Pith. sign in

REVIEW 2 major objections 5 minor 18 cited by

Colliders are Testing neither Locality via Bell's Inequality nor Entanglement versus Non-Entanglement

T0 review · 2 major / 5 minor · reviewed 2026-08-06 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read At colliders, measuring only momenta cannot test locality via Bell's inequality or entanglement versus non-entanglement.

desk verdict A solid Bell-locality no-go for momentum-only collider tests, but the entanglement claim conflates classical simulability with quantum separability and overreaches. read the letter →

arxiv 2507.15949 v1 pith:37HKMOSM submitted 2025-07-21 hep-ph hep-exquant-ph

Steven A. Abel , Herbi K. Dreiner , Rhitaja Sengupta , Lorenzo Ubaldi This is my paper
classification hep-phhep-exquant-ph
keywords Bell'sinequalitylocalhiddenvariablesquantumentanglementtop-quarkpairproductionspincorrelationsdetectionloopholecollidertestsKasdayconstruction
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper argues for a no-go result: collider experiments that measure only final-state momenta cannot test locality through Bell's inequality, and cannot distinguish entangled from non-entangled states. The reason is that the normalized differential cross section for the process—a function of commuting momentum directions—is itself a local hidden variable theory (LHVT), and LHVTs automatically satisfy Bell's inequality and are not entangled. The same construction is applied to tau pairs from Z and Higgs decays, top-quark pairs at the LHC, and Higgs decays to W and Z bosons, reproducing the observed angular distributions while remaining non-entangled. If correct, the ATLAS and CMS entanglement observations for top pairs are not tests of entanglement, because extracting the spin density matrix from lepton directions requires assuming the very quantum mechanics being tested.

What carries the argument

The Kasday construction: take the full differential cross section $f(\hat{p}_a,\hat{p}_b)$ over final-state unit momenta and declare it to be the joint hidden-variable distribution $F(\hat{\lambda}_a,\hat{\lambda}_b)$, with each particle responding deterministically by emitting its decay product along its assigned hidden direction. This works only because all measured momentum components commute, so a joint probability distribution over them exists; the same construction fails for non-commuting spin components such as $S_x,S_y$. It transforms any collider angular distribution into a manifestly local, non-entangled model.

What would settle it

A concrete disproof would be a collider measurement that uses only final-state momenta and no phase-space cuts, whose normalized correlation function violates Bell's inequality for a two-state decay; the paper's construction predicts every such function is an LHVT and therefore satisfies it.

Watch

Extended reading notes

Core claim

For reactions such as $e^+e^- \to Z \to \tau^+\tau^- \to \pi^+\pi^-\nu\bar{\nu}$, $pp \to H \to \tau^+\tau^-$, $pp \to t\bar{t} \to b\ell^+\nu\bar{b}\ell^-\bar{\nu}$, and $H \to V V^*$, the paper claims that the full normalized differential cross section as a function of the final-state unit momenta is itself an LHVT. Since the momentum components commute, one can identify hidden variables with the measured momentum directions, with response functions that are delta functions and a distribution equal to the cross section itself. Because an LHVT necessarily satisfies Bell's inequality and is non-entangled, the same data that would seem to reveal spin entanglement are exactly reproduced by a local, separable model. The only bridge from measured lepton directions to the top-spin density matrix uses quantum field theory; the paper calls that circular when the question is whether quantum mechanics itself passed the test.

Load-bearing premise

The load-bearing premise is that using quantum mechanics to convert measured lepton directions into spin directions disqualifies the test as circular; if a trusted quantum analyzer is allowed instead, the same data could certify entanglement non-circularly.

Editorial extensions

If this is right

  • Bell-inequality tests based on $t\bar{t}$, $\tau^+\tau^-$, or $H\to VV^*$ angular distributions cannot exclude local hidden variable theories, because the measured angular distribution itself satisfies Bell's inequality.
  • The ATLAS and CMS observation of an entanglement parameter below $-1/3$ in top pairs is reinterpreted as the slope of an LHVT-compatible angular distribution, not as evidence of quantum entanglement, unless one first assumes the Standard Model's quantum decay dynamics.
  • Momentum cuts used to isolate transverse vector-boson components act as data rejection and can generate spurious Bell violations through the detection loophole, so fair-sampling assumptions are unjustified.
  • For $H\to ZZ^*$ and $H\to WW^*$, Bell's inequality does not apply because massive spin-1 bosons have three spin states, and the CGLMP inequality cannot be applied directly to angular measurements.
  • No current collider process that measures only final-state momenta can serve as a fundamental test of locality or of entanglement versus non-entanglement.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Beyond the paper: if one allows trusted quantum analyzers as standard device calibration, rather than demanding a foundational test of quantum mechanics, ATLAS/CMS-style quantum tomography of top pairs can still certify entanglement as a quantum-information protocol; what fails is only the stronger claim of a fundamental test.
  • The no-go logic generalizes: any experiment that infers spin correlations from commuting kinematic variables inherits the same construction, so distinguishing LHVTs would require direct non-commuting spin measurements, such as spin analyzers acting on the tops before they decay, which are not available at colliders.
  • A testable extension suggested by the reasoning is to scan collider observables defined purely on final-state momenta, with no cuts, for any violation of the appropriate Bell inequality; the paper's construction predicts none will occur.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. The paper argues that collider experiments cannot test locality via Bell's inequality nor entanglement versus non-entanglement when only final-state momenta are measured. The central construction, adapted from Kasday (1971) and Abel, Dittmar, and Dreiner (1992), takes the normalized differential cross section over final-state momenta and identifies it with the distribution of local hidden variables, because all momentum observables commute. This LHVT reproduces the data by construction, satisfies Bell's inequality, and is claimed to be non-entangled. The argument is applied to tau-pair production at LEP and the LHC, top-quark pair production at the LHC, and Higgs decays to vector bosons. The paper also warns that momentum cuts can produce spurious Bell violations, analogous to the detection loophole.

