The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two $W$ bosons, the lightest neutralinos ($\tilde\chi^0_1$), and quarks, are presented. The signal is characterised by the presence of a single charged lepton ($e^{\pm}$ or $\mu^{\pm}$) from a $W$ boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb$^{-1}$ of proton-proton collision data taken at a centre-of-mass energy $\sqrt{s}=13$ TeV delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 TeV (1.4 TeV) are excluded at 95% confidence level for a light $\tilde\chi^0_1$.
Post-fit $m_{T}$ distribution in the SR 2J b-veto N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
Post-fit $m_{T}$ distribution in the SR 2J b-veto N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
Post-fit $m_{T}$ distribution in the SR 2J b-tag N-1 region. N-1 refers to all cuts except for the requirement on $m_T$ being applied. Uncertainties include statistical and systematic uncertainties. The value 9999 is used as a placeholder for infinity.
A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using 139 $\mathrm{fb}^{-1}$ of data collected by the ATLAS detector at the Large Hadron Collider during $pp$ collisions at $\sqrt{s}=13$ TeV. The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic $t\bar{t}$ decay channel, and the hadronically decaying top quark must have transverse momentum above $350$ GeV. The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be $-0.043\pm0.020$, in agreement with the SM prediction of $-0.037\pm0.003$. Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits.
Data measurements and predictions of the energy asymmetry in three bins of the jet angle $\theta_j$. The SM prediction was obtained from simulations of $t\bar{t}j$ events with MadGraph5_aMC@NLO + Pythia 8 at NLO in QCD for $t\bar{t}j$ + PS, including MC statistical and scale uncertainties.
Correlation coefficients $\rho_{i,j}$ for the statistical and systematic uncertainties between the $i$-th and $j$-th bin of the differential $A_E$ measurement as a function of the jet scattering angle $\theta_j$
The effects on the energy asymmetry of $1\sigma$ variations in its influencing nuisance parameters for the three $\theta_j$ bins. These are extracted from the samples of the posterior distribution with $\sigma_i^{(j)} = c_{ij}/\sqrt{c_{jj}}$ being the estimated shift of bin $i$ in conjunction with a shift $\Delta\theta_j$ of nuisance parameter $j$. The data statistical (Data stat.) uncertainty is obtained from running the unfolding with all nuisance parameters being fixed to their post-marginalised values, the MC statistical uncertainty on the response matrix ($t\bar{t}$ response MC stat.) is evaluated using a bootstrapping method from the covariance matrix of the ensemble of repeated unfolding results with varied response matrices. The $\gamma$ variations denote the statistical uncertainties of the background predictions in the corresponding bin of the $\Delta E$ vs $\theta_{j}$ distribution. The numbers appended to the $W$+jets PDF variations denote the corresponding NNPDF3.0 PDF sets.
A search for long-lived particles decaying into hadrons and at least one muon is presented. The analysis selects events that pass a muon or missing-transverse-momentum trigger and contain a displaced muon track and a displaced vertex. The analyzed dataset of proton-proton collisions at $\sqrt{s} = 13$ TeV was collected with the ATLAS detector and corresponds to 136 fb$^{-1}$. The search employs dedicated reconstruction techniques that significantly increase the sensitivity to long-lived particle decays that occur in the ATLAS inner detector. Background estimates for Standard Model processes and instrumental effects are extracted from data. The observed event yields are compatible with those expected from background processes. The results are presented as limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model, and interpreted as exclusion limits in scenarios with pair-production of long-lived top squarks that decay via a small $R$-parity-violating coupling into a quark and a muon. Top squarks with masses up to 1.7 TeV are excluded for a lifetime of 0.1 ns, and masses below 1.3 TeV are excluded for lifetimes between 0.01 ns and 30 ns.
Vertex selection acceptance for the $\tilde{t}$ $R$-hadron benchmark model as a function of the transverse decay distance $r_{DV}$.
Vertex selection efficiency for the $\tilde{t}$ $R$-hadron benchmark model as a function of the transverse decay distance $r_{DV}$.
Track multiplicity $n_{Tracks}$ for preselected DVs in MET-triggered events with at least one muon passing the full selection. Along with the data shown with black markers, the stacked filled histograms represent the background estimates, and predictions for signal scenarios are overlaid with dashed lines. The errors include statistical and systematic uncertainties and are indicated by hatched bands. The DV full selection requirements, $n_{Tracks} \geq 3$ and $m_{DV} > 20$ GeV are visualized with a black arrow.
