Covariant description of kinetic freeze-out through a finite spacelike layer

Molnár, E.; Csernai, L. P.; Magas, V. K.; Nyíri, Á.; Tamosiunas, K.

doi:10.1103/physrevc.74.024907

Cited by 20 publications

(58 citation statements)

References 21 publications

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“…Although the present solution mathematically is achieved taking an infinitely short relaxation time, in reality, one can show, see Ref. [1], that the complete thermalization of the interacting component can be achieved with good accuracy if τ 0 is smaller than τ by a factor of 2 or more. For a thorough analysis of this approach, see Refs.…”

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

“…Please note that, although τ 0 is assumed to be a constant for simplicity, the characteristic FO length is increasing with time or distance such as, τ 0 (L − s)/L. The detailed treatment and analysis of the escape rate can be found in [1,10,11]. Now, if we describe the time evolution of the particle FO, then dσ µ = (1, 0, 0, 0), x µ dσ µ = t and p µ dσ µ = p 0 , thus eq.…”

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

“…For a thorough analysis of this approach, see Refs. [1,12] and the Appendix. Here we mention that in our calculations we use only one type of particles, namely massless pions, therefore the chemical composition of our system remains unchanged during the kinetic FO.…”

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

“…(13)(14)] from Ref. [1], which can be used in both time-like and space-like FO cases. The equations depend on the projection, s = x µ dσ µ , in the direction of the FO normal vector, dσ µ , where the four vector x µ denotes the particle coordinate, having its origin at the inner surface of the FO layer.…”

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

“…Through the paper we are going to use the notation from Ref. [1], recall the governing equations and the major results for comparison. We have made this paper sole and complete and widely understandable without the need to consult our previous work where the original ideas were first introduced.…”

Section: Introductionmentioning

confidence: 99%

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Covariant description of kinetic freeze-out through a finite time-like layer

Molnár

Csernai

Magas

et al. 2007

J. Phys. G: Nucl. Part. Phys.

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Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

Section: Freeze-out From a Finite Time-like Layermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Covariant description of kinetic freeze-out through a finite time-like layer

Molnár

Csernai

Magas

et al. 2007

J. Phys. G: Nucl. Part. Phys.

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Freeze-out of the expanding system

Magas

Csernai

Molnár

The IVth International Conference on Quarks and Nuclear Physics

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Abstract. The freeze out (FO) of the expanding systems, created in relativistic heavy ion collisions, is discussed. We start with kinetic FO model, which realizes complete physical FO in a layer of given thickness, and then combine our gradual FO equations with Bjorken type system expansion into a unified model. We shall see that the basic FO features, pointed out in the earlier works, are not smeared out by the expansion.PACS. 51.10.+y -24.10. At highest energies available nowadays in relativistic heavy ion collisions at RHIC the total number of the produced particles exceeds 6000, therefore one can expect that the produced system behaves as a "matter" and generates collective effects. Indeed strong collective flow patterns have been measured at RHIC, which suggests that the hydrodynamical models are well justified during the intermediate stages of the reaction: from the time when local equilibrium is reached until the freeze out (FO), when the hydrodynamical description breaks down. During this FO stage, the matter becomes so dilute and cold that particles stop interacting and stream towards the detectors freely, their momentum distribution freezes out. The FO stage is essentially the last part of a collision process and the main source for observables.Nowadays, FO is usually simulated in two extreme ways: A) FO on a hypersurface with zero thickness, B) FO described by volume emission model or hadron cascade, which in principle requires an infinite time and space for a complete FO. At first glance it seems that one can avoid troubles with FO modeling using hydro+cascade two module model [1], since in hadron cascades gradual FO is realized automatically. However, in a such a scenario there is an uncertain point, actually uncertain hypersurface, where one switchs from hydrodynamical to kinetic modeling. First of all it is not clear how to determine such a hypersurface. This hypersurface in general may have both time-like and space-like parts. Mathematically this problem is very similar to hydro to FO phase transition on the infinitely narrow FO hypersurface, therefore for example all the problems discussed for FO on the hypersurface with space-like normal vectors will take place here. Another complication is that while for the post FO domain we have mixture of non-interacting ideal gases, now for the hadron cascade we should generate distributions for the interacting hadronic gas of all possible species, as a starting point for the further cascade evolution. The volume emission models are based on the kinetic equations [2,3] defining the evolution of the distribution functions, and therefore these also require to generate initial distribution functions for the interacting hadronic species on some hypersurface.In this work we present FO model which allows us to study FO in a layer of any thichness, L, from 0 to ∞, and which connects the pre FO hydrodynamical quantities, like energy density, e, baryon density, n, with post FO distribution function in a relatively simple way. Many building blocks of the model are ...

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Continuous decoupling of dynamically expanding systems

Knoll

2009

Nuclear Physics A

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The question of decoupling and freeze-out is reinvestigated and analysed in terms of transparent semi-classical decoupling formulae, which provide a smooth decoupling in time both, for single and two particle inclusive spectra. They generalise frequently employed instantaneous freeze-out procedures and provide simple relations between the damping width and the duration of the decoupling process. The implications on physical phenomena arising from the expansion and decay dynamics of the highly compressed hadronic matter generated in high energy nuclear collisions are discussed.

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Covariant description of kinetic freeze-out through a finite spacelike layer

Cited by 20 publications

References 21 publications

Covariant description of kinetic freeze-out through a finite time-like layer

Covariant description of kinetic freeze-out through a finite time-like layer

Freeze-out of the expanding system

Continuous decoupling of dynamically expanding systems

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