Lepton pair decays of the $K_L$ meson in the light-front model

We analyze the $K_L$ lepton pair decays of $K_L \to l^+\l^-\gamma$ and $K_L \to l^+l^-l'^+l'^- (l, l'=e, \mu)$ within the framework of the light-front model. With the $K_L \to \gamma^* \gamma^*$ form factors evaluated in the model, we calculate the decay branching ratios of the modes and we find out that our results are all consistent with the experimental data. In addition, we have a discussion about the $K_L \to l^+l^-$ decay.