2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/178679A search for the decay $K_S\toπ^0γγ$ has been made using the NA48 detector at the CERN SPS. Using data collected in 1999 during a 40-hour run with a high-intensity $K_S$ beam, an upper limit for the branching ratio $BR(K_S\toπ^0γγ, z\ge 0.2)<3.3\times\nolinebreak 10^{-7}$ has been obtained at 90% confidence level, where $z=m_{γγ}^2/m_{K_0}^2$.12 pages, 4 figures; Submitted to Phys. Lett. BHigh Energy Physics - Experimenttext