Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. D/Physical review. D.

Bell inequality is violated in B0→J/ψK*(892)0 decays

Marco E. Fabbrichesi, Roberto Floreanini B, Emidio Gabrielli A, Luca Marzola

Published Feb 23, 2024• 28 citations
Publisher

Abstract

The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb Collaboration on the helicity amplitudes for the decay B0→J/ψK*(892)0 to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above 5σ (nominally 84σ ) and Bell inequality is violated with a significance well above 5σ (nominally 36σ )—thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the B mesons into vector mesons, but with lesser significance. Published by the American Physical Society 2024

DOI
10.1103/physrevd.109.l031104

Related papers

Bell inequality is violated in $B^0\to J/ψ\, K^{\star}(892)^0$ decays

Marco E. Fabbrichesi, Roberto Floreanini B, Emidio Gabrielli A +1 more

The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb collaboration on the helicity amplitudes for the decay $B^0\to J/ψ\,K^*(892)^0$ to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above 5$σ$ (nominally 84$σ$) and Bell inequality is violated with a significance well above 5$σ$ (nominally 36$σ$) -- thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the $B$ mesons into vector mesons, but with lesser significance.

arXiv:2305.04982•May 8, 2023•0 citations

Entanglement and Bell Inequality Violation in B → ϕϕ Decays

Emidio Gabrielli A, Luca Marzola

The decays of the B meson into vector mesons, observed during the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of ϕ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allow access to entanglement and to the Bell inequality violation with a significance exceeding the 5σ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the B meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test.

Symmetry•Aug 13, 2024•15 citations

Entanglement and Bell inequality violation in $B\to \it{ΦΦ}$ decays

Emidio Gabrielli A, Luca Marzola

The decays of the $B$ meson into vector mesons, observed at the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of $\itΦ$ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allows access to entanglement and to the Bell inequality violation with a significance exceeding the 5$σ$ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the $B$ meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test.

arXiv:2408.05010•Aug 9, 2024•0 citations

Bell inequality is violated in charmonium decays

Marco E. Fabbrichesi, Roberto Floreanini B, Emidio Gabrielli A +1 more

The experimental data on the helicity amplitudes of charmonium decays allow us to measure entanglement in final state spin correlations and test possible violations of the Bell inequality. We find that the Bell inequality is violated with a significance of 5 σ or more in the decays η c , χ c 0 , J / ψ → Λ + Λ ¯ , J / ψ → Ξ − + Ξ ¯ + , Ξ 0 + Ξ ¯ 0 , Σ − + Σ ¯ + , Σ 0 + Σ ¯ 0 , ψ ( 3686 ) → Ξ − + Ξ ¯ + , Σ − + Σ ¯ + , Σ 0 + Σ ¯

arXiv:2406.17772•Physical review. D/Physical review. D.•Sep 23, 2024•27 citations

Quantum entanglement and Bell inequality violation at colliders

Alan J. Barr, Marco E. Fabbrichesi, Roberto Floreanini B +2 more

The study of entanglement in particle physics has been gathering pace in the past few years. It is a new field that is providing important results about the possibility of detecting entanglement and testing Bell inequality at colliders for final states as diverse as top-quark, τ-lepton pairs and Λ-baryons, massive gauge bosons and vector mesons. In this review, after presenting definitions, tools and basic results that are necessary for understanding these developments, we summarize the main findings—as published by the beginning of year 2024—including analyses of experimental data in B meson decays and top-quark pair production. We include a detailed discussion of the results for both qubit and qutrits systems, that is, final states containing spin one-half and spin one particles. Entanglement has also been proposed as a new tool to constrain new particles and fields beyond the Standard Model and we introduce the reader to this promising feature as well.

arXiv:2402.07972•Progress in Particle and Nuclear Physics•Jul 18, 2024•91 citations

