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

Abstract

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.

arXiv comment49 pages in total, author list starting page 33, 10 figures, 10 tables, submitted to JHEP. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2018-17

References in corpus (62)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The anti-k_t jet clustering algorithm
• An Introduction to PYTHIA 8.2
• A Brief Introduction to PYTHIA 8.1
• FastJet user manual
• Asymptotic formulae for likelihood-based tests of new physics
• A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX
• A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Parton distributions for the LHC Run II
• Event generation with SHERPA 1.1
• Herwig++ Physics and Manual
• Parton distributions with LHC data
• The ATLAS Simulation Infrastructure
• PDF4LHC recommendations for LHC Run II
• Parton distributions in the LHC era: MMHT 2014 PDFs
• Scattering Amplitudes with Open Loops
• Top++: a program for the calculation of the top-pair cross-section at hadron colliders
• Herwig 7.0 / Herwig++ 3.0 Release Note
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• Comix, a new matrix element generator
• Performance of the ATLAS Trigger System in 2015
• Single-top Wt-channel production matched with parton showers using the POWHEG method
• Two-loop soft anomalous dimensions for single top quark associated production with a W- or H-
• QCD matrix elements and truncated showers
• -- HATHOR -- HAdronic Top and Heavy quarks crOss section calculatoR
• Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
• Single-top hadroproduction in association with a W boson
• Muon reconstruction performance of the ATLAS detector in proton--proton collision data at $\sqrt{s}$=13 TeV
• NLO single-top production matched with shower in POWHEG: s- and t-channel contributions
• Production and Integration of the ATLAS Insertable B-Layer
• Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1
• Performance of pile-up mitigation techniques for jets in $pp$ collisions at $\sqrt{s}=8$ TeV using the ATLAS detector
• Improved luminosity determination in pp collisions at sqrt(s) = 7 TeV using the ATLAS detector at the LHC
• Electron and photon performance measurements with the ATLAS detector using the 2015-2017 LHC proton-proton collision data
• Squark and Gluino Production at Hadron Colliders
• Threshold resummation for squark-antisquark and gluino-pair production at the LHC
• ATLAS $b$-jet identification performance and efficiency measurement with $t\bar{t}$ events in $pp$ collisions at $\sqrt{s}=13$ TeV
• Jet reconstruction and performance using particle flow with the ATLAS Detector
• Soft gluon resummation for the production of gluino-gluino and squark-antisquark pairs at the LHC
• Soft-gluon resummation for squark and gluino hadroproduction
• HATHOR for single top-quark production: Updated predictions and uncertainty estimates for single top-quark production in hadronic collisions
• ATLAS data quality operations and performance for 2015-2018 data-taking
• Correcting the Colour-Dipole Cascade Model with Fixed Order Matrix Elements
• Performance of missing transverse momentum reconstruction with the ATLAS detector using proton-proton collisions at $\sqrt{s}$ = 13 TeV
• NLO matrix elements and truncated showers
• HistFitter software framework for statistical data analysis
• Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data
• Angular correlations of lepton pairs from vector boson and top quark decays in Monte Carlo simulations
• Hadronic top-quark pair-production with one jet and parton showering
• NNLL-fast: predictions for coloured supersymmetric particle production at the LHC with threshold and Coulomb resummation
• Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at sqrt(s)=8 TeV proton-proton collisions using the ATLAS experiment
• An Introduction to Explicit R-Parity Violation
• Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb^-1 of sqrt(s) = 7 TeV proton-proton collisions
• Search for new phenomena in final states with large jet multiplicities and missing transverse momentum using sqrt(s)=7 TeV pp collisions with the ATLAS detector
• NNLL resummation for squark and gluino production at the LHC
• Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run
• NNLL resummation for squark-antisquark pair production at the LHC
• Towards NNLL resummation: hard matching coefficients for squark and gluino hadroproduction
• Jet Substructure by Accident
• Search for new phenomena in final states with large jet multiplicities and missing transverse momentum with ATLAS using $\sqrt{s}=13$ TeV proton--proton collisions
• Search for new phenomena with large jet multiplicities and missing transverse momentum using large-radius jets and flavour-tagging at ATLAS in 13 TeV $pp$ collisions

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• ABCDisCo: Automating the ABCD Method with Machine Learning
• Unveiling Hidden Physics at the LHC
• Sound speed resonance of the stochastic gravitational wave background
• Search for supersymmetry in final states with missing transverse momentum and three or more $b$-jets in 139 fb${}^{-1}$ of proton$-$proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
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• Prospects of Gluino searches in multi-lepton channels in the light of ongoing LHC RUN-III
• Electric dipole moments from the perspective of a scalar triplet and singlet extension of the MSSM: A study of neutrons, electrons, mercury, and b and c quarks
• Revisiting the gluino mass limits in the pMSSM in the light of the latest LHC data and Dark Matter constraints
• Vacuum Stability Constraints on Flavor Mixing Parameters and Their Effect on Gluino Decays
• Search for squarks and gluinos in $pp$ collisions at $\sqrt{s}=13$ TeV and $13.6$ TeV in events with $\tau$-leptons, jets and missing transverse momentum using the ATLAS detector