Observation of quantum entanglement in top-quark pairs using the ATLAS detector

The ATLAS Collaboration, et al. (2023) Observation of quantum entanglement in top-quark pairs using the ATLAS detector. arXiv, (doi: 10.48550/arXiv.2311.07288) (Unpublished)

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 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±0.002 (stat.)±0.021 (syst.) for 340<mtt¯<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.

• Item Type: Articles
• Status: Unpublished
• Refereed: No
• Glasgow Author(s) Enlighten ID: Robson, Professor Aidan and Warrack, Neil and Howarth, Dr James and Mince, Mr Laurynas and Borbely, Mr Albert and Watton, Mr Elliot and Blue, Dr Andrew and Procter, Mr Tomasz and Doyle, Professor Anthony and Miralles Lopez, Mr Marcos and Bates, Dr Richard and Callea, Dr Giuseppe and Simpson, Mr Ethan and Buckley, Professor Andy and Connelly, Dr Ian and O'Shea, Professor Val and Owen, Professor Mark and Watson, Ms Harriet and Spiteri, Dr Dwayne and Friend, Mr Johnny and Jamieson, Dr Jonathan and Cunningham, Dr Liam and Bussey, Dr Peter and Fabbri, Dr Federica and Buttar, Professor Craig and Wraight, Dr Kenneth and Britton, Professor David and Rozario, Mr Zefran and Fenton, Mr Michael
• Authors: The ATLAS Collaboration, , Bates, R. L., Blue, A., Borbely, A., Britton, D., Buckley, A. G., Bussey, P. J., Buttar, C. M., Callea, G., Connelly, I. A., Cunningham, W. R., Doyle, A. T., Fabbri, F., Fenton, M. J., Friend, J., Howarth, J., Jamieson, J., Mince, L., Miralles Lopez, M., O'Shea, V., Owen, M., Procter, T., Robson, A., Rozario, Z. M.A., Simpson, E. L., Spiteri, D. P., Warrack, N., Watson, H., Watton, E., and Wraight, K.
• College/School: College of Science and Engineering; College of Science and Engineering > School of Physics and Astronomy
• Journal Name: arXiv
• Published Online: 13 November 2023
• Copyright Holders: Copyright © 2023 CERN for the benefit of the ATLAS Collaboration
• Publisher Policy: Reproduced under a Creative Commons License

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