2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39872Starting from general considerations about the different concepts which exist for the definition of the quark mass near the pair production threshold, we introduce the definition of a mass with a dynamic degree of freedom that extends the previously given concept of the static PS mass.18 pages in LaTeX including 5 PostScript figures, talk given by Stefan Groote at the Laboratory of Nuclear Studies, Cornell Univerity, Ithaca, NY, Aug 23rd, 2000High Energy Physics - Phenomenologytext