2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/44600After a brief review (in the first part) of some relevant properties of the high-energy parton-parton scattering amplitudes, in the second part we shall discuss the infrared finiteness and some analyticity properties of the loop-loop scattering amplitudes in gauge theories, when going from Minkowskian to Euclidean theory, and we shall see how they can be related to the still unsolved problem of the s-dependence of the hadron-hadron total cross-sections.Talk given at the ``XIth International Conference on Elastic and Diffractive Scattering'' (EDS 2005), XVIIth Rencontre de Blois, Chateau de Blois (France), 15-20 May 2005; 6 pagesHigh Energy Physics - Phenomenologytext