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| CMS-SUS-16-051 ; CERN-EP-2017-109 | ||
| Search for top squark pair production in pp collisions at $ \sqrt{s} = $ 13 TeV using single lepton events | ||
| CMS Collaboration | ||
| 14 June 2017 | ||
| J. High Energy Phys. 10 (2017) 019 | ||
| Abstract: A search for top squark pair production in pp collisions at $ \sqrt{s} = $ 13 TeV is performed using events with a single isolated electron or muon, jets, and a large transverse momentum imbalance. The results are based on data collected in 2016 with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. No significant excess of events is observed above the expectation from standard model processes. Exclusion limits are set in the context of supersymmetric models of pair production of top squarks that decay either to a top quark and a neutralino or to a bottom quark and a chargino. Depending on the details of the model, we exclude top squarks with masses as high as 1120 GeV. Detailed information is also provided to facilitate theoretical interpretations in other scenarios of physics beyond the standard model. | ||
| Links: e-print arXiv:1706.04402 [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.
Additional technical material for CMS speakers can be found here. |
| Figures | |
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Figure 1:
Simplified-models diagrams corresponding to top squark pair production, followed by the specific decay modes targeted in this paper. (a) $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ t } \tilde{\chi}^0_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $; (b) $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{b} } \tilde{ \chi }^{-}_1 $; (c) $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $. Charge-conjugate decays are implied. |
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Figure 1-a:
Simplified-model diagram corresponding to top squark pair-production and decay: $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ t } \tilde{\chi}^0_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $. |
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Figure 1-b:
Simplified-model diagram corresponding to top squark pair-production and decay: $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{b} } \tilde{ \chi }^{-}_1 $. Charge-conjugate decays are implied. |
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Figure 1-c:
Simplified-model diagram corresponding to top squark pair-production and decay: $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $. Charge-conjugate decays are implied. |
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Figure 2:
Distributions in $ {E_{\mathrm {T}}^{\text {miss}}} $ for a top quark enriched control region of e$\mu$ events with at least one b-tagged jet. The ratio of data to simulation as a function of $ {E_{\mathrm {T}}^{\text {miss}}} $ is also shown. |
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Figure 3:
Comparison of the modeling of kinematic distributions in data and simulation relevant for the estimate of the single lepton backgrounds. (a) Distribution in $ {M_{\ell \mathrm{ b } }} $ in a control sample with 1 or 2 jets, with 60 $ < {M_{\mathrm {T}}} < $ 120 GeV and $ E_{\mathrm {T}}^{\text {miss}} > $ 250 GeV. The distribution is shown separately for events with 0 and $\geq $1 jet passing the requirement of the medium b tagging WP. The lower panel shows the ratio of the transfer factors (TF) from the 0 tags to the $\geq $1 tags samples, in data and simulation. The uncertainty shown is statistical only. (b) Distribution in the number of b-tagged jets in the same control sample. The shaded band shows the uncertainty resulting from a 50% systematic uncertainty in the heavy flavor component of the W+jets sample. (c) Comparison of the $ {E_{\mathrm {T}}^{\text {miss}}} $ distribution between data and simulation in the $ \gamma $+jets control region. The uncertainty shown is statistical only. |
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Figure 3-a:
Distribution in $ {M_{\ell \mathrm{ b } }} $ in a control sample with 1 or 2 jets, with 60 $ < {M_{\mathrm {T}}} < $ 120 GeV and $ E_{\mathrm {T}}^{\text {miss}} > $ 250 GeV. The distribution is shown separately for events with 0 and $\geq $1 jet passing the requirement of the medium b tagging WP. The lower panel shows the ratio of the transfer factors (TF) from the 0 tags to the $\geq $1 tags samples, in data and simulation. The uncertainty shown is statistical only. |
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Figure 3-b:
Distribution in the number of b-tagged jets in the same control sample. The shaded band shows the uncertainty resulting from a 50% systematic uncertainty in the heavy flavor component of the W+jets sample. |
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Figure 3-c:
Distribution in the number of b-tagged jets in the same control sample. The shaded band shows the uncertainty resulting from a 50% systematic uncertainty in the heavy flavor component of the W+jets sample. |
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Figure 4:
