Search for squarks and gluinos in final states with jets and missing transverse momentum using 139 fb$^{-1}$ of $\sqrt{s}$ =13 TeV $pp$ collision data with the ATLAS detector

The collaboration
JHEP 02 (2021) 143, 2021.

Abstract
A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. The results are interpreted in the context of various $R$-parity-conserving models where squarks and gluinos are produced in pairs or in association and a neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.30 TeV for a simplified model containing only a gluino and the lightest neutralino, assuming the latter is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.85 TeV are excluded if the lightest neutralino is massless. These limits extend substantially beyond the region of supersymmetric parameter space excluded previously by similar searches with the ATLAS detector.

• #### Post-fit distribution 1

Data from Figure 8(a)

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Observed $m_{\mathrm{eff}}$ distributions in signal regions MB-SSd. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 2

Data from Figure 9(a)

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Observed metSig distributions in signal regions MB-SSd. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 3

Data from Figure 8(b)

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Observed $m_{\mathrm{eff}}$ distributions in signal regions MB-GGd. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 4

Data from Figure 9(b)

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Observed metSig distributions in signal regions MB-GGd. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 5

Data from Figure 8(c)

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Observed $m_{\mathrm{eff}}$ distributions in signal regions MB-C. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 6

Data from Figure 9(c)

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Observed metSig distributions in signal regions MB-C. The histograms show the MC background predictions normalised by the background-only fit. The...

• #### Post-fit distribution 7

Data from Figure 10(a)

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Observed BDT-GGd1 score distributions in signal regions GGd1. The histograms show the MC background predictions normalised by the background-only fit....

• #### Post-fit distribution 8

Data from Figure 10(b)

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Observed BDT-GGo1 score distributions in signal regions GGo1. The histograms show the MC background predictions normalised by the background-only fit....

• #### Signal acceptance 1

Data from Aux.Figure 16(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd1

• #### Signal acceptance 2

Data from Aux.Figure 17(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd2

• #### Signal acceptance 3

Data from Aux.Figure 18(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd3

• #### Signal acceptance 4

Data from Aux.Figure 19(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd4

• #### Signal acceptance 5

Data from Aux.Figure 24(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo1

• #### Signal acceptance 6

Data from Aux.Figure 25(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo2

• #### Signal acceptance 7

Data from Aux.Figure 26(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo3

• #### Signal acceptance 8

Data from Aux.Figure 27(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo4

• #### Signal acceptance 9

Data from Aux.Figure 13(a)

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Signal region acceptance for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-1600

• #### Signal acceptance 10

Data from Aux.Figure 14(a)

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Signal region acceptance for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-2200

• #### Signal acceptance 11

Data from Aux.Figure 15(a)

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Signal region acceptance for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-2800

• #### Signal acceptance 12

Data from Aux.Figure 20(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-1000

• #### Signal acceptance 13

Data from Aux.Figure 21(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-2200

• #### Signal acceptance 14

Data from Aux.Figure 22(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-3400

• #### Signal acceptance 15

Data from Aux.Figure 23(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and neutralino in SR 5j-1600

• #### Signal acceptance 16

Data from Aux.Figure 28(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-1000

• #### Signal acceptance 17

Data from Aux.Figure 29(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-2200

• #### Signal acceptance 18

Data from Aux.Figure 30(a)

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Signal region acceptance for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-3400

• #### Signal efficiency 1

Data from Aux.Figure 16(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd1....

• #### Signal efficiency 2

Data from Aux.Figure 17(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd2....

• #### Signal efficiency 3

Data from Aux.Figure 18(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd3....

• #### Signal efficiency 4

Data from Aux.Figure 19(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR BDT-GGd4....

• #### Signal efficiency 5

Data from Aux.Figure 24(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo1....

• #### Signal efficiency 6

Data from Aux.Figure 25(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo2....

• #### Signal efficiency 7

Data from Aux.Figure 26(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo3....

• #### Signal efficiency 8

Data from Aux.Figure 27(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR BDT-GGo4....

• #### Signal efficiency 9

Data from Aux.Figure 13(b)

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Signal region efficiency for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-1600....

• #### Signal efficiency 10

Data from Aux.Figure 14(b)

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Signal region efficiency for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-2200....

• #### Signal efficiency 11

Data from Aux.Figure 15(b)

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Signal region efficiency for simplified model with squark pair production and decays to a quark and neutralino in SR 2j-2800....

• #### Signal efficiency 12

Data from Aux.Figure 20(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-1000....

• #### Signal efficiency 13

Data from Aux.Figure 21(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-2200....

• #### Signal efficiency 14

Data from Aux.Figure 22(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR 4j-3400....

• #### Signal efficiency 15

Data from Aux.Figure 23(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and neutralino in SR 5j-1600....

