Rapidity and pt dependence of identified-particle elliptic flow at RHIC

Elliptic flow has been measured by the BRAHMS experiment as a function of transverse momentum and pseudorapidity for the Au+Au reaction at root(NN)-N-S = 200 GeV. Identified-particle upsilon(2)(eta, p(t)) values were obtained with the two BRAHMS spectrometers at pseudorapidities. eta approximate to 0, 1 and 3.4. The results show that the differential upsilon(2)(eta, p(t)) values for a given particle type are essentially constant over the covered pseudorapidity range. It is suggested that the dominant cause of the observed fall-off of the integral upsilon(2) values going away from mid-rapidity is a corresponding softening of the particle spectra.