Search for supersymmetry at $\sqrt{s}=13$ TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 76 (2016) 259, 2016.
Inspire Record 1424844 DOI 10.17182/hepdata.72792

A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ($e$ or $\mu$) with the same electric charge or at least three isolated leptons. The search also utilises $b$-tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton-proton collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.2 fb$^{-1}$. No significant excess over the Standard Model expectation is observed. The results are interpreted in several simplified supersymmetric models and extend the exclusion limits from previous searches. In the context of exclusive production and simplified decay modes, gluino masses are excluded at 95% confidence level up to 1.1-1.3 TeV for light neutralinos (depending on the decay channel), and bottom squark masses are also excluded up to 540 GeV. In the former scenarios, neutralino masses are also excluded up to 550-850 GeV for gluino masses around 1 TeV.

24 data tables

Missing transverse momentum distribution after SR0b3j selection, beside the $E_\mathrm{T}^\mathrm{miss}$ requirement. The results in the signal region correspond to the last inclusive bin. The systematic uncertainties include theory uncertainties for the backgrounds with prompt SS/3L and the full systematic uncertainties for data-driven backgrounds. For illustration the distribution for a benchmark SUSY scenario ($pp\to \tilde g\tilde g$, $\tilde g\to qq(\tilde\ell\ell/\tilde\nu\nu)$, $m_{\tilde g}=1.3$ TeV, $m_{\tilde\chi_1^0}=0.5$ TeV) is also shown.

Missing transverse momentum distribution after SR0b5j selection, beside the $E_\mathrm{T}^\mathrm{miss}$ requirement. The results in the signal region correspond to the last inclusive bin. The systematic uncertainties include theory uncertainties for the backgrounds with prompt SS/3L and the full systematic uncertainties for data-driven backgrounds. For illustration the distribution for a benchmark SUSY scenario ($pp\to \tilde g\tilde g$, $\tilde g\to qqWZ\tilde\chi_1^0$, $m_{\tilde g}=1.1$ TeV, $m_{\tilde\chi_1^0}=0.4$ TeV) is also shown.

Missing transverse momentum distribution after SR1b selection, beside the $E_\mathrm{T}^\mathrm{miss}$ requirement. The results in the signal region correspond to the last inclusive bin. The systematic uncertainties include theory uncertainties for the backgrounds with prompt SS/3L and the full systematic uncertainties for data-driven backgrounds. For illustration the distribution for a benchmark SUSY scenario ($pp\to \tilde b_1\tilde b_1^*$, $\tilde b_1\to tW\tilde\chi_1^0$, $m_{\tilde b_1}=600$ GeV, $m_{\tilde\chi_1^0}=50$ GeV) is also shown.

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Version 7
Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at $\sqrt{s}$=13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 12 (2017) 085, 2017.
Inspire Record 1623207 DOI 10.17182/hepdata.79538

A search for pair production of a scalar partner of the top quark in events with four or more jets plus missing transverse momentum is presented. An analysis of 36.1 fb$^{-1}$ of $\sqrt{s}$=13 TeV proton-proton collisions collected using the ATLAS detector at the LHC yields no significant excess over the expected Standard Model background. To interpret the results a simplified supersymmetric model is used where the top squark is assumed to decay via $\tilde{t}_1 \rightarrow t^{(*)} \tilde\chi^0_1$ and $\tilde{t}_1\rightarrow b\tilde\chi^\pm_1 \rightarrow b W^{(*)} \tilde\chi^0_1$, where $\tilde\chi^0_1$ ($\chi^\pm_1$) denotes the lightest neutralino (chargino). Exclusion limits are placed in terms of the top-squark and neutralino masses. Assuming a branching ratio of 100% to $t \tilde\chi^0_1$, top-squark masses in the range 450-950 GeV are excluded for $\tilde\chi^0_1$ masses below 160 GeV. In the case where $m_{\tilde{t}_1}\sim m_t+m_{\tilde\chi^0_1}$, top-squark masses in the range 235-590 GeV are excluded.

540 data tables

Distribution of $E_\text{T}^\text{miss}$ for SRA-TT after the likelihood fit. The stacked histograms show the SM expectation and the hatched uncertainty band around the SM expectation shows the MC statistical and detector-related systematic uncertainties. A representative signal point is shown for each distribution.

