CMS-SUS-16-033 ; CERN-EP-2017-072 | ||
Search for supersymmetry in multijet events with missing transverse momentum in proton-proton collisions at 13 TeV | ||
CMS Collaboration | ||
25 April 2017 | ||
Phys. Rev. D 96 (2017) 032003 | ||
Abstract: A search for supersymmetry is presented based on multijet events with large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of $ \sqrt{s} = $ 13 TeV. The data, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, were collected with the CMS detector at the CERN LHC in 2016. The analysis utilizes four-dimensional exclusive search regions defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No evidence for a significant excess of events is observed relative to the expectation from the standard model. Limits on the cross sections for the pair production of gluinos and squarks are derived in the context of simplified models. Assuming the lightest supersymmetric particle to be a weakly interacting neutralino, 95% confidence level lower limits on the gluino mass as large as 1800 to 1960 GeV are derived, and on the squark mass as large as 960 to 1390 GeV, depending on the production and decay scenario. | ||
Links: e-print arXiv:1704.07781 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; |
Figures & Tables | Summary | Additional Figures & Tables | References | CMS Publications |
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Additional information on efficiencies needed for reinterpretation of these results are available here.
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Figures | |
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Figure 1:
Example Feynman diagrams for the simplified model signal scenarios considered in this study: the (upper left) T1tttt, (upper right) T1tbtb, (lower left) T5qqqqVV, and (lower right) T2tt scenarios. In the T5qqqqVV model, the flavors of the quark ${\mathrm{ q } }$ and antiquark ${\mathrm{ \bar{q} } }$ differ from each other if the gluino $ \tilde{g} $ decays as $\tilde{g} \to \mathrm{ q } \mathrm{ \bar{q} } \tilde{ \chi }^{\pm} _1$, where $\tilde{ \chi }^{\pm} _1$ is the lightest chargino. |
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Figure 1-a:
Example Feynman diagrams for the simplified model signal scenarios considered in this study: the (upper left) T1tttt, (upper right) T1tbtb, (lower left) T5qqqqVV, and (lower right) T2tt scenarios. In the T5qqqqVV model, the flavors of the quark ${\mathrm{ q } }$ and antiquark ${\mathrm{ \bar{q} } }$ differ from each other if the gluino $ \tilde{g} $ decays as $\tilde{g} \to \mathrm{ q } \mathrm{ \bar{q} } \tilde{ \chi }^{\pm} _1$, where $\tilde{ \chi }^{\pm} _1$ is the lightest chargino. |
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Figure 1-b:
Example Feynman diagrams for the simplified model signal scenarios considered in this study: the (upper left) T1tttt, (upper right) T1tbtb, (lower left) T5qqqqVV, and (lower right) T2tt scenarios. In the T5qqqqVV model, the flavors of the quark ${\mathrm{ q } }$ and antiquark ${\mathrm{ \bar{q} } }$ differ from each other if the gluino $ \tilde{g} $ decays as $\tilde{g} \to \mathrm{ q } \mathrm{ \bar{q} } \tilde{ \chi }^{\pm} _1$, where $\tilde{ \chi }^{\pm} _1$ is the lightest chargino. |
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Figure 1-c:
Example Feynman diagrams for the simplified model signal scenarios considered in this study: the (upper left) T1tttt, (upper right) T1tbtb, (lower left) T5qqqqVV, and (lower right) T2tt scenarios. In the T5qqqqVV model, the flavors of the quark ${\mathrm{ q } }$ and antiquark ${\mathrm{ \bar{q} } }$ differ from each other if the gluino $ \tilde{g} $ decays as $\tilde{g} \to \mathrm{ q } \mathrm{ \bar{q} } \tilde{ \chi }^{\pm} _1$, where $\tilde{ \chi }^{\pm} _1$ is the lightest chargino. |
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Figure 1-d:
Example Feynman diagrams for the simplified model signal scenarios considered in this study: the (upper left) T1tttt, (upper right) T1tbtb, (lower left) T5qqqqVV, and (lower right) T2tt scenarios. In the T5qqqqVV model, the flavors of the quark ${\mathrm{ q } }$ and antiquark ${\mathrm{ \bar{q} } }$ differ from each other if the gluino $ \tilde{g} $ decays as $\tilde{g} \to \mathrm{ q } \mathrm{ \bar{q} } \tilde{ \chi }^{\pm} _1$, where $\tilde{ \chi }^{\pm} _1$ is the lightest chargino. |
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Figure 2:
