Pomeron and P' exchange amplitudes for $pi$--N scattering

I t is one of the most interesting problems to separate pomeron and P ' exchange amplitudes for elastic scattering. Previously we have analysed the It = 0 amplitudes for ~ -~ ' scattering at 6 GeV/c and have studied the p,'opertics of the pomeron term 11) under the assumption that the imaginary part of the helicity-nonflip amplitude due to the P ' trajectory has the form of Alex p [ B l t ] J 0 ( r V t ) with r_~10 -1acre. In this pape,' we discuss the properties of the pomeron (P) and P ' exchange amplitudes on the other promising models, since the tensor exchange amplitudes may not be described well by the dual a.bsorptive model ('~) as was pointed out hy some authors 13). Rcceutly, Fr, RRO Fo.~'ras et al. (~) have tried to separate thc imaginary part of the forward scattering amplitude into two parts