Two-loop QCD helicity amplitudes for $gg\to Zg$ and $gg\to Z\gamma$

Abstract

We compute the helicity amplitudes for the processes $gg\to Zg$ and $gg\to Z\gamma$ to two loops in massless QCD. The perturbative expansion of these processes starts only at the one-loop level, such that our results are a crucial ingredient to the NLO corrections to $Z\gamma$ and $Z+$jet production through gluon fusion.

Comments: 27 pages, files with the analytic results for the amplitudes are included with the submission. v3 fixed typo in formulas (4.2) and (4.9). Fixed mistake in ancillary files, now uploaded in standard arXiv anc folder. arXiv admin note: text overlap with arXiv:1112.1531