Resonances and the Weinberg – Tomozawa 56 - baryon – 35 - meson interaction

Resonances and the Weinberg–Tomozawa 56-baryon –35-meson interaction. Abstract. Vector meson degrees of freedom are incorporated into the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian by using a scheme which relies on spin–flavor SU(6) symmetry. The corresponding Bethe-Salpeter approximation successfully reproduces previous SU(3)–flavor WT results for the lowest-lying s–wave negative parity baryon resonances, and it also provides some information on the dynamics of the heavier ones. Moreover, it also predicts the existence of an isoscalar spin-parity 3 2 − K * N bound state (strangeness +1) with a mass around 1.7–1.8 GeV, unstable through K * decay. Neglecting d-wave KN decays, this state turns out to be quite narrow (Γ ≤ 15 MeV) and it might provide clear signals in reactions like γp → ¯ K 0 pK + π − by looking at the three body pK + π − invariant mass.