Distribution of $E_\text{T}^\text{miss}$ for SRA-TT after the likelihood fit. The stacked histograms show the SM expectation and the hatched uncertainty band around the SM expectation shows the MC statistical and detector-related systematic uncertainties. A representative signal point is shown for each distribution.

Distribution of $E_\text{T}^\text{miss}$ for SRA-TT after the likelihood fit. The stacked histograms show the SM expectation and the hatched uncertainty band around the SM expectation shows the MC statistical and detector-related systematic uncertainties. A representative signal point is shown for each distribution.

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Version 5
Search for long-lived charginos based on a disappearing-track signature in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 06 (2018) 022, 2018.
Inspire Record 1641262 DOI 10.17182/hepdata.78375

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 $\mathrm{fb}^{-1}$ 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.

188 data tables

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

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

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

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Version 2
Search for heavy charged long-lived particles in the ATLAS detector in 31.6 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} = 13$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 092007, 2019.
Inspire Record 1718558 DOI 10.17182/hepdata.86565

A search for heavy charged long-lived particles is performed using a data sample of 36.1 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} = 13$ TeV collected by the ATLAS experiment at the Large Hadron Collider. The search is based on observables related to ionization energy loss and time of flight, which are sensitive to the velocity of heavy charged particles traveling significantly slower than the speed of light. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined as model-independently as possible, by referencing several representative physics cases that yield long-lived particles within supersymmetric models, such as gluinos/squarks ($R$-hadrons), charginos and staus. No significant deviations from the expected Standard Model background are observed. Upper limits at 95% confidence level are provided on the production cross sections of long-lived $R$-hadrons as well as directly pair-produced staus and charginos. These results translate into lower limits on the masses of long-lived gluino, sbottom and stop $R$-hadrons, as well as staus and charginos of 2000 GeV, 1250 GeV, 1340 GeV, 430 GeV and 1090 GeV, respectively.

30 data tables

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Lower mass requirement for signal regions.</b> <ul> <li><a href="86565?version=1&table=Table1">Gluinos and squarks</a></li> <li><a href="86565?version=1&table=Table2">Staus and charginos</a></li> </ul> <b>Discovery regions:</b> <ul> <li><a href="86565?version=1&table=Table3">Yields</a></li> <li><a href="86565?version=1&table=Table6">p0-values and limits</a></li> </ul> <b>Signal yield tables:</b> <ul> <li><a href="86565?version=1&table=Table4">MS-agnostic R-hadron search</a></li> <li><a href="86565?version=1&table=Table5">Full-detector R-hadron search</a></li> <li><a href="86565?version=1&table=Table7">MS-agnostic search for metastable gluino R-hadrons</a></li> <li><a href="86565?version=1&table=Table8">Full-detector direct-stau search</a></li> <li><a href="86565?version=1&table=Table9">Full-detector chargino search</a></li> </ul> <b>Limits:</b> <ul> <li><a href="86565?version=1&table=Table10">Gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table11">Sbottom R-hadron search</a></li> <li><a href="86565?version=1&table=Table12">Stop R-hadron search</a></li> <li><a href="86565?version=1&table=Table13">Stau search</a></li> <li><a href="86565?version=1&table=Table14">Chargino search</a></li> <li><a href="86565?version=1&table=Table15">Meta-stable gluino R-hadron search</a></li> <li><a href="86565?version=1&table=Table17">Meta-stable gluino R-hadron search</a></li> </ul> <b>Acceptance and efficiency:</b> <ul> <li><a href="86565?version=1&table=Table16">MS-agnostic R-hadron search</a></li> </ul> <b>Truth quantities:</b> <ul> <li><a href="86565?version=1&table=Table18">Flavor composition of 800 GeV stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table19">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the generic model</a></li> <li><a href="86565?version=1&table=Table20">Flavor composition of 800 GeV stop R-hadrons simulated using the Regge model</a></li> <li><a href="86565?version=1&table=Table21">Flavor composition of 800 GeV anti-stop R-hadrons simulated using the Regge model</a></li> </ul> <b>Reinterpretation material:</b> <ul> <li><a href="86565?version=1&table=Table22">ETmiss trigger efficiency as function of true ETmiss</a></li> <li><a href="86565?version=1&table=Table23">Single-muon trigger efficiency as function of |eta| and beta</a></li> <li><a href="86565?version=1&table=Table24">Candidate reconstruction efficiency for ID+Calo selection</a></li> <li><a href="86565?version=1&table=Table25">Candidate reconstruction efficiency for loose selection</a></li> <li><a href="86565?version=1&table=Table26">Efficiency for a loose candidate to be promoted to a tight candidate</a></li> <li><a href="86565?version=1&table=Table27">Resolution and average of reconstructed dE/dx mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table28">Resolution and average of reconstructed ToF mass for a given simulated mass for ID+calo candidates</a></li> <li><a href="86565?version=1&table=Table29">Resolution and average of reconstructed ToF mass for a given simulated mass for FullDet candidates</a></li> </ul> <p><b>Pseudo-code snippets</b> and <b>example SLHA setups</b> are available in the "Resources" linked on the left, and more detailed reinterpretation material is available at <a href="http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf">http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-32/hepdata_info.pdf</a>.</p>

