Polarization of gluon jets in photon-photon scattering

We show that the linear polarization of a gluon emerging from the reaction $\text{e}\text{+}\text{e}\text{→}\text{e}\text{+}\text{e}\text{+}\text{g}\text{+}\text{g}$ is large - on the order of 20%. This polarization arises from the process γ + γ → quark loop → g + g, which is expected to dominate the two gluon jet cross section. The polarization can be used to test quantum chromodynamics (QCD), even if the gluon jets cannot be distinguished clearly from the background of quark jets. If the QCD prediction is accepted, our result can be used to enhance the signal of gluon jets, thereby aiding in the study of their properties.