Monoenergetic electron-beam stimulated light-dressing-induced resonance in a helium atom

We present a theoretical study of energetic electron-beam excitation of 'six-level helium atom' embedded in a laser field. The angular distribution of the scattered electron-beam, which contains all information about the combined interactions, is analyzed and exhibits a resonant peak in the vicinity of the 1sns-1snp (n = 2, 3) transitions. Here, we show that this resonant feature can be stimulated by means of the transferred momentum between the collision partners during the scattering process. By manipulating the latter parameter, one can enhance the resonant peak or lead to its attenuation and even to its cancellation. Our findings are supported by additional calculations based on the time-dependent perturbation theory, where a spurious divergence is expected at a resonant region.