Entanglement and Bell inequalities with boosted t t ¯

Zhongtian Dong, Dorival Gonçalves, Kyoungchul Kong +1 more

The Large Hadron Collider provides a unique opportunity to study quantum entanglement and violation of Bell inequalities at the highest energy available today. In this paper, we will investigate these quantum correlations with top quark pair production, which represents a system of two-qubits. The semileptonic top pair channel has a factor of 6 increase in statistics and easier reconstruction with respect to the dileptonic channel. Although measuring the spin polarization of the hadronic top quark is known to be challenging, our study indicates that it is feasible to reconstruct the spin density matrix of the two-qubit system using an optimal hadronic polarimeter. This is achieved with the aid of jet substructure techniques and NN-inspired reconstruction methods, which improve the mapping between subjets and quarks. We find that entanglement can already be observed at more than the 5 σ level with existing data, and violation of Bell inequalities may be probed above the 4 σ level at the HL-LHC with 3 ab − 1 of data. Published by the American Physical Society 2024

arXiv:2305.07075•Physical review. D/Physical review. D.•Jun 24, 2024•63 citations
The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb Collaboration on the helicity amplitudes for the decay B0→J/ψK*(892)0 to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above 5σ (nominally 84σ ) and Bell inequality is violated with a significance well above 5σ (nominally 36σ )—thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the B mesons into vector mesons, but with lesser significance. Published by the American Physical Society 2024
Bell inequality is violated in B0→J/ψ K⋆(892)0B^0\to J/ψ\, K^{\star}(892)^0B0→J/ψK⋆(892)0 decays
The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb collaboration on the helicity amplitudes for the decay B0→J/ψ K∗(892)0B^0\to J/ψ\,K^*(892)^0B0→J/ψK∗(892)0 to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above 5σσσ (nominally 84σσσ) and Bell inequality is violated with a significance well above 5σσσ (nominally 36σσσ) -- thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the BBB mesons into vector mesons, but with lesser significance.
The decays of the B meson into vector mesons, observed during the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of ϕ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allow access to entanglement and to the Bell inequality violation with a significance exceeding the 5σ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the B meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test.
Entanglement and Bell inequality violation in B→ΦΦB\to \it{ΦΦ}B→ΦΦ decays
The decays of the BBB meson into vector mesons, observed at the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of Φ\itΦΦ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allows access to entanglement and to the Bell inequality violation with a significance exceeding the 5σσσ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the BBB meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test.
The study of entanglement in particle physics has been gathering pace in the past few years. It is a new field that is providing important results about the possibility of detecting entanglement and testing Bell inequality at colliders for final states as diverse as top-quark, τ-lepton pairs and Λ-baryons, massive gauge bosons and vector mesons. In this review, after presenting definitions, tools and basic results that are necessary for understanding these developments, we summarize the main findings—as published by the beginning of year 2024—including analyses of experimental data in B meson decays and top-quark pair production. We include a detailed discussion of the results for both qubit and qutrits systems, that is, final states containing spin one-half and spin one particles. Entanglement has also been proposed as a new tool to constrain new particles and fields beyond the Standard Model and we introduce the reader to this promising feature as well.
The Large Hadron Collider provides a unique opportunity to study quantum entanglement and violation of Bell inequalities at the highest energy available today. In this paper, we will investigate these quantum correlations with top quark pair production, which represents a system of two-qubits. The semileptonic top pair channel has a factor of 6 increase in statistics and easier reconstruction with respect to the dileptonic channel. Although measuring the spin polarization of the hadronic top quark is known to be challenging, our study indicates that it is feasible to reconstruct the spin density matrix of the two-qubit system using an optimal hadronic polarimeter. This is achieved with the aid of jet substructure techniques and NN-inspired reconstruction methods, which improve the mapping between subjets and quarks. We find that entanglement can already be observed at more than the 5 σ level with existing data, and violation of Bell inequalities may be probed above the 4 σ level at the HL-LHC with 3 ab − 1 of data. Published by the American Physical Society 2024