Two-loop QCD corrections to massless quark-gluon scattering

We present the O(alpha (4)(s)) virtual QCD corrections to the scattering process of massless quark q (q) over bar --> gg due to the interference of tree and two-loop amplitudes and to the self-interference of one-loop amplitudes. We work in conventional dimensional regularisation and our results are renormalised in the (MS) over bar scheme. The structure of the infrared divergences agrees with that predicted by Catani while expressions for the finite remainder are given for the q (q) over bar --> gg and the qg --> qg (g (q) over bar --> g (q) over bar) scattering processes in terms of logarithms and polylogarithms that are real in the physical region. These results, together with those previously obtained for quark-quark scattering, are important ingredients in the next-to-next-to-leading order contribution to inclusive jet production at hadron colliders. (C) 2001 Elsevier Science B.V. All rights reserved.