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Tests of quantum contextuality in particle physics

M. Fabbrichesi ¹, R. Floreanini¹, E. Gabrielli ^2,1,3, and L. Marzola ^3,4

¹INFN, Sezione di Trieste, Via Valerio 2, I-34127 Trieste, Italy
²Physics Department, University of Trieste, Strada Costiera 11, I-34151 Trieste, Italy
³Laboratory of High-Energy and Computational Physics, NICPB, Rävala 10, 10143 Tallinn, Estonia
⁴Institute of Computer Science, University of Tartu, Narva mnt 18, 51009 Tartu, Estonia

Phys. Rev. D 112, 033005 – Published 19 August, 2025

DOI: https://doi.org/10.1103/22zl-ltxm

Abstract

Quantum contextuality refers to the impossibility of assigning a predefined, intrinsic value to a physical property of a system independently of the context in which the property is measured. It is, perhaps, the most fundamental feature of quantum mechanics. The many states with different spin that particle physics provides are the ideal setting for testing contextuality. We verify that the polarization states of single spin-1 massive particles produced at colliders are contextual. We test $W^{+}$ gauge bosons produced in top-quark decays, $J / ψ$ and $K^{*} (892)^{0}$ mesons in $B$ -meson decays and $ϕ$ mesons in $χ_{c}^{0}$ and $χ_{c}^{1}$ charmonium decays by reinterpreting the data and the analyses of the ATLAS, LHCb, Belle II and BESIII experimental collaborations, respectively. The polarization states of these four particles show contextuality with a significance larger than $5 σ$ . We also discuss the presence of quantum contextuality in spin states of bipartite systems formed by spin- $1 / 2$ particles. We test $Λ$ and $Σ$ baryons reinterpreting two BESIII data analyses, and pairs of top quarks utilizing a recent analysis of the CMS Collaboration. Quantum contextuality is present with a significance exceeding $5 σ$ also in these cases. In addition, we study the feasibility of testing quantum contextuality by means of $Z$ boson production in association with the Higgs boson, $Z$ and $W$ bosons pairs created in Higgs boson decays and with pairs of $τ$ leptons. For the latter, we use Monte Carlo simulations that mimic the settings of SuperKEKB and of future lepton colliders. Experiments at high energies, though not designed for the purpose, perform surprisingly well in testing for quantum contextuality.

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References (82)

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Phys. Rev. D 112, 033005– Published 19 August, 2025

Vol. 112, Iss. 3 — 1 August 2025

Received 30 April 2025
Accepted 29 July 2025

DOI: https://doi.org/10.1103/22zl-ltxm

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Tests of quantum contextuality in particle physics

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