Lower mass requirement for signal regions.

Lower mass requirement for signal regions.

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Version 4
Search for direct production of electroweakinos in final states with one lepton, missing transverse momentum and a Higgs boson decaying into two $b$-jets in (pp) collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 80 (2020) 691, 2020.
Inspire Record 1755298 DOI 10.17182/hepdata.90607

The results of a search for electroweakino pair production $pp \rightarrow \tilde\chi^\pm_1 \tilde\chi^0_2$ in which the chargino ($\tilde\chi^\pm_1$) decays into a $W$ boson and the lightest neutralino ($\tilde\chi^0_1$), while the heavier neutralino ($\tilde\chi^0_2$) decays into the Standard Model 125 GeV Higgs boson and a second $\tilde\chi^0_1$ are presented. The signal selection requires a pair of $b$-tagged jets consistent with those from a Higgs boson decay, and either an electron or a muon from the $W$ boson decay, together with missing transverse momentum from the corresponding neutrino and the stable neutralinos. The analysis is based on data corresponding to 139 $\mathrm{fb}^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. No statistically significant evidence of an excess of events above the Standard Model expectation is found. Limits are set on the direct production of the electroweakinos in simplified models, assuming pure wino cross-sections. Masses of $\tilde{\chi}^{\pm}_{1}/\tilde{\chi}^{0}_{2}$ up to 740 GeV are excluded at 95% confidence level for a massless $\tilde{\chi}^{0}_{1}$.

159 data tables

The post-fit $m_{CT}$ distribution is shown in the validation region VR-onLM after all the selection requirements are applied other than the $m_{CT}$ cut. The stacked histograms show the expected SM backgrounds. The hatched bands represent the sum in quadrature of systematic and statistical uncertainties of the total SM background. The red line with arrow indicates the $m_{CT}$ cut used in SR selection. The first and the last bin include the underflow and overflow events (where present), respectively.

The post-fit $m_{CT}$ distribution is shown in the validation region VR-onLM after all the selection requirements are applied other than the $m_{CT}$ cut. The stacked histograms show the expected SM backgrounds. The hatched bands represent the sum in quadrature of systematic and statistical uncertainties of the total SM background. The red line with arrow indicates the $m_{CT}$ cut used in SR selection. The first and the last bin include the underflow and overflow events (where present), respectively.

The post-fit $m_{CT}$ distribution is shown in the validation region VR-onLM after all the selection requirements are applied other than the $m_{CT}$ cut. The stacked histograms show the expected SM backgrounds. The hatched bands represent the sum in quadrature of systematic and statistical uncertainties of the total SM background. The red line with arrow indicates the $m_{CT}$ cut used in SR selection. The first and the last bin include the underflow and overflow events (where present), respectively.

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Version 2
Search for a scalar partner of the top quark in the all-hadronic $t\bar{t}$ plus missing transverse momentum final state at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 80 (2020) 737, 2020.
Inspire Record 1793461 DOI 10.17182/hepdata.93906

