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Search for long-lived charginos based on a disappearing-track signature in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The collaboration
JHEP 1806 (2018) 022, 2018

Abstract (data abstract)
CERN-LHC. This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino. It is based on an integrated luminosity of 36.1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV collected by the ATLAS experiment at the LHC. The final state of interest is a disappearing track accompanied by at least one jet with high transverse momentum from initial-state radiation or by four jets from the gluino decay chain. The use of short track segments reconstructed from the innermost tracking layers significantly improves the sensitivity to short chargino lifetimes. The results are found to be consistent with Standard Model predictions. Exclusion limits are set at 95% confidence level on the mass of charginos and gluinos for different chargino lifetimes. For a pure wino with a lifetime of about 0.2 ns, chargino masses up to 460 GeV are excluded. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns.

• Tracklet pT EW VR (fake)

Data from the publication's Figure 7a

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Pixel-tracklet $p_{T}$ spectrum of fake tracklet in electroweak channel in the low-Emiss region.

• Tracklet pT EW VR (muon)

Data from the publication's Figure 7a

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Pixel-tracklet $p_{T}$ spectrum of muon background in electroweak channel in the low-Emiss region.

• Tracklet pT EW VR (hadron/electron)

Data from the publication's Figure 7a

10.17182/hepdata.78375.v3/t3

Pixel-tracklet $p_{T}$ spectrum of hadron and electron background in electroweak channel in the low-Emiss region.

• Tracklet pT EW VR (signal)

Data from the publication's Figure 7a

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Pixel-tracklet $p_{T}$ spectrum of signal ($\tau_{\tilde{\chi}_{1}^{\pm}}$ = 0.2 ns and $m_{\tilde{\chi}_{1}^{\pm}}$ = 400 GeV) in electroweak channel in the low-Emiss...

• Tracklet pT EW VR (total background)

Data from the publication's Figure 7a

10.17182/hepdata.78375.v3/t5

Pixel-tracklet $p_{T}$ spectrum of total background in electroweak channel in the low-Emiss region.

• Tracklet pT EW VR (obs)

Data from the publication's Figure 7a

10.17182/hepdata.78375.v3/t6

Pixel-tracklet $p_{T}$ spectrum of observed data in electroweak channel in the low-Emiss region.

• Tracklet pT Strong VR (fake)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t7

Pixel-tracklet $p_{T}$ spectrum of fake tracklet in strong channel in the low-Emiss region.

• Tracklet pT Strong VR (muon)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t8

Pixel-tracklet $p_{T}$ spectrum of muon background in strong channel in the low-Emiss region.

• Tracklet pT Strong VR (hadron/electron)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t9

Pixel-tracklet $p_{T}$ spectrum of hadron and electron background in strong channel in the low-Emiss region.

• Tracklet pT Strong VR (signal)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t10

Pixel-tracklet $p_{T}$ spectrum of signal ($m_{\tilde{g}}$ = 1600 GeV, $m_{\tilde{\chi}_{1}^{\pm}} = 500 GeV$) in strong channel in the low-Emiss region.

• Tracklet pT Strong VR (total background)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t11

Pixel-tracklet $p_{T}$ spectrum of total background in strong channel in the low-Emiss region.

• Tracklet pT Strong VR (obs)

Data from the publication's Figure 7b

10.17182/hepdata.78375.v3/t12

Pixel-tracklet $p_{T}$ spectrum of observed data in strong channel in the low-Emiss region.

• Tracklet pT EW SR (fake)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t13

Pixel-tracklet $p_{T}$ spectrum of fake tracklet in electroweak channel in the high-Emiss region.

• Tracklet pT EW SR (muon)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t14

Pixel-tracklet $p_{T}$ spectrum of muon background in electroweak channel in the high-Emiss region.

• Tracklet pT EW SR (hadron/electron)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t15

Pixel-tracklet $p_{T}$ spectrum of hadron and electron background in electroweak channel in the high-Emiss region.

• Tracklet pT EW SR (signal)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t16

Pixel-tracklet $p_{T}$ spectrum of signal ($\tau_{\tilde{\chi}_{1}^{\pm}}$ = 0.2 ns and $m_{\tilde{\chi}_{1}^{\pm}}$ = 400 GeV) in electroweak channel in the high-Emiss...

• Tracklet pT EW SR (total background)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t17

Pixel-tracklet $p_{T}$ spectrum of total background in electroweak channel in the high-Emiss region.

• Tracklet pT EW SR (obs)

Data from the publication's Figure 7c

10.17182/hepdata.78375.v3/t18

Pixel-tracklet $p_{T}$ spectrum of observed data in electroweak channel in the high-Emiss region.

• Tracklet pT Strong SR (fake)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t19

Pixel-tracklet $p_{T}$ spectrum of fake tracklet in strong channel in the high-Emiss region.

• Tracklet pT Strong SR (muon)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t20

Pixel-tracklet $p_{T}$ spectrum of muon background in strong channel in the high-Emiss region.

• Tracklet pT Strong SR (hadron/electron)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t21

Pixel-tracklet $p_{T}$ spectrum of hadron and electron background in strong channel in the high-Emiss region.

• Tracklet pT Strong SR (signal)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t22

Pixel-tracklet $p_{T}$ spectrum of signal ($m_{\tilde{g}}$ = 1600 GeV, $m_{\tilde{\chi}_{1}^{\pm}} = 500 GeV$) in strong channel in the high-Emiss region.

• Tracklet pT Strong SR (total background)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t23

Pixel-tracklet $p_{T}$ spectrum of total background in strong channel in the high-Emiss region.

