One-Boson-Exchange Modes and Two- and Three-Pion Exchange in Nucleon-Nucleon Interaction. I

The experimental values for the left-hand-cut contributions in T= 1 nudeon,nucleon scattering in the elastic region are analysed by the one-, twoand three~pion-exchange contributions. As the two-pion-exchange amplitudes, we use the ones calculatecl. by Furuichi and Watari from the CGLN amplitudes for N+N~TC+TC. The three-pion-exch~~~e amplitudes are treat~d phenomenologically by bosonizing them. The results show that we can explain nucleon-nucleon scattering by the uncorrelated two-pion-exchange contributions without scalar meson if we take the small cutoff for the squared momentum of the exchanged pions as tma"X"'-'9J1.2. It is also found that the three-pion-exchange modes would not contribute if we take g1t2/4TC as 14.4, the usually assumed value, or larger and that the effective coupling constants of the three-pion modes are g~v/4TC<10 aridg~s/4TC<20, assuming the reso.nance masses as the effective masses for the three-pion modes.