Muon pair production in electron-positron collisions close to threshold in the presence of a strong laser field
Within the framework of strong-field quantum electrodynamics, we study the creation of muon-antimuon pairs in laser-assisted collisions of electrons with positrons, whose center-of-mass energy is close to the threshold of the process. Our focus lies on incident collision energies slightly below the threshold, where the associated energy gap has to be overcome by multiphoton absorption from the applied high-intensity laser field while the collision occurs. We calculate the cross section of the process and discuss its nonperturbative dependencies on the energy gap and the laser parameters. Three qualitatively different interaction regimes are identified, where the influence of the laser field either has a classical or fully quantum nature. In the latter case, an exponential dependence of the cross section on the collision parameters is found, which resembles the Schwinger effect.