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| CMS-PAS-SUS-17-002 | ||
| Search for supersymmetry in events with tau leptons and missing transverse momentum in proton-proton collisions at $\sqrt{s}= $ 13 TeV | ||
| CMS Collaboration | ||
| December 2017 | ||
| Abstract: A search for supersymmetry is performed using events with $\tau$ leptons in the final state with 13 TeV data recorded in 2016, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Models of direct $\widetilde{\tau}$-pair production, where each $\widetilde{\tau}$ is expected to decay to a $\tau$ lepton and the lightest supersymmetric particle, the $\widetilde{\chi}^{0}_1$, as well as neutralino-chargino and chargino pair production with decays to $\tau$ leptons are investigated. Several exclusive search regions are defined to maximize the sensitivity to various new physics topologies, based on final states with one hadronically decaying $\tau$ lepton and an electron or muon from the decay of the second $\tau$, as well as final states with one electron and one muon from the decay of the $\tau$ leptons. The data are consistent with the standard model expectation, and 95% CL limits are set for several scenarios. For neutralino-chargino production with mass-degenerate chargino ($\widetilde{\chi}^{\pm}_1$) or neutralino ($\widetilde{\chi}^{0}_2$), exclusion limits on the $\widetilde{\chi}^{\pm}_1$ and $\widetilde{\chi}^{0}_2$ masses can reach up to 560 GeV, depending on the masses of the intermediate $\widetilde{\tau}$ and the $\widetilde{\chi}^{0}_1$. The upper limit on cross section times the square of the branching fraction for direct $\widetilde{\tau}$-pair production is set to be 0.66 pb for a $\widetilde{\tau}$ mass of 90 GeV and a $\widetilde{\chi}^{0}_1$ mass of 1 GeV. | ||
| Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1-a:
Diagrams showing the investigated models for (left) direct $ \tilde{ \tau} $ -pair production and (right) $ {\tilde{\chi}^0_2} {\tilde{\chi}^{\pm}_1} $ production. |
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Figure 1-b:
Diagrams showing the investigated models for (left) direct $ \tilde{ \tau} $ -pair production and (right) $ {\tilde{\chi}^0_2} {\tilde{\chi}^{\pm}_1} $ production. |
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Figure 2:
Relative composition of background processes to the total prediction for the (left) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (right) $ {\mathrm {e}\mu} $ channel after the SR selection. |
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Figure 2-a:
Relative composition of background processes to the total prediction for the (left) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (right) $ {\mathrm {e}\mu} $ channel after the SR selection. |
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Figure 2-b:
Relative composition of background processes to the total prediction for the (left) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (right) $ {\mathrm {e}\mu} $ channel after the SR selection. |
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Figure 2-c:
Relative composition of background processes to the total prediction for the (left) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (right) $ {\mathrm {e}\mu} $ channel after the SR selection. |
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Figure 3:
Estimation of the DY+jets background: comparison of simulation to data after the shape corrections and the normalization to data. Shown are (left) the invariant di-muon mass, (middle) $ {{p_{\mathrm {T}}} ^\text {miss}} $, and (right) $\Delta R(\mu,\mu $). |
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Figure 3-a:
Estimation of the DY+jets background: comparison of simulation to data after the shape corrections and the normalization to data. Shown are (left) the invariant di-muon mass, (middle) $ {{p_{\mathrm {T}}} ^\text {miss}} $, and (right) $\Delta R(\mu,\mu $). |
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Figure 3-b:
Estimation of the DY+jets background: comparison of simulation to data after the shape corrections and the normalization to data. Shown are (left) the invariant di-muon mass, (middle) $ {{p_{\mathrm {T}}} ^\text {miss}} $, and (right) $\Delta R(\mu,\mu $). |
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Figure 3-c:
Estimation of the DY+jets background: comparison of simulation to data after the shape corrections and the normalization to data. Shown are (left) the invariant di-muon mass, (middle) $ {{p_{\mathrm {T}}} ^\text {miss}} $, and (right) $\Delta R(\mu,\mu $). |
