When the Machine Chimes the Bell: Entanglement and Bell Inequalities with Boosted $t\bar{t}$

Abstract

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 spacelike separation requirement for the two causally disconnected top quarks requires they fly relativistically away from each other, which motivates the use of the boosted top-tagging with the semi-leptonic top pair 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 $5\sigma$ level with existing data, and violation of Bell inequalities may be probed above 4$\sigma$ level at the HL-LHC with 3 ab${}^{-1}$ of data.

12 pages, 6 figures, 2 tables. Updated to match with the published version

References in corpus (21)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Demonstration of entanglement-by-measurement of solid state qubits
• Quantum information with top quarks in QCD
• Quantum tops at the LHC: from entanglement to Bell inequalities
• Spin Correlation Effects in Top Quark Pair Production at the LHC
• Improved tests of entanglement and Bell inequalities with LHC tops
• Quantum discord and steering in top quarks at the LHC
• Testing entanglement and Bell inequalities in $H\to ZZ$
• Constraining new physics in entangled two-qubit systems: top-quark, tau-lepton and photon pairs
• Quantum information and CP measurement in $H\to {\tau }^{+}{\tau }^{-}$ at future lepton colliders
• Quantum entanglement and top spin correlations in SMEFT at higher orders
• Measurement of ttbar Spin Correlation in ppbar Collisions Using the CDF II Detector at the Tevatron
• Laboratory-frame tests of quantum entanglement in $H\to WW$
• Lorentz Boost Networks: Autonomous Physics-Inspired Feature Engineering
• Measurement of spin correlation in ttbar production using dilepton final states
• Bell-type inequalities for systems of relativistic vector bosons
• Machine learning the Higgs boson-top quark CP phase
• Direct Higgs-top CP-phase measurement with $t\bar{t}h$ at the 14 TeV LHC and 100 TeV FCC
• Boosting to identify: pseudoscalar searches with di-leptonic tops
• Measurements of differential cross-sections in top-quark pair events with a high transverse momentum top quark and limits on beyond the Standard Model contributions to top-quark pair production with the ATLAS detector at $\sqrt{s}=13$ TeV
• Differential $t\bar{t}$ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb${}^{-1}$ of ATLAS data

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• Quantum tops at circular lepton colliders
• Entanglement in flavored scalar scattering
• Quantum Information meets High-Energy Physics: Input to the update of the European Strategy for Particle Physics
• Optimizing Entanglement and Bell Inequality Violation in Top Anti-Top Events
• Entanglement and Bell nonlocality with bottom-quark pairs at hadron colliders
• Entanglement and Bell inequality violation in vector diboson systems produced in decays of spin-0 particles
• Spin Correlations in $t\bar{t}$ Production and Decay at the LHC in QCD Perturbation Theory
• Quantum Tomography at Colliders: With or Without Decays
• Imprints of screened dark energy on nonlocal quantum correlations
• Spin correlations and Bell nonlocality in $\Lambda \bar{\Lambda }$ pair production from $e^{+}{e}^{-}$ collisions with a thrust cut
• Analytical Insights on Hadronic Top Quark Polarimetry
• Higher-Order Corrections to Quantum Observables in $h\to W{W}^{\ast }$
• Quantum Entanglement is Quantum: ZZ Production at the LHC
• Three-Body Non-Locality in Particle Decays
• Qubit entanglement from forward scattering
• Top-quark spin correlations as a tool to distinguish pseudoscalar $A\to ZH$ and scalar $H\to ZA$ signatures in $Zt\bar{t}$ final states at the LHC
• Top-philic Machine Learning
• Quantum state tomography with muons
• Particle Collisions & Quantum Entanglement in High-Energy Collisions
• Nonlocal Advantage of Quantum Coherence in Top Quarks
• Experimental characterization of the hierarchy of quantum correlations in top quark pairs
• Single-spin measurements and heavy new physics in the $e^{+}{e}^{-}\to t\bar{t}$ process at an FCC-ee
• Colliders are not Testing Locality via Bell's Inequality nor Providing an Unconditional Proof of Entanglement
• Gedanken Experiments of Entanglement in Particle Physics: Interactions, Operators and Bell Inequalities in Flavor Space
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