First search for KL→π0π0νν¯

The first search for the rare kaon decay K-L ->pi(0)pi(0)nu(nu) over bar has been performed by the E391a collaboration at the KEK 12-GeV proton synchrotron. An upper limit of 4.7x10(-5) at the 90% confidence level was set for the branching ratio of the decay K-L ->pi(0)pi(0)nu(nu) over bar using about 10% of the data collected during the first period of data taking. First limits for the decay mode K-L ->pi(0)pi P-0, where P is a pseudoscalar particle, were also set.