Dr Pok Man Lo, University of Wroclaw

Thermodynamics of Broad Resonances

In this talk we discuss the physics of the lightest resonances of QCD, i.e. the sigma and kappa mesons. These resonances are so broad that the standard Breit–Wigner dispersive analysis can not be applied. We motivate a theoretical analysis of the experimental phase shift data on pion-pion and pion-Kaon scattering. This allows us to explore the effects of broad resonances on thermodynamics. We also examine the role of chiral symmetry breaking in describing these phenomena by comparing different theoretical approaches, including the chiral effective model and lattice calculations.