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arxiv: 2607.00971 · v1 · pith:KYN5KNTAnew · submitted 2026-07-01 · ✦ hep-ph

Quantum entanglement of photon pairs at proton-proton colliders

Yue Pan , Yipin Wang , Leyun Gao , Qiang Li , Chen Zhou This is my paper

Pith reviewed 2026-07-02 09:49 UTC · model grok-4.3

classification ✦ hep-ph
keywords quantum entanglementdiphoton systemsBethe-Heitler processproton-proton collidersphoton polarizationHiggs decaycontinuum production
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The pith

A method using the Bethe-Heitler process in trackers measures quantum entanglement of photon pairs at proton-proton colliders.

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

The paper proposes using the Bethe-Heitler process in detector trackers to analyze the polarization of diphoton systems produced in proton-proton collisions. This process converts photons into electron-positron pairs whose angular distribution carries information about the original photon polarizations. By measuring these distributions, researchers can test for quantum entanglement in high-energy diphoton events. Such measurements would extend studies of quantum correlations into the relativistic regime accessible at colliders like the LHC. Simulations suggest detectable signals in continuum production but very weak ones in Higgs decays.

Core claim

Diphoton systems serve as qubits whose entanglement can be measured at high-energy colliders through the analyzing power of the Bethe-Heitler process in the tracker material. Photons scatter off nuclei to produce electron-positron pairs, and the joint angular distribution of these pairs encodes the polarization state of the diphoton system. This enables exploration of quantum entanglement properties at the high-energy frontier.

What carries the argument

The Bethe-Heitler process in the tracker, providing spin analyzing power via joint angular distributions of electron-positron pairs from photon conversion.

If this is right

  • Statistical significance of entanglement in Higgs to diphoton is 0.007 sigma under HL-LHC conditions.
  • Continuum diphoton process q bar q to gamma gamma can reach about 1.5 sigma.
  • Absence of dedicated polarimeters at colliders is addressed by this tracker-based method.
  • This helps understand quantum nature of particles and search for new physics.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If the method works, it could be extended to other high-energy processes involving polarized particles.
  • Successful measurement would allow testing of quantum mechanics predictions at energies far above previous experiments.
  • Detector material effects might need careful calibration in real data to achieve the simulated sensitivities.

Load-bearing premise

The joint angular distribution of electron-positron pairs produced in the Bethe-Heitler process accurately reflects the polarization of the incoming diphoton system with little dilution from other effects.

What would settle it

Observing no correlation or incorrect angular distributions in the electron-positron pairs from photon conversions in the tracker would falsify the claim that this process encodes the diphoton polarization.

Figures

Figures reproduced from arXiv: 2607.00971 by Chen Zhou, Leyun Gao, Qiang Li, Yipin Wang, Yue Pan.

Figure 1
Figure 1. Figure 1: FIG. 1. Illustration of the Higgs boson decaying into two pho [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. (a) Differential cross-section of the positron polar [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
read the original abstract

Diphoton systems, with photon polarizations measurable at low energies, serve as ideal qubits and were first used to demonstrate quantum entanglement. However, due to the current absence of dedicated polarimeters at high-energy colliders, the entanglement properties of diphoton systems remain largely unexplored at the high-energy frontier. Studying quantum entanglement at the high-energy frontier, where particle colliders serve as a natural relativistic laboratory, helps us better understand the quantum nature and seek new physics. In this letter, we propose a novel method to measure the entanglement of diphoton systems at proton-proton colliders. The photon spin analyzing power arises from the Bethe-Heitler process occurring in the tracker, where photons scatter off nuclei to produce electron-positron pairs whose joint angular distribution encodes the polarization of the diphoton system. Simulation results show that, under HL-LHC conditions, the statistical significance of quantum entanglement in the Higgs $\to \gamma\gamma$ process is $0.007\sigma$, while measuring the continuum diphoton process $q\bar{q} \to \gamma\gamma$ alone can reach about $1.5\sigma$.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 0 minor

Summary. The manuscript proposes a novel method to measure quantum entanglement of diphoton systems produced at proton-proton colliders. Photon polarization is analyzed via the Bethe-Heitler process in tracker material, where the joint angular distribution of electron-positron pairs from photon conversion encodes the diphoton polarization state. Simulations under HL-LHC conditions are reported to yield a statistical significance of 0.007σ for entanglement in the Higgs → γγ channel and 1.5σ for the continuum q q-bar → γγ process.

