2. Protons with energy 1.0MeV scatter off a fixed spherical potential whose range is known to be a = 10-13 cm. The total elastic scattering cross section σ and the differential cross section do/d are measured to a precision of about one percent. (a) Assuming that the energy is not near any resonance of the potential, show that the only phase shifts that can be reliably determined from the data are do and ₁.

2. Protons with energy 1.0MeV scatter off a fixed spherical potential whose range is known to be a = 10-13 cm. The total elastic scattering cross section σ and the differential cross section do/d are measured to a precision of about one percent. (a) Assuming that the energy is not near any resonance of the potential, show that the only phase shifts that can be reliably determined from the data are do and ₁.