Abstract
Identified mid-rapidity particle spectra of π±, K ±, and p(p̄) from 200 GeV p + p and d + Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (RdAu) between protons (p + p̄) and charged hadrons (h) in the transverse momentum range 1.2 <pT <3.0 GeV/c is measured to be 1.19±0.05(stat) ±0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + p̄)/h in minimum-bias d + Au collisions is found to be a factor of 2 lower than that in Au + Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.