A search for direct pair production of scalar partners of the top quark (top squarks or scalar third-generation up-type leptoquarks) in the all-hadronic $t\bar{t}$ plus missing transverse momentum final state is presented. The analysis of 139 fb$^{-1}$ of ${\sqrt{s}=13}$ TeV proton-proton collision data collected using the ATLAS detector at the LHC yields no significant excess over the Standard Model background expectation. To interpret the results, a supersymmetric model is used where the top squark decays via $\tilde{t} \to t^{(*)} \tilde{\chi}^0_1$, with $t^{(*)}$ denoting an on-shell (off-shell) top quark and $\tilde{\chi}^0_1$ the lightest neutralino. Three specific event selections are optimised for the following scenarios. In the scenario where $m_{\tilde{t}}> m_t+m_{\tilde{\chi}^0_1}$, top squark masses are excluded in the range 400-1250 GeV for $\tilde{\chi}^0_1$ masses below $200$ GeV at 95 % confidence level. In the situation where $m_{\tilde{t}}\sim m_t+m_{\tilde{\chi}^0_1}$, top squark masses in the range 300-630 GeV are excluded, while in the case where $m_{\tilde{t}}< m_W+m_b+m_{\tilde{\chi}^0_1}$ (with $m_{\tilde{t}}-m_{\tilde{\chi}^0_1}\ge 5$ GeV), considered for the first time in an ATLAS all-hadronic search, top squark masses in the range 300-660 GeV are excluded. Limits are also set for scalar third-generation up-type leptoquarks, excluding leptoquarks with masses below $1240$ GeV when considering only leptoquark decays into a top quark and a neutrino.

59 data tables

<b>- - - - - - - - Overview of HEPData Record - - - - - - - -</b> <br><br> <b>Exclusion contours:</b> <ul> <li><a href="?table=stop_obs">Stop exclusion contour (Obs.)</a> <li><a href="?table=stop_obs_down">Stop exclusion contour (Obs. Down)</a> <li><a href="?table=stop_obs_up">Stop exclusion contour (Obs. Up)</a> <li><a href="?table=stop_exp">Stop exclusion contour (Exp.)</a> <li><a href="?table=stop_exp_down">Stop exclusion contour (Exp. Down)</a> <li><a href="?table=stop_exp_up">Stop exclusion contour (Exp. Up)</a> <li><a href="?table=LQ3u_obs">LQ3u exclusion contour (Obs.)</a> <li><a href="?table=LQ3u_obs_down">LQ3u exclusion contour (Obs. Down)</a> <li><a href="?table=LQ3u_obs_up">LQ3u exclusion contour (Obs. Up)</a> <li><a href="?table=LQ3u_exp">LQ3u exclusion contour (Exp.)</a> <li><a href="?table=LQ3u_exp_down">LQ3u exclusion contour (Exp. Down)</a> <li><a href="?table=LQ3u_exp_up">LQ3u exclusion contour (Exp. Up)</a> </ul> <b>Upper limits:</b> <ul> <li><a href="?table=stop_xSecUpperLimit_obs">stop_xSecUpperLimit_obs</a> <li><a href="?table=stop_xSecUpperLimit_exp">stop_xSecUpperLimit_exp</a> <li><a href="?table=LQ3u_xSecUpperLimit_obs">LQ3u_xSecUpperLimit_obs</a> <li><a href="?table=LQ3u_xSecUpperLimit_exp">LQ3u_xSecUpperLimit_exp</a> </ul> <b>Kinematic distributions:</b> <ul> <li><a href="?table=SRATW_metsigST">SRATW_metsigST</a> <li><a href="?table=SRBTT_m_1fatjet_kt12">SRBTT_m_1fatjet_kt12</a> <li><a href="?table=SRC_RISR">SRC_RISR</a> <li><a href="?table=SRD0_htSig">SRD0_htSig</a> <li><a href="?table=SRD1_htSig">SRD1_htSig</a> <li><a href="?table=SRD2_htSig">SRD2_htSig</a> </ul> <b>Cut flows:</b> <ul> <li><a href="?table=cutflow_SRATT">cutflow_SRATT</a> <li><a href="?table=cutflow_SRATW">cutflow_SRATW</a> <li><a href="?table=cutflow_SRAT0">cutflow_SRAT0</a> <li><a href="?table=cutflow_SRB">cutflow_SRB</a> <li><a href="?table=cutflow_SRC">cutflow_SRC</a> <li><a href="?table=cutflow_SRD0">cutflow_SRD0</a> <li><a href="?table=cutflow_SRD1">cutflow_SRD1</a> <li><a href="?table=cutflow_SRD2">cutflow_SRD2</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>SRATT:</b> <a href="?table=Acc_SRATT">Acc_SRATT</a> <a href="?table=Eff_SRATT">Eff_SRATT</a> <li> <b>SRATW:</b> <a href="?table=Acc_SRATW">Acc_SRATW</a> <a href="?table=Eff_SRATW">Eff_SRATW</a> <li> <b>SRAT0:</b> <a href="?table=Acc_SRAT0">Acc_SRAT0</a> <a href="?table=Eff_SRAT0">Eff_SRAT0</a> <li> <b>SRBTT:</b> <a href="?table=Acc_SRBTT">Acc_SRBTT</a> <a href="?table=Eff_SRBTT">Eff_SRBTT</a> <li> <b>SRBTW:</b> <a href="?table=Acc_SRBTW">Acc_SRBTW</a> <a href="?table=Eff_SRBTW">Eff_SRBTW</a> <li> <b>SRBT0:</b> <a href="?table=Acc_SRBT0">Acc_SRBT0</a> <a href="?table=Eff_SRBT0">Eff_SRBT0</a> <li> <b>SRC1:</b> <a href="?table=Acc_SRC1">Acc_SRC1</a> <a href="?table=Eff_SRC1">Eff_SRC1</a> <li> <b>SRC2:</b> <a href="?table=Acc_SRC2">Acc_SRC2</a> <a href="?table=Eff_SRC2">Eff_SRC2</a> <li> <b>SRC3:</b> <a href="?table=Acc_SRC3">Acc_SRC3</a> <a href="?table=Eff_SRC3">Eff_SRC3</a> <li> <b>SRC4:</b> <a href="?table=Acc_SRC4">Acc_SRC4</a> <a href="?table=Eff_SRC4">Eff_SRC4</a> <li> <b>SRC5:</b> <a href="?table=Acc_SRC5">Acc_SRC5</a> <a href="?table=Eff_SRC5">Eff_SRC5</a> <li> <b>SRD0:</b> <a href="?table=Acc_SRD0">Acc_SRD0</a> <a href="?table=Eff_SRD0">Eff_SRD0</a> <li> <b>SRD1:</b> <a href="?table=Acc_SRD1">Acc_SRD1</a> <a href="?table=Eff_SRD1">Eff_SRD1</a> <li> <b>SRD2:</b> <a href="?table=Acc_SRD2">Acc_SRD2</a> <a href="?table=Eff_SRD2">Eff_SRD2</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 $\it{m}_{\tilde{\chi}^{0}_{1}}$ vs. $\it{m}_{\tilde{t}}$. Masses that are within the contours are excluded.

