Interpolation Grids for Inclusive Z-Boson Production at NNLO perturbative QCD

This project demonstrates the use of interpolation grids for NNLO predictions in perturbative QCD of the inclusive Z-Boson production cross section at the LHC. An automated workflow combining the parton level Monte Carlo event generator, NNLOJET, and the grid interpolation library, fastNLO, is used for this purpose. The closure of the approximate grids is verified by comparing results to a full Monte Carlo event generation at parton level and an analysis of the scale uncertainty, statistical uncertainty, and PDF dependence of the prediction is performed. The uncertainty due to the interpolation bias as well as the statistical uncertainties have been reduced below the desired 0.1\% accuracy dictated by the experimental precision. The scale and PDF uncertainties due to the underlying theoretical models have the same order of magnitude. The resulting theoretical predictions are compatible with experimental measurements by the CMS collaboration within these uncertainties. In addition, prototypes for further automatisation in the Monte Carlo event generation are discussed.