Report on the spin-filtering test performed at COSY in autumn 2011

In autumn 2011, the PAX Collaboration completed the spin-filtering experiment with protons at COSY. The main result of this study is a measurement of the spin-dependent proton-proton cross section that confirms the present understanding of the proton-proton interaction in the spin-filtering process; the measured spin-dependent cross section is in excellent agreement with the theoretical predictions.