Estimation of the branching ratio of the decay [ital K][sub [ital L]][sup 0][r arrow][ital e][sup +][ital e[minus]][ital e+][ital e[minus]] from the [ital K][sub [ital L]][sup 0][r arrow][ital e][sup +][ital e[minus]][ital X] process

In an experiment to search for the decay [ital K][sub [ital L]][sup 0][r arrow][ital ee] using the 12-GeV Proton Synchrotron at KEK, we observed 18 events with the [ital e][sup +][ital e[minus]] effective mass greater than 470 MeV/[ital c][sup 2]. They are presumed to come mainly from the decay [ital K][sub [ital L]][sup 0][r arrow][ital e][sup +][ital e[minus]][ital e+][ital e[minus]]. Subtracting the background from the decay [ital K][sub [ital L]][sup 0][r arrow][ital ee][gamma] and the external conversion of [gamma] in the decays [ital K][sub [ital L]][sup 0][r arrow][gamma][gamma] and [ital K][sub [ital L]][sup 0][r arrow][ital ee][gamma], the branching ratio of the decay [ital K][sub [ital L]][sup 0][r arrow][ital e][sup +][ital e[minus]][ital e+][ital e[minus]] is estimated to be (6[plus minus]2[plus minus]1)[times]10[sup [minus]8]. It is consistent with the previous experimental values.