2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42242We present constraints on products of two leptoquark (LQ) coupling constants. The bounds are obtained from meson decays, in particular leptonic π, K, D, D_s, B, B_s decays. Furthermore semileptonic meson decays and mixing in neutral meson systems are discussed. We use the Buchmueller-Rueckl-Wyler-model for scalar and vector LQs. Bounds on R-parity violation can be extracted directly from the corresponding LQ bounds. Our results are listed in the Tables 6 (for LQs) and 7 (for SUSY particles) with english captions. The bounds of Davidson/Bailey/Campbell were updated. The SUSY-bounds of Dreiner/Polesello/Thormeier were reproduced.80 Pages, German Diploma Thesis in German, Abstract and Summary Tables in EnglishHigh Energy Physics - Phenomenologytext