The nucleons, as one of the most fundamental building blocks of visible matter, are built up of quarks and gluons. However, the interactions and dynamics inside the nucleons, which are mediated by the strong force and ......

Already when the quark model was introduced in 1964, Gell-Mann suggested that hadrons might be composed of more than three quarks. This idea is experiencing a renaissance during the last decade. In 2016, the Λ(1405) hyperon ......