O(alpha(s)) QCD corrections to spin correlations in the e(-)e(+) -> tt process at the NLC

Using a generic spin basis, we present a general formalism of one-loop radi ative corrections to the spin correlations in the top quark pair production at the Next Linear Collider, and calculate the O(alpha(s)) QCD corrections under the soft gluon approximation. We find that: (a) in off-diagonal basi s, the O(alpha(s)) QCD corrections to e(L)(-)e(+) (e(R)(-)e(+)) scattering process increase the differential cross sections of the dominant spin compo nent t(up arrow)(t) over bar(down arrow) (t(down arrow)(t) over bar(up arro w)) by similar to 30% and similar to (0.1% - 3%) depending on the scatterin g angle for root s = 400 GeV and 1 TeV, respectively; (b) in off-diagonal b asis (helicity basis), the dominant spin component makes up 99.8% (similar to 53%) of the total cross section at both tree and one-loop level for root s = 400 GeV, and the off-diagonal basis therefore remains to be the optima l spin basis after the inclusion of O(alpha(s)) QCD corrections. (C) 1999 E lsevier Science B.V. All rights reserved.