as well as HBT correlations and corresponding radius parameters, utilizing simple analytic formulas. We call attention to the fact that the final tilt angle of the fireball, an important observable quantity, is not independent on the exact definition of it: one gets different angles from the single-particle spectra and from HBT measurements. Taken together, it is pointed out that these observables may be sufficient for the determination of the magnitude of the rotation of the fireball. We argue that observing this rotation and its dependence on collision energy would reveal the softness of the equation of state. Thus determining the rotation may be a powerful tool for the experimental search for the critical point in the phase diagram of strongly interacting matter.Comment: 17 pages, 12 figure panel

    Excitation function of elastic pppp scattering from a unitarily extended Bialas-Bzdak model

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    The Bialas-Bzdak model of elastic proton-proton scattering assumes a purely imaginary forward scattering amplitude, which consequently vanishes at the diffractive minima. We extended the model to arbitrarily large real parts in a way that constraints from unitarity are satisfied. The resulting model is able to describe elastic pppp scattering not only at the lower ISR energies but also at s=\sqrt{s}=7 TeV in a statistically acceptable manner, both in the diffractive cone and in the region of the first diffractive minimum. The total cross-section as well as the differential cross-section of elastic proton-proton scattering is predicted for the future LHC energies of s=\sqrt{s}=8, 13, 14, 15 TeV and also to 28 TeV. A non-trivial, significantly non-exponential feature of the differential cross-section of elastic proton-proton scattering is analyzed and the excitation function of the non-exponential behavior is predicted. The excitation function of the shadow profiles is discussed and related to saturation at small impact parameters.Comment: Talk by T. Csorgo presented at the WPCF 2014 conference, Gyongyos, Hungary, August 25-29 201

    Simple solutions of fireball hydrodynamics for self-similar elliptic flows

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    Simple, self-similar, elliptic solutions of non-relativistic fireball hydrodynamics are presented, generalizing earlier results for spherically symmetric fireballs with Hubble flows and homogeneous temperature profiles. The transition from one dimensional to three dimensional expansions is investigated in an efficient manner.Comment: 12 pages, 4 figures in 8 .eps files, references to recent data added, accepted in Physics Letters

    Detailed description of accelerating, simple solutions of relativistic perfect fluid hydrodynamics

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    In this paper we describe in full details a new family of recently found exact solutions of relativistic, perfect fluid dynamics. With an ansatz, which generalizes the well-known Hwa-Bjorken solution, we obtain a wide class of new exact, explicit and simple solutions, which have a remarkable advantage as compared to presently known exact and explicit solutions: they do not lack acceleration. They can be utilized for the description of the evolution of the matter created in high energy heavy ion collisions. Because these solutions are accelerating, they provide a more realistic picture than the well-known Hwa-Bjorken solution, and give more insight into the dynamics of the matter. We exploit this by giving an advanced simple estimation of the initial energy density of the produced matter in high energy collisions, which takes acceleration effects (i.e. the work done by the pressure and the modified change of the volume elements) into account. We also give an advanced estimation of the life-time of the reaction. Our new solutions can also be used to test numerical hydrodynamical codes reliably. In the end, we also give an exact, 1+1 dimensional, relativistic hydrodynamical solution, where the initial pressure and velocity profile is arbitrary, and we show that this general solution is stable for perturbations.Comment: 34 pages, 8 figures, detailed write-up of http://arxiv.org/abs/nucl-th/0605070

    Reduction principles for quantile and Bahadur-Kiefer processes of long-range dependent linear sequences

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    In this paper we consider quantile and Bahadur-Kiefer processes for long range dependent linear sequences. These processes, unlike in previous studies, are considered on the whole interval (0,1)(0,1). As it is well-known, quantile processes can have very erratic behavior on the tails. We overcome this problem by considering these processes with appropriate weight functions. In this way we conclude strong approximations that yield some remarkable phenomena that are not shared with i.i.d. sequences, including weak convergence of the Bahadur-Kiefer processes, a different pointwise behavior of the general and uniform Bahadur-Kiefer processes, and a somewhat "strange" behavior of the general quantile process.Comment: Preprint. The final version will appear in Probability Theory and Related Field
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