Characterization of the quantum state of top quark pairs produced in proton-proton collisions at = 13 TeV using the beam and helicity bases
Using 138 fb of 13 TeV proton-proton collision data collected by the CMS experiment, this study characterizes the quantum state of top quark-antiquark pairs by measuring spin correlations in the beam and helicity bases to decompose the system into Bell and spin eigenstates and evaluate properties like purity, entropy, and entanglement, with all results aligning with Standard Model predictions.