| We report the first model independent measurement of charged particle multiplicities in quark and gluon jets, Nq and Ng, produced at the Tevatron in pp¯ collisions with center-of-mass energy 1.8 TeV and recorded by the Collider Detector at Fermi-lab. The measurements are made for jets with average energies 41 and 53 GeV by counting charged particle tracks in cones with opening angle of thetac = 0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q = Ejetthetac varies in the range from 12 GeV to 25 GeV. At Q = 19.2 GeV, the ratio of multiplicities r = Ng/Nq is found to be 1.64 +/- 0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with re-summed perturbative QCD calculations and are consistent with recent e +e- measurements. |
