Dispersive analysis of the Primakoff reaction gamma K -> K pi

We provide a dispersion-theoretical representation of the reaction amplitudes gamma K -> K pi in all charge channels, based on modern pion-kaon P-wave phase shift input. Crossed-channel singularities are fixed from phenomenology as far as possible. We demonstrate how the subtraction constants can be matched to a low-energy theorem and radiative couplings of the K(892) resonances, thereby providing a model-independent framework for future analyses of high-precision kaon Primakoff data.