Analysing power A_y in the reaction p(pol) p --> p p eta close to   threshold
  Measurements of the eta meson production with a polarised proton beam in the reaction p(pol) p --> p p eta have been carried out at an excess energy of Q = 40 MeV. The dependence of the analysing power A_y on the polar angle theta^*_q of the eta meson in the center of mass system (CMS) has been studied. The data indicate the possibility of an influence of p- and d-waves to the close to threshold eta production. 
P. Winter, H.-H. Adam, F. Bauer, A. Budzanowski, R. Czyzykiewicz, T.   Goetz, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian,...