Feasibility study of the forward-backward asymmetry of the e ⁺e^- → tt̄ process in all-hadronic decay modes at √s = 500 GeV with the ILD detector

We have studied the measurement accuracy of the forward-backward asymmetry of the e⁺e^- → tt̄ process in the 6-jet mode at √s = 500 GeV with the ILD detector. In the analysis the vertex charges of b-jets were used to distinguisht from t̄ in each event. The distribution of the cosine of the reconstructed polar angle of so identifiedt or t̄ showed a clear forward-backward asymmetry. After the correction for charge misidenti-fication the forward-backward asymmetry was determined to be A ^t _FB = 0.334±0.0079 for 500 fb^-1 with the beam polarization combination of P(e⁺, e^-) = (+30%,-80%), demonstrating a very good statistical accuracy (∼ 2%) even in the 6-jet mode.