Exclusive production ratio of neutral to charged kaon pair in e+e− annihilation continuum via a relativistic quark model

A completely relativistic quark model in the Bethe-Salpeter framework is employed to calculate the exclusive production ratio of the neutral to charged kaon pair in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation continuum region below the $J/\mathrm{\ensuremath{\Psi}}$ mass. The valence quark charge plays the key role. The cancellation of the diagrams for the same charge case (${K}_{S}+{K}_{L}$) and the noncancellation of the diagrams for the different charge case (${K}^{\ensuremath{-}}+{K}^{+}$) lead to the ratio as ${({m}_{s}\ensuremath{-}{m}_{d})}^{2}/{M}_{kaon}^{2}\ensuremath{\approx}1/10$.