Quantum entanglement autodistillation in baryon pair decays
H. Feng, Hao Tang, Wu-zhong Guo, Qin Qin · Physical review. D/Physical review. D. · 2025
We study the spin-entangled mixed state of a spin- 1 / 2 baryon–antibaryon pair produced in the process e + e − → J / ψ , ψ ′ → B B ¯ . We show that the spin entanglement of the system can increase following the decays B → b + M and B ¯ → b ¯ + M ¯ , where b , b ¯ are spin- 1 / 2 baryons and M , M ¯ are spin-0 mesons. This phenomenon, known as entanglement autodistillation, manifests as a probabilistic amplification of entanglement during the decay process. We analyze the underlying mechanism and show that this phenomenon depends only on the initial state of the B B ¯ system and the decay parameter α D , but not on the decay parameter ϕ D . This effect only arises when parity is violated in the decay, when α D ≠ 0 .