A COMPARISON OF B AND UDS QUARK JETS TO GLUON JETS

Symmetric three-jet events are selected from hadronic Z(0) decays such that the two lower energy jets art: each produced at an angle of abou t 150 degrees with respect to the highest energy jet. In some cases, a displaced secondary vertex is reconstructed in one of the two lower e nergy jets, which permits the other lower energy jet to be identified as a gluon jet through anti-tagging. In other cases, the highest energ y jet is tagged as a b jet or as a light quark (uds) jet using seconda ry vertex or track impact parameter and momentum information. Comparin g the two lower energy jets of the events with a tag in the highest en ergy jet to the anti-tagged gluon jets yields a direct comparison of b , uds and gluon jets, which are produced with the same energy of about 24 GeV and under the same conditions. We observe b jets and gluon jet s to have similar properties as measured by the angular distribution o f particle energy around the jet directions and by the fragmentation f unctions. In contrast, gluon jets are found to be significantly broade r and to have a markedly softer fragmentation function than uds jets. For the k(perpendicular to) jet finder with y(cut)=0.02, we find [n(ch .)](gluon)/[n(ch.)](b quark) = 1.089 +/- 0.024 (stat.) +/- 0.024 (syst .) [n(ch.)](gluon)/[n(ch.)](uds quark) = 1.390 +/- 0.038 (stat.) +/- 0 .032 (syst.) as the ratios of the mean charged particle multiplicity i n the gluon jets compared to the b and uds jets. Results are also repo rted using the cone jet finder.