Identified hadron transverse momentum spectra in Au+Au collisions at √sNN=62.4 GeV

Transverse momentum spectra of pions, kaons, protons, and antiprotons from Au+Au collisions at root s(NN) = 62.4 GeV have been measured by the PHOBOS experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The identification of particles relies on three different methods: low momentum particles stopping in the first detector layers; the specific energy loss (dE/dx) in the silicon spectrometer, and time-of-flight measurement. These methods cover the transverse momentum ranges 0.03-0.2, 0.2-1.0, and 0.5-3.0 GeV/c, respectively. Baryons are found to have substantially harder transverse momentum spectra than mesons. The p(T) region in which the proton to pion ratio reaches unity in central Au+Au collisions at root s(NN) = 62.4 GeV fits into a smooth trend as a function of collision energy. At low transverse mass, the spectra of various species exhibit a significant deviation from transverse mass scaling. The observed particle yields at very low p(T) are comparable to extrapolations from higher p(T) for kaons, protons and antiprotons. By comparing our results to Au+Au collisions at root s(NN) = 200 GeV, we conclude that the net proton yield at midrapidity is proportional to the number of participant nucleons in the collision.