Why and are so narrow?
K. P. Khemchandani🇧🇷 · A. Martínez Torres🇧🇷 · A. Hosaka🇯🇵 · H. Nagahiro🇯🇵 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷
The baryons are expected to be naturally narrower as compared to their nonstrange and strange counterparts since they have only one light quark and, thus, their decay involves producing either a light meson and doubly strange baryon or both meson and baryon with strangeness which involves, relatively, more energy. In fact, some 's have full widths of the order of even 10-20 MeV when, in principle, they have a large phase space to decay to some open channels. Such is the case of , for which the width has been found to be of the order of 10 MeV in the latest {\it BABAR} and BELLE data. In this manuscript we study why some 's are so narrow. Based on a coupled channel calculation of the pseudoscalar meson-baryon and vector meson-baryon systems with chiral and hidden local symmetry Lagrangians, we find that the answer lies in the intricate hadron dynamics. We find that the known mass, width, spin-parity and branching ratios of can be naturally explained in terms of coupled channel meson-baryon dynamics. We find another narrow resonance which can be related to . We also look for exotic states and but find none. In addition we provide the cross sections for which can be useful for understanding the enhanced yield of reported in recent studies of heavy ion collisions.