Jet-Like Correlations between Forward and Mid-Rapidity

Abstract

Mid-rapidity azimuthal correlations probe di-jets originating mainly from gluon-gluon hard-scattering. Measurements of such correlations have revealed significant (gluon-)jet modification in central Au+Au collisions. Azimuthal correlations at forward rapidity with a mid-rapidity high- p T hadron, on the other hand, are sensitive primarily to quark-gluon hard-scattering and may probe quark-jet modification in nuclear medium. They may be also sensitive to the Color Glass Condensate by separating d-side and Au-side in d+Au collisions. We present the first results on correlations of charged hadrons at forward rapidity in the STAR FTPCs ( 2.7 < | η | < 3.9 , p T < 2 GeV / c ) with high- p T charged hadrons at mid-rapidity from the main TPC ( | η | < 1 , p T > 3 GeV / c ) . Preliminary results from pp, d+Au, and Au+Au collisions at s NN = 200 GeV are compared. Implications of the results are discussed.