Some problems of determination of the spin structure of the scattering   amplitude and experiments at NICA
  The existing experimental data are examined under different assumptions about the structure of the scattering amplitude of the proton-proton and proton-antiproton elastic scattering at high energy to obtain the value of rho(s,t), the ratio of the real to imaginary part of the scattering amplitude in the Coulomb-hadron interference region. It is shown that the deviation of rho(s,t) obtained from the experimental data of the proton-antiproton scattering at 3.8 < P_L <6.2 GeV/c from the dispersion analysis is concern in all examined assumptions. 
O.V. Selyugin
hep-ph hep-ex