A search is presented for new phenomena in events characterised by high jet multiplicity, no leptons (electrons or muons), and four or more jets originating from the fragmentation of $b$-quarks ($b$-jets). The search uses 139 fb$^{-1}$ of $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider during Run 2. The dominant Standard Model background originates from multijet production and is estimated using a data-driven technique based on an extrapolation from events with low $b$-jet multiplicity to the high $b$-jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits that constrain simplified models of R-parity-violating supersymmetry are determined. The exclusion limits reach 950 GeV in top-squark mass in the models considered.
<b>- - - - - - - - Overview of HEPData Record - - - - - - - -</b> <br><br> <b>Exclusion contours:</b> <ul> <li><a href="?table=stbchionly_obs">Stop to bottom quark and chargino exclusion contour (Obs.)</a> <li><a href="?table=stbchionly_exp">Stop to bottom quark and chargino exclusion contour (Exp.)</a> <li><a href="?table=stbchi_obs">Stop to higgsino LSP exclusion contour (Obs.)</a> <li><a href="?table=stbchi_exp">Stop to higgsino LSP exclusion contour (Exp.)</a> <li><a href="?table=sttN_obs">Stop to top quark and neutralino exclusion contour (Obs.)</a> <li><a href="?table=sttN_exp">Stop to top quark and neutralino exclusion contour (Exp.)</a> </ul> <b>Upper limits:</b> <ul> <li><a href="?table=stbchionly_xSecUL_obs">Obs Xsection upper limit in stop to bottom quark and chargino</a> <li><a href="?table=stop_xSecUL_obs">Obs Xsection upper limit in higgsino LSP</a> <li><a href="?table=stbchionly_xSecUL_exp">Exp Xsection upper limit in stop to bottom quark and chargino</a> <li><a href="?table=stop_xSecUL_exp">Exp Xsection upper limit in higgsino LSP</a> </ul> <b>Kinematic distributions:</b> <ul> <li><a href="?table=SR_yields">SR_yields</a> </ul> <b>Cut flows:</b> <ul> <li><a href="?table=cutflow">cutflow</a> </ul> <b>Acceptance and efficiencies:</b> As explained in <a href="https://twiki.cern.ch/twiki/bin/view/AtlasPublic/SupersymmetryPublicResults#summary_of_auxiliary_material">the twiki</a>. <ul> <li> <b>stbchi_6je4be:</b> <a href="?table=stbchi_Acc_6je4be">stbchi_Acc_6je4be</a> <a href="?table=stbchi_Eff_6je4be">stbchi_Eff_6je4be</a> <li> <b>stbchi_7je4be:</b> <a href="?table=stbchi_Acc_7je4be">stbchi_Acc_7je4be</a> <a href="?table=stbchi_Eff_7je4be">stbchi_Eff_7je4be</a> <li> <b>stbchi_8je4be:</b> <a href="?table=stbchi_Acc_8je4be">stbchi_Acc_8je4be</a> <a href="?table=stbchi_Eff_8je4be">stbchi_Eff_8je4be</a> <li> <b>stbchi_9ji4be:</b> <a href="?table=stbchi_Acc_9ji4be">stbchi_Acc_9ji4be</a> <a href="?table=stbchi_Eff_9ji4be">stbchi_Eff_9ji4be</a> <li> <b>stbchi_6je5bi:</b> <a href="?table=stbchi_Acc_6je5bi">stbchi_Acc_6je5bi</a> <a href="?table=stbchi_Eff_6je5bi">stbchi_Eff_6je5bi</a> <li> <b>stbchi_7je5bi:</b> <a href="?table=stbchi_Acc_7je5bi">stbchi_Acc_7je5bi</a> <a href="?table=stbchi_Eff_7je5bi">stbchi_Eff_7je5bi</a> <li> <b>stbchi_8je5bi:</b> <a href="?table=stbchi_Acc_8je5bi">stbchi_Acc_8je5bi</a> <a href="?table=stbchi_Eff_8je5bi">stbchi_Eff_8je5bi</a> <li> <b>stbchi_9ji5bi:</b> <a href="?table=stbchi_Acc_9ji5bi">stbchi_Acc_9ji5bi</a> <a href="?table=stbchi_Eff_9ji5bi">stbchi_Eff_9ji5bi</a> <li> <b>stbchi_8ji5bi:</b> <a href="?table=stbchi_Acc_8ji5bi">stbchi_Acc_8ji5bi</a> <a href="?table=stbchi_Eff_8ji5bi">stbchi_Eff_8ji5bi</a> <li> <b>sttN_6je4be:</b> <a href="?table=sttN_Acc_6je4be">sttN_Acc_6je4be</a> <a href="?table=sttN_Eff_6je4be">sttN_Eff_6je4be</a> <li> <b>sttN_7je4be:</b> <a href="?table=sttN_Acc_7je4be">sttN_Acc_7je4be</a> <a href="?table=sttN_Eff_7je4be">sttN_Eff_7je4be</a> <li> <b>sttN_8je4be:</b> <a href="?table=sttN_Acc_8je4be">sttN_Acc_8je4be</a> <a