Search for Low Mass Exotic mesonic structures. Part II: attempts to understand the experimental results

Abstract

Our previous paper, part I of the same study, shows the different experimental spectra used to conclude on the genuine existence of narrow, weakly excited mesonic structures, having masses below and a little above the pion (M=139.56 MeV) mass. This work \cite{previous} was instigated by the observation, in the $\Sigma^{+}$ disintegration: $\Sigma^{+}\to$pP$^{0}$, P$^{0}\to\mu^{-}\mu^{+}$ \cite{park}, of a narrow range of dimuon masses. The authors conclude on the existence of a neutral intermediate state P$_{0}$, with a mass M=214.3 MeV $\pm$ 0.5 MeV. We present here some attempts to understand the possible nature of the structures observed in part I.