Observed data yields compared with the SM background estimations for the 31 signal regions of Tables 2 and 3. The total uncertainty in the background estimate, determined as the sum in quadrature of statistical and systematic uncertainties, is shown as a shaded band. The expectations for three signal hypotheses are overlaid. The corresponding numbers in parentheses in the legend refer to the masses in GeV of the top squark and the neutralino. |
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Figure 5:
The exclusion limits at 95% CL for direct top squark pair production with decay $\tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ t } \tilde{\chi}^0_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $. The interpretation is done in the two-dimensional space of $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$. The color indicates the 95% CL upper limit on the cross section times branching fraction at each point in the $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$ plane. The area to the left of and below the thick black curve represents the observed exclusion region at 95% CL assuming 100% branching fraction, while the dashed red lines indicate the expected limits at 95% CL and their ${\pm }$1$\sigma $ experimental standard deviation uncertainties. The thin black lines show the effect of the theoretical uncertainties ($\sigma _\text {theory}$) in the signal cross section. The whited out region is discussed in Section 7. |
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Figure 6:
The exclusion limit at 95% CL for direct top squark pair production with decay $\tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{b} } \tilde{ \chi }^{-}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } ^{\pm }\tilde{\chi}^0_1 $. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/$2. The interpretation is done in the two-dimensional space of $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$. The color indicates the 95% CL upper limit on the cross section times branching fraction at each point in the $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$ plane. The area between the thick black curves represents the observed exclusion region at 95% CL assuming 100% branching fraction, while the dashed red lines indicate the expected limits at 95% CL and their ${\pm }$1$\sigma $ experimental standard deviation uncertainties. The thin black lines show the effect of the theoretical uncertainties ($\sigma _\text {theory}$) in the signal cross section. |
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Figure 7:
The exclusion limit at 95% CL for direct top squark pair production with decay $\tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b } \tilde{ \chi }^{+}_1 \mathrm{ \bar{t} } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } ^{\pm }\tilde{\chi}^0_1 $. The mass splitting of the chargino and neutralino is fixed to 5 GeV. The interpretation is done in the two-dimensional space of $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$. The color indicates the 95% CL upper limit on the cross section at each point in the $m_{\tilde{ \mathrm{ t } } }$ vs. $m_{\tilde{\chi}^0_1 }$ plane. The area between the thick black curves represents the observed exclusion region at 95% CL, while the dashed red lines indicate the expected limits at 95% CL and their ${\pm }$1$\sigma $ experimental standard deviation uncertainties. The thin black lines show the effect of the theoretical uncertainties ($\sigma _\text {theory}$) in the signal cross section. |
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Figure 8:
Correlation matrix for the background predictions for the signal regions for the standard selection (in percent). The labelling of the regions follows the convention of Fig.4. |
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Figure 9:
Correlation matrix for the background predictions for the signal regions for the compressed selection (in percent). The labelling of the regions follows the convention of Fig.4. |
| Tables | |
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Table 1:
Summary of the event preselection. The symbol $ {p_{\mathrm {T}}} ^{\mathrm {lep}}$ denotes the ${p_{\mathrm {T}}}$ of the lepton, while $ {p_{\mathrm {T}}} ^{\text {sum$ {p_{\mathrm {T}}} $}}$ is the scalar $ {p_{\mathrm {T}}} $ sum of PF candidates in a cone around the lepton but excluding the lepton. For veto tracks this variable is calculated using charged PF candidates, while in the case of selected and veto leptons neutral PF candidates are also included. Light-flavor jets are defined as jets originating from u, d, s quarks or gluons. |
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Table 2:
Definitions for the 27 signal regions of the standard selection. At least one b-tagged jet satisfying the medium WP algorithm is required in all search regions. To suppress the W+jets background in signal regions with $ {M_{\ell \mathrm{ b } }} > $ 175 GeV, we instead use the more strict tight WP requirement. |
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Table 3:
Summary of the compressed selection and the requirements for the four corresponding signal regions. The symbol $\Delta \phi ( {E_{\mathrm {T}}^{\text {miss}}},\ell ) $ denotes the angle between $ {\vec p}_{\mathrm {T}}^{\, \text {miss}} $ and the $ {\vec p}_{\mathrm {T}}$ of the lepton. |
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Table 4:
