Parity violation in QCD process

Parity violation in the QCD process is studied using helicity-dependent top-quark pair productions at the Large Hadron Collider experiment. Though no violation can be found in the standard model (SM), new physics beyond the SM predicts the violation in general. In order to evaluate the violation, we utilize an effective operator analysis in a case that new particles predicted by the new physics are too heavy to be directly detected. By using this method, we try to discriminate supersymmetric SM from a universal extra-dimension model via an asymmetry measurement of the top-quark pair production. We also discuss the asymmetry from the SM electroweak top pair production process and that from the little Higgs model.