A dispersive approach to the CP conserving $K\to \pi {\ell }^{+}{\ell }^{-}$ radiative decays

Véronique Bernard, Sébastien Descotes-Genon, Marc Knecht +1

We reconsider the constraints on the form factors $W_{+}(s)$ and $W_S(s)$, describing the radiative decay modes $K^{+}\to {\pi }^{+}{\ell }^{+}{\ell }^{-}$ and $K_S\to {\pi }^0{\ell }^{+}{\ell }^{-}$, associated wi…