Non-perturbative chiral approach to Kp -->gamma Y reactions

Abstract

A recently developed nonperturbative chiral approach to describe the S=-1 meson-baryon reactions has been extended to investigate the near threshold $K^- p \to γΛ, γΣ^0$ reactions. With the parameters governed by chiral SU(3) symmetry, we show that the predicted branching ratios $Γ_{K^- p \to γΛ}/Γ_{K^- p \to all}$ and $Γ_{K^-p\to γΣ^0}/Γ_{K^- p \to all}$ are close to the experimental values. The coupling with the $η$ channels, which was shown to be important in the $S=-1$ meson-baryon reactions, is also found to be significant here. Our results are consistent with the interpretation of the $Λ(1405)$ as a quasi-bound meson-baryon state as found in other similar chiral approaches.