Multiplicities in Au-Au and Cu-Cu collisions at \sqrt{s_{NN}} = 62.4 and 200 GeV

Abstract

Likelihood ratio tests are performed for the hypothesis that charged-particle multiplicities measured in Au-Au and Cu-Cu collisions at $\sqrt{s_{NN}} = 62.4$ and 200 GeV are distributed according to the negative binomial form. Results suggest that the hypothesis should be rejected in the all classes of collision systems and centralities of PHENIX-RHIC measurements. However, the application of the least-squares test statistic with systematic errors included shows that for the collision system Au-Au at $\sqrt{s_{NN}} = 62.4$ GeV the hypothesis could not be rejected in general.Comment: 21 pages, 8 figures, 8 tables, inference from the least-squares test statistic has been improved, conclusions changed, to appear in Phys. Rev. C. arXiv admin note: text overlap with arXiv:1101.078