Second-order Born calculation of the (e, 3e) process on the He atom in coplanar constant θ12 mode

We present the results of our first as well as second Born calculation for the (e, 3e) process on the He atom using the three Coulomb wave approach at two incident electron energies of 1099 and 5599 eV. We demonstrate the importance of second-order projectile-target interaction in the breaking of symmetry of the fivefold differential cross section (FDCS) about the direction of momentum transfer in constant theta(12) mode in coplanar geometry. Further, we note that the second Born calculation results in a shifting of the recoil peak, splitting of binary peak as well as enhancement of the recoil peak and also makes significant non-dipolar contributions to the FDCS.