Measurement of the transverse target and beam-target asymmetries in   $\eta$ meson photoproduction at MAMI
  We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the $\vec \gamma \vec p\to\eta p$ reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of $\eta$ meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed. 
C.S.Akondi, J.R.M.Annand, H.J.Arends, R.Beck, A.Bernstein, N.Borisov,   A.Braghieri, W.J.Briscoe, S.Cherepnya, C.Collicott, ...
nucl-ex hep-ex nucl-th