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Figure 4:
Control plots for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel after the SR selection. Shown is (top left) $ {M_\mathrm {T}} _{\rm sum}$, (top right) $ {M_\mathrm {T}} $(e), (bottom left) $\Delta \eta (e,\tau)$, and (bottom right) $\Delta \mathrm{h}i (e,\tau)$. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 4-a:
Control plots for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel after the SR selection. Shown is (top left) $ {M_\mathrm {T}} _{\rm sum}$, (top right) $ {M_\mathrm {T}} $(e), (bottom left) $\Delta \eta (e,\tau)$, and (bottom right) $\Delta \mathrm{h}i (e,\tau)$. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 4-b:
Control plots for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel after the SR selection. Shown is (top left) $ {M_\mathrm {T}} _{\rm sum}$, (top right) $ {M_\mathrm {T}} $(e), (bottom left) $\Delta \eta (e,\tau)$, and (bottom right) $\Delta \mathrm{h}i (e,\tau)$. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 4-c:
Control plots for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel after the SR selection. Shown is (top left) $ {M_\mathrm {T}} _{\rm sum}$, (top right) $ {M_\mathrm {T}} $(e), (bottom left) $\Delta \eta (e,\tau)$, and (bottom right) $\Delta \mathrm{h}i (e,\tau)$. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 4-d:
Control plots for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel after the SR selection. Shown is (top left) $ {M_\mathrm {T}} _{\rm sum}$, (top right) $ {M_\mathrm {T}} $(e), (bottom left) $\Delta \eta (e,\tau)$, and (bottom right) $\Delta \mathrm{h}i (e,\tau)$. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 5:
QCD multijet background estimate in the $ {\mathrm {e}\mu} $ channel: (left) sketch of the four regions used for the matrix method to determine the QCD background (relative isolation values refer to those of the $\mu $ candidate) and (right) distance of the reconstructed muon track to the primary vertex in $z$ direction ($d_z$) with the QCD multijet background determined with the matrix method from data, and with corrected simulations of the other backgrounds. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 5-a:
QCD multijet background estimate in the $ {\mathrm {e}\mu} $ channel: (left) sketch of the four regions used for the matrix method to determine the QCD background (relative isolation values refer to those of the $\mu $ candidate) and (right) distance of the reconstructed muon track to the primary vertex in $z$ direction ($d_z$) with the QCD multijet background determined with the matrix method from data, and with corrected simulations of the other backgrounds. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 5-b:
QCD multijet background estimate in the $ {\mathrm {e}\mu} $ channel: (left) sketch of the four regions used for the matrix method to determine the QCD background (relative isolation values refer to those of the $\mu $ candidate) and (right) distance of the reconstructed muon track to the primary vertex in $z$ direction ($d_z$) with the QCD multijet background determined with the matrix method from data, and with corrected simulations of the other backgrounds. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. |
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Figure 6:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-a:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-b:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-c:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-d:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-e:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-f:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-g:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-h:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 6-i:
Comparison of several signals with background for the main search variables for the three different channels, (top) $ {\mathrm {e}\tau _{\mathrm h}} $, (middle) $ {\mu \tau _{\mathrm h}} $, and (bottom) $ {\mathrm {e}\mu} $ for $ {{p_{\mathrm {T}}} ^\text {miss}} $ (left column), $ {M_{\rm T2}} $ (middle column) and $ {D\zeta} $ (right column) after applying the SR selection. The black points show the data, the filled histograms represent the stacked SM background events, and three open histograms represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles. |
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Figure 7:
