% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Aad:599171,
      author       = {Aad, Georges and others},
      collaboration = {{ATLAS Collaboration}},
      title        = {{O}bservation of quantum entanglement in top-quark pairs
                      using the {ATLAS} detector},
      reportid     = {PUBDB-2023-07195, arXiv:2311.07288. CERN-EP-2023-230},
      year         = {2023},
      note         = {45 pages in total, author list starting page 28, 4 figures,
                      2 tables, submitted to Nature. All figures including
                      auxiliary figures are available at
                      http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2021-24},
      abstract     = {We report the highest-energy observation of entanglement,
                      in top$-$antitop quark events produced at the Large Hadron
                      Collider, using a proton$-$proton collision data set with a
                      center-of-mass energy of $\sqrt{s}=13$ TeV and an integrated
                      luminosity of 140 fb$^{-1}$ recorded with the ATLAS
                      experiment. Spin entanglement is detected from the
                      measurement of a single observable $D$, inferred from the
                      angle between the charged leptons in their parent top- and
                      antitop-quark rest frames. The observable is measured in a
                      narrow interval around the top$-$antitop quark production
                      threshold, where the entanglement detection is expected to
                      be significant. It is reported in a fiducial phase space
                      defined with stable particles to minimize the uncertainties
                      that stem from limitations of the Monte Carlo event
                      generators and the parton shower model in modelling
                      top-quark pair production. The entanglement marker is
                      measured to be $D=-0.547 \pm 0.002~\text{(stat.)} \pm
                      0.021~\text{(syst.)}$ for $340 < m_{t\bar{t}} < 380 $ GeV.
                      The observed result is more than five standard deviations
                      from a scenario without entanglement and hence constitutes
                      both the first observation of entanglement in a pair of
                      quarks and the highest-energy observation of entanglement to
                      date.},
      keywords     = {top, pair production (INSPIRE) / particle, stability
                      (INSPIRE) / parton, showers (INSPIRE) / threshold,
                      production (INSPIRE) / quark, pair (INSPIRE) / quark,
                      production (INSPIRE) / entanglement, quantum (INSPIRE) /
                      anti-top (INSPIRE) / ATLAS (INSPIRE) / Monte Carlo (INSPIRE)
                      / GeV (INSPIRE) / spin (INSPIRE) / lepton (INSPIRE) / CERN
                      LHC Coll (INSPIRE) / phase space (INSPIRE) / TeV (INSPIRE)},
      cin          = {ATLAS},
      cid          = {I:(DE-H253)ATLAS-20120731},
      pnm          = {611 - Fundamental Particles and Forces (POF4-611)},
      pid          = {G:(DE-HGF)POF4-611},
      experiment   = {EXP:(DE-H253)LHC-Exp-ATLAS-20150101},
      typ          = {PUB:(DE-HGF)25},
      eprint       = {2311.07288},
      howpublished = {arXiv:2311.07288},
      archivePrefix = {arXiv},
      SLACcitation = {$\%\%CITATION$ = $arXiv:2311.07288;\%\%$},
      doi          = {10.3204/PUBDB-2023-07195},
      url          = {https://bib-pubdb1.desy.de/record/599171},
}