Table 4.

Expected and observed event yields after the fit in the signal regions. The dielectron and dimuon categories are summed together. The “–” symbol represents backgrounds with no simulated events passing the selections. The signal yields refer to pre-fit values corresponding to a cross section multiplied by $\mathcal{B}(\text{A}\to \text{Zh})\mathcal{B}(\text{h}\to \text{b}\overline{\text{b}})$ of 0.1 pb (gluon–gluon fusion for $m_{\text{A}}=300\text{GeV}$, and in association with b  quarks for $m_{\text{A}}=1000\text{GeV}$)

Signal region	$0\ell$, 1 b  tag	$0\ell$, 2 b  tag	$0\ell$, $\ge$3 b  tag	$2\ell$, 1 b  tag	$2\ell$, 2 b  tag	$2\ell$, $\ge$3 b  tag
Data	$2452\pm 50$	$398\pm 20$	$45\pm 7$	$10512\pm 103$	$2188\pm 47$	$129\pm 11$
$\text{Z}$+jets	$740\pm 12$	$48\pm 1$	$2.0\pm 0.2$	$4118\pm 15$	$175\pm 1$	$18\pm 1$
$\text{Z}$+b	$220\pm 6$	$13\pm 1$	$0.46\pm 0.06$	$4127\pm 18$	$365\pm 3$	$23\pm 1$
$\text{Z}$+$\text{b}\overline{\text{b}}$	$134\pm 3$	$86\pm 2$	$2.5\pm 0.3$	$1547\pm 11$	$1113\pm 7$	$51\pm 2$
$\text{t+X}$	$74\pm 3$	$18\pm 1$	$3.0\pm 0.4$	$25\pm 0$	$10.0\pm 0.1$	-
$\text{t}\overline{\text{t}}$	$750\pm 12$	$143\pm 3$	$31\pm 3$	$592\pm 3$	$473\pm 3$	$26\pm 1$
$\text{V}$, $\text{V}$	$76\pm 2$	$32\pm 1$	$0.93\pm 0.11$	$139\pm 1$	$53\pm 1$	$3.5\pm 0.1$
$\text{W}$+jets	$458\pm 13$	$65\pm 3$	$2.4\pm 0.3$	$3.7\pm 0.1$	–	–
Total bkg.	$2451\pm 26$	$405\pm 8$	$42\pm 5$	$10552\pm 35$	$2189\pm 12$	$121\pm 3$
Pre-fit bkg.	$2467\pm 26$	$427\pm 8$	$28\pm 5$	$10740\pm 35$	$2250\pm 12$	$100\pm 3$
$m_{\text{A}}=300\text{GeV}$	–	–	–	$3.1\pm 0.2$	$3.3\pm 0.2$	$0.10\pm 0.01$
$m_{\text{A}}=1000\text{GeV}$	$27.3\pm 5.2$	$28.6\pm 5.4$	$3.5\pm 0.7$	$5.4\pm 1.0$	$6.1\pm 1.2$	$1.2\pm 0.2$