Minicharged particles in light-shining-through-wall-experiments and the photon polarization tensor.

Babette Doebrich, Holger Gies & Felix Karbstein
A first theoretical feasibility study for a novel "light-shining-through-wall" scenario in the presence of an external magnetic field is performed. In contrast to standard scenarios, the barrier is not traversed by means of weakly interacting on-shell particles, but by virtual minicharged particle-antiparticle states. The study of this process heavily relies on the knowledge of the photon polarization tensor in the non-perturbative regime, and in particular requires its full momentum dependence, thereby rendering conventional approximations inapplicable....