Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at √sոո=200 GeV

Identified mid-rapidity particle spectra of pi(+/-), K+/-, and p((p) over bar) 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 (R-dAu) between protons (p + (p) over bar) and charged hadrons (h) in the transverse momentum range 1.2 <p(T) <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 + (p) over bar)/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. (c) 2005 Elsevier B.V. All rights reserved.