Calculation of differential cross sections for proton-impact excitation of then=2levels of helium

Differential cross sections for the proton-impact $1{}_{}{}^1{}_{}{}^{}S\to 2{}_{}{}^1{}_{}{}^{}S$ and $1{}_{}{}^1{}_{}{}^{}S\to 2{}_{}{}^1{}_{}{}^{}P$ excitations of atomic helium are calculated at 25-, 50-, and 100-keV proton energies using the Glauber approximation. The sum of the results are compared with an earlier multistate eikonal calculation as well as with a very recent measurement. The angular dependence of the cross sections predicted by the Glauber theory is in reasonable agreement with the eikonal results and the observed data.