href="?table=sttN_Eff_8je4be">sttN_Eff_8je4be</a> <li> <b>sttN_9ji4be:</b> <a href="?table=sttN_Acc_9ji4be">sttN_Acc_9ji4be</a> <a href="?table=sttN_Eff_9ji4be">sttN_Eff_9ji4be</a> <li> <b>sttN_6je5bi:</b> <a href="?table=sttN_Acc_6je5bi">sttN_Acc_6je5bi</a> <a href="?table=sttN_Eff_6je5bi">sttN_Eff_6je5bi</a> <li> <b>sttN_7je5bi:</b> <a href="?table=sttN_Acc_7je5bi">sttN_Acc_7je5bi</a> <a href="?table=sttN_Eff_7je5bi">sttN_Eff_7je5bi</a> <li> <b>sttN_8je5bi:</b> <a href="?table=sttN_Acc_8je5bi">sttN_Acc_8je5bi</a> <a href="?table=sttN_Eff_8je5bi">sttN_Eff_8je5bi</a> <li> <b>sttN_9ji5bi:</b> <a href="?table=sttN_Acc_9ji5bi">sttN_Acc_9ji5bi</a> <a href="?table=sttN_Eff_9ji5bi">sttN_Eff_9ji5bi</a> <li> <b>sttN_8ji5bi:</b> <a href="?table=sttN_Acc_8ji5bi">sttN_Acc_8ji5bi</a> <a href="?table=sttN_Eff_8ji5bi">sttN_Eff_8ji5bi</a> </ul> <b>Truth Code snippets</b> and <b>SLHA</a> files are available under "Resources" (purple button on the left)
The observed exclusion contour at 95% CL as a function of the $\it{m}_{\tilde{\chi}^{\pm}_{1}}$ vs. $\it{m}_{\tilde{t}}$. Masses that are within the contours are excluded. Limits are shown for $B(\tilde{t} \rightarrow b \chi^{+}_{1})$ equal to unity.
The expected exclusion contour at 95% CL as a function of the $\it{m}_{\tilde{\chi}^{\pm}_{1}}$ vs. $\it{m}_{\tilde{t}}$. Masses that are within the contour are excluded. Limits are shown for $B(\tilde{t} \rightarrow b \chi^{+}_{1})$ equal to unity.
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell $W$ and $Z$ bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of $\sqrt{s}$ = 13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015-2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full dataset are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV.
Distributions in SR-low of the data and post-fit background prediction for m<sub>T</sub>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt̄, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.
Distributions in SR-low of the data and post-fit background prediction for H<sup>boost</sup>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt̄, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.
Distributions in SR-low of the data and post-fit background prediction for m<sub>eff</sub><sup>3ℓ</sup>/H<sup>boost</sup>. The SR-low event selections are applied for each distribution except for the variable shown, where the selection is indicated by a red arrow. The normalization factor for the WZ background is derived from the background-only estimation described in Section 7. The expected distribution for a benchmark signal model is included for comparison. The first (last) bin includes underflow (overflow). The "Top-quark like" category contains the tt̄, Wt, and WW processes while the "Others" category contains backgrounds from triboson production and processes that include a Higgs boson, 3 or more tops, and tops produced in association with W or Z bosons. The bottom panel shows the ratio of the data to the post-fit background prediction. The hatched bands indicate the combined theoretical, experimental, and MC statistical uncertainties.
A search for the direct production of the supersymmetric partners of $\tau$-leptons (staus) in final states with two hadronically decaying $\tau$-leptons is presented. The analysis uses a dataset of $pp$ collisions corresponding to an integrated luminosity of $139$ fb$^{-1}$, recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed. Limits are derived in scenarios of direct production of stau pairs with each stau decaying into the stable lightest neutralino and one $\tau$-lepton in simplified models where the two stau mass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidence level for a massless lightest neutralino.
