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| CMS-PAS-FTR-18-037 | ||
| HL-LHC searches for new physics in hadronic final states with boosted W bosons or top quarks using razor variables | ||
| CMS Collaboration | ||
| February 2019 | ||
| Abstract: We present High-Luminosity LHC (HL-LHC) projections of the Run 2 search for new physics in hadronic final states with boosted W bosons or top quarks using razor variables. Data event yields and signal/background cross sections from the 2016 analysis are scaled to obtain the HL-LHC sensitivity for center-of-mass energy of 14 TeV and integrated luminosity of 3 ab$^{-1}$. Different scenarios for systematic uncertainties are considered. The projection results are interpreted in terms of gluino pair production where each gluino decays to a top quark, an anti-top quark, and a neutralino; or to a top quark and a top squark; and direct top squark pair production where each top squark decays to a top quark and a neutralino. | ||
| Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
Signal models considered in this analysis: T5ttcc (top left), T1tttt (top right), and T2tt (bottom). |
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Figure 1-a:
Signal models considered in this analysis: T5ttcc (top left), T1tttt (top right), and T2tt (bottom). |
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Figure 1-b:
Signal models considered in this analysis: T5ttcc (top left), T1tttt (top right), and T2tt (bottom). |
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Figure 1-c:
Signal models considered in this analysis: T5ttcc (top left), T1tttt (top right), and T2tt (bottom). |
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Figure 2:
Generator-level W boson and top quark ${p_{\mathrm {T}}}$ distributions for several signal points from the T5ttcc simplified model, compared to the ${{{\mathrm {t}\overline {\mathrm {t}}}}}$+jets background. Only a set of events selected with a requirement of a jet with size 0.8, ${p_{\mathrm {T}}} > $ 200 GeV, and razor variable $ {R^{2}} > 0.04$, as explained in the text, are shown. |
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Figure 2-a:
Generator-level W boson and top quark ${p_{\mathrm {T}}}$ distributions for several signal points from the T5ttcc simplified model, compared to the ${{{\mathrm {t}\overline {\mathrm {t}}}}}$+jets background. Only a set of events selected with a requirement of a jet with size 0.8, ${p_{\mathrm {T}}} > $ 200 GeV, and razor variable $ {R^{2}} > 0.04$, as explained in the text, are shown. |
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Figure 2-b:
Generator-level W boson and top quark ${p_{\mathrm {T}}}$ distributions for several signal points from the T5ttcc simplified model, compared to the ${{{\mathrm {t}\overline {\mathrm {t}}}}}$+jets background. Only a set of events selected with a requirement of a jet with size 0.8, ${p_{\mathrm {T}}} > $ 200 GeV, and razor variable $ {R^{2}} > 0.04$, as explained in the text, are shown. |
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Figure 3:
The $ {\mathrm {p}} {\mathrm {p}}\to {\mathrm {\tilde{g}}}{\mathrm {\tilde{g}}}$ (left) and $ {\mathrm {p}} {\mathrm {p}}\to {\tilde{t}} {\tilde{t}} $ (right) production cross sections at NLO+NLL precision versus the gluino and top squark masses, respectively. |
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Figure 3-a:
The $ {\mathrm {p}} {\mathrm {p}}\to {\mathrm {\tilde{g}}}{\mathrm {\tilde{g}}}$ (left) and $ {\mathrm {p}} {\mathrm {p}}\to {\tilde{t}} {\tilde{t}} $ (right) production cross sections at NLO+NLL precision versus the gluino and top squark masses, respectively. |
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Figure 3-b:
The $ {\mathrm {p}} {\mathrm {p}}\to {\mathrm {\tilde{g}}}{\mathrm {\tilde{g}}}$ (left) and $ {\mathrm {p}} {\mathrm {p}}\to {\tilde{t}} {\tilde{t}} $ (right) production cross sections at NLO+NLL precision versus the gluino and top squark masses, respectively. |
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Figure 4:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-a:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-b:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-c:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-d:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-e:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 4-f:
Average percentage contributions of various systematic uncertainties to the overall background estimation under the background-only assumption as a function of bins in ${M_{R}}$ and ${R^{2}}$ for the W 4-5 jet (top), W 6 jet (middle), and Top (bottom) categories for the Run 2 (left) and YR18 (right) scenarios. |
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Figure 5:
${M_{R}} - {R^{2}}$ distributions shown in a one-dimensional representation for background predictions obtained for the W 4-5 jet (upper left), W 6 jet (upper right), and Top (lower) categories for the HL-LHC. Statistical and systematic uncertainties for the YR18 scenario are shown with the hatched and shaded error bars, respectively. Also shown are the signal benchmark models T5ttcc with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV, $m_{{\tilde{t}}} = $ 320 GeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; T1tttt with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; and T2tt with $m_{{\tilde{t}}} = $ 1.2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 100 GeV. |
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Figure 5-a:
${M_{R}} - {R^{2}}$ distributions shown in a one-dimensional representation for background predictions obtained for the W 4-5 jet (upper left), W 6 jet (upper right), and Top (lower) categories for the HL-LHC. Statistical and systematic uncertainties for the YR18 scenario are shown with the hatched and shaded error bars, respectively. Also shown are the signal benchmark models T5ttcc with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV, $m_{{\tilde{t}}} = $ 320 GeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; T1tttt with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; and T2tt with $m_{{\tilde{t}}} = $ 1.2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 100 GeV. |
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Figure 5-b:
${M_{R}} - {R^{2}}$ distributions shown in a one-dimensional representation for background predictions obtained for the W 4-5 jet (upper left), W 6 jet (upper right), and Top (lower) categories for the HL-LHC. Statistical and systematic uncertainties for the YR18 scenario are shown with the hatched and shaded error bars, respectively. Also shown are the signal benchmark models T5ttcc with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV, $m_{{\tilde{t}}} = $ 320 GeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; T1tttt with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; and T2tt with $m_{{\tilde{t}}} = $ 1.2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 100 GeV. |
