• • • We do not use the following data for averages, fits, limits, etc. • • • 
$4.9$ $\pm1.4$ 
^{ 1} 

LHC 
$4.8$ $\pm0.8$ ${}^{+1.6}_{1.3}$ 
^{ 2} 

ATLS 
$13.4$ $\pm7.3$ 
^{ 3} 

CMS 
$5.0$ $\pm4.3$ 
^{ 4} 

ATLS 
^{1}
AABOUD 2019R based on 12.2 to 20.3 fb${}^{1}$ of data from ATLAS and CMS at 8 TeV.

^{2}
AAD 2016U based on 20.3 fb${}^{1}$ of data, using a maximumlikelihood fit of a matrix element method discriminant. The same data set as in AAD 2015A is used. The result corresponds to an observed significance of 3.2 ${{\mathit \sigma}}$ .

^{3}
KHACHATRYAN 2016AZ based on 19.7 fb${}^{1}$ of data, using a multivariate analysis to separate signal and backgrounds. The same method is applied to 5.1 fb${}^{1}$ of data at $\sqrt {s }$ = 7 TeV, giving $7.1$ $\pm8.1$ pb. Combining both measurements, the observed significance is 2.5 ${{\mathit \sigma}}$ . A best fit value of $2.0$ $\pm0.9$ is obtained for the combined ratio of the measured values and SM expectations.

^{4}
AAD 2015A based on 20.3 fb${}^{1}$ of data, using a multivariate analysis to separate signal and backgrounds. The 95$\%$ CL upper bound of the cross section is 14.6 pb. The results are consistent with the SM prediction of $5.61$ $\pm0.22$ pb at approximate NNLO.
