  The first dedicated search for the rare neutral-kaon decay
$K_L^0\to\pi^0\nu\bar{\nu}$ has been carried out in the E391a experiment at the
KEK 12-GeV proton synchrotron. The final upper limit of 2.6 $\times 10^{-8}$ at
the 90% confidence level was set on the branching ratio for the decay.

High Energy Physics - Experiment