Polarisation observables constitute a powerful tool for establishing the production mechanism of the eta meson and for infering the presence of higher partial waves in the final system. Measurements of the proton analysing power for the p(pol.)p->pp eta reaction have been performed by the COSY-11 group at three different excess energies: Q = 10, 37 and 40 MeV. Data at Q = 40 MeV indicate that the eta meson is probably produced in partial waves higher than s wave.
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E-print: http://xxx.lanl.gov/abs/nucl-ex/0312006
AIP
Conf.Proc.
717 (2004) 858-862