  The charged particle multiplicities of two- and three-jet events from the
reaction e+e- -> Z0 -> hadrons are measured for Z0 decays to light quark (uds)
flavors. Using recent theoretical expressions to account for biases from event
selection, results corresponding to unbiased gluon jets are extracted over a
range of jet energies from about 11 to 30 GeV. We find consistency between
these results and direct measurements of unbiased gluon jet multiplicity from
upsilon and Z0 decays. The unbiased gluon jet data including the direct
measurements are compared to corresponding results for quark jets. We perform
fits based on analytic expressions for particle multiplicity in jets to
determine the ratio r = Ng/Nq of multiplicities between gluon and quark jets as
a function of energy. We also determine the ratio of slopes, r(1) =
(dNg/dy)/(dNq/dy), and of curvatures, r(2) = (d2Ng/dy2)/(d2Nq/dy2), where y
specifies the energy scale. At 30 GeV, we find r = 1.422 +/- 0.051, r(1) =
1.761 +/- 0.071 and r(2) = 1.98 +/- 0.13, where the uncertainties are the
statistical and systematic terms added in quadrature. These results are in
general agreement with theoretical predictions. In addition, we use the
measurements of the energy dependence of Ng and Nq to determine an effective
value of the ratio of QCD color factors, CA/CF. Our result, CA/CF = 2.23 +/-
0.14 (total), is consistent with the QCD value of 2.25.
