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Polarized top decay into polarized W: t(up)->W(up) + b at O(alpha_s)

M. Fischer·S. Groote·J. G. Körner·M. C. Mauser·B. Lampe
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Abstract

We consider the decay of a polarized top quark into a polarized W-boson plus a bottom quark, followed by the decay of the W-boson into a pair of leptons or quarks. The polar angle distribution of the top spin relative to the W-momentum and the polar angle distribution of the lepton (or quark) in the W-rest frame is governed by three polarized and three unpolarized rate functions which are related to the double density matrix elements of the decay $t \to W^+ + b$. We obtain analytical expressions for the $O(α_s)$ radiative corrections to the three polarized and three unpolarized rate functions. We also provide a comprehensive discussion of the dependence of the longitudinal, transverse and normal polarization of the top quarks produced at $e^+e^-$-colliders on beam polarization parameters.

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M. Fischer, S. Groote, J. G. Körner, M. C. Mauser, B. Lampe. 1999-03-02. Polarized top decay into polarized W: t(up)->W(up) + b at O(alpha_s). https://doi.org/10.1016/s0370-2693(99)00194-x

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