Significance. If the Bethe-Heitler analyzing power can be shown to encode polarization with high fidelity and without substantial dilution, the approach would enable the first exploration of diphoton entanglement at collider energies, extending quantum-information studies into the relativistic regime. The reported significances, however, are marginal to negligible, which limits the practical impact even if the underlying assumption holds.

major comments (3)
  1. [Abstract] Abstract: The reported statistical significance of 0.007σ for the Higgs → γγ channel is negligible and indicates that the proposed method provides essentially no sensitivity to entanglement in this channel, which is load-bearing for the central claim that the technique enables measurements at the high-energy frontier.
  2. [Abstract] Abstract: No details are supplied on the simulation assumptions, background modeling, detector effects, or the precise mapping from e+e− angular distributions to the entanglement witness, preventing assessment of whether the 1.5σ result for the continuum channel is robust or already incorporates dilution from multiple scattering.
  3. [Abstract] The manuscript does not address the characteristic pair opening angle m_e/E_γ ≲ 8 mrad at E_γ ≈ 60–125 GeV or quantify multiple-scattering deflections in tracker material (θ_MS ≈ 13.6 MeV/(βp) √(x/X0)), which are comparable in size and could suppress the analyzing power below usability.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the careful review and constructive comments on our manuscript proposing a Bethe-Heitler-based method to probe diphoton entanglement at pp colliders. We agree that the reported significances are marginal and that additional details and limitations must be addressed. We provide point-by-point responses below and will revise the manuscript accordingly.

read point-by-point responses

  1. Referee: [Abstract] Abstract: The reported statistical significance of 0.007σ for the Higgs → γγ channel is negligible and indicates that the proposed method provides essentially no sensitivity to entanglement in this channel, which is load-bearing for the central claim that the technique enables measurements at the high-energy frontier.

    Authors: We agree that 0.007σ constitutes negligible sensitivity for the Higgs → γγ channel and does not support a claim of practical measurement capability there. The manuscript's primary contribution is the conceptual proposal of using tracker conversions for polarization analysis at collider energies; the continuum qq̄ → γγ channel provides the only non-negligible reach under our assumptions. We will revise the abstract to explicitly note the lack of sensitivity in the Higgs channel and to position the continuum result as the relevant demonstration of the method. revision: yes

  2. Referee: [Abstract] Abstract: No details are supplied on the simulation assumptions, background modeling, detector effects, or the precise mapping from e+e− angular distributions to the entanglement witness, preventing assessment of whether the 1.5σ result for the continuum channel is robust or already incorporates dilution from multiple scattering.

    Authors: As a letter-format manuscript, detailed simulation parameters were omitted. In the revision we will add an explicit description of the assumptions (HL-LHC luminosity 3000 fb⁻¹, photon acceptance, conversion probability, and the construction of the entanglement witness from the joint e⁺e⁻ angular distribution). The quoted 1.5σ does not incorporate multiple-scattering dilution or full detector effects; we will state this clearly and note that the number is an idealized estimate. revision: yes

  3. Referee: [Abstract] The manuscript does not address the characteristic pair opening angle m_e/E_γ ≲ 8 mrad at E_γ ≈ 60–125 GeV or quantify multiple-scattering deflections in tracker material (θ_MS ≈ 13.6 MeV/(βp) √(x/X0)), which are comparable in size and could suppress the analyzing power below usability.

    Authors: We acknowledge that the intrinsic opening angle is a few mrad and that multiple scattering in tracker material can produce deflections of comparable magnitude, which would dilute the analyzing power. Our present simulation assumes perfect angular reconstruction without these effects. We will add a paragraph discussing this limitation, providing order-of-magnitude estimates, and stating that a dedicated GEANT4-level study is required to determine whether the analyzing power remains usable. This discussion will be included without new quantitative results. revision: partial

Circularity Check

0 steps flagged

No circularity: proposal and simulation outputs are independent of the entanglement claim.

full rationale

The paper proposes using Bethe-Heitler conversion in tracker material to analyze diphoton polarization and reports simulation-derived significances (0.007σ and 1.5σ) as numerical outputs rather than quantities defined in terms of the entanglement witness itself. No self-definitional steps, fitted inputs renamed as predictions, or load-bearing self-citations appear in the provided text. The derivation chain consists of a physical proposal plus Monte Carlo results; these are not equivalent to the input assumptions by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review; no explicit free parameters, axioms, or invented entities are identifiable from the provided text.

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