Experimental-theoretical comparisons of 11S to 21P differential magnetic sublevel cross sections for electron-helium scattering at 60 eV and 80 eV

Experimental absolute differential cross sections (DCS) for the excitations 1 1 S to 2 1 P and 2 3 P in helium are reported at incident electron energies of 60 eV and 80 eV, and at scattering angles between 5 degrees and 136 degrees . By combining the present DCS measurements for the 2 1 P excitation with results of recent electron-photon coincidence measurements, absolute DCS for the excitation of the individual magnetic sublevels 2 1 P 0 and 2 1 P +or-1 are obtained from purely experimental data. These magnetic sublevel cross sections, as well as their sum, are compared with results of calculations in the multichannel eikonal, distorted-wave and first-order many-body theories.