Hadronic observables in Z+jet events can be subject to large NLO corrections at TeV scales, with K-factors that even reach values of order 50 in some cases. We develop a method, LoopSim, by which approximate NNLO predictions can be obtained for such observables, supplementing NLO Z+jet and NLO Z+2-jet results with a unitarity-based approximation for missing higher loop terms. We first test the method against known NNLO results for Drell-Yan lepton pt spectra. We then show our approximate NNLO results for the Z+jet observables. Finally we examine whether the LoopSim method can provide useful information even in cases without giant K-factors, with results for observables in dijet events that can be compared to early LHC data.
@article{arxiv.1006.2144,
title = {Giant QCD K-factors beyond NLO},
author = {Mathieu Rubin and Gavin P. Salam and Sebastian Sapeta},
journal= {arXiv preprint arXiv:1006.2144},
year = {2014}
}
Comments
38 pages, 13 figures; v2 includes additional references