Results for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 7-a:
Results for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 7-b:
Results for the $ {\mathrm {e}\tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 8:
Results for the $ {\mu \tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 8-a:
Results for the $ {\mu \tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 8-b:
Results for the $ {\mu \tau _{\mathrm h}} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 9:
Results for the $ {\mathrm {e}\mu} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 9-a:
Results for the $ {\mathrm {e}\mu} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 9-b:
Results for the $ {\mathrm {e}\mu} $ channel for pre-fit (top) and post-fit (bottom) in the search bins. The black points show the data, the filled histograms represent the stacked SM background events, and three star-shaped markers represent signal models (not stacked), where the numbers in the brackets represent the masses of the corresponding sparticles in GeV. The filled error bars represent the pre-fit predictions, while the light blue (green) band in the ratio plot represent the pre-fit (post-fit) results. In the lower panels, the black solid points represent the pre-fit (post-fit) comparison of observation over unmodified (fitted) expectation. |
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Figure 10:
Expected and observed limits on the cross section for neutralino-chargino production with decay through $ \tilde{ \tau} $ with (top left) $x=0.95$, (top right) $x=0.5$, and (bottom) $x=0.05$, where $m_{\tilde{ \tau}} = m_{{\tilde{\chi}^0_1}} + x(m_{{\tilde{\chi}^0_2}} -m_{{\tilde{\chi}^0_1}})$. The branching ratio of the $ {\tilde{\chi}^0_2} $ is assumed to be BR($ {\tilde{\chi}^0_2} \to \tilde{ \tau} \tau)=1$. The area enclosed by the thick black curve represents the observed exclusion region, while the dashed red lines indicate the expected limits and their $ \pm 1 \sigma $ standard deviation ranges. |
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Figure 10-a:
Expected and observed limits on the cross section for neutralino-chargino production with decay through $ \tilde{ \tau} $ with (top left) $x=0.95$, (top right) $x=0.5$, and (bottom) $x=0.05$, where $m_{\tilde{ \tau}} = m_{{\tilde{\chi}^0_1}} + x(m_{{\tilde{\chi}^0_2}} -m_{{\tilde{\chi}^0_1}})$. The branching ratio of the $ {\tilde{\chi}^0_2} $ is assumed to be BR($ {\tilde{\chi}^0_2} \to \tilde{ \tau} \tau)=1$. The area enclosed by the thick black curve represents the observed exclusion region, while the dashed red lines indicate the expected limits and their $ \pm 1 \sigma $ standard deviation ranges. |
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Figure 10-b:
Expected and observed limits on the cross section for neutralino-chargino production with decay through $ \tilde{ \tau} $ with (top left) $x=0.95$, (top right) $x=0.5$, and (bottom) $x=0.05$, where $m_{\tilde{ \tau}} = m_{{\tilde{\chi}^0_1}} + x(m_{{\tilde{\chi}^0_2}} -m_{{\tilde{\chi}^0_1}})$. The branching ratio of the $ {\tilde{\chi}^0_2} $ is assumed to be BR($ {\tilde{\chi}^0_2} \to \tilde{ \tau} \tau)=1$. The area enclosed by the thick black curve represents the observed exclusion region, while the dashed red lines indicate the expected limits and their $ \pm 1 \sigma $ standard deviation ranges. |
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Figure 10-c:
Expected and observed limits on the cross section for neutralino-chargino production with decay through $ \tilde{ \tau} $ with (top left) $x=0.95$, (top right) $x=0.5$, and (bottom) $x=0.05$, where $m_{\tilde{ \tau}} = m_{{\tilde{\chi}^0_1}} + x(m_{{\tilde{\chi}^0_2}} -m_{{\tilde{\chi}^0_1}})$. The branching ratio of the $ {\tilde{\chi}^0_2} $ is assumed to be BR($ {\tilde{\chi}^0_2} \to \tilde{ \tau} \tau)=1$. The area enclosed by the thick black curve represents the observed exclusion region, while the dashed red lines indicate the expected limits and their $ \pm 1 \sigma $ standard deviation ranges. |
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Figure 11:
Excluded and observed exclusion limits on the cross section of direct $\tilde{ \tau} _{\rm L}$ production. The expected limits (dashed red line) and their $ \pm 1 \sigma $ and $ \pm 2 \sigma $ standard variations are shown as green and yellow bands, respectively. The observed limit is shown by the solid line with dots. |
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Figure 11-a:
