Light scalars as tetraquarks or two-meson states from large-N-c and unitarized Chiral Perturbation Theory

摘要

By means of unitarized Chiral Perturbation Theory it is possible to obtain a remarkable description of meson-meson scattering amplitudes up to 1.2 GeV, and generate poles associated to scalar and vector resonances. Since Chiral Perturbation Theory is the QCD low energy effective theory, it is then possible to study its large-N-c limit where q (q) over bar states are easily identified. The vectors thus generated follow closely a q (q) over bar behavior, whereas the light scalar poles follow the large-N-c behavior expected for a dominant tetraquark or two-meson structure.