Status of Nucleon Resonances with Masses $M<M_N+M_{\ddot{I}}€$

Abstract

We discuss different interpretations of peaks observed a few years ago by Tatischeff et al. in missing mass spectra of the reaction $pp->p{i}^{+}pX$, which were declared as new exited nucleon states with small masses. A study of the possible production of such states in the process ${\hat{I}}^{3}p->p{i}^{+}{N}^{\ast }->p{i}^{+}+{\hat{I}}^3{\hat{I}}^{3}n$ by analyzing the invariant mass spectrum of ${\hat{I}}^3{\hat{I}}^{3}n$ is proposed. It is shown that the data, obtained recently at MAMI-B, can allow to analyze this process and to get information about an existence of exited nucleon states with small masses.

4 pages, 2 figures, LaTeX with ws-p8-50x6-00.cls. Talk presented at the NSTAR2001 Workshop, Mainz, Germany, March 7-10, 2001