Elastic scattering of protons by helium targets are analyzed using the effective-channel approach at incident laboratory energies of 590 and 720 MeV. The helium nuclear form factor obtained from the electron scattering is used in the direct elastic channel to improve the large angle behavior of the cross section. Lack of reliable $p-p$ and $p-n$ data at these energy ranges severely limits the accurate determination of the input parameters, and makes the present analysis less definite than in the 1 GeV case studied earlier. However, the qualitative features of the result of the calculation show that the effect of the inelastic channels specifically associated with the excitations of the target system during the collision is large at large angles, and that the calculated cross sections are somewhat lower than the experimental data. The Coulomb effect is also studied at the 590 MeV case and found to be small.

NUCLEAR REACTIONS ${}_{}{}^4{}_{}{}^{}\mathrm{He}(p,p)$ elastic cross sections at 0.59, 0.72, and 1.00 GeV, calculated by the effective-channel approach.

• Received 14 January 1976

DOI:https://doi.org/10.1103/PhysRevC.14.1102