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 <P_{x'}(Y)> on Y shows the S-shape behaviour. The slope at midrapidity F had been determined. The QGSM reproduces the <P_{x}> distribution satisfactorily, but underestimates the parameter F. 
L.Chkhaidze, T.Djobava, L.Kharkhelauri, M.Mosidze