Continuous Particle Emission Research Articles

Energy dependence of pion interferometry scales in ultra-relativistic heavy ion collisions

A study of energy behavior of the pion spectra and interferometry scales is carried out for the top SPS, RHIC and LHC energies within the hydrokinetic approach. The latter allows one to describe evolution of quark–gluon and hadron matter as well as continuous particle emission from the fluid in agreement with the underlying kinetic equations. The main mechanisms that lead to the paradoxical, at first sight, behavior of the interferometry scales, are exposed. In particular, a slow decrease and apparent saturation of Rout/Rside ratio with an energy growth happens due to a strengthening of positive correlations between space and time positions of pions emitted at the radial periphery of the system. Such en effect is a consequence of the two factors: a developing of the pre-thermal collective transverse flows and an increase of the initial energy density in the fireball.

Hydrokinetic model of the matter evolution in A + A collisions at RHIC and LHC energies

Using the hydrokinetic model of pionic emission in heavy ion collisions, we study the effects of continuous particle emission for 3D azimuthal symmetric Bjorken-type expansion. We describe RHIC pion data in central A + A collisions and make predictions for LHC based on the hydrokinetic model and initial conditions taken from the color glass condensate model.

New Computer Program for Three-Dimensional Relativistic Hydrodynamical Model

An effective computer program for three dimensional relativistic hydrodynamical model has been developed. It implements a new approach to the early hot phase of relativistic heavy-ion collisions. The computer program simulates time-space evolution of nuclear matter in terms of ideal-fluid dynamics. Equations of motions of hydrodynamics are solved making use of finite difference methods. Commonly-used algorithms of numerical relativistic hydrodynamics RHLLE and MUSTA-FORCE have been applied in simulations. To speed-up calculations, parallel processing has been made available for solving hydrodynamical equations. The test results of simulations for 3D, 2D and Bjorken expansion are reported in this paper. As a next step we plan to implement the hadronization algorithm by implementing the continuous particle emission for freeze-out and comparing it with Cooper-Frye formula.

Particle emission in hydrodynamics: a problem needing a solution

A survey of various mechanisms for particle emission in hydrodynamics is presented. First, in the case of sudden freeze out, the problem of negative contributions in the Cooper-Frye formula and ways out are presented. Then the separate chemical and thermal freeze out scenario is described and the necessity of its inclusion in a hydrodynamical code is discussed. Finally, we show how to formulate continuous particle emission in hydrodynamics and discuss extensively its consistency with data. We point out in various cases that the interpretation of data is quite influenced by the choice of the particle emission mechanism.

Particle abundances and spectra in the hydrodynamical description of relativistic nuclear collisions with light projectiles

We show that a hydrodynamical model with continuous particle emission instead of sudden freeze-out may explain both the observed strange particle and pion abundances and transverse mass spectra for light projectiles at SPS energy. We found that the observed enhancement of pion production corresponds, within the context of continuous emission, to the maximal entropy production.

Confronting Particle Emission Scenarios with Strangeness Data

We show that a hadron gas model with continuous particle emission instead of freeze-out may solve some of the problems (high values of the freeze-out density and specific net charge) that one encounters in the latter case when studying strange particle ratios such as those from the experiment WA85. This underlines the necessity to understand better particle emission in hydrodynamics to be able to analyze data. It also reopens the possibility of a quark-hadron transition occurring with phase equilibrium instead of explosively.

A test of particle emission scenarios: Strange particle ratios

We show that a hadron gas model with continuous particle emission instead of freeze-out may solve some of the problems that one encounters in the latter case when studying strange particle ratios such as those by WA85.

Particle emission in the hydrodynamical description of relativistic nuclear collisions

The usual particle emission scenario used in hydrodynamics presupposes that particles instantaneously stop interacting once they reach some three dimensional surface. Here we set up a new formalism to study continuous particle emission during the whole expansion of thermalized matter. This scenario changes completely the usual interpretation of transverse momentum spectra, may help to understand data on strange particle ratios and is possible to include in hydrodynamical codes.

Continuous particle emission: a probe of thermalized matter evolution?

Continuous particle emission during the whole expansion of thermalized matter is studied and a new formula for the observed transverse mass spectrum is derived. In some limit, the usual emission in the freeze-out scenario (Cooper-Frye formula) may be recovered. This scenario changes completely the usual interpretation of transverse momentum spectra, may help to understand data on strange particle ratios and is possible to include in hydrodynamical codes.

24 O 03 Continuous particle emission mass monitoring in a pulverized coal fired power plant

24 O 03 Continuous particle emission mass monitoring in a pulverized coal fired power plant