Speaker
Description
Nowadays, experimentally observed states that are often assigned to the light meson or charmonium sector might indicate an exotic nature. Such exotic particles include e.g. glueballs, hybrids, and tetraquarks. Not only do these states pose a theoretical challenge, but experimentally it is often difficult to distinguish exotic and non-exotic matter and to characterise their nature. In such cases, it helps to compare different production mechanisms and decay patterns. This provides additional constraints and allows for a coupled channel partial wave analysis to describe the different spectra simultaneously, respecting unitarity and analyticity. The importance need of adequate models to interpret data is rising not only due to rising statistics which enhance the sensitivity towards theoretical models. Therefore, gluon-poor two-photon fusion events and gluon-rich hadronic reactions as e.g. radiative $J/\psi$ decays can be used to disentangle the highly populated light meson spectrum. The talk will discuss recent experimental results from coupled channel analyses as and interlink with modern analysis methods. Special emphasis will be on the models used and the associated software tools.
