Cronin effect and high-p⊥ suppression in d+Au collisions -: art. no. 024903

Great interest has attached to recent d+Au, root s = 200A GeV data at RHIC, obtained with the BRAHMS detector. Between pseudorapidities eta = 0 and eta = 3.2 the appropriately defined ratio R[dAu/pp], comparing transverse-momentum spectra of d+Au to pp, exhibits a steady decrease with.. This diminution is examined within a two-stage simulation. In the first stage, initial nucleon-nucleon interactions are treated in parallel, as if occurring simultaneously, whereas the second stage is a considerably reduced energy hadronic cascade. This approach is by no means a standard hadronic cascade, never entailing an overly high density of cascading particles. Indeed a condition is imposed on the total multiplicity at the outset of the second stage permitting no overlap of intermediate interacting prehadrons. The result is an adequate description of the data, including the so-called Cronin effect. Additionally there is, in the second stage, clear evidence for suppression of relatively high transverse momentum eta = 0 leading mesons (i.e., the Cronin effect is appreciably muted by final state interactions).