The observed upper limits on the model cross-section in units of pb for simplified models with combined ${\tilde{\tau}}^{+}_{R,L} {\tilde{\tau}}^{-}_{R,L}$ production. Three points at ${M({\tilde{\chi}}^{0}_{1})}=200GeV$ were removed from the plot but kept in the table because they overlapped with the plot's legend and are far from the exclusion contour.
The observed upper limits on the model cross-section in units of pb for simplified models with ${\tilde{\tau}}_L {\tilde{\tau}}_L$ only production. Three points at $M({\tilde{\chi}}^{0}_{1})=200GeV$ were removed from the plot but kept in the table because they overlapped with the plot's legend and are far from the exclusion contour.
The observed 95\% CL exclusion contours for the combined fit of SR-lowMass and SR-highMass for simplified models with combined ${\tilde{\tau}}^{+}_{R,L} {\tilde{\tau}}^{-}_{R,L}$ production.
The results of a search for direct pair production of top squarks and for dark matter in events with two opposite-charge leptons (electrons or muons), jets and missing transverse momentum are reported, using 139 fb$^{-1}$ of integrated luminosity from proton-proton collisions at $\sqrt{s} = 13$ TeV, collected by the ATLAS detector at the Large Hadron Collider during Run 2 (2015-2018). This search considers the pair production of top squarks and is sensitive across a wide range of mass differences between the top squark and the lightest neutralino. Additionally, spin-0 mediator dark-matter models are considered, in which the mediator is produced in association with a pair of top quarks. The mediator subsequently decays to a pair of dark-matter particles. No significant excess of events is observed above the Standard Model background, and limits are set at 95% confidence level. The results exclude top squark masses up to about 1 TeV, and masses of the lightest neutralino up to about 500 GeV. Limits on dark-matter production are set for scalar (pseudoscalar) mediator masses up to about 250 (300) GeV.
Two-body selection. Distributions of $m_{T2}$ in $SR^{2-body}_{110,\infty}$ for (a) different-flavour and (b) same-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference dark-matter signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction.
Two-body selection. Distributions of $m_{T2}$ in $SR^{2-body}_{110,\infty}$ for (a) different-flavour and (b) same-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference dark-matter signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction.
Three-body selection. Distributions of $M_{\Delta}^R$ in (a,b) $SR_{W}^{3-body}$ and (c,d) $SR_{T}^{3-body}$ for (left) same-flavour and (right) different-flavour events satisfying the selection criteria of the given SR, except the one for the presented variable, after the background fit. The contributions from all SM backgrounds are shown as a histogram stack. ''Others'' includes contributions from $VVV$, $t\bar{t} t$, $t\bar{t}t\bar{t}$, $t\bar{t} W$, $t\bar{t} WW$, $t\bar{t} WZ$, $t\bar{t} H$, and $tZ$ processes. The hatched bands represent the total statistical and systematic uncertainty. The rightmost bin of each plot includes overflow events. Reference top squark pair production signal models are overlayed for comparison. Red arrows in the upper panels indicate the signal region selection criteria. The bottom panels show the ratio of the observed data to the total SM background prediction, with hatched bands representing the total uncertainty in the background prediction; red arrows show data outside the vertical-axis range.
Several extensions of the Standard Model predict the production of dark matter particles at the LHC. An uncharted signature of dark matter particles produced in association with $VV=W^\pm W^\mp$ or $ZZ$ pairs from a decay of a dark Higgs boson $s$ is searched for using 139 fb$^{-1}$ of $pp$ collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. The $s\to V(q\bar q)V(q\bar q)$ decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted $VV$ pairs using jets in the calorimeter and tracking information. Dark Higgs scenarios with $m_s > 160$ GeV are excluded.
Data overlaid on SM background post-fit yields stacked in each SR and CR category and E<sub>T</sub><sup>miss</sup> bin with the maximum-likelihood estimators set to the conditional values of the CR-only fit, and propagated to SR and CRs. Pre-fit uncertainties cover differences between the data and pre-fit background prediction.
Dominant sources of uncertainty for three dark Higgs scenarios after the fit to Asimov data generated from the expected values of the maximum-likelihood estimators including predicted signals with m<sub>Z'</sub> = 1 TeV and m<sub>s</sub> of (a) 160 GeV, (b) 235 GeV, and (c) 310 GeV. The uncertainty in the fitted signal yield relative to the theory prediction is presented. Total is the quadrature sum of statistical and total systematic uncertainties, which consider correlations.
