Littlest Higgs Model and Spin Correlation of Top Quark Production at High Energy Linear e⁺ e^- Colliders

Based on the littlest Higgs model, we investigate the spin correlation of the top quark pair production via the process e⁺ e^- → tt at the high energy linear e⁺ e^- collider (ILC) with a centre-of-mass energy √S=800GeV. Our numerical results show that the gauge boson Z_H generates very small corrections to the spin correlation observable C in all the parameter space allowed by the electroweak data. However, with reasonable values of the free parameters, the value of the relative correction parameter R’_BH=(C_BH-C_SM)/C_SM can reach 10%, which might be detected in future ILC experiments.