"Ranking" of "Evidence for $t\bar{t}t\bar{t}$ production in the multilepton final state in proton-proton collisions at $\sqrt{s}$=13 TeV with the ATLAS detector"

Ranking of the nuisance parameters included in the fit according to their impact on the signal strength $\mu$. Only the 20 most highly ranked nuisance parameters are shown in the thumbnail figure. The empty blue rectangles correspond to the pre-fit impact on $\mu$ and the filled blue ones to the post-fit impact on $\mu$, both referring to the upper $x$-axis scale. The impact of each nuisance parameter, $\Delta\mu$, is computed by comparing the nominal best-fit value of $\mu$ with the result of the fit when fixing the nuisance parameter to its best-fit value, $\hat{\theta}$, shifted by its pre-fit (post-fit) uncertainties $\pm \Delta\theta$ ($\pm \Delta\hat{\theta}$). The black points show the pulls of the parameter relative to their nominal values, $\theta_0$. The nominal value for all parameters is $\theta_0 = 0$. The pulls of the most impactful parameters and their relative post-fit errors, $\Delta\hat{\theta}/\Delta\theta$, are referenced to the lower $x$-axis scale. In the table, POI means Parameter of Interest.