Constraints on antisymmetric tensor fields from Bhabha scattering

Antisymmetric tensor fields are a compelling prediction of string theory. This makes them an interesting target for particle physics because antisymmetric tensors may couple to electromagnetic dipole moments, thus opening a possible discovery opportunity for string theory. The strongest constraints on electromagnetic dipole couplings would arise from couplings to electrons, where these couplings would contribute to Møller and Bhabha scattering. Previous measurements of Bhabha scattering constrain the couplings to $$ , where $$ is the mass of the antisymmetric tensor field and $$ is an effective mass scale appearing in the electromagnetic dipole coupling.