Complete QED Theory of Multiphoton Trident Pair Production in Strong Laser Fields

Electron-positron pair creation by multiphoton absorption in the collision of a relativistic electron with a strong laser beam is calculated within laser-dressed quantum electrodynamics. Total production rates, positron spectra, and relative contributions of different reaction channels are obtained in various interaction regimes. We study the process in a manifestly nonperturbative domain which is shown accessible to future experiments utilizing the electron beam lines at novel x-ray laser facilities or all-optical setups based on laser acceleration. Our theory moreover allows us to add further insights into the experimental data from SLAC [D. Burke et al., Phys. Rev. Lett. 79, 1626 (1997).].