O(α_s) corrections to the polar angle dependence of the longitudinal spin-spin correlation asymmetry in e⁺e ^-→q̄q

We provide analytical results for the O(α _s ) corrections to the polar angle dependence of the longitudinal spin-spin correlation asymmetry in e⁺e^-→q̄q. For top quark pair production the O(α_s) corrections to the longitudinal spin-spin asymmetry are strongly polar angle dependent and can amount up to ≃4% in the q²-range from above t̄t threshold up to √q² = 100 GEV. The O(α _s ) radiative corrections to the correlation asymmetry are below ≈1% in the forward direction where the cross section is largest. In the e⁺e^-→qq̄b̄b case the O(α _s ) corrections reduce the asymmetry value from its m _b =0 value of -100% to approximately -96% for q ²-values around the Z peak and are practically independent of the value of the polar angle θ. This reduction can be traced to finite anomalous contributions from residual mass effects which survive the m _b →0 limit. We discuss the role of the anomalous contributions and the pattern of how they contribute to spin-flip and non-flip terms.