Rising cross-section and the real part of the forward amplitude in proton-proton scattering

In measurements performed at the CERN intersecting storage ring (ISR), a rising total cross-section for pp scattering was observed. On the other hand, a constant asymptotic cross-section was anticipated on the basis of lower-energy data. The consequences of the different behaviour of the total cross-section is discussed. The real part of the forward amplitude is calculated from the total cross-section with the aid of dispersion relations. The results are then compared with available measured real parts, in particular with those in the ISR energy region obtained by a Coulomb interference experiment. (8 refs)