Aula Conversi (Dip. di Fisica - Edificio G. Marconi)
Aula Conversi
Dip. di Fisica - Edificio G. Marconi
Description
The existence of multiquark resonances has been experimentally established. The number of states and the amount of details on their properties have been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of more tetraquarks. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems affecting theoretical models, like the absence of selection rules limiting the number of states predicted, motivate alternative directions in model building. Some ideas in this direction will be presented.
