Centrality dependence of rapidity spectra of negative pions in 12 C + 12 C and 12 C + 181 Ta collisions at 4.2 GeV/ c per nucleon

The centrality dependences of the experimental rapidity as well as transversemomentumversus rapidity spectra of negative pions were analyzed quantitatively in 12 C+ 12 C and 12 C+ 181 Ta collisions at 4.2 GeV/ c per nucleon using fitting the pion spectra by Gaussian distribution function. The experimental results were compared systematically with the predictions of the Quark-Gluon-String Model (QGSM) adapted to intermediate energies.