Table 1.

Description of the simulated samples used in the analysis

Generator	PDF	Matrix element	Tune
MG5_aMC+Py8 ($\le 2j$ NLO)  [37]	$\mathrm{NNPDF}3.0$ (NLO) [43]	NLO ($2\to \text{Z}$+0,1,2)	$\text{CUETP8M1}$ [44]
MG5_aMC+Py8 ($\le 4j$ LO)  [37, 53]	$\mathrm{NNPDF}2.3$ (LO) [48]	LO ($2\to \text{Z}$+0,1,2,3,4)	$\text{CUETP8M1}$ [44]
MG5_aMC+CA3 (Z +1 NLO)  [37]	$\text{PB}\text{NLO}\text{set2}$ (NLO) [20]	NLO ($2\to \text{Z}$+1)	–
MG5_aMC+CA3 (Z +2 NLO)  [37]	$\mathrm{PB}\mathrm{NLO}\mathrm{set}2$ (NLO) [20]	NLO ($2\to \text{Z}$+2)	–
MG5_aMC+CA3 (Z $\le 3j$ LO)  [37, 51]	$\mathrm{PB}\mathrm{NLO}\mathrm{set}2$ (NLO) [20]	LO ($2\to \text{Z}$+0,1,2,3)	–
Geneva (Z +0 NNLO)  [22–25]	$\mathrm{NNPDF}3.1$ (NLO) [54]	NNLO ($2\to \text{Z}$)	$\text{CUETP8M1}$ [44]