Ponente
Descripción
Quantum entanglement is one of the defining features of quantum mechanics. In high-energy
colliders, quantum properties are experimentally accessible, the most important example being top
quark pair production at the LHC. This channel lead to the discovery of spin entanglement in 2024
[1-2].
In this work [3], we study how energetic final-state radiation modifies the spin entanglement of fermion–antifermion pairs, and demonstrate that it can lead to measurable decoherence. The study is performed at parton level using simulations computed with MadGraph5_aMC@NLO, using t tbar g
and tau+ tau- gamma production processes. The spin density matrix is reconstructed as a function of the
FSR energy.
We conclude that a statistically significant observation of decoherence can be obtained with current
data in associated pp -> t tbar g production at the LHC and in e+e- -> tau+ tau- gamma production at Belle II. Future electron-positron colliders operating well above the t tbar g production threshold or at the Z pole, respectively, could further enable differential measurements of quantum entanglement as a function of the FSR energy.
[1] ATLAS Collaboration. Nature 633, 542 (2024).
[2] CMS Collaboration. PRD 110, 112016 (2024).
[3] Aoude et. al. arXiv:2604.16268v3. Submitted to PRL.
