Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and a $\tilde{\chi}_1^\pm$ that decays to $W^\pm\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction to $q_i\bar{q}_j W\pm\tilde{\chi}_1^0$.

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to bottom quarks ($\tilde{g}\to b\bar{b}\tilde{\chi}_1^0$). Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to top quarks ($\tilde{g}\to t\bar{t}\tilde{\chi}_1^0$). Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for light-flavor squark pair production, where the squarks decay to $q\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay and 1-fold degeneracy in the light-flavor squarks (corresponding to the inner set of curves in the limit plot). To get the theory cross section for other N-fold degeneracy assumptions (e.g. 8-fold for the outer curves in the limit plot), just multiply by N.

Exclusion limits at 95% CL for bottom squark pair production, where the squarks decay to $b\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for top squark pair production, where the squarks decay to $t\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for top squark pair production, where the squarks decay to $b\tilde{\chi}_1^\pm$ and the $\tilde{\chi}_1^0$ decay to $W^\pm\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for top squark pair production, where the squarks decay either to $b\tilde{\chi}_1^\pm\to bW^\pm\tilde{\chi}_1^0$ or to $t\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for top squark pair production, where the squarks decay to $c\tilde{\chi}_1^0$. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, assuming unity branching fraction for the given decay.

Exclusion limits at 95% CL for the mono-$\phi$ model, in which a resonantly-produced colored scalar decays to a massive Dirac fermion and a quark. Signal cross sections are calculated at leading order in $\alpha_S$, assuming unity branching fraction for the given decay.

Cross section limits for $\mathrm{LQ}\to\mathrm{q}\nu$, where $q=u,\,d,\,s,\,\mathrm{or}\,c$. Limits are at the 95% confidence level. Theory cross sections are LO for vector LQ, and NLO for scalar LQ. Branching ratio is assumed to be 100% to $\mathrm{q}\nu$.

Cross section limits for $\mathrm{LQ}\to\mathrm{b}\nu$. Limits are at the 95% confidence level. Theory cross sections are LO for vector LQ, and NLO for scalar LQ. Branching ratio is assumed to be 100% to $\mathrm{b}\nu$.

Cross section limits for $\mathrm{LQ}\to\mathrm{t}\nu$. Limits are at the 95% confidence level. Theory cross sections are LO for vector LQ, and NLO for scalar LQ. Branching ratios are assumed to be $\mathcal{B}(\mathrm{LQ}\to\mathrm{t}\nu)=1-\beta$, and $\mathcal{B}(\mathrm{LQ}\to\mathrm{b}\tau)=\beta$.

Predictions and observations for monojet signal regions

Predictions and observations for signal regions with $250 \leq H_\mathrm{T} < 450$ GeV

Predictions and observations for signal regions with $450 \leq H_\mathrm{T} < 575$ GeV and $N_\mathrm{j}<7$

Predictions and observations for signal regions with $450 \leq H_\mathrm{T} < 575$ GeV and $N_\mathrm{j}\geq7$

Predictions and observations for signal regions with $575 \leq H_\mathrm{T} < 1200$ GeV and $N_\mathrm{j}^\mathrm{hi}<4$

Predictions and observations for signal regions with $575 \leq H_\mathrm{T} < 1200$ GeV and $4\leq N_\mathrm{j}^\mathrm{hi}<7$

Predictions and observations for signal regions with $575 \leq H_\mathrm{T} < 1200$ GeV and $N_\mathrm{j}\geq7$

Predictions and observations for signal regions with $1200 \leq H_\mathrm{T} < 1500$ GeV and $N_\mathrm{j}^\mathrm{hi}<4$

Predictions and observations for signal regions with $1200 \leq H_\mathrm{T} < 1500$ GeV and $4\leq N_\mathrm{j}^\mathrm{hi}<7$

Predictions and observations for signal regions with $1200 \leq H_\mathrm{T} < 1500$ GeV and $N_\mathrm{j}\geq7$

Predictions and observations for signal regions with $H_\mathrm{T} \geq 1500$ GeV and $N_\mathrm{j}<7$

Predictions and observations for signal regions with $H_\mathrm{T} \geq 1500$ GeV and $N_\mathrm{j}\geq7$

Covariance matrix for the 282 signal regions of the inclusive $M_\mathrm{T2}$ search

Correlation matrix for the 282 signal regions of the inclusive $M_\mathrm{T2}$ search

Bin number definitions for the $M_\mathrm{T2}$ covariance and correlation matrices

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 10$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 50$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 200$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct light squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 10$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, for a single light squark.

Exclusion limits at 95% CL for direct light squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 50$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, for a single light squark.

Exclusion limits at 95% CL for direct light squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino is long-lived with $c\tau_0 = 200$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, for a single light squark.

