Table 3.

Number of events in the VR3A and VR3B $t\overline{t}Z$ validation regions together with the expectation for some signal points in the ${\tilde{t}}_2^{}$ simplified model. The errors on the backgrounds include both statistical and systematic uncertainties. Only statistical uncertainties are shown for the signal points

	VR3A	VR3B
Data	24	13
Total SM	19 $\pm$ 5	12.1 $\pm$ 3.2
MC exp. $t\overline{t}Z$	7.9 $\pm$ 2.1	5.9 $\pm$ 1.6
MC exp. $tZ$	2.7 $\pm$ 2.7	1.5 $\pm$ 1.5
Data-driven non-prompt	5.9 $\pm$ 2.9	2.7 $\pm$ 1.4
MC exp. diboson, triboson	1.5 $\pm$ 0.5	1.9 $\pm$ 0.6
MC exp. $t\overline{t}W$	0.35 $\pm$ 0.10	0.05 $\pm$ 0.02
MC exp. $Wh$, $Zh$, $t\overline{t}h$	0.3 $\pm$ 0.3	0.05 $\pm$ 0.05
($m_{{\tilde{t}}_2^{}},m_{{\tilde{\mathit{\chi }}}_1^0})=(500,20)$ GeV	1.6 $\pm$ 0.6	7.5 $\pm$ 1.2
($m_{{\tilde{t}}_2^{}},m_{{\tilde{\mathit{\chi }}}_1^0})=(500,120)$ GeV	3.3 $\pm$ 0.8	3.9 $\pm$ 0.8
($m_{{\tilde{t}}_2^{}},m_{{\tilde{\mathit{\chi }}}_1^0})=(550,20)$ GeV	0.6 $\pm$ 0.3	4.6 $\pm$ 0.7
($m_{{\tilde{t}}_2^{}},m_{{\tilde{\mathit{\chi }}}_1^0})=(550,220)$ GeV	2.7 $\pm$ 0.5	2.2 $\pm$ 0.5