CERN Accelerating science

Preprint
Report number	JINR-P1-2004-95 ; P1-2004-95
Title	Study of Collective Properties of Hyperons Produced in C-C Collisions at a Momentum of 4.2 GeV/c per Nucleon
Author(s)	Djobava, T D ; Djobava, T D ; Kladnitskaya, E N ; Kharkhelauri, L L
Affiliation	(Veksler and Baldin Laboratory of High Energies, Dubna) ; (High Energy Physics Institute TSU, Tbilisi, Georgia)
Publication	2004
Imprint	22 Jun 2004
Number of pages	14
Subject category	Particle Physics - Experiment
Abstract	The collective properties of \Lambda hyperons produced in C-C collisions at a momentum of 4.2 GeV/c per nucleon have been investigated. Characteristics of protons and \pi^{-}mesons, co-produced with \Lambda's, were also studied. The directed (in-plane) flow of \Lambda hyperons and co-produced protons have been observed by investigating the dependence of the mean transverse momentum in the reaction plane \langle p_x \rangle on the rapidity y in the c. m. system for C-C collisions. \Lambda's and protons flow consistently in the same direction. However, the magnitude of the \Lambda flow is smaller than that of protons. From the transverse momentum distributions of \Lambda hyperons and protons with respect to the reaction plane, the flow F (the measure of the collective transverse momentum transfer in the reaction plane) has been extracted. The mean transverse momentum of \Lambda's in the reaction plane in the forward rapidity region y>0 has also been estimated. Temperatures have been obtained from the non-invariant kinetic energy (E_k), transverse momentum and transverse mass distributions of \Lambda hyperons, protons and \pi^{-} mesons, produced associatively with \Lambda's. The temperatures of protons produced with and without 's do not reveal any significant difference when compared. A similar tendency has also been observed for \pi^{-}mesons. The Quark-Gluon String Model reproduces quite well the experimental results.
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