Probing Anomalous Top Quark Couplings at the Future Linear Colliders

Abstract

In terms of an effective Lagrangian we investigate the possibilities of probing anomalous top quark couplings, $t \bar{t} H$, $\gamma t \bar{t}$, $Z t \bar{t}$ and $tWb$ at the future linear colliders. It is found that probing anomalous top quark couplings, $t \bar{t} H$, $\gamma t \bar{t}$, $Z t \bar{t}$ and $tWb$ at the future linear colliders. It is found that at a linear collider with a c.m.energy $\sqrt s \sim 0.5-1.5$ TeV and a high luminosity of 10-1000 fb$^{-1}$, $e^+e^- \to t \bar{t} H$ is an ideal process in probing anomalous $t \bar t H$ couplings. We also study in detail the effects of anomalous couplings on $t \bar{t}$ spin correlations in the top pair production as well as the top quark decay processes with three bases (helicity, beam line and off-diagonal bases). Our results show that with a c. m. energy $\sqrt s \sim 0.5-1$ TeV and a high luminosity of 1-100 fb$^{-1}$, the anomalous couplings $\gamma t \bar{t}$, $Z t\bar{t}$ and $tWb$ may be sensitively probed.