High-pT Physics in STAR Original Research Article

Recent results of the STAR collaboration related to high transverse momentum phenomena are reviewed, which profit greatly from increased statistical reach from the large data sample collected in 2004 and improvement of particle identification at high pT. Dijet structures are observed even in central Au+Au collisions. At sufficiently high momentum a fragmentation pattern as in elementary collisions is observed, however the probability of observing a dijet partner hadron is strongly reduced. Beyond pT=6 GeV/c all hadron species measured show a similar suppression. At lower pT interesting modifications are seen. A jet-correlated enhancement of long range in pseudorapidity is observed close to a trigger hadron. On the opposite side of the trigger a broad correlation structure is visible with an enhanced yield, which for certain kinematic conditions exhibits a double peak in central Au+Au collisions, whose origin is still under discussion. First results in d+Au collisions demonstrating the potential of photon physics in STAR are also presented.