In 1964, introducing quarks to describe the known mesons and baryons, Murray Gell-Mann suggested the existence of further multiquark configurations beyond those reported in his paper, quark-antiquark and three quarks. The first hadron that cannot be described by the classical Gell-Mann configurations, the X(3872), was discovered by BELLE in 2003, confirmed by BABAR and seen in many other High Energy experiments. Since then, a wealth of Exotic Hadrons have been observed, mesons and baryons .
I shall illustrate this new chapter of Particle Spectroscopy with a selection of results on the structure and symmetry pattern of the Exotic Hadrons, reviewing recent experimental discoveries and future perspectives.
Angelo Esposito, Valerio Ippolito, Laura Cardani