Postdecay quantum entanglement in top pair production
J. A. Aguilar–Saavedra
Abstract
Top pairs produced at the Large Hadron Collider exhibit quantum entanglement of their spins near threshold and for boosted, central $t\overline{t}$ pairs. The entanglement is maintained between the decay products, in particular, between the top quark and the ${W}^{\ensuremath{-}}$ boson from the antiquark (or vice versa, between $\overline{t}$ and ${W}^{+}$) in certain kinematical regions. Therefore, $t\overline{t}$ production provides a rare opportunity to verify the spin entanglement between a fermion and a boson. The $tW$ entanglement can be probed at the $7\ensuremath{\sigma}$ level near threshold with run 2 data and at the $5\ensuremath{\sigma}$ 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 $4\ensuremath{\sigma}$ level at the LHC run 3.