Determination of Differences between Quark and Gluon Jets in 3-Jet Events

A comparison of the properties of quark and gluon jets has been made for the reaction e^+ e^- -> q qbar g recorded by the ALEPH Detector at CERN. A high purity sample of gluon jets is obtained by tagging b bbar quarks and energy ordering the jets within the events containing 3-jets (b bbar g). The highest energy jet is accepted to be a quark or antiquark jet with high probability, because of the bremsstrahlung nature of gluon jet. The jets under study have an energy of about 25 GeV. It is observed that the mean particle multiplicity is found to be larger for gluon than quark jets at the same energy and the gluon jets yield a softer particle energy spectrum.