O(αs) corrections to longitudinal spin-spin correlations in e+e−→qq̄

We calculate the O(αs) corrections to longitudinal spin-spin correlations in e+e−→qq̄. For top quark pair production the O(αs) corrections to the longitudinal spin-spin asymmetry amount to less than 1% in the q2-range from above tt̄-threshold up to q2=1000 GeV. In the e+e−→bb̄ case the O(αs) corrections reduce the asymmetry value from its m=0 value of −1 to approximately −0.96 for q2-values around the Z-peak. This reduction can be traced to finite anomalous contributions from residual mass effects which survive the m→0 limit. We discuss the role of the anomalous contributions and the pattern of how they contribute to spin-flip and no-flip terms.