Significance. If the entanglement claim were correct, it would invalidate the ATLAS and CMS entanglement observations and a large body of recent proposals, which would be a substantial result. The Bell-locality half of the paper is a clean and essentially correct application of the Kasday/Fine construction: any joint distribution over commuting momentum observables admits an LHVT, so fixed no-setting momentum measurements cannot violate Bell's inequality. The numerical reproduction of the ATLAS t-tbar distribution is a useful validation. However, the entanglement half is not established: the paper conflates classical simulability of momentum correlations with separability of the spin density matrix, and its 'circularity' argument rests on a nonstandard device-independent epistemic premise rather than a theorem. The paper is therefore most valuable as a corrective to over-strong claims about Bell tests at colliders, but its central entanglement no-go needs substantial reframing.

major comments (2)
  1. [Section 3.3 and Section 6] The entanglement no-go is not established. An LHVT for the momentum distribution is a classical joint distribution F(λ_+,λ_-); it is not a separable quantum density matrix ρ_sep = Σ_i p_i ρ_i^+ ⊗ ρ_i^-. To show that entanglement cannot be tested, the paper would need to prove that no separable spin state, combined with the Standard Model decay map, reproduces the measured lepton angular distribution. The paper does not do this; instead it asserts in Sec. 3.3 that 'it is not permissible to use quantum mechanics when testing for quantum mechanics' and repeats this premise in Sec. 6. That is a device-independent epistemic criterion, not a theorem. Under the standard quantum-information convention in which the measurement apparatus is trusted and characterized by QM, the map from ρ_tbar to P(q_+,q_-) is invertible for analyzing power 1, so the ATLAS value D̄ = -0.537 (Eq. (3.11)) excludes separable states. Consequently, the Sec. 6 claim that entanglement testing is 'inherently not possible' overstates what is proven.
  2. [Section 3.3 and Section 6] Calling the Kasday LHVT 'by construction not entangled' is a category error. Entanglement and separability are properties of bipartite quantum states, as in Eq. (3.3) and the Peres-Horodecki criterion of Eqs. (3.8)-(3.9); a classical hidden-variable model is neither entangled nor separable in the quantum sense. The existence of an LHVT means the momentum correlations are classically simulable, not that the underlying spin state is separable. The paper should either prove the stronger statement about separable states or explicitly restrict its conclusion to classical simulability, which is sufficient for the Bell-locality no-go but not for the entanglement no-go.
minor comments (5)
  1. [Section 3.3, Eq. (3.4)] Equation (3.4) appears to have an incorrect normalization: for a distribution over two solid angles, the denominator should be 16π², not 4π²; as written, the right-hand side integrates to 4 over dΩ+dΩ-, not 1. The text and figures use correctly normalized distributions, so this is likely a typographical error, but it should be corrected because Eq. (3.4) defines the coefficients B± and C.
  2. [Section 5, Eqs. (5.5)-(5.7)] The 'alternative LHVT' used to illustrate the effect of momentum cuts employs a complex response function P(p̂_a|λ) = (1/√2)(1 + i√(3c) p̂_a·λ), which is not a valid probability for each λ; the integrated distribution being real does not cure this. The Kasday delta-function construction described later in the same section is the valid way to make the point about cuts.
  3. [Section 2] The construction in Sec. 2 is essentially Fine's theorem for commuting observables; citing Fine (1982) would help place the Kasday adaptation and the 1992 paper in the broader literature.
  4. [Section 3.1] The decay is written as τ± → π±ντ; for τ+ the neutrino should be an antineutrino, so the notation should be τ± → π± ντ(ν̄τ) to be accurate.
  5. [Section 3.3] The paper relies on the companion paper Ref. [56] for a key distinction between the coefficients B,C in the differential cross section and B,C in the density matrix; if that paper is not yet published, the argument should be made self-contained.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the Kasday construction is a self-contained local model for the commuting momentum distribution, and the self-citations are re-derived rather than load-bearing.

full rationale

The paper's own derivation is not circular. In Section 2, Eqs. (2.5)-(2.9), the hidden-variable distribution is deliberately identified with the full differential cross section, F(hat_lambda_+, hat_lambda_-) = f(hat_p_+, hat_p_-); this is an explicit constructive step, not a hidden assumption of the conclusion. The Bell-inequality checks in Sections 3.1-3.3 and Appendix A are direct computations from the computed differential distributions, so the local-realist compatibility claim is not a fitted input renamed as a prediction. The only self-citations are to the authors' 1992 paper [54], whose argument is re-derived in Section 2, and to the companion paper [56], whose D-versus-D distinction is re-derived in Section 3.3; neither is load-bearing. The paper's accusation that ATLAS/CMS are circular ("This is a circular argument", Section 3.3) is an epistemic criterion about not using quantum mechanics in a quantum-mechanics test, not a theorem; whether that criterion is accepted is a correctness or philosophy question, not a circularity in the paper's own logic. The statement that the LHVT is "by construction not entangled" is definitional and may be a category error relative to quantum separability, but it does not make the derivation circular. Overall, the central construction is tautological in the benign sense that any distribution over commuting momenta admits a local hidden-variable model, and that tautology is the intended point of the no-go argument rather than a concealed circular step.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

The central claim rests on no fitted constants: the numerical fit coefficients in Figures 3 through 5 are illustrative and do not enter the argument. The load-bearing premises are the no-settings assumption and the device-independent criterion for entanglement tests. No new particles, forces, or dimensions are introduced.