Dilepton control regions utilizing combined bins in $ {E_{\mathrm {T}}^{\text {miss}}} $. |
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Table 5:
Result of the background estimates and data yields corresponding to 35.9 fb$^{-1}$, for the 31 signal regions of Tables 2 and 3. |
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Table 6:
Summary of the systematic uncertainties in the signal efficiency. |
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Table 7:
Background predictions and yields in data corresponding to 35.9 fb$^{-1}$ for aggregate signal regions. |
| Summary |
| We have reported on a search for top squark pair production in pp collisions at $ \sqrt{s} = $ 13 TeV in events with a single isolated electron or muon, jets, and large missing transverse momentum using data collected with the CMS detector during the 2016 run of the LHC, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The event data yields are consistent with the expectations from SM processes. The results are interpreted as exclusion limits in the context of supersymmetric models with pair production of top squarks that decay either to a top quark and a neutralino or to a bottom quark and a chargino. Assuming both top squarks decay to a top quark and a neutralino, we exclude at 95% CL top squark masses up to 1120 GeV for a massless neutralino and neutralino masses up to 515 GeV for a 950 GeV top squark mass. For a scenario where both top squarks decay to a bottom quark and a chargino, with the chargino mass the average of the masses of the neutralino and top squark, we exclude at the 95% CL top squark masses up to 1000 GeV for a massless neutralino and neutralino masses up to 450 GeV for a 800 GeV top squark mass. For the mixed decay scenario, with the mass splitting between the chargino and neutralino fixed to be 5 GeV, we exclude at the 95% CL top squark masses up to 980 GeV for a massless neutralino and neutralino masses up to 400 GeV for a 825 GeV top squark mass. |
| Additional Figures | |
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Additional Figure 1:
Comparison between postfit and prefit background predictions and data for 35.9 fb$^{-1}$ collected during 2016 pp collisions. |
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Additional Figure 2:
Covariance matrix for the background predictions for the signal regions for the standard selection. The labelling of the regions follows the convention of correlation matrices in the appendix of the paper. |
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Additional Figure 3:
Covariance matrix for the background predictions for the signal regions for the compressed selection. The labelling of the regions follows the convention of correlation matrices in the appendix of the paper. |
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Additional Figure 4:
Significances for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. Left: Observed, right: expected. |
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Additional Figure 4-a:
Observed significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. |
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Additional Figure 4-b:
Expected significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. |
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Additional Figure 5:
Significances for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$. Left: Observed, right: expected. |
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Additional Figure 5-a:
Observed significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$. |
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Additional Figure 5-b:
Expected significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$. |
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Additional Figure 6:
Significances for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5 as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. Left: Observed, right: expected. |
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Additional Figure 6-a:
Observed significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5 as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. |
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Additional Figure 6-b:
Expected significance for a model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5 as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. |
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Additional Figure 7:
Exclusion limit for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$ for various choices of the branching fraction between the two decays. Left: Observed, right: expected. |
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Additional Figure 7-a:
Observed exclusion limit for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$ for various choices of the branching fraction between the two decays. |
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Additional Figure 7-b:
Expected exclusion limit for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$ for various choices of the branching fraction between the two decays. |
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Additional Figure 8:
Exclusion limit for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$ for unpolarized top quarks (black lines), right-handed top quarks (red lines), and left-handed top quarks (blue lines). |
