Gauge theory of elementary particle Physics

Abstract

We perform a simultaneous analysis of s- and p-waves of the S=−1 meson–baryon scattering amplitude using all low-energy experimental data. For the first time, differential cross section data are included for chiral unitary coupled-channel models. From this model s- and p-wave amplitudes are extracted and we observe both well-known I(JP)=0(1/2−) s-wave states as well as a new I(JP)=1(1/2+) state absent in quark models and lattice QCD results. Multiple statistical and phenomenological tests suggest that, while the data clearly require an I=1 p-wave resonance, the new state just accounts for the absence of the decuplet Σ(1385)3/2+ in the model.