Search for Low Mass Exotic leptonic or bosonic structures

Recently, several papers discussed the existence of a low mass leptonic structure. It was suggested that the ${\mathrm{\Sigma }}^{+}$ disintegration: ${\mathrm{\Sigma }}^{+}\to$pP${}^0$, P${}^0\to {\mu }^{-}{\mu }^{+}$ proceeds through an intermediate particle P${}^0$ having a mass close to M$\approx$~214.3 MeV. The present work intends to look at other available data, in order to observe the eventual existence of a small peak or shoulder, at a mass close to M=214.3 MeV, which can strengthen the existence of a state produced by two leptons of opposite electric charge.