Quantum Entanglement with Top Quarks at the LHC

In this report, our goal is the detection of entanglement between the spins of top quark and anti-quark produced in pairs at the Large Hadron Collider (LHC). We show that entanglement can be observed by direct measurement of the angular separation between the leptons arising from the decay of the top–antitop pair. The detection can be achieved with high statistical significance, using the current data recorded during Run 2 at the LHC. We perform an analysis optimisation using different working points: beta ($\beta$ =momentum/energy) to be less than 0.55, 0.65, 0.75, 0.85 and 0.9. These selections make the energy analysis more sensitive to the entanglement. The smaller is beta, the more gluon - gluon initiated $t\bar{t}$ events are present. We ran the fit multiple times and we found the optimal working point at $\beta$ = 0.7.