Researchers Saša Prelovšek Komelj from the Department of Theoretical Physics and M. Padmanath from Mainz find evidence for the longest-lived exotic state composed of quarks. Their article in Physical Review Letters establishes this state with an ab-initio study based on the fundamental theory for the first time. The state consists of two charm quarks together with antiquarks u and d, and was experimentally discovered at CERN by the LHCb collaboration in July 2021 - Nature Physics. It contains more than three quarks and therefore represents an exotic hadron. Conventional hadrons, for example, proton and neutron, are composed of up to three quarks. Investigations of exotic hadrons reveal whether the mechanisms responsible for their existence are analogous to those that bind protons and neutrons to nuclei, which are in turn responsible for the energy released in nuclear fusion and fission.