Impact of In-Medium on the Proton–Nucleon Scattering Amplitude in the Proton–Nucleus Scattering at Incident Energies 12.7–1000 MeV

The effect of nuclear medium on the proton-nucleon amplitude of scattering is investigated by analysing experimental data on the elastic scattering differential cross sections of protons on the target nucleus 90Zr at the wide range of incident energies from 12.7 to 1000 MeV. This effect has a major impact on the proton-nucleon cross section σ, the most physically significant parameter of the proton–nucleus interaction potential. The in-medium parameter σ, which effectively reproduces experimental data at low incident energies, is significantly smaller than that in the case of scattering on the free nucleon. In contrast, at high incident energies, both the “in-medium” and “free” parameters σ are fairly similar to one another.