• #### Signal efficiency 16

Data from Aux.Figure 28(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-1000....

• #### Signal efficiency 17

Data from Aux.Figure 29(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-2200....

• #### Signal efficiency 18

Data from Aux.Figure 30(b)

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Signal region efficiency for simplified model with gluino pair production and decays to two quarks and chargino in SR 6j-3400....

• #### Exp.Contour 1

Data from Figure 13

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Exclusion limits in the mass plane of the lightest neutralino and first- and second-generation squarks assuming squark pair production and...

• #### Obs.Contour 1

Data from Figure 13

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Exclusion limits in the mass plane of the lightest neutralino and first- and second-generation squarks assuming squark pair production and...

• #### Exp.Contour 2

Data from Figure 13

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Exclusion limits in the mass plane of the lightest neutralino and non degenerated squark pair production and direct decays obtained...

• #### Obs.Contour 2

Data from Figure 13

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Exclusion limits in the mass plane of the lightest neutralino and non degenerated squark pair production and direct decays obtained...

• #### Exp.Contour 3

Data from Figure 14

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Exclusion limits in the mass plane of the lightest neutralino and the gluino for gluino pair production with direct decays...

• #### Obs.Contour 3

Data from Figure 14

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Exclusion limits in the mass plane of the lightest neutralino and the gluino for gluino pair production with direct decays...

• #### Exp.Contour 4

Data from Figure 15(a)

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Exclusion limits in the mass plane of the lightest neutralino and squarks. The expected limits are indicated with dark dashed...

• #### Obs.Contour 4

Data from Figure 15(a)

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Exclusion limits in the mass plane of the lightest neutralino and squarks. The observed limits are indicated by the medium...

• #### Exp.Contour 5

Data from Figure 15(b)

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Exclusion limits for squark pair production with a one-step decay via an intermediate chargino. The neutralino mass is fixed at...

• #### Obs.Contour 5

Data from Figure 15(b)

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Exclusion limits for squark pair production with a one-step decay via an intermediate chargino. The neutralino mass is fixed at...

• #### Exp.Contour 6

Data from Figure 16(a)

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Exclusion limits in the mass plane of the lightest neutralino and gluinos. The expected limits are indicated with dark dashed...

• #### Obs.Contour 6

Data from Figure 16(a)

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Exclusion limits in the mass plane of the lightest neutralino and gluinos. The observed limits are indicated by the medium...

• #### Exp.Contour 7

Data from Figure 16(b)

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Exclusion limits for gluino pair production with a one-step decay via an intermediate chargino. The neutralino mass is fixed at...

• #### Obs.Contour 7

Data from Figure 16(b)

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Exclusion limits for gluino pair production with a one-step decay via an intermediate chargino. The neutralino mass is fixed at...

• #### Exp.Contour 8

Data from Figure 17(a)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### Obs.Contour 8

Data from Figure 17(a)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### Exp.Contour 9

Data from Figure 17(b)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### Obs.Contour 9

Data from Figure 17(b)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### Exp.Contour 10

Data from Figure 17(c)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### Obs.Contour 10

Data from Figure 17(c)

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Exclusion limits for the model with combined production of squark pairs, gluino pairs, and of squark--gluino pairs. The neutralino mass...

• #### X-section U.L. 1

Data from Aux.Figure 10(a)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### X-section U.L. 2

Data from Aux.Figure 10(b)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### X-section U.L 3

Data from Aux.Figure 11(a)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### X-section U.L 4

Data from Aux.Figure 11(b)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### X-section U.L 5

Data from Aux.Figure 12(a)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### X-section U.L 6

Data from Aux.Figure 12(b)

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The observed upper limits on signal cross section corresponding to the best expected signal region in each mass point for...

• #### Cut flow 1

Data from Aux.Table 10

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Cut-flow for model-independent search regions targeting squarks for SS direct model points. Expected yields are normalized to a luminosity of...

• #### Cut flow 2

Data from Aux.Table 11

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Cut-flow for model-independent search regions targeting gluinos for GG direct model points. Expected yields are normalized to a luminosity of...

• #### Cut flow 3

Data from Aux.Table 12

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Cut-flow for model-independent search regions targeting squarks and gluinos in models with one-step decay. Expected yields are normalized to a...

• #### Cut flow 4

Data from Aux.Table 13

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Cut-flow for BDT search regions targeting gluinos in models with one-step decays. Expected yields are normalized to a luminosity of...

• #### Cut flow 5

Data from Aux.Table 14

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Cut-flow for BDT search regions targeting gluinos in models with direct decays. Expected yields are normalized to a luminosity of...

Version 2 modifications: Archive of full likelihoods in the HistFactory JSON format added to the entry.