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 $K^{-}p\to \gamma \Lambda ,\gamma {\Sigma }^0$ reactions. With the parameters governed by chiral SU(3) symmetry, we show that the predicted branching ratios ${\Gamma }_{K^{-}p\to \gamma \Lambda }/{\Gamma }_{K^{-}p\to all}$ and ${\Gamma }_{K^{-}p\to \gamma {\Sigma }^0}/{\Gamma }_{K^{-}p\to all}$ are close to the experimental values. The coupling with the $\eta$ 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 $\Lambda (1405)$ as a quasi-bound meson-baryon state as found in other similar chiral approaches.

Comments: 19 pages, 2 figures, RevTeX