The expected exclusion contour at 95% CL as a function of the $\it{m}_{\tilde{\chi}^{0}_{1}}$ vs. $\it{m}_{\tilde{t}}$. Masses that are within the contour are excluded.

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Search for new phenomena in final states with large jet multiplicities and missing transverse momentum using $\sqrt(s) = 13$ TeV proton$-$proton collisions recorded by ATLAS in Run 2 of the LHC

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 10 (2020) 062, 2020.
Inspire Record 1811596 DOI 10.17182/hepdata.93733

Results of a search for new particles decaying into eight or more jets and moderate missing transverse momentum are presented. The analysis uses 139 fb$^{-1}$ of proton$-$proton collision data at $\sqrt{s} = 13$ TeV collected by the ATLAS experiment at the Large Hadron Collider between 2015 and 2018. The selection rejects events containing isolated electrons or muons, and makes requirements according to the number of $b$-tagged jets and the scalar sum of masses of large-radius jets. The search extends previous analyses both in using a larger dataset and by employing improved jet and missing transverse momentum reconstruction methods which more cleanly separate signal from background processes. No evidence for physics beyond the Standard Model is found. The results are interpreted in the context of supersymmetry-inspired simplified models, significantly extending the limits on the gluino mass in those models. In particular, limits on the gluino mass are set at 2 TeV when the lightest neutralino is nearly massless in a model assuming a two-step cascade decay via the lightest chargino and second-lightest neutralino.

0 data tables

Search for phenomena beyond the Standard Model in events with large $b$-jet multiplicity using the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 81 (2021) 11, 2021.
Inspire Record 1821239 DOI 10.17182/hepdata.95683

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.

0 data tables

Search for new phenomena in events with two opposite-charge leptons, jets and missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
JHEP 04 (2021) 165, 2021.
Inspire Record 1844425 DOI 10.17182/hepdata.98627

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.

0 data tables

Search for bottom-squark pair production in $pp$ collision events at $\sqrt{s} = 13$ TeV with hadronically decaying $\tau$-leptons, $b$-jets and missing transverse momentum using the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Brad ; et al.
Phys.Rev.D 104 (2021) 032014, 2021.
Inspire Record 1851675 DOI 10.17182/hepdata.99788

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.

0 data tables