arXiv subjects

Yu. M. Sinyukov

Publications and source records attributed to Yu. M. Sinyukov.

64 records · Page 4Linked to original sources

arXiv2004

Sudden freeze-out vs continuous emission: duality in hydro-kinetic approach to A+A collisions

The problem of spectra formation in hydrodynamic approach to A+A collisions is discussed. It is analyzed in terms of the two different objects: distribution and emission functions. We show that though the process of particle liberation, described by the emission function, is, usually, continuous in time, the observable spectra can be also expressed by means of the Landau/Cooper-Frye prescription. We argue that such an approximate duality results from some symmetry properties that systems in A+A collisions reach to the end of hydrodynamic evolution and reduction of the collision rate at post hydrodynamic stage

nucl-th↗

arXiv2004

Pion entropy and phase-space densities in A+A collisions

We propose a method to estimate the entropy of thermal pions in A+A collisions irrespective of unknown form of freeze-out (isothermal) hypersurface and transverse flows developed. We analyse the average phase-space densities and entropies of the thermal pions vs their multiplicities and collision energies. The behaviour of these values apparently indicates the deconfinement and chiral phase transitions in relativistic nuclear-nucleus collisions

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arXiv2003

Correlation search for coherent pion emission in heavy ion collisions

The methods allowing to extract the coherent component of pion emission conditioned by the formation of a quasi-classical pion source in heavy ion collisions are suggested. They exploit a nontrivial modification of the quantum statistical and final state interaction effects on the correlation functions of like and unlike pions in the presence of the coherent radiation. The extraction of the coherent pion spectrum from pi+pi-, pi+pi+ and pi-pi- correlation functions and single--pion spectra is discussed in detail for large expanding systems produced in ultra-relativistic heavy ion collisions.

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arXiv2002

Reconstruction of Hadronization Stage in Pb+Pb Collisions at 158A GeV/c

Recent data on hadron multiplicities in central Pb+Pb collisions at 158A GeV/c at mid-rapidity are analyzed within the concept of chemical freeze-out. A non-uniformity of the baryon chemical potential along the beam axis is taken into account. An approximate analytical solution of the hydrodynamic equations for a chemically frozen Boltzmann-like gas is found. The Cauchy conditions for hydrodynamic evolution of the hadron resonance gas are fixed at the thermal freeze-out hypersurface from analysis of one-particle momentum spectra and HBT correlations. The proper time of chemical freeze-out and physical conditions at the hadronization stage, such as energy density and averaged transverse velocity, are found.

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arXiv2002

On freeze-out problem in hydro-kinetic approach to A+A collisions

A new method for evaluating spectra and correlations in the hydrodynamic approach is proposed. It is based on an analysis of Boltzmann equations (BE) in terms of probabilities for constituent particles to escape from the interacting system. The conditions of applicability of Cooper-Frye freeze-out prescription are considered within the method. The results are illustrated with a non-relativistic exact solution of BE for expanding spherical fireball as well as with approximate solutions for ellipsoidally expanding ones.

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arXiv2001

Simple solutions of fireball hydrodynamics for self-similar elliptic flows

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.

hep-ph↗

arXiv1999

Boson spectra and correlations for thermal locally equilibrium systems

The single- and multi- particle inclusive spectra for strongly inhomogeneous thermal boson systems are studied using the method of statistical operator. The thermal Wick's theorem is generalized and the analytical solution of the problem for an boost-invariant expanding boson gas is found. The results demonstrate the effects of inhomogeneity for such a system: the spectra and correlations for particles with wave-lengths larger than the system's homogeneity lengths change essentially as compared with the results based on the local Bose-Einstein thermal distributions. The effects noticeable grow for overpopulated media, where the chemical potential associated with violation of chemical equilibrium is large enough.

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arXiv1999

Thermodynamics of multi-boson phenomena

Using the method of locally equilibrium statistical operator we consider the thermalized relativistic quantum fields in an oscillatory trap. We compare this thermal picture of the confined boson gas with non-relativistic model of independent factorized sources. We find that they are equivalent in the limit of very large effective sizes $R$, more exactly, when the Compton wave length $1/m$ and thermal wave length $1/\sqrt{% mT}$ are much smaller than {\}$R$ . Under this conditions we study the influence of Bose condensation in finite volumes on the structure of the Wigner function, momentum spectra and correlation function.

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arXiv1999

"Pion laser" phenomenon and other possible signatures of the DCC at RHIC and LHC energies

The decay of fireballs containing the disoriented chiral condensate (DCC) in A+A collisions has been analyzed. We found that the high phase-space density and probably the large final fireball volume are the favorable factors to extract a DCC signal from the thermal background. Both of these factors are expected to take place at RHIC and LHC energies. A coherent pion component then can be observed in pion spectra, in Bose-Einstein correlations and in distribution of the ratio of neutral to total pions.

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arXiv1998

On final conditions in high energy heavy ion collisions

Motivated by the recent experimental observations, we discuss the freeze-out properties of the fireball created in central heavy ion collisions. We find that the freeze-out conditions, like temperature, velocity gradient near center of the fireball, are similar for different colliding systems and beam energies. This means that the transverse flow is stronger in the collisions of heavy nuclei than that of the light ones.

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