Exploring Entanglement and the Quest for Toponium

by Prof. Regina Demina (University of Rochester (US))

Thursday 22 Jan 2026, 10:30 → 12:30 Europe/Stockholm

92110 (Ångströmlaboratoriet)

While quantum mechanics underpins particle physics, truly quantumeffects are surprisingly difficult to establish in high-energy interactions. Arare exception comes from recent observations of quantum entanglement intop–antitop quark pairs by the ATLAS and CMS experiments. In certain regions ofphase space, these particles appear to lie outside the causality cone, makingthe result even more intriguing. In this talk, I will review the details ofthese groundbreaking measurements, their implications, and potentialcriticisms. Additionally, I will explore an exciting possibility: the discoveryof toponium, a bound state of top and antitop quarks. If confirmed, thiswould be the heaviest known particle, with a mass of 343 GeV—surpassing eventhe heaviest nucleus, Oganesson, at 279 GeV.