ZZ production at hadron colliders in NNLO QCD

We report on the first calculation of next-to-next-to-leading order (NNLO) QCD corrections to the inclusive production of Z-boson pairs at hadron colliders. Numerical results are presented for pp collisions with centre-of-mass energy (root s) ranging from 7 to 14 TeV. The NNLO corrections increase the NLO result by an amount varying from 11% to 17% as root s goes from 7 to 14 TeV. The loop-induced gluon fusion contribution provides about 60% of the total NNLO effect. When going from NLO to NNLO the scale uncertainties do not decrease and remain at the +/- 3% level. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license