Institut de recherche sur les lois fondamentales de l'Univers

There are indeed indications from these experiments about resonances (hybrid mesons, glueballs, tetraquarks, etc)  beyond the quark model classification. However a close collaboration between theorists and experimentalists is necessary to draw robust conclusions about their existence. To this end the Joint Physics Analysis Center (JPAC) was set up between Jefferson Lab and Indiana University. Its goal is to provide the theoretical framework, based on the principles of the S-Matrix theory, for the analysis of hadron spectroscopy experiments data. Our main results concern baryons (hard and photoproduction of pion and kaon), light mesons (eta, omega and phi decays) and heavy meson (“XYZ states”) spectroscopy. To facilitate the interactions with the community a interactive webpage, where the models can be dowloaded and simulated, was recently created: