arXiv subjects

L. Chkhaidze

Publications and source records attributed to L. Chkhaidze.

12 recordsLinked to original sources

arXiv2016

Study of collective flows of protons and $π^{-}$ -mesons in p(C, Ta) and He(Li, C) collisions at momenta of 4.2, 4.5 and 10 AGeV/c

Collective flows of protons and $π^{-}$-mesons are studied at the momenta of 4.2, 4.5 and 10 AGeV/c for p(C, Ta) and He(Li, C) interactions. The data were obtained from the streamer chamber (SKM-200-GIBS) and from the Propane Bubble Chamber (PBC-500) systems utilized at JINR. The method of Danielewicz and Odyniec has been employed in determining the directed transverse flow of particles. The values of the transverse flow parameter and the strength of the anisotropic emission were defined for each interacting nuclear pair. It is found that the directed flows of protons and pions decrease with increase of the energy and the mass numbers of colliding nucleus pairs. The $π^{-}$-meson and proton flows exhibit opposite directions in all studied interactions, and the flows of protons are directed in the reaction plane. The Ultra-relativistic Quantum Molecular Dynamical Model (UrQMD), enlarged by the Statistical Multi-fragmentation Model (SMM), satisfactorily describes obtained experimental results.

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arXiv2009

Anisotropic Collective Flow of Lambda Hyperons Produced in C + C Collisions at 4.2 AGeV/c

Features of anisotropic collective flow and spectral temperatures have been determined for lambda hyperons emitted from C + C collisions, at incident momentum of 4.2 AGeV/c, measured using the Propane Bubble Chamber of JINR at Dubna. Moreover, characteristics of protons and of negative pions, emitted from those collisions, have been determined and provided for comparison. The directed and elliptic flows of lambdas both agree in sign with the corresponding flows of protons. Parameters of the directed and elliptic flows for lambdas agree further, within errors, with the corresponding parameters for the co-produced protons. This contrasts an earlier finding by the E895 Collaboration of the directed flow being significantly weaker for lambdas than protons, in the much heavier Au + Au system, at comparable incident momentum. Particle spectral temperatures in the C + C collisions have been determined focusing independently on either center-of-mass energy, transverse energy or transverse momentum distributions. For either protons or negative pions, the temperatures were found to be approximately the same, no matter whether the emission of those particles was associated with lambda production or not. Results of the measurements have been compared to the results of simulations within the Quark-Gluon String Model.

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arXiv2007

Collective Flow of Protons and Negative Pions in Nucleus-Nucleus Collisions at Momentum of $4.2 ÷4.5$ AGeV/c

Collective flow of protons and negative pions has been studied within the momentum region of $4.2 ÷4.5$ AGeV/c ($E =3.4 ÷3.7$ AGeV) for different projectile-target combinations involving carbon and, specifically, He-C, C-C, C-Ne, C-Cu and C-Ta. The data stem from the SKM-200-GIBS streamer chamber and from Propane Bubble Chamber systems utilized at JINR. The directed flow of protons grows dramatically in the carbon region when the counterpart nucleus grows in mass between He and Ta. The elliptic proton flow points out of the reaction plane and also strengthens as system mass increases. Within the reaction plane, the negative pions flow in the same direction as protons for the lighter of the investigated systems, He-C, C-C and C-Ne, and in the opposite direction for the heavier, C-Cu and C-Ta. The Quark-Gluon String Model reproduces observed changes in the flow with system mass.

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arXiv2002

Differential Transverse Flow in Central C-Ne and C-Cu Collisions at 3.7 GeV/nucleon

Differential transverse flow of protons and pions in central C-Ne and C-Cu collisions at a beam energy of 3.7 GeV/nucleon was measured as a function of transverse momentum at the SKM-200-GIBS setup of JINR. In agreement with predictions of a transversely moving thermal model, the strength of proton differential transverse flow is found to first increase gradually and then saturate with the increasing transverse momentum in both systems. While pions are preferentially emitted in the same direction of the proton transverse flow in the reaction of C-Ne, they exhibit an anti-flow to the opposote direction of the proton transverse flow in the reaction of C-Cu due to stronger shadowing effects of the heavier target in thr whole range of transverse momentum.

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arXiv2001

Study of Multiparticle Azimuthal Correlations in Central CNe, MgMg, CCu and OPb Interactions at Energy of 3.7 GeV per Nucleon

Azimuthal correlations between protons and between pions have been investigated in central CNe, MgMg, CCu and OPb collisions at energy of 3.7 GeV/nucleon. "Back-to-back" (negative) correlations have been observed for protons in CNe, CCu and for pi^{-}-mesons in CNe and MgMg collisions. For pi^{-}-mesons "side-by-side" (positive) azimuthal correlations have been observed for heavy systems of CCu and OPb. The Quark Gluon String Model satisfactorily describes the experimental results both for protons and pi^{-}-mesons.

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arXiv2000

Results from SKM-200-GIBS on multiparticle azimuthal correlations in C-Ne and C-Cu collisions at energy of 3.7 GeV per nucleon

The transverse momentum technique is used to analyse charged-particle exclusive data in central C-Ne and C-Cu interactions at energy of 3.7 GeV per nucleon. Clear evidence of in-plane and out-of-plane (squeeze-out) flow effects for protons and pi^{-} mesons have been obtained. In C-Ne interactions in-plane flow of pi^{-} mesons is in the same direction as for the protons, while in C-Cu collisions pions show antuflow behaviour. From the transverse momentum and azimuthal distributions of protons and pi^{-} mesons with respect to the reaction plane, the flow (the measure of the amount of collective transverse momentum transfer in the reaction plane) and the parameter a_{2} (the measure of the anisotropic emission strength) have been extracted. The flow effects increase with the mass of the particle and the mass number of target A_{T}. The comparison of our in-plane flow results with flow data for various projectile/target configurations was made using the scaled flow F_{S}=F/(A_{P} ^{1/3}+A_{T}^{1/3}). F_{S} demonstrates a common scaling behaviour for flow values from different systems. The Quark Gluon String Model (QGSM) was used for the comparison with the experimental data. The QGSM yields a signature of in-plane and out-of-plane flow effects in C-ne and C-Cu collisions for protons.

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arXiv1999

Study of collective matter flow in central C-Ne and C-Cu collisions at energy of 3.7 GeV per nucleon

The transverse momentum technique is used to analyse charged-particle exclusive data in the central C-Ne and C-Cu interactions at energy of 3.7 Gev per nucleon. The clear evidence of in-plane and out-of-plane (squeeze-out) flow effects for protons and $π^{-}$ mesons have been obtained. In C-Ne interactions the $π^{-}$ mesons in-plane flow is in the same direction to the protons, while in C-Cu collisions pions show antiflow behaviour. From the transverse momentum and azimuthal distributions of protons and pi^{-} mesons with respect to the reaction plane the flow F (the measure of the amount of collective transverse momentum transfer in the reaction plane) and the parameter a_{2} (the measure of the strength of the anisotropic emission) have been extracted. The flow effects increase with the mass of the particle and atomic number of target A_{T}. The comparison of our in-plane flow results with flow data of various projectile/target configurations had been done by a scaled flow F_{S}=F/(A_{P}^{1/3}+A_{T}^{1/3}). F_{S} demonstrates a common scaling behaviour among flow values from different systems.

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arXiv1999

The analysis of pi^{-} mesons produced in nucleus-nucleus collisions at a momentum of 4.5 GeV/c/nucleon in light front variables

The light front analysis of pi^{-} mesons in He(Li,C), C-Ne, C-Cu and O-Pb collisions is carried out. The phase space of secondary pions is divided into two parts in one of which the thermal equilibrium assumption seems to be in a good agreement with the data. Corresponding temperatures T are extracted and their dependence on (A_{P}*A_{T})^{1/2} is studied. The results are compared with the predictions of the Quark-Gluon String Model (QGSM). The QGSM satisfactorily reproduces the experimental data for light and intermediate-mass nuclei.

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arXiv1998

The Light Front Analysis of pi^{-} Mesons Produced in the Relativistic Nucleus-Nucleus Collisions

The light front analysis of pi^{-} mesons in A_{P} (He, C, Mg, O) + A_{T} (Li,C, Ne, Mg,Cu,Pb) collisions is carried out. The phase space of secondary pions is naturally divided into two parts in one of which the thermal equilibration assumption seems to be in a good agreement with data. Corresponding temperatures are extracted and compared to the results of other experiments. The dependence of the average temperature T on (A_{P}*A_{T})^{1/2} is studied.

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arXiv1998

Light-Front Analysis of pi^{-} Mesons Produced in Mg - Mg Collisions at 4.3 a Gev/c

Light-front analysis of pi^{-} mesons in Mg-Mg collisions is carried out. The phase space of secondary pions is naturally divided into two parts in one of which the thermal equilibration assumption seems to be in a good agreement with data. Corresponding temperatures are extracted and compared to the results of other experiments. The experimental results have been compared with the predictions of the Quark Gluon String Model (QGSM) and satisfactory agreement between the experimental data and the model has been found.

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arXiv1998

The comparison of characteristics of pi^{-} mesons produced in central Mg-Mg interactions with the quark gluon string model predictions

A detailed study of pion production in central Mg-Mg collisions at a momentum of 4.3 GeV/c per incident nucleon was carried out with use of the setup GIBS. The average kinematical characteristics of pions (multiplicity n_, momentum P, transverse momentum P_{T}, emission angle Q, rapidity Y) and corresponding distributions have been obtained. The experimental results have been compared with the predictions of the Quark Gluon String Model (QGSM) and satisfactory agreement between the experimental data and the model has been found. The QGSM reproduces also the dependence of average P_{T} on n_{-}. The temperatures of pi^{-} mesons have been estimated in the rapidity interval of 0.5<=Y<=2.1. A satisfactory fit for pi^{-} mesons has been achieved by using a form involving two temperatures T_{1} and T_{2}. It was found that the QGSM underestimates T_{2} by (10-15)%. The data have been analyzed using the transverse momentum technique. The observed dependence of the on Y shows the S-shape behaviour. The slope at midrapidity F had been determined. The QGSM reproduces the distribution satisfactorily, but underestimates the parameter F.

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arXiv1998

The observation of collective effects in central C-Ne and C-Cu collisions at a momentum of 4.5 GeV/c per nucleon

The transverse momentum technique is used to analyse charged-particle exclusive data in the central C-Ne and C-Cu interactions at a momentum of 4.5 Gev/c per nucleon.The results are presented in terms of the mean transverse momentum per nucleon projected onto the estimated reaction plane as a function of the rapidity Y in the laboratory system. The observed dependence shows the typical S-shape behaviour reflecting the presence of flow effects. The value of flow F is obtained that increases with the atomic number of the target. The Monte Carlo cascade Quark Gluon String Model (QGSM) is used for the comparison with the experimental data. The QGSM reproduces the spectra and the mean kinematical characteristics of the protons ( .... ) but underestimates their transverse flow.

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