• Tracklet pT Strong SR (obs)

Data from the publication's Figure 7d

10.17182/hepdata.78375.v3/t24

Pixel-tracklet $p_{T}$ spectrum of observed data in strong channel in the high-Emiss region.

• Exclusion contour EW (exp)

Data from the publication's Figure 8

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Expected exclusion limit at 95% CL obtained in the electroweak production channel in terms of the chargino lifetime ($\tau_{\tilde{\chi}_{1}^{\pm}}$) and...

• Exclusion contour EW (obs)

Data from the publication's Figure 8

10.17182/hepdata.78375.v3/t26

Observed exclusion limit at 95% CL obtained in the electroweak production channel in terms of the chargino lifetime ($\tau_{\tilde{\chi}_{1}^{\pm}}$) and...

• Exclusion contour Strong 0.2 ns (exp)

Data from the publication's Figure 9a

10.17182/hepdata.78375.v3/t27

Expected exclusion limit at 95% CL obtained in the strong production channel in terms of the gluino and chargino masses....

• Exclusion contour Strong 0.2 ns (obs)

Data from the publication's Figure 9a

10.17182/hepdata.78375.v3/t28

Observed exclusion limit at 95% CL obtained in the strong production channel in terms of the gluino and chargino masses....

• Exclusion contour Strong 1.0 ns (exp)

Data from the publication's Figure 9b

10.17182/hepdata.78375.v3/t29

Expected exclusion limit at 95% CL obtained in the strong production channel in terms of the gluino and chargino masses....

• Exclusion contour Strong 1.0 ns (obs)

Data from the publication's Figure 9b

10.17182/hepdata.78375.v3/t30

Observed exclusion limit at 95% CL obtained in the strong production channel in terms of the gluino and chargino masses....

• Exclusion contour EW 2 (exp)

Data from the publication's Auxiliary figure 1

10.17182/hepdata.78375.v3/t31

Expected exclusion limit at 95% CL obtained in the electroweak production channel in terms of the chargino lifetime ($\tau_{\tilde{\chi}_{1}^{\pm}}$) and...

• Exclusion contour EW 2 (obs)

Data from the publication's Auxiliary figure 1

10.17182/hepdata.78375.v3/t32

Observed exclusion limit at 95% CL obtained in the electroweak production channel in terms of the chargino lifetime ($\tau_{\tilde{\chi}_{1}^{\pm}}$) and...

• Upper Limit EW

Data from the publication's Auxiliary figure 1

10.17182/hepdata.78375.v3/t33

Model dependent upper limits on cross-section (pb) for the electroweak production are shown by grey numbers in terms of the...

• Acceptance times Efficiency EW

Data from the publication's Auxiliary figure 2

10.17182/hepdata.78375.v3/t34

Total acceptance $\times$ efficiency of the electroweak channel. The total signal acceptance $\times$ efficiency is defined as the probability of...

• Acceptance times Efficiency Strong

Data from the publication's Auxiliary figure 3

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Total acceptance $\times$ efficiency of the strong channel. In white regions, no simulation sample is available. The left-upper triangle region...

• Tracklet Acceptance EW

Data from the publication's Auxiliary figure 9a

10.17182/hepdata.78375.v3/t36

The generator-level acceptance for charginos produced in the electroweak channel as a function of the chargino $eta$ and chargino decay...

• Tracklet Acceptance times Efficiency EW

Data from the publication's Auxiliary figure 9b

10.17182/hepdata.78375.v3/t37

The acceptance $\times$ efficiency after reconstruction, for selecting and reconstructing charginos produced in the electroweak channel as a function of...

• Tracklet Acceptance Strong

Data from the publication's Auxiliary figure 9c

10.17182/hepdata.78375.v3/t38

The generator-level acceptance for charginos produced in the strong channel as a function of the chargino $\eta$ and chargino decay...

• Tracklet Acceptance times Efficiency Strong

Data from the publication's Auxiliary figure 9d

10.17182/hepdata.78375.v3/t39

The acceptance $\times$ efficiency after reconstruction, for selecting and reconstructing charginos produced in the strong channel as a function of...

• Cutflow EW

Data from the publication's Table 1

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Summary of the selection criteria, and the corresponding observed number of events in data as well as the expected number...

• Cutflow Strong

Data from the publication's Table 1

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Summary of the selection criteria, and the corresponding observed number of events in data as well as the expected number...

• Efficiency and Acceptance Table EW

Data from the publication's Table 2

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The event and tracklet generator-level acceptance and selection efficiency for a few electroweak signal models studied in this search. The...

• Efficiency and Acceptance Table Strong

Data from the publication's Table 2

10.17182/hepdata.78375.v3/t43

The event and tracklet generator-level acceptance and selection efficiency for a few strong signal models studied in this search. The...

• Signal systematic uncertainties

Data from the publication's Table 3

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Systematic uncertainties in the signal event yields at $m_{\tilde{\chi}_{1}^{\pm}}$ = 400 GeV for the electroweak channel and at $m_{\tilde{g}}$ =...

• Number in SR

Data from the publication's Table 4

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Observed events, expected background for null signal, and expected signal yields for two benchmark models: electroweak channel with ($m_{\tilde{\chi}_{1}^{\pm}}$, $\tau_{\tilde{\chi}_{1}^{\pm}}$)...

• Systematic impact

Data from the publication's Table 5

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Effects of systematic uncertainties on the signal exclusion significance at $m_{\tilde{\chi}_{1}^{\pm}}$ = 400 GeV for the electroweak channel and at...

• Upper Limit Strong

Data from the publication's Auxiliary table 1

10.17182/hepdata.78375.v3/t47

Cross-section upper limits for the strong production, presented in unit of fb. Left-upper triangle region is unphysical because the wino...

Version 3 modifications: Fix the acceptance times efficiency table.