Schematic illustration of the 10 kinematic search intervals in the $ {H_{\text {T}}^{\text {miss}}} $ versus $ {H_{\mathrm {T}}} $ plane. Intervals 1 and 4 are discarded for $ {N_{\text {jet}}} \geq $ 7. The intervals labeled C1, C2, and C3 are control regions used to evaluate the QCD background. The rightmost and topmost bins are unbounded, extending to $ {H_{\mathrm {T}}} =\infty $ and $ {H_{\text {T}}^{\text {miss}}} =\infty $, respectively. |
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Figure 3:
The lost-lepton background in the 174 search regions of the analysis as determined directly from $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $, single top quark, W+jets, diboson, and rare-event simulation (points, with statistical uncertainties) and as predicted by applying the lost-lepton background determination procedure to simulated electron and muon control samples (histograms, with statistical uncertainties). The results in the lower panel are obtained through bin-by-bin division of the results in the upper panel, including the uncertainties, by the central values of the "predicted'' results. The 10 results (8 results for $ {N_{\text {jet}}} \geq 7$) within each region delineated by vertical dashed lines correspond sequentially to the 10 (8) kinematic intervals of $ {H_{\mathrm {T}}} $ and $ {H_{\text {T}}^{\text {miss}}} $ indicated in Table 1 and Fig. 2. |
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Figure 4:
The background from hadronically decaying $\tau $ leptons in the 174 search regions of the analysis as determined directly from $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $, single top quark, and W+jets simulation (points, with statistical uncertainties) and as predicted by applying the hadronically decaying $\tau $ lepton background determination procedure to a simulated muon control sample (histograms, with statistical uncertainties). The results in the lower panel are obtained through bin-by-bin division of the results in the upper panel, including the uncertainties, by the central values of the "predicted'' results. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 5:
The ${\mathrm{ Z } \to \nu \bar{\nu} }$ background in the 174 search regions of the analysis as determined directly from Z($\to \nu \bar{\nu} $)+jets simulation (points, with statistical uncertainties), and as predicted by applying the ${\mathrm{ Z } \to \nu \bar{\nu} }$ background determination procedure to statistically independent Z($\to \ell ^{+} \ell ^{-} $)+jets simulated event samples (histogram, with shaded regions indicating the quadrature sum of the systematic uncertainty associated with the assumption that $\mathcal {F}_{j,b}$ is independent of $ {H_{\mathrm {T}}} $ and $ {H_{\text {T}}^{\text {miss}}} $, and the statistical uncertainty). For bins corresponding to $ {N_{{\mathrm{ b } }\text {-jet}}} =$ 0, the agreement is exact by construction. The results in the lower panel are obtained through bin-by-bin division of the results in the upper panel, including the uncertainties, by the central values of the "predicted'' results. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 6:
The QCD background in the low-$ {\Delta \phi }$ control region (CR) as predicted by the rebalance-and-smear (R&S ) method (histograms, with statistical and systematic uncertainties added in quadrature), compared to the corresponding data from which the expected contributions of top quark, W+jets, and Z+jets events have been subtracted (points, with statistical uncertainties). The lower panel shows the ratio of the measured to the predicted results and its propagated uncertainty. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 7:
The QCD background in the 174 search regions of the analysis as determined directly from QCD simulation (points, with statistical uncertainties) and as predicted by applying the low-$ {\Delta \phi }$ extrapolation QCD background determination procedure to simulated event samples (histograms, with statistical and systematic uncertainties added in quadrature). Bins without a point have no simulated QCD events in the search region, while bins without a histogram have no simulated QCD events in the corresponding control region. The results in the lower panel are obtained through bin-by-bin division of the results in the upper panel, including the uncertainties, by the central values of the "predicted'' results. No result is given in the lower panel if the value of the prediction is zero. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 8:
