Hadron Correlation in Jets on the Near and Away Sides of High-pT Triggers in Heavy-ion Collisions
Abstract
Correlation between trigger and associated particles in jets produced on near and away sides of high-pT triggers in heavy-ion collisions is studied. Hadronization of jets on both sides is treated by thermal-shower and shower-shower recombination. Energy loss of semihard and hard partons traversing the nuclear medium is parametrized in a way that renders good fit of the single-particle inclusive distributions at all centralities. The associated hadron distribution in the near-side jet can be determined showing weak dependence on system size because of trigger bias. The inverse slope increases with trigger momentum in agreement with data. The distribution of associated particle in the away-side jet is also studied with careful attention given to antitrigger bias that is due to the longer path length that the away-side jet recoiling against the trigger jet must propagate in the medium to reach the opposite side. Centrality dependence is taken into account after determining a realistic probability distribution of the dynamical path length of the parton trajectory within each class of centrality. For symmetric dijets with pTtrig=pTassoc(away) it is shown that the per-trigger yield is dominated by tangential jets. The average parton momentum for the recoil jet is shown to be always larger than that of the trigger jet for fixed pTtrig and centrality and for any measurable pTassoc(away). With the comprehensive treatment of dijet production described here it is possible to answer many questions regarding the behavior of partons in the medium under conditions that can be specified on measurable hadron momenta.