Table 1.

Expected and observed event yields at $\sqrt{s}=7$ and 8$\text{TeV}$. The contributions from $\mathrm{t}\overline{\mathrm{t}}$, Z+jets, and other processes with nonprompt leptons have been determined from data control samples, as described in the text. Backgrounds with at least three bosons in the decay chain comprised of WZZ, $\mathrm{Z}\mathrm{Z}\mathrm{Z}$, WWZ, WWW, $\mathrm{t}\overline{\mathrm{t}}\mathrm{W}$, $\mathrm{t}\overline{\mathrm{t}}\mathrm{Z}$, $\mathrm{t}\overline{\mathrm{t}}\mathrm{W}\mathrm{W}$, $\mathrm{t}\overline{\mathrm{t}}\mathit{\gamma }$ and $\mathrm{W}\mathrm{W}\mathit{\gamma }$ events, are referred to as $\mathrm{V}\mathrm{V}\mathrm{V}$. Combined statistical and systematic uncertainties are shown, except for the WZ signal where only statistical uncertainties are shown

Sample	$\mathrm{e}\mathrm{e}\mathrm{e}$	$\mathrm{e}\mathrm{e}\mathit{\mu }$	$\mathit{\mu }\mathit{\mu }\mathrm{e}$	$\mathit{\mu }\mathit{\mu }\mathit{\mu }$	Total
$\sqrt{s}=7\text{TeV}$; $\mathcal{L}=4.9{\text{fb}}^{-1}$
Nonprompt leptons	2.2 ± 2.1	1.5${}_{-1.5}^{+4.8}$	2.4${}_{-2.4}^{+5.1}$	1.8${}_{-1.8}^{+7.5}$	7.9${}_{-5.0}^{+13.0}$
ZZ	2.0 ± 0.3	3.5 ± 0.5	2.7 ± 0.4	5.1 ± 0.7	13.3 ± 1.9
Z$\mathit{\gamma }$	0	0	0.5 ± 0.5	0	0.5 ± 0.5
VVV	1.6 ± 0.8	2.0 ± 1.0	2.4 ± 1.2	3.0 ± 1.5	9.0 ± 4.5
Total background ($N_{\text{bkg}}$)	3.8 ± 2.3	6.0 ± ${}_{-1.9}^{+4.9}$	8.0${}_{-2.4}^{+5.1}$	9.9${}_{-2.4}^{+7.7}$	30.7${}_{-7.0}^{+13.9}$
WZ	44.7 ± 0.5	49.8 ± 0.5	56.0 ± 0.5	73.8 ± 0.6	224.3 ± 1.1
Total expected	50.5 ± 2.3	56.8${}_{-1.9}^{+5.0}$	64.0${}_{-2.8}^{+5.3}$	83.7${}_{-2.5}^{+7.7}$	255${}_{-7.0}^{+14.0}$
Data ($N_{\text{obs}}$)	64	62	70	97	293
$\sqrt{s}=8\text{TeV}$; $\mathcal{L}=19.6{\text{fb}}^{-1}$
Nonprompt leptons	18.4 ± 12.7	32.0 ± 21.0	54.4 ± 33.0	62.4 ± 37.7	167.1 ± 55.8
ZZ	2.1 ± 0.3	2.4 ± 0.4	3.2 ± 0.5	4.7 ± 0.7	12.3 ± 1.0
$\mathrm{Z}\mathit{\gamma }$	3.4 ± 1.3	0.4 ± 0.4	5.2 ± 1.8	0	9.1 ± 2.2
$\mathrm{W}{\mathit{\gamma }}^{\ast }$	0	0	0	2.8 ± 1.0	2.8 ± 1.0
VVV	6.7 ± 2.2	8.7 ± 2.8	11.6 ± 3.8	14.8 ± 5.1	41.9 ± 7.3
Total background ($N_{\text{bkg}}$)	30.6 ± 13.0	43.5 ± 21.2	74.4 ± 33.3	84.7 ± 38.1	233.2 ± 56.3
WZ	211.1 ± 1.6	262.1 ± 1.8	346.7 ± 2.1	447.8 ± 2.4	1267.7 ± 4.0
Total expected	241.6 ± 13.1	305.7 ± 21.3	421.0 ± 33.3	532.4 ± 38.2	1500.8 ± 56.5
Data ($N_{\text{obs}}$)	258	298	435	568	1559