Comparison between the predictions for the number of QCD events in the 174 search regions of the analysis as determined from the rebalance-and-smear (R&S, histograms) and low-$ {\Delta \phi }$ extrapolation (points) methods. For both methods, the error bars indicate the combined statistical and systematic uncertainties. The lower panel shows the ratio of the low-$ {\Delta \phi }$ extrapolation to the R&S results and its propagated uncertainty. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 9:
The observed numbers of events and prefit SM background predictions in the 174 search regions of the analysis, where "prefit'' means there is no constraint from the likelihood fit. Numerical values are given in Tables B.1-B.5. The hatching indicates the total uncertainty in the background predictions. The lower panel displays the fractional differences between the data and SM predictions. The labeling of the bin numbers is the same as in Fig. 3. |
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Figure 10:
The observed numbers of events and prefit SM background predictions in the 12 aggregate search regions, with fractional differences displayed in the lower panel, where "prefit'' means there is no constraint from the likelihood fit. The hatching indicates the total uncertainty in the background predictions. The numerical values are given in Table B.6. |
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Figure 11:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-a:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-b:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-c:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-d:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-e:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 11-f:
The observed numbers of events and SM background predictions for regions in the search region parameter space particularly sensitive to the production of events in the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T2tt, (lower left) T2bb, and (lower right) T2qq scenarios. The selection requirements are given in the figure legends. The hatched regions indicate the total uncertainties in the background predictions. The (unstacked) results for two example signal scenarios are shown in each instance, one with $ {\Delta m} \gg $ 0 and the other with $ {\Delta m} \approx $ 0, where ${\Delta m}$ is the difference between the gluino or squark mass and the sum of the masses of the particles into which it decays. |
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Figure 12:
The 95% CL upper limits on the production cross sections for the (upper left) T1tttt, (upper right) T1bbbb, (middle left) T1qqqq, (middle right) T5qqqqVV, and (lower left) T1tbtb simplified models, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections [61,62,63,64,65], with the corresponding $\pm $1standard deviation uncertainties [80]. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. (Lower right) The corresponding 95% NLO+NLL exclusion curves for the mixed models of gluino decays to heavy squarks. For the T1tbtb model, the results are restricted to $ {m_{\tilde{ \chi }^0_1}} >$ 25 GeV for the reason stated in the text. |
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Figure 12-a:
The 95% CL upper limits on the production cross sections for the T1tttt simplified model, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections, with the corresponding $\pm $1standard deviation uncertainties. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. |
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Figure 12-b:
The 95% CL upper limits on the production cross sections for the T1bbbb simplified model, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections, with the corresponding $\pm $1standard deviation uncertainties. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. |
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Figure 12-c:
The 95% CL upper limits on the production cross sections for the T1qqqq simplified model, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections, with the corresponding $\pm $1standard deviation uncertainties. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. |
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Figure 12-d:
The 95% CL upper limits on the production cross sections for the T5qqqqVV simplified model, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections, with the corresponding $\pm $1standard deviation uncertainties. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. |
