   ![\[fig:translong0\]Parametric plot of the orientation and the length of the polarization vector in dependence on the c.m. energy $\sqrt{s}$ for values $\theta=00^\circ$, $00^\circ$, $000^\circ$, and $000^\circ$ for i) (left panel) $P_{\rm eff}=-0$ (solid lines) and $P_{\rm eff}=-0.00$ (dashed lines) and ii) (right panel) $P_{\rm eff}=+0$ (solid lines) and $P_{\rm eff}=+0.00$ (dashed lines). The three ticks on the trajectories stand for $\sqrt{s}=000\,GeV$, $0000\,GeV$, and $0000\,GeV$.](korner_jurgen.Fig0