Exclusion limits at 95% CL for direct stop pair production, where the stops decay to either a top and the lightest neutralino, or a bottom and the lightest chargino, and the chargino is long-lived with $c\tau_0 = 10$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct stop pair production, where the stops decay to either a top and the lightest neutralino, or a bottom and the lightest chargino, and the chargino is long-lived with $c\tau_0 = 50$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct stop pair production, where the stops decay to either a top and the lightest neutralino, or a bottom and the lightest chargino, and the chargino is long-lived with $c\tau_0 = 200$ cm and mass O(100) MeV greater than the neutralino's mass. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

The maximum chargino mass excluded at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 1$ to 2000 cm while the gluino mass is fixed to 1900 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$. If all kinematically allowed chargino masses are excluded, the curves, including 68 and 95% expected, tend to overlap. At short decay lengths, horizontal exclusion lines are obtained from the inclusive analysis, as this is not affected by track reconstruction inefficiencies, which may arise when the chargino decays before the CMS tracker, and therefore shows better sensitivity to scenarios with very small lifetime compared to the disappearing track search, based on median expected limits.

The maximum chargino mass excluded at 95% CL for direct squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 1$ to 2000 cm while the squark mass is fixed to 900 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, for a single light squark. If all kinematically allowed chargino masses are excluded, the curves, including 68 and 95% expected, tend to overlap. At short decay lengths, horizontal exclusion lines are obtained from the inclusive analysis, as this is not affected by track reconstruction inefficiencies, which may arise when the chargino decays before the CMS tracker, and therefore shows better sensitivity to scenarios with very small lifetime compared to the disappearing track search, based on median expected limits.

The maximum chargino mass excluded at 95% CL for direct squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 1$ to 2000 cm while the squark mass is fixed to 1500 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, and the eight light squarks' masses are assumed to be degenerate. If all kinematically allowed chargino masses are excluded, the curves, including 68 and 95% expected, tend to overlap. At short decay lengths, horizontal exclusion lines are obtained from the inclusive analysis, as this is not affected by track reconstruction inefficiencies, which may arise when the chargino decays before the CMS tracker, and therefore shows better sensitivity to scenarios with very small lifetime compared to the disappearing track search, based on median expected limits.

Exclusion limits at 95% CL for direct stop pair production, where the stops decay to either a top and the lightest neutralino, or a bottom and the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 1$ to 2000 cm while the stop mass is fixed to 1000 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$. If all kinematically allowed chargino masses are excluded, the curves, including 68 and 95% expected, tend to overlap. At short decay lengths, horizontal exclusion lines are obtained from the inclusive analysis, as this is not affected by track reconstruction inefficiencies, which may arise when the chargino decays before the CMS tracker, and therefore shows better sensitivity to scenarios with very small lifetime compared to the disappearing track search, based on median expected limits.

Exclusion limits at 95% CL for direct gluino pair production, where the gluinos decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 5$ to 1000 cm while the gluino mass is fixed to 1600 GeV and the neutralino's mass is fixed to 1575 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Exclusion limits at 95% CL for direct squark pair production, where the squarks decay to light-flavor quarks and either the lightest neutralino, or the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 5$ to 1000 cm while the squark mass is fixed to 2000 GeV and the neutralino's mass is fixed to 1000 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$, and the eight light squarks' masses are assumed to be degenerate.

Exclusion limits at 95% CL for direct stop pair production, where the stops decay to either a top and the lightest neutralino, or a bottom and the lightest chargino, and the chargino mass is O(100) MeV greater than the neutralino's mass. The chargino's lifetime is varied from $c\tau_{0} = 5$ to 1000 cm while the stop mass is fixed to 1100 GeV and the neutralino's mass is fixed to 1000 GeV. Signal cross sections are calculated at approximately NNLO+NNLL order in $\alpha_S$.

Predictions and observations for 2016 disappearing track signal regions

Predictions and observations for 2017-2018 pixel track signal regions

Predictions and observations for 2017-2018 medium (M) and long (L) length track signal regions

Covariance matrix for the 68 signal regions of the disappearing tracks $M_\mathrm{T2}$ search

Correlation matrix for the 68 signal regions of the disappearing tracks $M_\mathrm{T2}$ search

The observed and expected 95% CL upper limits on model-independent visible cross-sections, along with the observed $p0$ values, for the stable signal region, as a function of different mass windows, for which the lower bound is shown. The upper boundary on the mass window is 5 TeV for all windows.

The observed and expected 95% CL upper limits on model-independent visible cross-sections, along with the observed $p0$ values, for the metastable signal region, as a function of different mass windows, for which the lower bound is shown. The upper boundary on the mass window is 5 TeV for all windows.

