E787 and E949
Plot of data from the E787 and E949 study of K+→π+ννbar, showing the range and energy distributions of charged pions passing all other cuts. The circles represent E787 data and the triangles E949 data. The group of events around E = 108 MeV are due to K+→π+π0 background. The simulated distribution of K+→π+ννbar is indicated by dots. The solid line (dashed line) box represents the signal region for E949 (E787).