The ratios (μ) of the 95% C.L. upper limits on the combined s→ W<sup>±</sup>W<sup>∓</sup> and s→ ZZ cross section to simplified model expectations for the m<sub>Z'</sub>=0.5 TeV scenario, for various m<sub>s</sub> hypotheses. The observed limits (solid line) are consistent with the expectation under the SM-only hypothesis (dashed line) within uncertainties (filled band), except for a small excess for m<sub>s</sub>=160 GeV, discussed in the text.
A search for pair production of bottom squarks in events with hadronically decaying $\tau$-leptons, $b$-tagged jets and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at $\sqrt{s}$ = 13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an integrated luminosity of 139 fb$^{-1}$. The observed data are compatible with the expected Standard Model background. Results are interpreted in a simplified model where each bottom squark is assumed to decay into the second-lightest neutralino $\tilde \chi_2^0$ and a bottom quark, with $\tilde \chi_2^0$ decaying into a Higgs boson and the lightest neutralino $\tilde \chi_1^0$. The search focuses on final states where at least one Higgs boson decays into a pair of hadronically decaying $\tau$-leptons. This allows the acceptance and thus the sensitivity to be significantly improved relative to the previous results at low masses of the $\tilde \chi_2^0$, where bottom-squark masses up to 850 GeV are excluded at the 95% confidence level, assuming a mass difference of 130 GeV between $\tilde \chi_2^0$ and $\tilde \chi_1^0$. Model-independent upper limits are also set on the cross section of processes beyond the Standard Model.
The expected exclusion contour at $95\%$ CL as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Masses within the contour are excluded.
The observed exclusion contour at $95\%$ CL as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Masses within the contour are excluded.
Acceptance in the Single-bin SR as a function of the M(Sbottom) vs. M(N2) with the $\Delta M$(N2,N1) = 130 GeV. Keep in mind that the acceptance is given in units of $10^{-4}$.
A search for the electroweak production of charginos and sleptons decaying into final states with two electrons or muons is presented. The analysis is based on 139 fb$^{-1}$ of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at $\sqrt{s}=13$ TeV. Three $R$-parity-conserving scenarios where the lightest neutralino is the lightest supersymmetric particle are considered: the production of chargino pairs with decays via either $W$ bosons or sleptons, and the direct production of slepton pairs. The analysis is optimised for the first of these scenarios, but the results are also interpreted in the others. No significant deviations from the Standard Model expectations are observed and limits at 95 % confidence level are set on the masses of relevant supersymmetric particles in each of the scenarios. For a massless lightest neutralino, masses up to 420 GeV are excluded for the production of the lightest-chargino pairs assuming $W$-boson-mediated decays and up to 1 TeV for slepton-mediated decays, whereas for slepton-pair production masses up to 700 GeV are excluded assuming three generations of mass-degenerate sleptons.
- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Background Fit results:</b> <ul> <li><a href="89413?version=4&table=Background fit 1">CRs</a> <li><a href="89413?version=4&table=Background fit 2">VRs</a> <li><a href="89413?version=4&table=Background fit 5">inclusive DF-0J SRs</a> <li><a href="89413?version=4&table=Background fit 6">inclusive DF-1J SRs</a> <li><a href="89413?version=4&table=Background fit 3">inclusive SF-0J SRs</a> <li><a href="89413?version=4&table=Background fit 4">inclusive SF-1J SRs</a> </ul> <b>Kinematic distributions in VRs:</b> <ul> <li><a href="89413?version=4&table=VR kinematics 1">$m_{T2}$ in VR-top-low</a> <li><a href="89413?version=4&table=VR kinematics 2">$m_{T2}$ in VR-top-high</a> <li><a href="89413?version=4&table=VR kinematics 3">$E_T^{miss}$ in VR-WW-0J</a> <li><a href="89413?version=4&table=VR kinematics 4">$E_T^{miss}$ in VR-WW-1J</a> <li><a href="89413?version=4&table=VR kinematics 5">$E_T^{miss}$ sig in VR-VZ</a> <li><a href="89413?version=4&table=VR kinematics 6">$E_T^{miss}$ sig in VR-top-WW</a> </ul> <b>Kinematic distributions in SRs:</b> <ul> <li><a href="89413?version=4&table=SR kinematics 1">$m_{T2}$ in SR-SF-0J</a> <li><a href="89413?version=4&table=SR kinematics 2">$m_{T2}$ in SR-SF-1J</a> <li><a href="89413?version=4&table=SR kinematics 3">$m_{T2}$ in SR-DF-0J</a> <li><a href="89413?version=4&table=SR kinematics 4">$m_{T2}$ in SR-DF-1J</a> </ul> <b>Systematic uncertaities:</b> <ul> <li><a href="89413?version=4&table=Systematic uncertainties">dominant systematic uncertainties in the inclusive SRs</a> </ul> <b>Exclusion contours:</b> <ul> <li><a href="89413?version=4&table=Exclusion contour (exp) 1">expected exclusion contour direct chargino-pair production via W decay grid</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 1">observed exclusion