Event Handedness in $e^+e^-$ Annihilation to Three Jets

Abstract

We discuss rescattering effects that can be measured in $e^+e^-$ annihilation to three jets through a single gauge boson, by using triple product (``event handedness'') correlations of the $Z$ ($\gamma^*$) polarization with jet momenta. The gauge boson polarization may be produced either by polarized beams or through the natural polarization (left-right asymmetry) of the $Z$. QCD rescattering does not generate triple product correlations at one loop for massless quarks. We therefore calculate the QCD contribution for massive quarks, as well as the contribution of $W$ and $Z$ exchange loops for massless quarks. Due to various cancellations, the standard model predictions for triple-product correlations at the $Z$ are very small, making such measurements potentially sensitive to physics beyond the standard model. For example, the effects of a new gauge boson that couples only to baryon number may be larger than the standard model contributions; however the effects would probably still be too small to effectively constrain it.