  It is shown that above-threshold ionization peaks disappear when the kinetic
energy associated with the nondipole radiation-pressure-induced photoelectron
momentum in the laser propagation direction becomes comparable to the photon
energy, and how peaks can be made reappear if knowledge of the length and
direction of the photoelectron momentum is at hand and an
emission-direction-dependent momentum shift is accounted for. The reported
findings should be observable with intense mid-infrared laser pulses.
