《polarised antineutrons》.pdfVIP

EPJ manuscript No. (will be inserted by the editor) A method to polarise antiprotons in storage rings and create 9 polarised antineutrons 0 0 Berthold Schoch 2 Physikalisches Institut, Universit¨at, Bonn, D-53115 Bonn, Germany l u J Received: date / Revised version: date 9 Abstract. An intense circularely polarised γ-beam interacts with a cooled antiproton beam in a storage ] ring. Due to spin dependent absorption cross sections for the reaction γ + p → π − + n a built-up of h polarisation of the stored antiprotons takes place. Figures-of-merit around 0.1 can be reached in principle p- over a wide range of antiproton energies. In this process polarised antineutrons with polarisation Pn ≻ 70% c emerge. The method is presented for the case of a 300 MeV/c cooled antiproton beam. c a. PACS. 13.88.+e polarisation in interactions and scattering – 29.20.Dh Storage rings – 29.27.Hj polarised s beams c i s y 1 Introduction * Spin=3/2 h p [ The preparation of polarised beams of nucleons and antin- ucleons at energies in the GeV region poses challenging p / 1 technical problems. In the case of protons powerful sources g v of polarised protons exist. Starting from low energies a 4 cascade of accelerators, all equipped with polarisation con- 7 serving beam optics, brings the proton beam to its design 0 Spin=1/2 6 1 energy. Antiprotons, however, are produced with high en- . ergy proton beams. Large acceptance storage rings are 7 used to collect and cool the produced antiprotons in or- Fig. 1. The int