assumptions (4)
  • domain assumption Collider experiments measure only final-state momenta; there are no freely chosen, spacelike-separated analyzer settings.
    Stated in the abstract and Section 1; the entire no-go theorem depends on the absence of measurement settings. If independent spin settings could be imposed, Bell tests would be possible.
  • domain assumption The differential cross section over momentum directions can be identified as a hidden-variable distribution with deterministic response functions, and this counts as an LHVT.
    This is the Kasday construction, Sections 2 and 3. The identification F=f is mathematically valid for a single fixed joint observable, though it makes LHVT reproduction trivial.
  • ad hoc to paper A test of entanglement must not presuppose quantum mechanics to connect measured momenta to spins.
    Introduced in Section 3.3 and Section 6 as the reason the ATLAS/CMS identification of D with D is circular. Standard quantum information allows trusted, calibrated measurement devices, so this premise is contested and load-bearing for the entanglement part of the claim.
  • standard math Rotationally invariant correlation functions P(cos theta) can be inserted directly into Bell's inequality (2.4).
    Used in Sections 2 and 3 to test the computed distributions. The authors do not justify why the momentum-direction correlation function should obey the same inequality as spin-analyzer correlations; the LHVT existence already guarantees the inequality.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Colliders are Testing neither Locality via Bell's Inequality nor Entanglement versus Non-Entanglement." pith.science (2026). https://pith.science/paper/37HKMOSM

@misc{pith2026250715949,
  author       = {Pith},
  title        = {Pith review of: Colliders are Testing neither Locality via Bell's Inequality nor Entanglement versus Non-Entanglement},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/37HKMOSM}},
  note         = {Machine review of arXiv:2507.15949}
}
abstract

Recently there has been an increased interest in possible tests of locality via Bell's inequality or tests of entanglement at colliders, in particular at the LHC. These have involved various physical processes, such as $t \bar t$, or $\tau^+\tau^-$ production, or the decay of a Higgs boson to 2 vector bosons $H\to VV^*$. We argue that \textit{none} of these proposals constitute a test of locality via Bell's inequality or a test of quantum entanglement versus non-entanglement. In all cases what is measured are the momenta of the final state particles. Using the construction proposed by Kasday (1971) in a different context, and adapted to collider scenarios by Abel, Dittmar, and Dreiner (1992), it is straightforward to construct a local hidden variable theory (LHVT) which exactly reproduces the data. This construction is only possible as the final state momenta all commute. This LHVT satisfies Bell's inequality and is by construction \textit{not} entangled. Thus a test of locality via Bell's inequality or a test of entanglement versus non-entanglement is inherently \textit{not} possible.

Discussion (0). Sign in to comment.

Forward citations

Cited by 18 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Quantum Information of Photon Pairs at Lepton Colliders

    hep-ph 2026-06 unverdicted novelty 7.0 of 10

    A factorization framework and two-qubit description allow photon pairs at lepton colliders to be treated as qubits for measuring Bell inequality violation, quantum discord, and nonstabilizerness using Belle data.

  2. Leggett-Garg Inequality Violation in Muon $g-2$ Experiments

    hep-ph 2026-06 conditional novelty 7.0 of 10

    Analysis of ~10 billion muon decays from Fermilab g-2 data shows 5.5σ Leggett-Garg inequality violation via reconstructed temporal polarization correlators.

  3. Automated computation of spin-density matrices and quantum observables for collider physics

    hep-ph 2025-10 unverdicted novelty 7.0 of 10

    An automated framework in MadGraph5_aMC@NLO computes tree-level production spin-density matrices and quantum observables for generic collider processes, with validation on ttbar and VV and new applications to multi-to...

  4. High Energy Photon Polarimetry at Lepton Colliders: Quantum Information from Converted Photons

    hep-ph 2026-07 conditional novelty 6.5 of 10

    Converted photons in Belle II enable high-significance measurements of Bell nonlocality, discord, concurrence, magic and steerability for macroscopically separated GeV diphotons, provided opening-angle resolution reac...

  5. Hadron Structure from the Hierarchy of Quantum Correlations in Deep-Inelastic Scattering

    hep-ph 2026-07 conditional novelty 6.0 of 10

    Quantum-information measures of the DIS final electron-quark state are shown to be sensitive to transversity PDFs and can discriminate between different tensor-charge extractions.

  6. Bell Test of Photons from Electron-Positron Annihilation via POVM-based Compton Polarimetry

    quant-ph 2026-04 unverdicted novelty 6.0 of 10

    A POVM framework for multi-interaction Compton polarimetry converges to projective polarization measurements and enables Bell tests on entangled annihilation photons.

  7. Experimental characterization of the hierarchy of quantum correlations in top quark pairs

    quant-ph 2026-02 conditional novelty 6.0 of 10

    LHC top-quark data show quantum discord at >5σ, first evidence for steering at >3σ, no Bell correlations, and nonzero magic.

  8. Excluding Local Hidden Variables in $\Lambda\bar{\Lambda}$ Production: The Incompatibility with Angular-Momentum Conservation and CPT Invariance

    hep-ph 2026-01 conditional novelty 6.0 of 10

    Scalar h→ΛarΛ decay is incompatible with any angular-momentum-conserving LHVT, while pseudoscalar a→ΛarΛ can be mimicked by an LHVT only if CPT symmetry is relaxed.

  9. Parameter Inference from Final-State Entanglement in Higgs Decays

    hep-ph 2025-11 conditional novelty 6.0 of 10

    With a spin/color-weighted entanglement entropy built from Higgs branching ratios, the Standard Model Higgs and W masses sit near the global maximum, and the preferred coupling ratio is SM-like.