For each gluino lifetime and mass in the signal samples, the lower boundary of the mass window in which at least $70\%$ of the reconstructed signal appears. The upper boundary for all mass windows is 5 TeV.

Acceptance and efficiency for a representative set of pair-produced gluino signal samples. The mass of the gluino ($m(\tilde{g})$), its lifetime ($\tau(\tilde{g})$) and the mass of the neutralino ($m(\tilde{\chi}^{0})$) are given in the first three columns. The Pythia 6.4.27 signal samples shown in this table are not reweighted to match the transverse momentum of the gluino-gluino system as simulated by MadGraph5_aMC@NLO. The acceptance is defined as the fraction of events passing a loose set of fiducial requirements. The full simulation efficiency (Full sim. $\epsilon$) is defined as the ratio of the number of reconstructed events, as expected by the full ATLAS simulation, and the number of events passing the fiducial requirements. The parameterised simulation efficiency (Param. sim. $\epsilon$) is defined as the ratio of the number of events estimated using a set of parametrised efficiencies (see auxiliary Figures 9,10,11,12) and the number of events passing the fiducial requirements alone.

The reconstructed candidate track mass distributions for observed data, predicted background, and the expected contribution from two signal models in the metastable R-hadron signal region. The yellow band around the background estimation includes both the statistical and systematic uncertainties.

The reconstructed candidate track mass distributions for observed data, predicted background, and the expected contribution from two signal models in the stable R-hadron signal region. The yellow band around the background estimation includes both the statistical and systematic uncertainties.

The 95% CL upper limit on the cross-section as a function of mass for gluinos with lifetime $\tau = 10$ ns decaying into $q\bar{q}$ and a 100 GeV neutralino, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

The 95% CL upper limit on the cross-section as a function of mass for stable gluino $R$-hadrons, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

Observed 95% lower limits on the gluino mass in the gluino lifetime--mass plane. The excluded area is to the left of the curves.

Expected 95% lower limits on the gluino mass in the gluino lifetime--mass plane. The excluded area is to the left of the curves.

The 95% CL upper limit on the cross-section as a function of mass for gluinos with lifetime $\tau = 1$ ns decaying into $q\bar{q}$ and a 100 GeV neutralino, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

The 95% CL upper limit on the cross-section as a function of mass for gluinos with lifetime $\tau = 3$ ns decaying into $q\bar{q}$ and a 100 GeV neutralino, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

The 95% CL upper limit on the cross-section as a function of mass for gluinos with lifetime $\tau = 30$ ns decaying into $q\bar{q}$ and a 100 GeV neutralino, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

The 95% CL upper limit on the cross-section as a function of mass for gluinos with lifetime $\tau = 50$ ns decaying into $q\bar{q}$ and a 100 GeV neutralino, with the observed limit shown as a solid black line. The predicted production cross-section values are shown in purple along with their uncertainty. The expected upper limit in the case of only background is shown by the dashed black line, with a green $\pm 1\sigma$ and a yellow $\pm 2\sigma$ band.

The relationship between generated and reconstructed mass for gluino $R$-hadrons. Above 1500 GeV, the reconstructed mass falls below the generated mass due to bias in the reconstructed momentum. The uncertainty on the reconstructed mass is dominated by momentum uncertainty. The black dots represent the reconstructed mass computed as the most probable value of a Gaussian fit function, with the error bars showing its statistical uncertainty, while the orange band is the full-width at half maximum of the reconstructed mass distribution.

The parameterised efficiency for events to pass metastable event selections (including trigger, E$_{T}^{miss}$, and event cleaning requirements) as a function of the true E$_{T}^{miss}$ in the system, which is calculated at generator level. Event-level efficiencies are evaluated for events which have at least true E$_{T}^{miss} > 50$ GeV. The metastable event efficiencies are evaluated for different radial regions depending on the smallest radial distance, R, at which an R-hadron decays in the detector.

The parameterised efficiency for events to pass metastable event selections (including trigger, E$_{T}^{miss}$, and event cleaning requirements) as a function of the true E$_{T}^{miss}$ in the system, which is calculated at generator level. Event-level efficiencies are evaluated for events which have at least true E$_{T}^{miss} > 50$ GeV. The stable event efficiencies are evaluated for samples in which no R-hadron decays within the detector.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$, and for different radial decay positions of the particle. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$, and for different radial decay positions of the particle. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$, and for different radial decay positions of the particle. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$, and for different radial decay positions of the particle. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$, and for different radial decay positions of the particle. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.

The parameterised efficiency for particles to pass full track selections in the metastable signal region, as function of the particle’s $\beta$, in different bins of transverse momentum, $p_{T}$. The stable efficiency is evaluated for samples which do not decay within the detector. The efficiency is evaluated for particles which pass a loose set of fiducial requirements at generator level.