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Figure 12-e:
The 95% CL upper limits on the production cross sections for the T1tbtb simplified model, shown as a function of the gluino and LSP masses ${m_{ \tilde{g} } }$ and ${m_{\tilde{ \chi }^0_1}}$. The solid (black) curves show the observed exclusion contours assuming the NLO+NLL cross sections, with the corresponding $\pm $1standard deviation uncertainties. The dashed (red) curves present the expected limits with $\pm $1 standard deviation experimental uncertainties. The results are restricted to $ {m_{\tilde{ \chi }^0_1}} >$ 25 GeV for the reason stated in the text. |
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Figure 12-f:
The corresponding 95% NLO+NLL exclusion curves for the mixed models of gluino decays to heavy squarks. |
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Figure 13:
The 95% CL upper limits on the production cross section for the (upper left) T2tt, (upper right) T2bb, and (lower) T2qq simplified models, shown as a function of the squark and LSP masses ${m_{\tilde{ \mathrm{q} } }}$ and ${m_{\tilde{ \chi }^0_1}} $. The diagonal dotted line shown for the T2tt model corresponds to $ {m_{\tilde{ \mathrm{q} } }} - {m_{\tilde{ \chi }^0_1}} = {m_{\text {top}}} $. Note that for the T2tt model we do not present cross section upper limits in the unshaded diagonal region at low ${m_{\tilde{ \chi }^0_1}}$ for the reasons discussed in the text, and that there is a small region corresponding to $ {m_{\tilde{ \mathrm{ t } } }} \lesssim $ 230 GeV and $ {m_{\tilde{ \chi }^0_1}} \lesssim $ 20 GeV that is not included in the NLO+NLL exclusion region. The results labeled "one light $\tilde{ \mathrm{q} } $'' for the T2qq model are discussed in the text. The meaning of the curves is described in the Fig. 12 caption. |
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Figure 13-a:
The 95% CL upper limits on the production cross section for the T2tt simplified model, shown as a function of the squark and LSP masses ${m_{\tilde{ \mathrm{q} } }}$ and ${m_{\tilde{ \chi }^0_1}} $. The diagonal dotted line shown corresponds to $ {m_{\tilde{ \mathrm{q} } }} - {m_{\tilde{ \chi }^0_1}} = {m_{\text {top}}} $. Note that we do not present cross section upper limits in the unshaded diagonal region at low ${m_{\tilde{ \chi }^0_1}}$ for the reasons discussed in the text, and that there is a small region corresponding to $ {m_{\tilde{ \mathrm{ t } } }} \lesssim $ 230 GeV and $ {m_{\tilde{ \chi }^0_1}} \lesssim $ 20 GeV that is not included in the NLO+NLL exclusion region. The meaning of the curves is described in the Fig. 12 caption. |
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Figure 13-b:
The 95% CL upper limits on the production cross section for the T2bb simplified model, shown as a function of the squark and LSP masses ${m_{\tilde{ \mathrm{q} } }}$ and ${m_{\tilde{ \chi }^0_1}} $. The meaning of the curves is described in the Fig. 12 caption. |
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Figure 13-c:
The 95% CL upper limits on the production cross section for the T2qq simplified model, shown as a function of the squark and LSP masses ${m_{\tilde{ \mathrm{q} } }}$ and ${m_{\tilde{ \chi }^0_1}} $. The results labeled "one light $\tilde{ \mathrm{q} } $'' are discussed in the text. The meaning of the curves is described in the Fig. 12 caption. |
Tables | |
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Table 1:
Definition of the search intervals in the $ {H_{\text {T}}^{\text {miss}}} $ and $ {H_{\mathrm {T}}} $ variables. Intervals 1 and 4 are discarded for $ {N_{\text {jet}}} \geq $ 7. |
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Table 2:
Systematic uncertainties in the yield of signal events, averaged over all search regions. The variations correspond to different signal models and choices for the SUSY particle masses. Results reported as 0.0 correspond to values less than 0.05%. "Mixed T1'' refers to the mixed models of gluino decays to heavy squarks described in the introduction. |
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Table 3:
Definition of the aggregate search regions. Note that the cross-hatched region in Fig. 2, corresponding to large $ {H_{\text {T}}^{\text {miss}}} $ relative to $ {H_{\mathrm {T}}} $, is excluded from the definition of the aggregate regions. |
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Table A1:
