Postdecay quantum entanglement in top pair production

Top pairs produced at the Large Hadron Collider exhibit quantum entanglement of their spins near threshold and for boosted, central tt̄ pairs. The entanglement is maintained between the decay products, in particular, between the top quark and the W^- boson from the antiquark (or vice versa, between t̄ and W⁺) in certain kinematical regions. Therefore, tt̄ production provides a rare opportunity to verify the spin entanglement between a fermion and a boson. The $tW$ entanglement can be probed at the 7σ level near threshold with run 2 data and at the 5σ level in the boosted region with the foreseen run 3 luminosity. In addition, the entanglement between the two W bosons can be probed at the 4σ level at the LHC run 3.