2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/36970Recent results by the NA48 collaboration on neutral kaons rare decays into the pi+ pi- e+ e- final state are presented. A large CP-violating asymmetry A(K_L)=(13.9+-2.7+-2.0)% has been observed in the K_L to pi+ pi- e+ e- decay. The K_S to pi+ pi- e+ e- decay has been observed for the first time, showing no such asymmetry.6 pages, 5 figures, LaTeX. To be published in the Proceedings of the 30th International Symposium on Multiparticle Dynamics (ISMD 2000), Tihany, Lake Balaton, Hungary, 9-15 Oct 2000High Energy Physics - Experimenttext