Heavy ion collisions in the used nucleon model

It is shown that recently proposed by R.J. Glauber the used nucleon model combined with the assumption that the nucleon consists of two constituents (a quark and a diquark) describes well the PHOBOS data on particle production at midrapidity. 1. In this note we investigate the consequences of the used nucleon model [1] in the context of the PHOBOS data on particle production at midrapidity [2–4]. This model was formulated as a simple generalization of the wounded nucleon model [5] which fails to describe correctly the observed particle multiplicities. Contrary to the wounded nucleon model, we assume that the number of particles produced from one wounded nucleon does depend on the number of inelastic collisions this nucleon underwent. To formulate this model in more detail let us, for a while, consider nucleon-nucleus (mass number A) collision. For the incident nucleon contribution we have: the first inelastic collision produces n particles, where 2n ≡ (dn/dη)||η|<1 is the average multiplicity at midrapidity in a single protonproton collision. Following [1] we assume that the second collision produces a fraction μ of n, the third one μ, and so on. The number of particles produced (from the incident nucleon) after k collisions is: nk ≡ n ( 1 + μ+ ...+ μ ) = n 1− μ 1− μ . (1) Fellow of the Polish Science Foundation (FNP) scholarship for the year 2006 Address: Reymonta 4, 30-059 Krakow, Poland; e-mail: [email protected]