  Parity violation in QCD process is studied using helicity dependent top quark
pair productions at 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 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.