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Additional Figure 9:
Exclusion limits as presented in the note, with the addition of the most recent previous limits as presented during ICHEP 2016 or Moriond 2015. Left: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $, middle: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$, right: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5. |
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Additional Figure 9-a:
Exclusion limits as presented in the note, with the addition of the most recent previous limits as presented during ICHEP 2016 or Moriond 2015, for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $. |
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Additional Figure 9-b:
Exclusion limits as presented in the note, with the addition of the most recent previous limits as presented during ICHEP 2016 or Moriond 2015, for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$. |
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Additional Figure 9-c:
Exclusion limits as presented in the note, with the addition of the most recent previous limits as presented during ICHEP 2016 or Moriond 2015, for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5. |
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Additional Figure 10:
Exclusion limits as presented in the note, however the color map is showing the 95% confidence level on the signal strength modifier. Left: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $, middle: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$, right: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5. |
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Additional Figure 10-a:
Exclusion limits as presented in the note, however the color map is showing the 95% confidence level on the signal strength modifier: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ t } ^{(*)}\tilde{\chi}^0_1 $. |
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Additional Figure 10-b:
Exclusion limits as presented in the note, however the color map is showing the 95% confidence level on the signal strength modifier: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } \to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ as a function of $m_{\tilde{ \mathrm{ t } } }$ and $m_{\tilde{\chi}^0_1 }$. The mass of the chargino is chosen to be $(m_{\tilde{ \mathrm{ t } } } + m_{\tilde{\chi}^0_1 })/2$. |
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Additional Figure 10-c:
Exclusion limits as presented in the note, however the color map is showing the 95% confidence level on the signal strength modifier: for the model of direct top-squark production with decay $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \bar{ \tilde{ \mathrm{t} } } $, $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 / \mathrm{ t } \tilde{\chi}^0_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $, $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 }$ + 5 GeV, BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = 0.5. |
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Additional Figure 11:
Background predictions and data for the aggregated signal regions using 35.9 fb$^{-1}$ collected during 2016 pp collisions. |
| Additional Tables | |
png pdf |
Additional Table 1:
Cutflow table for $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \tilde{ \mathrm{ t } } ^{*}\to \mathrm{ t \bar{t} } \tilde{\chi}^0_1 \tilde{\chi}^0_1 $ signals for an integrated luminosity of 35.9 fb$^{-1}$. The uncertainties are purely statistical. No correction for signal contamination in data control regions are applied. |
png pdf |
Additional Table 2:
Cutflow table for $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \tilde{ \mathrm{ t } } ^{*}, \tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 / \mathrm{ b } \tilde{ \chi }^{\pm}_1 $ signals for an integrated luminosity of 35.9 fb$^{-1}$. The branching fraction for this model is BR($\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1 $) = BR($\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{ \chi }^{\pm}_1 $) = 0.5, and $m_{\tilde{ \chi }^{\pm}_1 } = m_{\tilde{\chi}^0_1 } + 5 GeV $. The uncertainties are purely statistical. No correction for signal contamination in data control regions are applied. |
png pdf |
Additional Table 3:
Cutflow table for $\mathrm{ p } \mathrm{ p } \to \tilde{ \mathrm{ t } } \tilde{ \mathrm{ t } } ^{*}\to \mathrm{ b \bar{b} } \tilde{ \chi }^{\pm}_1 \tilde{ \chi }^{\pm}_1 $, $\tilde{ \chi }^{\pm}_1 \to \mathrm{ W } \tilde{\chi}^0_1 $ signals with $m_{\tilde{ \chi }^{\pm}_1 } = (m_{\tilde{ \mathrm{ t } } }+m_{\tilde{\chi}^0_1 })/2$ for an integrated luminosity of 35.9 fb$^{-1}$. The uncertainties are purely statistical. No correction for signal contamination in data control regions are applied. |
|
Electronic version of the limit curves can be found as three rootfiles
here,
here, and
here.
The correlation and covariance matrices can be found as two rootfiles here, and here. A code snippet to calculate the $t_{\text{mod}} $ variables together with an example how to use it is provided here. |
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