Collective description of low energy mesonic states

The phenomenology of hadronic states at high energy is well described in the framework of quantum chromodynamics. By the other hand, that is the description of the low-energy regime, e.g., mesoniclike states, requires the introduction of effective degrees of freedom, a condition resulting from confinement. As an alternative to lattice gauge calculations, and own to the similarities with other quantum many-body systems, we have adopted a nonperturbative scheme where quarks are treated as quasiparticles. These quasiquarks interact between them, allowing mesonlike states to be described as collective superposition of quasiquark pairs. The results of the calculations, performed in the context of the random phase approximation method, show that this scheme is a suitable one to describe meson states up to energies of the order of couple of GeV.