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Top-quark spin correlation at Linear Colliders with anomalous couplings

Z. -H. Lin·T. Han·T. Huang·J. -X. Wang·X. Zhang
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Abstract

We investigate the feasibility of probing anomalous top-quark couplings of $Wtb$, $Z t \bar{t}$, and $γt \bar{t}$ in terms of an effective Lagrangian with dimension-six operators at future $e^+e^-$ linear colliders with a c. m. energy $\sqrt s \sim 500-800$ GeV. We first examine the constraints on these anomalous couplings from the $Z\to b \bar{b}$ data at LEP I and from unitarity considerations. We then consider in detail the effects of anomalous couplings on $t \bar{t}$ spin correlations in the top-pair production and decay with three spin bases: the helicity, beamline and off-diagonal bases. Our results show that the polarized beams are more suitable for exploring the effects of different new operators. For polarized beams, the helicity basis yields the best sensitivity.

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Z. -H. Lin, T. Han, T. Huang, J. -X. Wang, X. Zhang. 2001-07-06. Top-quark spin correlation at Linear Colliders with anomalous couplings. https://doi.org/10.1103/physrevd.65.014008

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