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Figure 5-c:
${M_{R}} - {R^{2}}$ distributions shown in a one-dimensional representation for background predictions obtained for the W 4-5 jet (upper left), W 6 jet (upper right), and Top (lower) categories for the HL-LHC. Statistical and systematic uncertainties for the YR18 scenario are shown with the hatched and shaded error bars, respectively. Also shown are the signal benchmark models T5ttcc with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV, $m_{{\tilde{t}}} = $ 320 GeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; T1tttt with $m_{{\mathrm {\tilde{g}}}} = $ 2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 300 GeV; and T2tt with $m_{{\tilde{t}}} = $ 1.2 TeV and $m_{{\tilde{\chi}^{0}_{1}}} = $ 100 GeV. |
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Figure 6:
Projected expected upper limits on the signal cross sections for the HL-LHC using the asymptotic CLs method versus gluino/top squark and neutralino masses for the T5ttcc (top left), T1tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected lower limits on the gluino/stop squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios, along with the 2016 analysis limit and the 300 fb$^{-1}$ limit for comparison. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 6-a:
Projected expected upper limits on the signal cross sections for the HL-LHC using the asymptotic CLs method versus gluino/top squark and neutralino masses for the T5ttcc (top left), T1tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected lower limits on the gluino/stop squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios, along with the 2016 analysis limit and the 300 fb$^{-1}$ limit for comparison. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 6-b:
Projected expected upper limits on the signal cross sections for the HL-LHC using the asymptotic CLs method versus gluino/top squark and neutralino masses for the T5ttcc (top left), T1tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected lower limits on the gluino/stop squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios, along with the 2016 analysis limit and the 300 fb$^{-1}$ limit for comparison. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 6-c:
Projected expected upper limits on the signal cross sections for the HL-LHC using the asymptotic CLs method versus gluino/top squark and neutralino masses for the T5ttcc (top left), T1tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected lower limits on the gluino/stop squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios, along with the 2016 analysis limit and the 300 fb$^{-1}$ limit for comparison. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 7:
Projected expected significance for the HL-LHC versus gluino/stop and neutralino masses for the T5ttcc (top left), T2tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected discovery bounds on the gluino/top squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 7-a:
Projected expected significance for the HL-LHC versus gluino/stop and neutralino masses for the T5ttcc (top left), T2tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected discovery bounds on the gluino/top squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
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Figure 7-b:
Projected expected significance for the HL-LHC versus gluino/stop and neutralino masses for the T5ttcc (top left), T2tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected discovery bounds on the gluino/top squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
png pdf |
Figure 7-c:
Projected expected significance for the HL-LHC versus gluino/stop and neutralino masses for the T5ttcc (top left), T2tttt (top right), and T2tt (bottom) models for the combined W 4-5 jet, W 6 jet, and Top categories for the YR18 scenario. The contours show the expected discovery bounds on the gluino/top squark and neutralino masses based on the Run 2 systematic uncertainties, YR18 systematic uncertainties, and statistical-only scenarios. The lower left white diagonal band in the T2tt plot corresponds to the region $|m_{\tilde{t}} - m_t - m_{\tilde{\chi}^0_1}| < $ 25 GeV, where the mass difference between the $\tilde{t}$ and the $\tilde{\chi}^0_1$ is very close to the top quark mass. In this region, the signal acceptance depends strongly on the $\tilde{\chi}^0_1$ mass and is therefore difficult to model. |
| Tables | |
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Table 1:
Summary of the scaling of uncertainties in the YR18 scenario for the background and signal processes for the HL-LHC projections. The "YR18 recommendation'' treatment note specifies that the scaling of the uncertainty was done based on CMS recommendations for the Yellow Report, reflecting the potential upgrade performance of the CMS detector, summarised in Ref. [14]. |
| Summary |
| We have presented the HL-LHC projection of the Run 2 search for new physics in hadronic final states with boosted W bosons or top quarks using the razor kinematic variables. Final states with boosted objects constitute an important search scenario, as they become more accessible at the increased center-of-mass energy at the HL-LHC. The projection study uses observed data yields and simulated signal and background events from the original analysis, which are scaled to obtain the HL-LHC sensitivity for center-of-mass energy of 14 TeV and integrated luminosity of 3 ab$^{-1}$. The background estimation and limit setting procedures are fully adopted from the Run 2 analysis done using 2016 data. Different scenarios for systematic uncertainties, based on a common convention with other CMS analyses and ATLAS are considered. The projection results are interpreted in terms of gluino pair production where the gluinos decay into either a top quark, an anti-top quark, and a neutralino; or to a top quark and a top squark, and direct top squark pair production where top squarks decay into top quarks and neutralinos. The HL-LHC would exclude gluinos and top squarks up to 2.6 TeV and 1.5 TeV respectively, while making discovery possible for gluinos and top squarks up to masses of 2.35 TeV and 1.4 TeV, respectively, thus providing a very strong test of naturalness scenarios for supersymmetry. |
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Compact Muon Solenoid LHC, CERN |
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