Photonic processes in Born-Infeld theory

We study the processes of photon-photon scattering and pho-ton splitting in a magnetic field in Born-Infeld theory. In both cases we combine the terms from the tree-level Born-Infeld La-grangian with the usual one-loop QED contributions, where those are approximated by the Euler-Heisenberg Lagrangian, includ-ing also the interference terms. For photon-photon scattering we obtain the total cross section in the low-energy approximation. For photon splitting we compute the total absorption coefficient in the hexagon (weak field) approximation, and also show that, due to the non-birefringence property of Born-Infeld theory, the selection rules found by Adler for the QED case continue to hold in this more general setting. We discuss the bounds on the free parameter of Born-Infeld theory that may be obtained from this type of processes. ar X i