  10. Bypassing Spin-Analyzing Power Dependence for Quantum Entanglement at Colliders: A Case Study of $\Lambda\bar{\Lambda}$

    hep-ph 2025-10 conditional novelty 6.0 of 10

    An entanglement witness for J/ψ→ΛΛ̄ built from angular-correlation ratios can certify entanglement without the parity-violating decay parameters, while angle-only ratio tests are shown to fail.

  11. Spin versus Magic: Lessons from Gluon and Graviton Scattering

    hep-th 2025-08 accept novelty 6.0 of 10

    For 2 to 2 scattering of massless spin-1/2 to spin-2 particles, the averaged generated magic decreases monotonically with spin, with maxima well below the two-qubit upper bound.

  12. Controlling Quantum discord and steering in Electron-Positron Annihilation Using Polarized Beams

    hep-ph 2026-05 unverdicted novelty 5.0 of 10

    Polarized lepton beams control quantum discord and steering in hyperon-antihyperon pairs from e+e- annihilation, with discord persisting in separable states via transverse polarization.

  13. Entanglement redistribution of hyperon-antihyperon pair via sequential decay

    hep-ph 2026-02 conditional novelty 5.0 of 10

    In e+e−→ψ→Ξ(→Λπ)Ξ̄(→Λ̄π), the ΛΛ̄ pair's concurrence and negativity can decrease relative to the mother pair yet stay nonzero except at θ=0 and π, while quantum discord can always increase.

  14. Manipulating Bell nonlocality and entanglement in polarized electron-positron annihilation

    hep-ph 2026-02 conditional novelty 5.0 of 10

    Polarized lepton beams can tune hyperon-antihyperon entanglement and Bell nonlocality, with transverse polarization capable of producing maximally entangled pairs.

  15. Amplituhedra for generic quantum processes via the TQNN representation of UQC

    quant-ph 2025-09 reject novelty 5.0 of 10

    The paper proposes a formal correspondence between topological quantum neural networks and amplituhedra, claiming generic quantum processes have amplituhedron representations.

  16. Understanding Bell locality tests at colliders

    hep-ph 2026-03 unverdicted novelty 4.0 of 10

    Under mild assumptions, local hidden variable theories become testable at colliders and can be disproved via Bell-like inequalities for muon and tau pairs.

  17. Gedanken Experiments of Entanglement in Particle Physics: Interactions, Operators and Bell Inequalities in Flavor Space

    hep-ph 2025-12 conditional novelty 4.0 of 10

    Mass-identification, kaon-decay, and weak-mixing observables can be cast as spin-like operators whose correlations violate a Bell-type bound (0.44+0.90=1.34>1) in an idealized Gedanken framework.

  18. Does the Weinberg angle allow a local hidden-variable description for the leptonic decays of an entangled $ZZ$ pair?

    hep-ph 2026-06 unverdicted novelty 3.0 of 10

    Derives algebraic conditions under which an LHVT reproduces QFT angular correlations in ZZ leptonic decays, existing only for a unique state and restricted θ_W when w≠0.

Reference graph

Works this paper leans on

96 extracted references · 17 canonical work pages · cited by 18 Pith papers

  1. [1]

    J. S. Bell, On the Einstein-Podolsky-Rosen paradox , Physics Physique Fizika 1 (1964) 195–200

    1964

  2. [2]

    J. F. Clauser, M. A. Horne, A. Shimony, and R. A. Holt, Proposed experiment to test local hidden variable theories , Phys. Rev. Lett. 23 (1969) 880–884

    1969

  3. [3]

    Bohm and Y

    D. Bohm and Y. Aharonov, Discussion of Experimental Proof for the Paradox of Einstein, Rosen, and Podolsky , Phys. Rev. 108 (1957) 1070–1076

    1957

  4. [4]

    Aspect, J

    A. Aspect, J. Dalibard, and G. Roger, Experimental test of Bell’s inequalities using time varying analyzers , Phys. Rev. Lett. 49 (1982) 1804–1807

    1982

  5. [5]

    Afik and J

    Y. Afik and J. R. M. de Nova, Entanglement and quantum tomography with top quarks at the LHC , Eur. Phys. J. Plus 136 (2021), no. 9 907, [ arXiv:2003.02280]

    arXiv 2021

  6. [6]

    Fabbrichesi, R

    M. Fabbrichesi, R. Floreanini, and G. Panizzo, Testing Bell Inequalities at the LHC with Top-Quark Pairs , Phys. Rev. Lett. 127 (2021), no. 16 161801, [arXiv:2102.11883]

    arXiv 2021

  7. [7]

    Severi, C

    C. Severi, C. D. E. Boschi, F. Maltoni, and M. Sioli, Quantum tops at the LHC: from entanglement to Bell inequalities , Eur. Phys. J. C 82 (2022), no. 4 285, [arXiv:2110.10112]

    arXiv 2022

  8. [8]

    Aoude, E

    R. Aoude, E. Madge, F. Maltoni, and L. Mantani, Quantum SMEFT tomography: Top quark pair production at the LHC , Phys. Rev. D 106 (2022), no. 5 055007, [arXiv:2203.05619]

    arXiv 2022

Show all 96 references
  1. [9]

    Afik and J

    Y. Afik and J. R. M. de Nova, Quantum information with top quarks in QCD , Quantum 6 (2022) 820, [ arXiv:2203.05582]

    2022 arXiv

  2. [10]

    J. A. Aguilar-Saavedra and J. A. Casas, Improved tests of entanglement and Bell inequalities with LHC tops , Eur. Phys. J. C 82 (2022), no. 8 666, [arXiv:2205.00542]

    2022 arXiv

  3. [11]

