Local Thermalization in the d + Au System

The extent of a locally equilibrated parton plasma in d + Au collisions at sqrt(s_NN) = 200 GeV is investigated as a function of collision centrality in a nonequilibrium-statistical framework. Based on a three-sources model, analytical solutions of a relativistic diffusion equation are in precise agreement with recent data for charged-particle pseudorapidity distributions. The moving midrapidity source indicates the size of the local thermal equilibrium region after hadronization. In central d + Au collisions it contains about 19% of the produced particles, and its relative importance rises with decreasing centrality.