Experimental study of the decay $K_L^0\toπ^0ν\barν$
The first dedicated search for the rare neutral-kaon decay $K_L^0\toπ^0ν\barν$ 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.
hep-ex↗