Phenomenology of light mesons with $J = 2, 3$

Abstract

In this thesis, I present the results for light mesons with $J=2,3$ within an effective hadronic model, the so-called extended Linear Sigma Model (eLSM). This model is based on the approximate chiral symmetry of QCD. Qualitative agreement between model results and PDG as well as LQCD data is obtained. Various predictions for the radiative decays can be tested in e.g., GlueX and CLAS12 experiments at Jefferson Lab. After applying the chiral model for well-established spin-2 mesons (with $J^{PC}=2^{++}$), I move on to their chiral partners (the axial-tensor mesons with $J^{PC}=2^{++}$), where the resonances are still missing. Large decay widths are predicted in the chiral model as well as in LQCD simulations.Furthermore, I describe the decays of the spin-2 tensor glueball $G_2(???)$ within the eLSM, which can be helpful in future experimental searches e.g., BESIII and LHCb experiments. Some isoscalar tensor resonances of PDG with a mass of around 2 GeV are studied, and at present, the best tensor glueball candidate turns out to be the broad resonance $f_2(1950)$. In the case of the ground-state spin-3 mesons ($J^{PC}=3^{--}$), our chiral model is limited to the $SU(3)$ flavor symmetry because of the yet unknown chiral partners ($J^{PC}=3^{++}$). The effective model results are in good agreement with the PDG data and LQCD results, and the predictions for the radiative decays can be interesting for photoproduction experiments such as GlueX and CLAS12. Additional estimates for the decay ratios of the $G_3(???)$ tensor glueball with $J^{PC}=3^{--}$ are also presented. The role of the glueball spectrum at non-zero temperature is explored within the Glueball Resonance Gas model below the critical temperature of the pure Yang-Mills sector of the QCD phase diagram. It turns out that the latest glueball spectrum from LQCD can well describe the pressure up to almost the critical temperature.