    Fabbrichesi, R

    M. Fabbrichesi, R. Floreanini, and E. Gabrielli, Constraining new physics in entangled two-qubit systems: top-quark, tau-lepton and photon pairs , Eur. Phys. J. C 83 (2023), no. 2 162, [ arXiv:2208.11723]. – 23 –

    2023 arXiv

  4. [12]

    Afik and J

    Y. Afik and J. R. M. de Nova, Quantum Discord and Steering in Top Quarks at the LHC, Phys. Rev. Lett. 130 (2023), no. 22 221801, [ arXiv:2209.03969]

    2023 arXiv

  5. [13]

    Severi and E

    C. Severi and E. Vryonidou, Quantum entanglement and top spin correlations in SMEFT at higher orders , JHEP 01 (2023) 148, [ arXiv:2210.09330]

    2023 arXiv

  6. [14]

    Z. Dong, D. Gon¸ calves, K. Kong, and A. Navarro,Entanglement and Bell inequalities with boosted tt¯, Phys. Rev. D 109 (2024), no. 11 115023, [ arXiv:2305.07075]

    2024 arXiv

  7. [15]

    J. A. Aguilar-Saavedra, Postdecay quantum entanglement in top pair production , Phys. Rev. D 108 (2023), no. 7 076025, [ arXiv:2307.06991]

    2023 arXiv

  8. [16]

    T. Han, M. Low, and T. A. Wu, Quantum entanglement and Bell inequality violation in semi-leptonic top decays , JHEP 07 (2024) 192, [ arXiv:2310.17696]

    2024 arXiv

  9. [17]

    Cheng, T

    K. Cheng, T. Han, and M. Low, Optimizing fictitious states for Bell inequality violation in bipartite qubit systems with applications to the tt ¯ system, Phys. Rev. D 109 (2024), no. 11 116005, [ arXiv:2311.09166]

    2024 arXiv

  10. [18]

    J. A. Aguilar-Saavedra and J. A. Casas, Entanglement Autodistillation from Particle Decays, Phys. Rev. Lett. 133 (2024), no. 11 111801, [ arXiv:2401.06854]

    2024 arXiv

  11. [19]

    Maltoni, C

    F. Maltoni, C. Severi, S. Tentori, and E. Vryonidou, Quantum detection of new physics in top-quark pair production at the LHC , JHEP 03 (2024) 099, [arXiv:2401.08751]

    2024 arXiv

  12. [20]

    J. A. Aguilar-Saavedra, A closer look at post-decay t¯t entanglement, Phys. Rev. D 109 (2024), no. 9 096027, [ arXiv:2401.10988]

    2024 arXiv

  13. [21]

    J. A. Aguilar-Saavedra, Full quantum tomography of top quark decays , Phys. Lett. B 855 (2024) 138849, [ arXiv:2402.14725]

    2024 arXiv

  14. [22]

    Maltoni, C

    F. Maltoni, C. Severi, S. Tentori, and E. Vryonidou, Quantum tops at circular lepton colliders, JHEP 09 (2024) 001, [ arXiv:2404.08049]

    2024 arXiv

  15. [23]

    C. D. White and M. J. White, Magic states of top quarks , Phys. Rev. D 110 (2024), no. 11 116016, [ arXiv:2406.07321]

    2024 arXiv

  16. [24]

    Z. Dong, D. Gon¸ calves, K. Kong, A. J. Larkoski, and A. Navarro,Hadronic top quark polarimetry with ParticleNet , Phys. Lett. B 862 (2025) 139314, [arXiv:2407.01663]

    2025 arXiv

  17. [25]

    Cheng, T

    K. Cheng, T. Han, and M. Low, Optimizing entanglement and Bell inequality violation in top antitop events , Phys. Rev. D 111 (2025), no. 3 033004, [arXiv:2407.01672]

    2025

  18. [26]

    Z. Dong, D. Gon¸ calves, K. Kong, A. J. Larkoski, and A. Navarro, Analytical insights on hadronic top quark polarimetry , JHEP 02 (2025) 117, [ arXiv:2407.07147]

    2025 arXiv

  19. [27]

    T. Han, M. Low, N. McGinnis, and S. Su, Measuring quantum discord at the LHC , JHEP 05 (2025) 081, [ arXiv:2412.21158]

    2025 arXiv

  20. [28]

    Aad et al., Observation of quantum entanglement with top quarks at the ATLAS detector , Nature 633 (2024), no

    A TLASCollaboration, G. Aad et al., Observation of quantum entanglement with top quarks at the ATLAS detector , Nature 633 (2024), no. 8030 542–547, [arXiv:2311.07288]. – 24 –

    2024 arXiv

  21. [29]

    Hayrapetyan et al., Observation of quantum entanglement in top quark pair production in proton–proton collisions at √s = 13 TeV, Rept

    CMS Collaboration, A. Hayrapetyan et al., Observation of quantum entanglement in top quark pair production in proton–proton collisions at √s = 13 TeV, Rept. Prog. Phys. 87 (2024), no. 11 117801, [ arXiv:2406.03976]

    2024 arXiv

  22. [30]

    CMS Collaboration, A. Hayrapetyan et al., Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using lepton+jets events from proton-proton collisions at s=13 TeV , Phys. Rev. D 110 (2024), no. 11 112016, [arXiv:2409.11067]

    2024 arXiv

  23. [31]

    M. M. Altakach, P. Lamba, F. Maltoni, K. Mawatari, and K. Sakurai, Quantum information and CP measurement in H →τ +τ - at future lepton colliders , Phys. Rev. D 107 (2023), no. 9 093002, [ arXiv:2211.10513]

    2023 arXiv

  24. [32]

