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Tamás Csörgő

Publications and source records attributed to Tamás Csörgő.

8 recordsLinked to original sources
arXiv2024

Scaling behaviour of $dN/dy$ in high-energy collisions

From a recently found family of analytic, finite and accelerating 1+1-dimensional solutions to perfect fluid relativistic hydrodynamics, we derive simple and powerful formulae to describe the rapidity and pseudorapidity density distributions. By introducing a new scaling function, we notice that the rapidity distribution data of the different experiments all collapse into a single curve. This data-collapsing (or scaling) behaviour in the rapidity distributions suggests that high-energy $p+p$ collisions may be described as collective systems.

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arXiv2022

New, spherical solutions of non-relativistic, dissipative hydrodynamics

We present a new family of exact solutions of dissipative fireball hydrodynamics for arbitrary bulk and shear viscosities. The main property of these solutions is a spherically symmetric, Hubble flow field. The motivation of this paper is mostly academic: we apply non-relativistic kinematics for simplicity and clarity. In this limiting case, the theory is particularly clear: the non-relativistic Navier-Stokes equations describe the dissipation in a well-understood manner. From the asymptotic analysis of our new exact solutions of dissipative fireball hydrodynamics, we could draw a surprising conclusion: this new class of exact solutions of non-relativistic dissipative hydrodynamics is asymptotically perfect.

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arXiv2019

Lifetime estimations from RHIC Au+Au data

We discuss a recently found family of exact and analytic, finite and accelerating, 1+1 dimensional solutions of perfect fluid relativistic hydrodynamics to describe the pseudorapidity densities and longitudinal HBT-radii and to estimate the lifetime parameter and the initial energy density of the expanding fireball in Au+Au collisions at RHIC with $\sqrt{s_{NN}}=130$ GeV and $200$ GeV colliding energies. From these exact solutions of relativistic hydrodynamics, we derive a simple and powerful formula to describe the pseudorapidity density distributions in high energy proton-proton and heavy ion collisions, and derive the scaling of the longitudinal HBT radius parameter as a function of the pseudorapidity density. We improve upon several oversimplifications in Bjorken's famous initial energy density estimate, and apply our results to estimate the initial energy densities of high energy reactions with data-driven pseudorapidity distributions. When compared to similar estimates at the LHC energies, our results indicate a surprising and non-monotonic dependence of the initial energy density on the energy of heavy ion collisions.

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arXiv2018

A new and finite family of solutions of hydrodynamics: Part III: Advanced estimate of the life-time parameter

We derive a new formula for the longitudinal HBT-radius of the two particle Bose-Einstein correlation function from a new family of finite and exact, accelerating solution of relativistic perfect fluid hydrodynamics for a temperature independent speed of sound. The new result generalizes the Makhlin-Sinyukov and Herrmann-Bertsch formulae and leads to an advanced life-time estimate of high energy heavy ion and proton-proton collisions.

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arXiv2016

Higher order anisotropies in the Buda-Lund model: Disentangling flow and density field anisotropies

The Buda-Lund hydro model describes an expanding ellipsoidal fireball, and fits the observed elliptic flow and oscillating HBT radii successfully. Due to fluctuations in energy depositions, the fireball shape however fluctuates on an event-by-event basis. The transverse plane asymmetry can be translated into a series of multipole anisotropy coefficients. These anisotropies then result in measurable momentum-space anisotropies, to be measured with respect to their respective symmetry planes. In this paper we detail an extension of the Buda-Lund model to multipole anisotropies and investigate the resulting flow coefficients and oscillations of HBT radii.

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arXiv2016

HBT radii from the multipole Buda-Lund model

The Buda-Lund model describes an expanding hydrodynamical system with ellipsoidal symmetry and fits the observed elliptic flow and oscillating HBT radii successfully. The ellipsoidal symmetry can be characterized by the second order harmonics of the transverse momentum distribution, and it can be also observed in the azimuthal oscillation of the HBT radii measured versus the second order reaction plane. The model may have to be changed to describe the experimentally indicated higher order asymmetries. In this paper we detail an extension of the Buda-Lund hydro model to investigate higher order flow harmonics and the triangular dependence of the azimuthally sensitive HBT radii.

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arXiv2012

From chi-squared to Bayesian model comparison and Levy expansions of Bose-Einstein correlations in e+e- reactions

The usual chi-squared method of fit quality assessment is a special case of the more general method of Bayesian model comparison which involves integrals of the likelihood and prior over all possible values of all parameters. We introduce new parametrisations based on systematic expansions around the stretched exponential or Fourier-transformed Lévy source distribution, and utilise the increased discriminating power of the Bayesian approach to evaluate the relative probability of these models to be true representations of a recently measured Bose-Einstein correlation data in e+e- annihilations at LEP.

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