Ordinary and exotic mesons in the extended LSM
Shahriyar Jafarzade (ASU, ExoHad postdoc), in collaboration with Francesco Giacosa (JKU), Péter Kovács (Wigner RCP) investigated the spectrum of both ordinary and exotic mesons within the framework of the extended Linear Sigma Model (eLSM). The model includes scalar, pseudoscalar, vector, axial-vector, and higher-spin mesons, enabling a comprehensive description of light mesons with quantum numbers $J = 0$, $1$, $2$, and $3$. Beyond conventional quark-antiquark configurations, the eLSM framework is extended to explore exotic states such as glueballs (bound states of gluons) and hybrid mesons, which contain both quark-antiquark pairs and excited gluonic fields. By analyzing the masses, decay widths, and mixing patterns, the study offers theoretical support for identifying these non-conventional states. The results demonstrate good agreement with experimental observations, providing theoretical support for the interpretation of certain resonances as exotic states and contributing to the ongoing efforts to map out the meson spectrum and understand non-perturbative QCD dynamics.