Dispersive analysis of the Primakoff reaction $$\gamma K \rightarrow K \pi $$
Maximilian Dax, Dominik Stamen, Bastian Kubis
Abstract
Abstract We provide a dispersion-theoretical representation of the reaction amplitudes $$\gamma K\rightarrow K \pi $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>γ</mml:mi> <mml:mi>K</mml:mi> <mml:mo>→</mml:mo> <mml:mi>K</mml:mi> <mml:mi>π</mml:mi> </mml:mrow> </mml:math> 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 $$K^*(892)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>892</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> </mml:mrow> </mml:math> resonances, thereby providing a model-independent framework for future analyses of high-precision kaon Primakoff data.