NLO QCD corrections to the production of t(t)over-barZ in gluon fusion

We compute the O(alpha(s)) QCD corrections to the partonic process gg -> t (t) over tildeZ at the LHC. This partonic channel is the dominant component of the scattering process pp -> t (t) over barZ, which will be important for measuring the t (t) over barZ electroweak couplings. We perform this calculation using a newly developed numerical technique for obtaining loop corrections. The O(alpha(s)) corrections increase the total cross section by up to 75% for reasonable choices of the renormalization and factorization scales. Inclusion of these contributions decreases the residual scale dependence of the cross section coming from uncalculated higher order terms to +/- 5%.