Limit on theK+→π++ν+ν¯Decay Rate

Abstract

The branching ratio for the process $K^{+}\to {\pi }^{+}+\nu +\overline{\nu }$ is shown by a counter spark chamber experiment to be less than 1.2×${10}^{-6\mathrm{}}$ of all decay modes, assuming a pion energy spectrum like that of $K^{+}\to {\pi }^0+e^{+}+\nu$. Our apparatus was sensitive to pions in the kinetic energy range 117-127 MeV.