Gluon identification in planar e+e− events

A method is proposed to identify gluon jets in the planar hadronic events recently found in e⁺e^? annihilation. If a fast hadron is detected at a given angle θ_h ? 30° with respect to the axis opposite to the thrust axis, it is most probably a quark (or antiquark) fragment. An explicit formula then predicts the angle and energy of the unbiased accompanying gluon.