    Ehat¨ aht, M

    K. Ehat¨ aht, M. Fabbrichesi, L. Marzola, and C. Veelken,Probing entanglement and testing Bell inequality violation with e+e- →τ +τ - at Belle II , Phys. Rev. D 109 (2024), no. 3 032005, [ arXiv:2311.17555]

    2024 arXiv

  25. [33]

    Lo Chiatto, Interference Resurrection of the τ Dipole through Quantum Tomography, arXiv:2408.04553

    P. Lo Chiatto, Interference Resurrection of the τ Dipole through Quantum Tomography, arXiv:2408.04553

    arXiv

  26. [34]

    Breuning, P

    C. Breuning, P. Bechtle, K. Desch, and C. Grefe, Prospects of measuring quantum entanglement in τ τfinal states at a future e+e − Higgs factory , EPJ Web Conf. 315 (2024) 01005, [ arXiv:2409.20239]

    2024 arXiv

  27. [35]

    T. Han, M. Low, and Y. Su, Entanglement and Bell Nonlocality in τ +τ − at the BEPC, arXiv:2501.04801

  28. [36]

    Zhang, B.-H

    Y. Zhang, B.-H. Zhou, Q.-B. Liu, S. Li, S.-C. Hsu, T. Han, M. Low, and T. A. Wu, Entanglement and Bell Nonlocality in τ +τ − at the LHC using Machine Learning for Neutrino Reconstruction, arXiv:2504.01496

    arXiv

  29. [37]

    Y. Afik, Y. Kats, J. R. M. de Nova, A. Soffer, and D. Uzan, Entanglement and Bell nonlocality with bottom-quark pairs at hadron colliders , Phys. Rev. D 111 (2025), no. 11 L111902, [ arXiv:2406.04402]

    2025 arXiv

  30. [38]

    Kats and D

    Y. Kats and D. Uzan, Prospects for measuring quark polarization and spin correlations in bb and cc samples at the LHC , JHEP 03 (2024) 063, [arXiv:2311.08226]

    2024 arXiv

  31. [39]

    A. J. Barr, Testing Bell inequalities in Higgs boson decays , Phys. Lett. B 825 (2022) 136866, [arXiv:2106.01377]

    2022 arXiv

  32. [40]

    J. A. Aguilar-Saavedra, A. Bernal, J. A. Casas, and J. M. Moreno, Testing entanglement and Bell inequalities in H →ZZ, Phys. Rev. D 107 (2023), no. 1 016012, [arXiv:2209.13441]

    2023 arXiv

  33. [41]

    Ashby-Pickering, A

    R. Ashby-Pickering, A. J. Barr, and A. Wierzchucka, Quantum state tomography, entanglement detection and Bell violation prospects in weak decays of massive particles, JHEP 05 (2023) 020, [ arXiv:2209.13990]

    2023

  34. [42]

    J. A. Aguilar-Saavedra, Laboratory-frame tests of quantum entanglement in H→WW, Phys. Rev. D 107 (2023), no. 7 076016, [ arXiv:2209.14033]. – 25 –

    2023 arXiv

  35. [43]

    Fabbrichesi, R

    M. Fabbrichesi, R. Floreanini, E. Gabrielli, and L. Marzola, Bell inequalities and quantum entanglement in weak gauge boson production at the LHC and future colliders, Eur. Phys. J. C 83 (2023), no. 9 823, [ arXiv:2302.00683]

    2023 arXiv

  36. [44]

    Aoude, E

    R. Aoude, E. Madge, F. Maltoni, and L. Mantani, Probing new physics through entanglement in diboson production , JHEP 12 (2023) 017, [ arXiv:2307.09675]

    2023 arXiv

  37. [45]

    Bernal, P

    A. Bernal, P. Caban, and J. Rembieli´ nski,Entanglement and Bell inequalities violation in H → ZZ with anomalous coupling , Eur. Phys. J. C 83 (2023), no. 11 1050, [arXiv:2307.13496]

    2023 arXiv

  38. [46]

    Bi, Q.-H

    Q. Bi, Q.-H. Cao, K. Cheng, and H. Zhang, New observables for testing Bell inequalities in W boson pair production , Phys. Rev. D 109 (2024), no. 3 036022, [arXiv:2307.14895]

    2024 arXiv

  39. [47]

    J. A. Aguilar-Saavedra, Tripartite entanglement in H→ZZ,WW decays, Phys. Rev. D 109 (2024), no. 11 113004, [ arXiv:2403.13942]

    2024 arXiv

  40. [48]

    Subba and R

    A. Subba and R. Rahaman, On bipartite and tripartite entanglement at present and future particle colliders , arXiv:2404.03292

    arXiv

  41. [49]

    A. Ruzi, Y. Wu, R. Ding, S. Qian, A. M. Levin, and Q. Li, Testing Bell inequalities and probing quantum entanglement at a muon collider , JHEP 10 (2024) 211, [arXiv:2408.05429]

    2024 arXiv

  42. [50]

    Grossi, G

    M. Grossi, G. Pelliccioli, and A. Vicini, From angular coefficients to quantum observables: a phenomenological appraisal in di-boson systems , JHEP 12 (2024) 120, [arXiv:2409.16731]

    2024 arXiv

  43. [51]

    Sullivan, Constraining New Physics with h → V V Tomography, arXiv:2410.10980

    M. Sullivan, Constraining New Physics with h → V V Tomography, arXiv:2410.10980

    arXiv

  44. [52]

    Y. Wu, R. Jiang, A. Ruzi, Y. Ban, X. Yan, and Q. Li, Testing Bell inequalities and probing quantum entanglement at CEPC , Phys. Rev. D 111 (2025), no. 3 036008, [arXiv:2410.17025]

    2025 arXiv

  45. [53]

    Grabarczyk, An improved Bell-CHSH observable for gauge boson pairs , arXiv:2410.18022

