2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/37316The neutral Kaon decays Ks->gamma gamma and Kl->pi0 gamma gamma are very sensitive to higher order loop effects of Chiral Perturbation Theory (ChPT). New measurements of the NA48 experiment show that ChPT contributions of O(p^6) cannot be neglected in these modes. In addition a new measurement of the related decay Kl->gamma gamma and an upper limit of the rate of Ks->pi0 gamma gamma are presented.12 pages, 9 included figures, to appear in proceedings of Heavy Quarks & Leptons 2002, May 28-31,2002, Vietri sul Mare, Salerno, ItalyHigh Energy Physics - Experimenttext