contour direct chargino-pair production via W decay grid</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 2">expected exclusion contour direct chargino-pair production via slepton decay grid</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 2">observed exclusion contour direct chargino-pair production via slepton decay grid</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 3">expected exclusion contour direct slepton-pair production grid</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 3">observed exclusion contour direct slepton-pair production grid</a> </ul> <br/><br/><b>AUXILIARY MATERIAL</b><br/> <b>Background Fit in binned SRs:</b> <ul> <li><a href="89413?version=4&table=Background fit 7">binned DF-0J SRs</a> <li><a href="89413?version=4&table=Background fit 8">binned DF-1J SRs</a> <li><a href="89413?version=4&table=Background fit 9">binned SF-0J SRs</a> <li><a href="89413?version=4&table=Background fit 10">binned SF-1J SRs</a> </ul> <b>Exclusion contours:</b> <ul> <li><a href="89413?version=4&table=Exclusion contour (exp) 4">expected exclusion contour left-handed slepton-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 4">observed exclusion contour left-handed slepton-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 5">expected exclusion contour right-handed slepton-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 5">observed exclusion contour right-handed slepton-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 6">expected exclusion contour selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 6">observed exclusion contour selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 7">expected exclusion contour left-handed selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 7">observed exclusion contour left-handed selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 8">expected exclusion contour right-handed selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 8">observed exclusion contour right-handed selectron-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 9">expected exclusion contour smuon-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 9">observed exclusion contour smuon-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 10">expected exclusion contour left-handed smuon-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 10">observed exclusion contour left-handed smuon-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (exp) 11">expected exclusion contour right-handed smuon-pair production</a> <li><a href="89413?version=4&table=Exclusion contour (obs) 11">observed exclusion contour right-handed smuon-pair production</a> </ul> <b>Cross section upper limits:</b> <ul> <li><a href="89413?version=4&table=xsec upper limits 1">upper limits on signal cross section for direct chargino-pair production via W decay</a> <li><a href="89413?version=4&table=xsec upper limits 2">upper limits on signal cross section for direct chargino-pair production via slepton decay</a> <li><a href="89413?version=4&table=xsec upper limits 3">upper limits on signal cross section for direct slepton-pair production</a> </ul> <b>Acceptances and Efficiencies for direct chargino-pair production via W decay grid </b> <ul> <li> <b>Acceptance</b> <br/> <a href="89413?version=4&table=Acceptance SR-DF-0J-[100,inf) for C1C1WW grid">SR-DF-0J-[100,inf) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[160,inf) for C1C1WW grid">SR-DF-0J-[160,inf) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[100,120) for C1C1WW grid">SR-DF-0J-[100,120) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[120,160) for C1C1WW grid">SR-DF-0J-[120,160) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[100,105) for C1C1WW grid">SR-DF-0J-[100,105) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[105,110) for C1C1WW grid">SR-DF-0J-[105,110) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[110,120) for C1C1WW grid">SR-DF-0J-[110,120) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[120,140) for C1C1WW grid">SR-DF-0J-[120,140) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[140,160) for C1C1WW grid">SR-DF-0J-[140,160) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[160,180) for C1C1WW grid">SR-DF-0J-[160,180) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[180,220) for C1C1WW grid">SR-DF-0J-[180,220) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[220,260) for C1C1WW grid">SR-DF-0J-[220,260) </a> <a href="89413?version=4&table=Acceptance SR-DF-0J-[260,inf) for C1C1WW grid">SR-DF-0J-[260,inf) </a><br/> <a href="89413?version=4&table=Acceptance SR-DF-1J-[100,inf) for C1C1WW grid">SR-DF-1J-[100,inf) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[160,inf) for C1C1WW grid">SR-DF-1J-[160,inf) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[100,120) for C1C1WW grid">SR-DF-1J-[100,120) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[120,160) for C1C1WW grid">SR-DF-1J-[120,160) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[100,105) for C1C1WW grid">SR-DF-1J-[100,105) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[105,110) for