    R. Grabarczyk, An improved Bell-CHSH observable for gauge boson pairs , arXiv:2410.18022

    arXiv

  46. [54]

    S. A. Abel, M. Dittmar, and H. K. Dreiner, Testing locality at colliders via Bell’s inequality?, Phys. Lett. B 280 (1992) 304–312

    1992

  47. [55]

    H. K. Dreiner, Bell’s inequality and tau physics at LEP , in 2nd Workshop on Tau Lepton Physics, 10, 1992. hep-ph/9211203

    1992 arXiv

  48. [56]

    Bechtle, C

    P. Bechtle, C. Breuning, H. Dreiner, and C. Duhr, A critical appraisal of tests of locality and of entanglement versus non-entanglement at colliders , BONN-TH-2025-23, 2025

    2025

  49. [57]

    S. Li, W. Shen, and J. M. Yang, Can Bell inequalities be tested via scattering cross-section at colliders ? , Eur. Phys. J. C 84 (2024), no. 11 1195, [arXiv:2401.01162]. – 26 –

    2024 arXiv

  50. [58]

    Kasday, Experimental test of quantum predictions for widely separated photons , Foundations of Quantum Mechanics, B

    L. Kasday, Experimental test of quantum predictions for widely separated photons , Foundations of Quantum Mechanics, B. d’Espagnat ed.(New York: Academic Press) (1971) 195

    1971

  51. [59]

    Alwall, R

    J. Alwall, R. Frederix, S. Frixione, V. Hirschi, F. Maltoni, O. Mattelaer, H. S. Shao, T. Stelzer, P. Torrielli, and M. Zaro, The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations, JHEP 07...

    2014 arXiv

  52. [60]

    Degrande, C

    C. Degrande, C. Duhr, B. Fuks, D. Grellscheid, O. Mattelaer, and T. Reiter, UFO - The Universal FeynRules Output , Comput. Phys. Commun. 183 (2012) 1201–1214, [arXiv:1108.2040]

    2012 arXiv

  53. [61]

    MadGraph 5 model: HEFT, https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Models/HiggsEffective

  54. [62]

    Ma and T

    K. Ma and T. Li, Testing Bell inequality through h→τ τat CEPC* , Chin. Phys. C 48 (2024), no. 10 103105, [ arXiv:2309.08103]

    2024 arXiv

  55. [63]

    Peres, Separability criterion for density matrices , Phys

    A. Peres, Separability criterion for density matrices , Phys. Rev. Lett. 77 (1996) 1413–1415, [quant-ph/9604005]

    1996 arXiv

  56. [64]

    Horodecki, Separability criterion and inseparable mixed states with positive partial transposition, Phys

    P. Horodecki, Separability criterion and inseparable mixed states with positive partial transposition, Phys. Lett. A 232 (1997) 333, [ quant-ph/9703004]

    1997 arXiv

  57. [65]

    Collins, N

    D. Collins, N. Gisin, N. Linden, S. Massar, and S. Popescu, Bell Inequalities for Arbitrarily High-Dimensional Systems , Phys. Rev. Lett. 88 (2002), no. 4 040404

    2002

  58. [66]

    Bernal, P

    A. Bernal, P. Caban, and J. Rembieli´ nski,Entanglement and Bell inequality violation in vector diboson systems produced in decays of spin-0 particles , Sci. Rep. 15 (2025), no. 1 23410, [ arXiv:2405.16525]

    2025 arXiv

  59. [67]

    Del Gratta, F

    M. Del Gratta, F. Fabbri, P. Lamba, F. Maltoni, and D. Pagani, Quantum properties of H → V V∗: precise predictions in the SM and sensitivity to new physics, arXiv:2504.03841

    arXiv

  60. [68]

    Dittmar and H

    M. Dittmar and H. K. Dreiner, How to find a Higgs boson with a mass between 155-GeV - 180-GeV at the LHC , Phys. Rev. D 55 (1997) 167–172, [hep-ph/9608317]

    1997 arXiv

  61. [69]

    Dittmar and H

    M. Dittmar and H. K. Dreiner, h0 —> W+ W- — > lepton+ lepton- lepton-neutrino anti-lepton-neutrino as the dominant SM Higgs search mode at the LHC for M(h0) = 155-GeV - 180-GeV , in Ringberg Workshop: The Higgs Puzzle - What can We Learn from LEP2, LHC, NLC, and FMC? , pp. 113...

    1996 arXiv

  62. [70]

    Dittmar, Lhc higgs search with l+nul-nubar final states , CMS-NOTE-1997-083, 1997

    M. Dittmar, Lhc higgs search with l+nul-nubar final states , CMS-NOTE-1997-083, 1997

    1997

  63. [71]

    Aad et al., Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC , Phys

    A TLASCollaboration, G. Aad et al., Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC , Phys. Lett. B 716 (2012) 1–29, [ arXiv:1207.7214]. – 27 –

    2012 arXiv

  64. [72]

    Chatrchyan et al., Observation of a New Boson at a Mass of 125 GeV with the CMS Experiment at the LHC , Phys

    CMS Collaboration, S. Chatrchyan et al., Observation of a New Boson at a Mass of 125 GeV with the CMS Experiment at the LHC , Phys. Lett. B 716 (2012) 30–61, [arXiv:1207.7235]

    2012 arXiv

  65. [73]

    A. J. Barr, P. Caban, and J. Rembieli´ nski, Bell-type inequalities for systems of relativistic vector bosons, Quantum 7 (2023) 1070, [ arXiv:2204.11063]

    2023 arXiv

  66. [74]

