Radiative Semileptonic Kaon Decays

J. Bijnens, G. Ecker, J. Gasser

We evaluate the matrix elements for the radiative kaon decays $K^{+}\to l^{+}{\nu }_l\gamma$, $l^{+}{\nu }_l{l}^{\prime +}{l}^{\prime -}$ and $K\to \pi l{\nu }_l\gamma$ \ ($l,l^{\prime }=e,\mu$) to next-to-leading order in chiral pertu…