"Aux Figure 08c" of "Search for nonresonant pair production of Higgs bosons in the $b\bar{b}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s}= 13$ TeV with the ATLAS detector"

The observed 95% CL exclusion limits as a function of the five relevant SMEFT coefficients: (a) c_H, (b) c_{H G}, (c) c_H□, (d) c_tH, and (e) c_tG, obtained from the combined ggF signal model, as shown by the solid black line.
The values of the other four coefficients are fixed to 0.
The blue and yellow bands show the 1σ and 2σ bands respectively on the expected exclusion limits, which are shown by the dashed black line.
The red line shows the predicted ggF HH cross-section as a function of the coefficient.
The VBF HH process is ignored for this result.

观测得到的95%置信水平（Confidence Level, CL）排除极限，以五个相关标准模型有效场论（Standard Model Effective Field Theory, SMEFT）系数为自变量：(a) c_H、(b) c_{HG}、(c) c_{H□}、(d) c_{tH} 以及 (e) c_{tG}，该结果基于联合胶子胶子融合（gluon-gluon fusion, ggF）信号模型得到，如图中黑色实线所示。
其余四个系数的取值均固定为0。
蓝色与黄色色带分别代表预期排除极限的1σ和2σ置信区间，预期排除极限由图中黑色虚线绘制。
红色曲线展示了以该系数为自变量的胶子胶子融合希格斯对（Higgs-Higgs, HH）产生截面的理论预言结果。
本结果未考虑矢量玻色子融合（Vector Boson Fusion, VBF）希格斯对产生过程。