Analysing power A_y in the reaction p(pol) p --> p p eta close to threshold

Abstract

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.

6 pages, 5 figures, in section 3.1 the formula of vec(p) containing fatal typos was removed, and the values in table were corrected