Absolute cumulative efficiencies in % for each step of the event selection process for representative models of gluino pair production. The uncertainties are statistical. Uncertainties reported as 0.0 correspond to values less than 0.05%. |
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Table A2:
Absolute cumulative efficiencies in % for each step of the event selection process for representative models of squark pair production. The uncertainties are statistical. Uncertainties reported as 0.0 correspond to values less than 0.05%. |
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Table B1:
Observed numbers of events and prefit background predictions in the $ N_{\text{jets}} = $ 2 search regions. The first uncertainty is statistical and second systematic. |
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Table B2:
Observed numbers of events and prefit background predictions in the 3 $ \leq {N_{\text {jet}}} \leq $ 4 search regions. The first uncertainty is statistical and second systematic. |
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Table B3:
Observed numbers of events and prefit background predictions in the 5 $ \leq N_{\text{jets}} \leq $ 6 search regions. The first uncertainty is statistical and second systematic. |
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Table B4:
Observed numbers of events and prefit background predictions in the 7 $ \leq N_{\text{jets}} \leq $ 8 search regions. The first uncertainty is statistical and second systematic. |
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Table B5:
Observed numbers of events and prefit background predictions in the $ N_{\text{jets}} \geq $ 9 search regions. The first uncertainty is statistical and second systematic. |
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Table B6:
Observed numbers of events and prefit background predictions in the aggregate search regions. The first uncertainty is statistical and second systematic. |
Summary |
A search for gluino and squark pair production is presented based on a sample of proton-proton collisions collected at a center-of-mass energy of 13 TeV with the CMS detector. The search is performed in the multijet channel, i.e., the visible reconstructed final state consists solely of jets. The data correspond to an integrated luminosity of 35.9 fb$^{-1}$. Events are required to have at least two jets, $H_{\mathrm{T}}> $ 300 GeV, and ${H_{\text{T}}^{\text{miss}}} > $ 300 GeV, where $H_{\mathrm{T}}$ is the scalar sum of jet transverse momenta $ p_{\mathrm{T}} $. The ${H_{\text{T}}^{\text{miss}}} $ variable, used as a measure of missing transverse momentum, is the magnitude of the vector $ p_{\mathrm{T}}$ sum of jets. Jets are required to have $p_{\mathrm{T}}> $ 30 GeV and to appear in the pseudorapidity range $| \eta | < $ 2.4. The data are examined in 174 exclusive four-dimensional search regions defined by the number of jets, the number of tagged bottom quark jets, $ H_{\mathrm{T}} $, and ${H_{\text{T}}^{\text{miss}}} $. Background from standard model processes is evaluated using control samples in the data. We also provide results for 12 aggregated search regions, to simplify use of our data by others. The estimates of the standard model background are found to agree with the observed numbers of events for all regions. The results are interpreted in the context of simplified models. We consider models in which pair-produced gluinos each decay to a $\mathrm{ t \bar{t} }$ pair and an undetected, stable, lightest-supersymmetric-particle (LSP) neutralino ${\tilde{\chi}^0_1}$ (T1tttt model); to a $\mathrm{ b \bar{b} }$ pair and the ${\tilde{\chi}^0_1}$ (T1bbbb model); to a light-flavored $ \mathrm{ q \bar{q} } $ pair and the ${\tilde{\chi}^0_1}$ (T1qqqq model); to a light-flavored quark and antiquark and either the second-lightest neutralino $ \tilde{ \chi }^0_2 $ or the lightest chargino $\tilde{ \chi }^{\pm}_1$, followed by decay of the $ \tilde{ \chi }^0_2 $ ($\tilde{ \chi }^{\pm}_1$) to the $\tilde{\chi}^0_1$ and an on- or off-shell ${\mathrm{ Z }}$ ({$\mathrm{ W }^\pm$}) boson (T5qqqqVV model); or to $\mathrm{ \bar{t} }\mathrm{ b }\tilde{ \chi }^{+}_1$ or $\mathrm{ t }\mathrm{ \bar{b} }\tilde{ \chi }^{-}_1$, followed by the decay of the $\tilde{ \chi }^{\pm}_1$ to the ${\tilde{\chi}^0_1}$ and an off-shell W boson (T1tbtb model). To provide more model independence, we also consider mixed scenarios in which a gluino can decay to $\mathrm{ t \bar{t} }\tilde{\chi}^0_1$, $\mathrm{ b \bar{b} }\tilde{\chi}^0_1$, $\mathrm{ \bar{t} }\mathrm{ b }\tilde{ \chi }^{+}_1$, or $\mathrm{ t }\mathrm{ \bar{b} }\tilde{ \chi }^{-}_1$ with various probabilities. Beyond the models for gluino production, we examine models for direct squark pair production. We consider scenarios in which each squark decays to a top quark and the ${\tilde{\chi}^0_1}$ (T2tt model); to a bottom quark and the ${\tilde{\chi}^0_1}$ (T2bb model); or to a light-flavored (u, d, s, c) quark and the ${\tilde{\chi}^0_1}$ (T2qq model). We derive upper limits at 95% confidence level on the model cross sections as a function of the gluino and LSP masses, or of the squark and LSP masses. Using the predicted cross sections with next-to-leading-order plus next-to-leading-logarithm accuracy as a reference, 95% confidence level lower limits on the gluino mass as large as 1800 to 1960 GeV are derived, depending on the scenario. The corresponding limits on the mass of directly produced squarks range from 960 to 1390 GeV. These results extend those from previous searches. |
Additional Figures | |
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Additional Figure 1:
Distributions of (a) $H_{\rm T}$, (b) $H_{\rm T}^{\rm miss}$, (c) the number of jets, and (d) the number of b-tagged jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 1-a:
Distribution of $H_{\rm T}$ from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 1-b:
Distribution of $H_{\rm T}^{\rm miss}$ from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 1-c:
Distribution of the number of jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 1-d:
Distributions of the number of b-tagged jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 2:
Distributions of (a) $H_{\rm T}$, (b) $H_{\rm T}^{\rm miss}$, (c) the number of jets, and (d) the number of b-tagged jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 2-a:
Distribution of $H_{\rm T}$ from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 2-b:
Distribution of $H_{\rm T}^{\rm miss}$ from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
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Additional Figure 2-c:
Distribution of the number of jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 2-d:
Distribution of the number of b-tagged jets from five representative gluino pair production signal models with ${m_{\tilde{ \mathrm{g} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf |
Additional Figure 3:
Distributions of (a) $H_{\rm T}$, (b) $H_{\rm T}^{\rm miss}$, (c) the number of jets, and (d) the number of b-tagged jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 3-a:
Distribution of $H_{\rm T}$ from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 3-b:
Distribution of $H_{\rm T}^{\rm miss}$ from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 3-c:
Distribution of the number of jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 3-d:
Distribution of the number of b-tagged jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \gg m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin contains the overflow events. Only statistical uncertainties are shown. |
png pdf |
Additional Figure 4:
Distributions of (a) $H_{\rm T}$, (b) $H_{\rm T}^{\rm miss}$, (c) the number of jets, and (d) the number of b-tagged jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. Each plot ignores the baseline requirement (if any) for its respective variable. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 4-a:
Distribution of $H_{\rm T}$ from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 4-b:
Distribution of $H_{\rm T}^{\rm miss}$ from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 4-c:
Distribution of the number of jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf root |
Additional Figure 4-d:
Distribution of the number of b-tagged jets from three representative squark pair production signal models with ${m_{\tilde{ \mathrm{q} } } \sim m_{\tilde{\chi}^0_1 }}$ after the baseline selection. The plot ignores the baseline requirement. The last bin in each plot contains the overflow events. Only statistical uncertainties are shown. |
png pdf |
Additional Figure 5:
SMS model significance for gluino models. |
png pdf root |
Additional Figure 5-a:
SMS model significance for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{t} \mathrm{\bar{t}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 5-b:
SMS model significance for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{b} \mathrm{\bar{b}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 5-c:
SMS model significance for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{\bar{t}} \mathrm{b} \tilde{\chi}^+_1 $ gluino model. |