C1C1WW grid">SR-DF-1J-[105,110) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[110,120) for C1C1WW grid">SR-DF-1J-[110,120) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[120,140) for C1C1WW grid">SR-DF-1J-[120,140) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[140,160) for C1C1WW grid">SR-DF-1J-[140,160) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[160,180) for C1C1WW grid">SR-DF-1J-[160,180) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[180,220) for C1C1WW grid">SR-DF-1J-[180,220) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[220,260) for C1C1WW grid">SR-DF-1J-[220,260) </a> <a href="89413?version=4&table=Acceptance SR-DF-1J-[260,inf) for C1C1WW grid">SR-DF-1J-[260,inf) </a><br/> <a href="89413?version=4&table=Acceptance SR-SF-0J-[100,inf) for C1C1WW grid">SR-SF-0J-[100,inf) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[160,inf) for C1C1WW grid">SR-SF-0J-[160,inf) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[100,120) for C1C1WW grid">SR-SF-0J-[100,120) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[120,160) for C1C1WW grid">SR-SF-0J-[120,160) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[100,105) for C1C1WW grid">SR-SF-0J-[100,105) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[105,110) for C1C1WW grid">SR-SF-0J-[105,110) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[110,120) for C1C1WW grid">SR-SF-0J-[110,120) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[120,140) for C1C1WW grid">SR-SF-0J-[120,140) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[140,160) for C1C1WW grid">SR-SF-0J-[140,160) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[160,180) for C1C1WW grid">SR-SF-0J-[160,180) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[180,220) for C1C1WW grid">SR-SF-0J-[180,220) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[220,260) for C1C1WW grid">SR-SF-0J-[220,260) </a> <a href="89413?version=4&table=Acceptance SR-SF-0J-[260,inf) for C1C1WW grid">SR-SF-0J-[260,inf) </a><br/> <a href="89413?version=4&table=Acceptance SR-SF-1J-[100,inf) for C1C1WW grid">SR-SF-1J-[100,inf) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[160,inf) for C1C1WW grid">SR-SF-1J-[160,inf) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[100,120) for C1C1WW grid">SR-SF-1J-[100,120) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[120,160) for C1C1WW grid">SR-SF-1J-[120,160) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[100,105) for C1C1WW grid">SR-SF-1J-[100,105) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[105,110) for C1C1WW grid">SR-SF-1J-[105,110) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[110,120) for C1C1WW grid">SR-SF-1J-[110,120) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[120,140) for C1C1WW grid">SR-SF-1J-[120,140) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[140,160) for C1C1WW grid">SR-SF-1J-[140,160) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[160,180) for C1C1WW grid">SR-SF-1J-[160,180) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[180,220) for C1C1WW grid">SR-SF-1J-[180,220) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[220,260) for C1C1WW grid">SR-SF-1J-[220,260) </a> <a href="89413?version=4&table=Acceptance SR-SF-1J-[260,inf) for C1C1WW grid">SR-SF-1J-[260,inf) </a><br/> <li> <b>Efficiency</b> <br/> <a href="89413?version=4&table=Efficiency SR-DF-0J-[100,inf) for C1C1WW grid">SR-DF-0J-[100,inf) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[160,inf) for C1C1WW grid">SR-DF-0J-[160,inf) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[100,120) for C1C1WW grid">SR-DF-0J-[100,120) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[120,160) for C1C1WW grid">SR-DF-0J-[120,160) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[100,105) for C1C1WW grid">SR-DF-0J-[100,105) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[105,110) for C1C1WW grid">SR-DF-0J-[105,110) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[110,120) for C1C1WW grid">SR-DF-0J-[110,120) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[120,140) for C1C1WW grid">SR-DF-0J-[120,140) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[140,160) for C1C1WW grid">SR-DF-0J-[140,160) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[160,180) for C1C1WW grid">SR-DF-0J-[160,180) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[180,220) for C1C1WW grid">SR-DF-0J-[180,220) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[220,260) for C1C1WW grid">SR-DF-0J-[220,260) </a> <a href="89413?version=4&table=Efficiency SR-DF-0J-[260,inf) for C1C1WW grid">SR-DF-0J-[260,inf) </a><br/> <a href="89413?version=4&table=Efficiency SR-DF-1J-[100,inf) for C1C1WW grid">SR-DF-1J-[100,inf) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[160,inf) for C1C1WW grid">SR-DF-1J-[160,inf) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[100,120) for C1C1WW grid">SR-DF-1J-[100,120) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[120,160) for C1C1WW