High pT particles @ RHIC. Motivation

Products of parton fragmentation (jet “leading particle”).
Early production in parton-parton scatterings with large Q2.
Direct probes of partonic phases of the reaction  Sensitive to hot/dense medium: parton energy loss (“jet quenching”).
Info on medium effects accessible through comparison to scaled "vacuum" (pp) yields (“binary scaling”):
Nucl. geom. scaling:
Production yields calculable via pQCD:

Products of parton fragmentation (jet “leading particle”).