png pdf root |
Additional Figure 5-d:
SMS model significance for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{q} \mathrm{\bar{q}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 5-e:
SMS model significance for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{q} \mathrm{\bar{q}} \mathrm{V} \tilde{\chi}^0_1 $ gluino model. |
png pdf |
Additional Figure 6:
SMS model significance for squark models. |
png pdf root |
Additional Figure 6-a:
SMS model significance for the $ \mathrm{pp} \to \tilde{\mathrm{t}} \overline{\tilde{\mathrm{t}}},\, \tilde{\mathrm{t}} \to \mathrm{t} \tilde{\chi}^0_1 $ squark model. |
png pdf root |
Additional Figure 6-b:
SMS model significance for the $ \mathrm{pp} \to \tilde{\mathrm{b}}\overline{\tilde{\mathrm{b}}},\, \tilde{\mathrm{b}} \to \mathrm{b} \tilde{\chi}^0_1 $ squark model. |
png pdf root |
Additional Figure 6-c:
SMS model significance for the $ \mathrm{pp} \to \tilde{\mathrm{q}} \overline{\tilde{\mathrm{q}}},\, \tilde{\mathrm{q}} \to \mathrm{q} \tilde{\chi}^0_1 $ squark model. |
png pdf |
Additional Figure 7:
SMS model signal efficiency for gluino models. |
png pdf root |
Additional Figure 7-a:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{t} \mathrm{\bar{t}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 7-b:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{b} \mathrm{\bar{b}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 7-c:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{\bar{t}} \mathrm{b} \tilde{\chi}^+_1 $ gluino model. |
png pdf root |
Additional Figure 7-d:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{q} \mathrm{\bar{q}} \tilde{\chi}^0_1 $ gluino model. |
png pdf root |
Additional Figure 7-e:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{g} \tilde{g},\, \tilde{g} \to \mathrm{q} \mathrm{\bar{q}} \mathrm{V} \tilde{\chi}^0_1 $ gluino model. |
png pdf |
Additional Figure 8:
SMS model signal efficiency for squark models. |
png pdf root |
Additional Figure 8-a:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{\mathrm{t}} \overline{\tilde{\mathrm{t}}},\, \tilde{\mathrm{t}} \to \mathrm{t} \tilde{\chi}^0_1 $ squark model. |
png pdf root |
Additional Figure 8-b:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{\mathrm{b}}\overline{\tilde{\mathrm{b}}},\, \tilde{\mathrm{b}} \to \mathrm{b} \tilde{\chi}^0_1 $ squark model. |
png pdf root |
Additional Figure 8-c:
SMS model signal efficiency for the $ \mathrm{pp} \to \tilde{\mathrm{q}} \overline{\tilde{\mathrm{q}}},\, \tilde{\mathrm{q}} \to \mathrm{q} \tilde{\chi}^0_1 $ squark model. |
png pdf root |
Additional Figure 9:
Pre-fit background covariance matrix. |
Additional Tables | |
png pdf |
Additional Table 1:
Observed numbers of events and post-fit backgrounds in the $ {N_{\text {jet}}} = $ 2 search regions. |
png pdf |
Additional Table 2:
Observed numbers of events and post-fit backgrounds in the 3 $ \geq {N_{\text {jet}}} \geq $ 4 search regions. |
png pdf |
Additional Table 3:
Observed numbers of events and post-fit backgrounds in the 5 $ \geq {N_{\text {jet}}} \geq $ 6 search regions. |
png pdf |
Additional Table 4:
Observed numbers of events and post-fit backgrounds in the 7 $ \geq {N_{\text {jet}}} \geq $ 8 search regions. |
png pdf |
Additional Table 5:
Observed numbers of events and post-fit backgrounds in the $ {N_{\text {jet}}} \geq $ 9 search regions. |
png pdf |
Additional Table 6:
Absolute cumulative efficiencies in % for additional representative models of gluino pair production. The uncertainties are statistical. Uncertainties reported as 0.0 correspond to values less than 0.05%. |
png pdf |
Additional Table 7:
Expected number of signal events in 35.9 fb$^{-1}$ of data for representative gluino pair production models in the aggregate search regions. Only statistical uncertainties are shown. |
png pdf |
Additional Table 8:
Expected number of signal events in 35.9 fb$^{-1}$ of data for additional representative gluino pair production models in the aggregate search regions. Only statistical uncertainties are shown. |
png pdf |
Additional Table 9:
Expected number of signal events in 35.9 fb$^{-1}$ of data for representative squark pair production models in the aggregate search regions. Only statistical uncertainties are shown. |
The values in the pre-fit background tables can be found in ROOT format here.
The values in the post-fit background tables can be found in ROOT format here. |
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