Azimuthal Correlations with High-pT Multi-Hadron Cluster Triggers in Au+Au Collisions at sqrt(sNN) = 200 GeV

Abstract

Di-hadron correlation measurements have been used to probe di-jet production in collisions at RHIC. A strong suppression of the away-side high-pT yield in these measurements is direct evidence that high-pT partons lose energy as they traverse the strongly interacting medium. However, since the momentum of the trigger particle is not a good measure of the jet energy, azimuthal di-hadron correlations have limited sensitivity to the shape of the fragmentation function. We explore the possibility to better constrain the initial parton energy by using clusters of multiple high-pT hadrons in a narrow cone as the 'trigger particle' in the azimuthal correlation analysis. We present first results from this analysis of multi-hadron triggered correlated yields in Au+Au collisions at sqrt(sNN) = 200 GeV from STAR. The results are compared to Pythia calculations, and the implications for energy loss and jet fragmentation are discussed.