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Статья

Aad, G.
Observation of Quantum Entanglement with Top Quarks at the ATLAS Detector / G.Aad, F.Ahmadov, I.N.Aleksandrov, V.A.Bednyakov, I.R.Boyko, G.Chelkov, A.Cheplakov, M.V.Chizhov, D.V.Dedovich, M.Demichev, M.I.Gostkin, S.N.Karpov, Z.M.Karpova, U.Kruchonak, V.Kukhtin, E.Ladygin, V.Lyubushkin, T.Lyubushkina, S.Malyukov, M.Mineev, E.Plotnikova, I.N.Potrap, N.A.Rusakovich, M.Shiyakova, A.Soloshenko, T.Turtuvshin, A.Vasyukov, I.Yeletskikh, A.Zhemchugov, N.I.Zimine, Y.Kulchitsky, [ATLAS Collab.] // Nature [Electronic resource]. – 2024. – Vol. 633, No. 8030. – P. 542-547. – URL: https://doi.org/10.1038/s41586-024-07824-z. – Bibliogr.: 120.

Entanglement is a key feature of quantum mechanics1–3 , with applications in fields such as metrology, cryptography, quantum information and quantum computation4–8 . It has been observed in a wide variety of systems and length scales, ranging from the microscopic9–13 to the macroscopic14–16 . However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top–antitop quark events produced at the Large Hadron Collider, using a proton–proton collision dataset with a centre-of- mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (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, at which 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 the 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 = −0.537 ± 0.002 (stat.) ± 0.019 (syst.) for m340 GeV < < 380 GeVtt . The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 346.2в - Взаимодействие протонов с протонами
Спец.(статьи,препринты) = С 346.6д1 - Чармоний, боттомоний, топ-кварк. Очарованные частицы и др. резонансы из тяжелых кварков