2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202627Resonances appearing in hadronic scattering processes are described by a two-phase model. In the one phase, scattering products are observed, whereas the other phase describes confinement. A so-called ``Resonance-Spectrum Expansion'' is derived, containing expressions that resemble Breit-Wigner formulae. This method also provides a straightforward explanation for the origin of the light scalar mesons without requiring extra degrees of freedom.LaTeX, 30 pages + 2 figuresHigh Energy Physics - Phenomenologytext