Jet-fragmentation properties in p p collisions at radical s =1. 8 TeV

The charged-particle fractional momentum distribution within jets, {ital D}({ital z}), has been measured in dijet events from 1.8-TeV {ital {bar p}p} collisions in the Collider Detector at Fermilab. As expected from scale breaking in quantum chromodynamics, the fragmentation function {ital D}({ital z}) falls more steeply as dijet invariant mass increases from 60 to 200 GeV/{ital c}{sup 2}. The average fraction of the jet momentum carried by charged particles is 0.65{plus minus}0.02(stat){plus minus}0.08(syst).