    Fabbri, J

    F. Fabbri, J. Howarth, and T. Maurin, Isolating semi-leptonic H → W W∗decays for Bell inequality tests , Eur. Phys. J. C 84 (2024), no. 1 20, [ arXiv:2307.13783]

    2024 arXiv

  67. [75]

    Binoth, M

    T. Binoth, M. Ciccolini, N. Kauer, and M. Kramer, Gluon-induced WW background to Higgs boson searches at the LHC , JHEP 03 (2005) 065, [ hep-ph/0503094]

    2005 arXiv

  68. [76]

    Binoth, M

    T. Binoth, M. Ciccolini, N. Kauer, and M. Kramer, Gluon-induced W-boson pair production at the LHC , JHEP 12 (2006) 046, [ hep-ph/0611170]

    2006 arXiv

  69. [77]

    P. M. Pearle, Hidden-variable example based upon data rejection , Phys. Rev. D 2 (1970) 1418–1425

    1970

  70. [78]

    Einstein, B

    A. Einstein, B. Podolsky, and N. Rosen, Can quantum mechanical description of physical reality be considered complete?, Phys. Rev. 47 (1935) 777–780

    1935

  71. [79]

    Mott, The scattering of fast electrons by atomic nuclei , Proc

    N. Mott, The scattering of fast electrons by atomic nuclei , Proc. Roy. Soc. A 40 (1929) 440

    1929

  72. [80]

    Mott and H

    N. Mott and H. Massey, The Theory of Atomic Collisions . Oxford, At the Clarendon Press, Oxford, UK, 1950

    1950

  73. [81]

    J. A. Wheeler and W. H. Zurek, eds., Quantum Theory and Measurement . Princeton University Press, 7, 2014

    2014

  74. [82]

    H. J. Lipkin, Cp violation and coherent decays of kaon pairs , Phys. Rev. 176 (1968) 1715–1718

    1968

  75. [83]

    H. J. Lipkin, Simple Symmetries in Epr Correlated Decays of Kaon and B Meson Pairs With CP Violation , Phys. Lett. B 219 (1989) 474–480

    1989

  76. [84]

    Di Domenico, Testing quantum mechanics in the neutral kaon system at a Phi factory, Nucl

    A. Di Domenico, Testing quantum mechanics in the neutral kaon system at a Phi factory, Nucl. Phys. B 450 (1995) 293–324

    1995

  77. [85]

    Apostolakis et al., An EPR experiment testing the nonseparability of the K0 anti-K0 wave function , Phys

    CPLEAR Collaboration, A. Apostolakis et al., An EPR experiment testing the nonseparability of the K0 anti-K0 wave function , Phys. Lett. B 422 (1998) 339–348

    1998

  78. [86]

    Foadi and F

    R. Foadi and F. Selleri, Quantum mechanics versus local realism and a recent EPR experiment on K0 anti-K0 pairs , Phys. Lett. B 461 (1999) 123–130

    1999

  79. [87]

    Pompili and F

    A. Pompili and F. Selleri, On a possible EPR experiment with B0(d) anti-B0(d) pairs, Eur. Phys. J. C 14 (2000) 469–478, [ hep-ph/9906347]

    2000 arXiv

  80. [88]

    B. C. Hiesmayr, A Generalized Bell Inequality and Decoherence for the K 0KO, Found. Phys. Lett. 14 (2001), no. 3 231–245, [ hep-ph/0010108]

    2001 arXiv

  81. [89]

    Go, Observation of Bell inequality violation in B mesons , J

    Belle Collaboration, A. Go, Observation of Bell inequality violation in B mesons , J. Mod. Opt. 51 (2004) 991, [ quant-ph/0310192]. – 28 –

    2004 arXiv

  82. [90]

    Caban, J

    P. Caban, J. Rembielinski, K. A. Smolinski, Z. Walczak, and M. Wlodarczyk, An Open quantum system approach to EPR correlations in K0 anti-K0 system , Phys. Lett. A 357 (2006) 6–11, [ quant-ph/0603169]

    2006 arXiv

  83. [91]

    Go et al., Measurement of EPR-type flavour entanglement in Upsilon(4S) — > B0 anti-B0 decays , Phys

    Belle Collaboration, A. Go et al., Measurement of EPR-type flavour entanglement in Upsilon(4S) — > B0 anti-B0 decays , Phys. Rev. Lett. 99 (2007) 131802, [quant-ph/0702267]

    2007 arXiv

  84. [92]

    Ichikawa, S

    T. Ichikawa, S. Tamura, and I. Tsutsui, Testing the EPR Locality using B-Mesons , Phys. Lett. A 373 (2008) 39–44, [ arXiv:0805.3632]

    2008 arXiv

  85. [93]

    Gondran and A

    M. Gondran and A. Gondran, Measurement in the de Broglie-Bohm interpretation: Double-slit, Stern-Gerlach and EPR-B , Phys. Res. Int. 2014 (2014) 605908, [arXiv:1309.4757]

    2014 arXiv

  86. [94]

    Gabrielli and L

    E. Gabrielli and L. Marzola, Entanglement and Bell Inequality Violation in B → ϕϕ Decays, Symmetry 16 (2024), no. 8 1036, [ arXiv:2408.05010]

    2024 arXiv

  87. [95]

    Bramon, R

    A. Bramon, R. Escribano, and G. Garbarino, Bell’s inequality tests: From photons to B-mesons , J. Mod. Opt. 52 (2005) 1681–1684, [ quant-ph/0410122]

    2005 arXiv

  88. [96]

    Bramon, R

    A. Bramon, R. Escribano, and G. Garbarino, Bell’s inequality tests with meson-antimeson pairs, Found. Phys. 36 (2006) 563–584, [ quant-ph/0501069]. – 29 –

    2006 arXiv

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.