  In the quasistatic regimes of nonlinear Breit-Wheeler and trident pair
creation, the rates can exhibit a non-analytic dependency on the fundamental
coupling of quantum electrodynamics (QED), in a form similar to Schwinger
vacuum pair creation. To reach this tunneling regime requires satisfying
competing requirements: high intensity but low strong-field parameter with
sufficient pair creation to be observed. Using a locally monochromatic
approach, we identify the parameter regime where tunneling pair-creation could
be measured for the first time in experiment. Studying several scenarios of
collisions with focussed Gaussian pulses, including a bremsstrahlung and an
inverse Compton source for nonlinear Breit-Wheeler and a Gaussian electron beam
for nonlinear trident, we find the position of the tunneling parameter regime
to be well-defined and robust.
