  Electron-positron pair production in combined laser and Coulomb fields is
studied. To this end, the Feynman diagram for multiphoton pair creation by muon
impact on a circularly polarized high-frequency laser beam is evaluated within
the framework of laser-dressed quantum electrodynamics employing relativistic
Volkov states. In the limit of low laser intensity, the result is shown to
coincide with the known expression for multiphoton pair creation by a proton
which is treated as an external Coulomb field. A scaling of the total pair
creation rate is analyzed. The recoil distribution is calculated numerically
and its dependence on the projectile mass is discussed. Energy spectra of the
created particles and angular spectra of the scattered muon are presented.
