Some rare decay modes of theKmeson in the modified baryon-loop model.KL→π0γγandKL→π0e+e−decays

Abstract

The $K_L\to {\pi }^0\gamma \gamma$ decay rate calculated in the zero-parameter modified baryon-loop model is found to be 38 and 43 ${\sec }^{-1\mathrm{}}$ for mean vector-meson masses of 0.9 and 0.8 GeV respectively. Using unitarity, a lower bound (and estimate) is obtained on the decay rate for $K_L\to {\pi }^0{e}^{+}{e}^{-}$ which goes via $K_L\to {\pi }^0 \left(\mathrm{virtual}\right)\gamma \left(\mathrm{virtual}\right)\gamma$ in the modified loop model. We find $\left[\frac{\Gamma (K_L\to {\pi }^0{e}^{+}{e}^{-})}{\Gamma (K_L\to \mathrm{all})}\right]\gtrsim 2.1\times {10}^{-13\mathrm{}}$.