Excluded and observed exclusion limits on the cross section of direct $\tilde{ \tau} _{\rm L}$ production. The expected limits (dashed red line) and their $ \pm 1 \sigma $ and $ \pm 2 \sigma $ standard variations are shown as green and yellow bands, respectively. The observed limit is shown by the solid line with dots. |
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Figure 11-b:
Excluded and observed exclusion limits on the cross section of direct $\tilde{ \tau} _{\rm L}$ production. The expected limits (dashed red line) and their $ \pm 1 \sigma $ and $ \pm 2 \sigma $ standard variations are shown as green and yellow bands, respectively. The observed limit is shown by the solid line with dots. |
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Figure 11-c:
Excluded and observed exclusion limits on the cross section of direct $\tilde{ \tau} _{\rm L}$ production. The expected limits (dashed red line) and their $ \pm 1 \sigma $ and $ \pm 2 \sigma $ standard variations are shown as green and yellow bands, respectively. The observed limit is shown by the solid line with dots. |
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Figure 11-d:
Excluded and observed exclusion limits on the cross section of direct $\tilde{ \tau} _{\rm L}$ production. The expected limits (dashed red line) and their $ \pm 1 \sigma $ and $ \pm 2 \sigma $ standard variations are shown as green and yellow bands, respectively. The observed limit is shown by the solid line with dots. |
| Tables | |
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Table 1:
Summary of the required lepton properties. |
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Table 2:
Requirements for additional leptons. Events with a third lepton (or a second same-flavor lepton) passing these conditions are rejected. |
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Table 3:
Definition of the search bin labelling. |
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Table 6:
The transfer factors as a function of $ {p_{\mathrm {T}}},\eta $ derived from the sideband. The uncertainties are statistical only. |
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Table 7:
Contributions to the systematic uncertainty considered for the DY+jets and $ {\mathrm{t} {}\mathrm{\bar{t}}} $ processes in order to assess systematic uncertainties on the extracted normalization. |
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Table 8:
Systematic uncertainties considered for background and signal. |
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Table 9:
Definition of combined search bins to be used for easier reinterpretation of the results. |
| Summary |
|
A search for supersymmetry has been performed with proton-proton collisions at a center-of-mass energy of 13 TeV recorded in 2016, corresponding to 35.9 fb$^{-1}$. Events are required to contain either one hadronically decaying $\tau$ lepton and an electron or muon, or and electron and a muon. The data are consistent with the standard model expectation, and 95% CL limits are set for several signal models. One model describes direct $ \tilde{ \tau} $ pair production, with each $ \tilde{ \tau} $ decaying to a $\tau$ lepton and the ${\widetilde{\chi}^0_1} $. For a $ \tilde{ \tau} $ mass of 90 GeV and a $ {\widetilde{\chi}^0_1} $ mass of 1 GeV, an upper limit on cross section times the square of the branching fraction is set to be 0.66 pb. Limits for neutralino ($ {\widetilde{\chi}^0_2} $ ) - chargino ($ {\widetilde{\chi}^0{\pm}_1} $) production are determined for decays of $ {\widetilde{\chi}^0_2} $ decays to a $\tau^+\tau^-$ pair and a $ {\widetilde{\chi}^0_1} $ , and the $ {\widetilde{\chi}^0{\pm}_1} $ decays to a $\tau^{\pm}$ and a $ {\widetilde{\chi}^0_1} $ , assuming mass degeneracy between $ {\widetilde{\chi}^0_2} $ and $ {\widetilde{\chi}^0{\pm}_1} $. Three different $m_{\tilde{ \tau}}$ mass scenarios have been defined: $m_{\tilde{ \tau}} = m_{{\widetilde{\chi}^0_1} } + x(m_{{\widetilde{\chi}^0_2} } -m_{{\widetilde{\chi}^0_1} })$ and $x=0.95$, 0.5 and 0.05. For $x=0.95$, $ {\widetilde{\chi}^0{\pm}_1} $ and $ {\widetilde{\chi}^0_2} $ masses can be excluded below 510 GeV for neutralino ($ {\widetilde{\chi}^0_1} $ ) masses below 200 GeV. For $x=0.5$, the limit on the $ {\widetilde{\chi}^0{\pm}_1} $ and $ {\widetilde{\chi}^0_2} $ mass can be extended to 560 GeV, while for $x=0.05$ the limit the $ {\widetilde{\chi}^0{\pm}_1} $ and $ {\widetilde{\chi}^0_2} $ mass reaches from 120-480 GeV. |
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