Abstract and subjects
Measurements of the mid-rapidity transverse energy distribution dE(T)/d eta are presented for p+p, d+Au, and Au+Au collisions at root S-NN = 62.4-200 GeV. The E-T distributions are compared with the number of participants, N-part, the number of constituent-quark participants, N-qp, and the number of color-strings (Additive Quark Model - AQM) calculated from a Glauber model. For Au+Au, < dE(T)/d eta >/(0.5N(part)) increases with N-part, while < dE(T)/d eta >/N-qp is approximately constant vs. centrality for root S-NN >= 62.4 GeV. This indicates that the two component ansatz, dE(T)(AA)/d eta = (dE(T)(PP)/d eta)[(1-x)N-part/2 + xN(coll)], which has been used to represent E-T distributions, is simply a proxy for N-qp, and that the N-coll term does not represent a hard-scattering component in E-T distributions. The dE(T)/d eta distributions of d+Au, and Au+Au are calculated from the measured p+p E-T distribution using two models (AQM and N-qp) that both reproduce the Au+Au data. For the asymmetric d+Au system, the N-qp model reproduces the data while the AQM does not. (C) 2014 Elsevier B.V. All rights reserved.