Observation of quantum entanglement in top quark pair production in proton-proton collisions at √ s = 13 TeV
- Author(s)
- , André H. Hoang
- Abstract
Entanglement is an intrinsic property of quantum mechanics and is predicted to be exhibited in the particles produced at the Large Hadron Collider. A measurement of the extent of entanglement in top quark-antiquark ( t t ¯ ) events produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed with the data recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 36.3 fb−1. The events are selected based on the presence of two leptons with opposite charges and high transverse momentum. An entanglement-sensitive observable D is derived from the top quark spin-dependent parts of the t t ¯ production density matrix and measured in the region of the t t ¯ production threshold. Values of D < − 1 / 3 are evidence of entanglement and D is observed (expected) to be − 0.480 − 0.029 + 0.026 ( − 0.467 − 0.029 + 0.026 ) at the parton level. With an observed significance of 5.1 standard deviations with respect to the non-entangled hypothesis, this provides observation of quantum mechanical entanglement within t t ¯ pairs in this phase space. This measurement provides a new probe of quantum mechanics at the highest energies ever produced.
- Organisation(s)
- Particle Physics
- External organisation(s)
- Österreichische Akademie der Wissenschaften (ÖAW)
- Journal
- Reports on Progress in Physics
- Volume
- 87
- No. of pages
- 33
- ISSN
- 0034-4885
- DOI
- https://doi.org/10.48550/arXiv.2406.03976
- Publication date
- 11-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103025 Quantum mechanics, 103012 High energy physics
- Keywords
- ASJC Scopus subject areas
- General Physics and Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/8c47c788-0967-45ea-986e-65f910a6dc75