Transverse Single Spin Asymmetries in Electron Scattering on Hydrogen Targets

The asymmetry in the scattering of transversely polarized electrons off unpolarized protons or deuterons arises from the imaginary part of the two-photon-exchange amplitude. The A4 collaboration at the MAMI accelerator has performed measurements at various beam energies between 300~MeV and 1.5~GeV both at forward and backward angles. We present an overview about published data and unpublished preliminary results in the elastic scattering and discuss future analyses for inelastic asymmetries in the resonance region.