Search for top squarks in events with a Higgs or $Z$ boson using 139 fb${}^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV with the ATLAS detector

Abstract

This paper presents a search for direct top squark pair production in events with missing transverse momentum plus either a pair of jets consistent with Standard Model Higgs boson decay into $b$-quarks or a same-flavour opposite-sign dilepton pair with an invariant mass consistent with a $Z$ boson. The analysis is performed using the proton-proton collision data at $\sqrt{s}=13$ TeV collected with the ATLAS detector during the LHC Run-2, corresponding to an integrated luminosity of 139 fb${}^{-1}$. No excess is observed in the data above the Standard Model predictions. The results are interpreted in simplified models featuring direct production of pairs of either the lighter top squark (${\tilde{t}}_1$) or the heavier top squark (${\tilde{t}}_2$), excluding at 95% confidence level ${\tilde{t}}_1$ and ${\tilde{t}}_2$ masses up to about 1220 and 875 GeV, respectively.

48 pages in total, author list starting page 32, 12 figures, 12 tables, published in Eur. Phys. J. C. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2018-21

References in corpus (19)

• PyTorch: An Imperative Style, High-Performance Deep Learning Library
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• Parton distributions for the LHC
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Event generation with SHERPA 1.1
• Two-loop soft anomalous dimensions for single top quark associated production with a W- or H-
• Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
• Next-to-next-to-leading-order collinear and soft gluon corrections for t-channel single top quark production
• NNLL resummation for s-channel single top quark production
• Luminosity determination in pp collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector at the LHC
• Simplified Models for a First Characterization of New Physics at the LHC
• HistFitter software framework for statistical data analysis
• Evaluation of three methods for calculating statistical significance when incorporating a systematic uncertainty into a test of the background-only hypothesis for a Poisson process
• Searching for Directly Decaying Gluinos at the Tevatron
• NNLL-fast: predictions for coloured supersymmetric particle production at the LHC with threshold and Coulomb resummation
• Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at sqrt(s) = 8 TeV
• Search for direct top squark pair production in events with a Z boson, b-jets and missing transverse momentum in sqrt(s)=8 TeV pp collisions with the ATLAS detector
• Search for direct top squark pair production in events with a Higgs or $Z$ boson, and missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector

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• The quest to discover supersymmetry at the ATLAS experiment
• Status of searches for electroweak-scale supersymmetry after LHC Run 2
• Probing mild-tempered neutralino dark matter through top-squark production at the LHC
• The Hierarchy Problem and the Top Yukawa: An Alternative to Top Partner Solutions
• Portable acceleration of CMS computing workflows with coprocessors as a service
• Naturalness-motivated composite Higgs model for generating the top Yukawa coupling
• Light Higgsinos for electroweak naturalness in mirage-mediated high-scale supersymmetry
• Triplet fermion WIMP dark matter in the general supersymmetric Georgi-Machacek model
• Implementation of full and simplified likelihoods in CheckMATE