grid">SR-DF-1J-[120,160) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[100,105) for C1C1WW grid">SR-DF-1J-[100,105) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[105,110) for C1C1WW grid">SR-DF-1J-[105,110) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[110,120) for C1C1WW grid">SR-DF-1J-[110,120) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[120,140) for C1C1WW grid">SR-DF-1J-[120,140) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[140,160) for C1C1WW grid">SR-DF-1J-[140,160) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[160,180) for C1C1WW grid">SR-DF-1J-[160,180) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[180,220) for C1C1WW grid">SR-DF-1J-[180,220) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[220,260) for C1C1WW grid">SR-DF-1J-[220,260) </a> <a href="89413?version=4&table=Efficiency SR-DF-1J-[260,inf) for C1C1WW grid">SR-DF-1J-[260,inf) </a><br/> <a href="89413?version=4&table=Efficiency SR-SF-0J-[100,inf) for C1C1WW grid">SR-SF-0J-[100,inf) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[160,inf) for C1C1WW grid">SR-SF-0J-[160,inf) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[100,120) for C1C1WW grid">SR-SF-0J-[100,120) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[120,160) for C1C1WW grid">SR-SF-0J-[120,160) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[100,105) for C1C1WW grid">SR-SF-0J-[100,105) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[105,110) for C1C1WW grid">SR-SF-0J-[105,110) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[110,120) for C1C1WW grid">SR-SF-0J-[110,120) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[120,140) for C1C1WW grid">SR-SF-0J-[120,140) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[140,160) for C1C1WW grid">SR-SF-0J-[140,160) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[160,180) for C1C1WW grid">SR-SF-0J-[160,180) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[180,220) for C1C1WW grid">SR-SF-0J-[180,220) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[220,260) for C1C1WW grid">SR-SF-0J-[220,260) </a> <a href="89413?version=4&table=Efficiency SR-SF-0J-[260,inf) for C1C1WW grid">SR-SF-0J-[260,inf) </a><br/> <a href="89413?version=4&table=Efficiency SR-SF-1J-[100,inf) for C1C1WW grid">SR-SF-1J-[100,inf) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[160,inf) for C1C1WW grid">SR-SF-1J-[160,inf) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[100,120) for C1C1WW grid">SR-SF-1J-[100,120) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[120,160) for C1C1WW grid">SR-SF-1J-[120,160) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[100,105) for C1C1WW grid">SR-SF-1J-[100,105) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[105,110) for C1C1WW grid">SR-SF-1J-[105,110) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[110,120) for C1C1WW grid">SR-SF-1J-[110,120) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[120,140) for C1C1WW grid">SR-SF-1J-[120,140) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[140,160) for C1C1WW grid">SR-SF-1J-[140,160) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[160,180) for C1C1WW grid">SR-SF-1J-[160,180) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[180,220) for C1C1WW grid">SR-SF-1J-[180,220) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[220,260) for C1C1WW grid">SR-SF-1J-[220,260) </a> <a href="89413?version=4&table=Efficiency SR-SF-1J-[260,inf) for C1C1WW grid">SR-SF-1J-[260,inf) </a><br/> </ul> <b>Cutflow:</b> <ul> <li><a href="89413?version=4&table=Cutflow 1">Cutflow for direct chargino-pair production via W decay $m(\tilde{\chi}^{\pm}_1,\tilde{\chi}^{0}_1)=(300,50) GeV$</a> <li><a href="89413?version=4&table=Cutflow 2">Cutflow for direct chargino-pair production via slepton decay $m(\tilde{\chi}^{\pm}_1,\tilde{l},\tilde{\chi}^{0}_1)=(600,300,1) GeV$</a> <li><a href="89413?version=4&table=Cutflow 3">Cutflow for direct slepton-pair production $m(\tilde{l},\tilde{\chi}^{0}_1)=(400,200) GeV$</a> </ul> <b>SimpleAnalysis framework implementation</b> of the search SRs is available under "Resources" (purple button on the left)
Observed events and predicted background yields from the fit for the CRs. For backgrounds whose normalisation is extracted from the fit, the yield expected from the simulation before the fit is also reported. The background denoted as "Other" in the Table includes the non-dominant background sources for this analysis, i.e. Z+jets, $t\bar t$ +V, Higgs and Drell-Yan events. A "–" symbol indicates that the background contribution is negligible.
Observed events and predicted post-fit background yields in the VRs. For backgrounds whose normalisation is extracted from the fit in the CRs, the yield expected from the simulation before the fit is also reported. The background denoted as "Other" includes the non-dominant background sources for this analysis, i.e. Z+jets, $t\bar t$ +V, Higgs and Drell-Yan events. A "–" symbol indicates that the background contribution is negligible.
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