Fig. 9.

Nominal QCD multijet simulation using pythia 8 (data points) and three-dimensional pdfs derived using a forward-folding kernel approach (black solid line), shown together with the five alternate shapes that are added to the multi-dimensional fit as shape nuisance parameters. The shapes for the high-purity (left) and low-purity (right) categories obtained with the 2017 simulation are shown for the projection on $m_{\mathrm{jet}1}$ (upper) and $m_{\mathrm{jj}}$ (lower). The projection on $m_{\mathrm{jet}2}$ is omitted since it is equivalent to the $m_{\mathrm{jet}1}$ projection except for statistical fluctuations. The pdfs and the simulations shown are normalized to unity. The normalization uncertainty of 50% is not shown. The distributions for 2016 simulations are similar