O(\alpha_s) Corrections to Longitudinal Spin-Spin Correlations in e+e- -> q qbar

Abstract

We calculate the $O({\alpha }_s)$ corrections to longitudinal spin-spin correlations in $e^{+}{e}^{-}\to q\bar{q}$. For top quark pair production the $O({\alpha }_s)$ corrections to the longitudinal spin-spin asymmetry amount to less than 1% in the $q^2$-range from above $t\bar{t}$-treshold up to $\sqrt{q^2}=1000GeV$. In the $e^{+}{e}^{-}\to b\bar{b}$ case the $O({\alpha }_s)$ corrections reduce the asymmetry value from its $m=0$ value of -1 to approximately -0.96 for $q^2$-values around the Z-peak. This reduction can be traced to finite anomalous contributions from residual mass effects which survive the $m\to 0$ limit. We discuss the role of the anomalous contributions and the pattern of how they contribute to spin-flip and no-flip terms.

Comments: 10 pages, 2 postscript figures