2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197178At the HERA collider at DESY, high energy electron and positron beams interact with proton beams. A review is presented of the variety of ways in which these collisions produce final states containing charm and beauty quarks.45 pages including 30 figures. Submitted to International Journal of Modern Physics AHigh Energy Physics - Phenomenologytext