Polarizing a stored proton beam by spin flip?

• DOI: 10.1016/j.physletb.2009.03.037
• Publication Date: 2009-03-26T09:19:29Z
• Authors: D. Oellers; L. Barion; S. Barsov; U. Bechstedt; P. Benati; S. Bertelli; D. Chiladze; G. Ciullo; M. Contalbrigo; P.F. Dalpiaz; J. Dietrich; N. Dolfus; S. Dymov; R. Engels; W. Erven; A. Garishvili; R. Gebel; P. Goslawski; K. Grigoryev; H. Hadamek; A. Kacharava; A. Khoukaz; A. Kulikov; G. Langenberg; A. Lehrach; P. Lenisa; N. Lomidze; B. Lorentz; G. Macharashvili; R. Maier; S. Martin; S. Merzliakov; I.N. Meshkov; H.O. Meyer; M. Mielke; M. Mikirtychiants; S. Mikirtychiants; A. Nass; M. Nekipelov; N.N. Nikolaev; M. Nioradze; G. d'Orsaneo; M. Papenbrock; D. Prasuhn; F. Rathmann; J. Sarkadi; R. Schleichert; A. Smirnov; H. Seyfarth; J. Sowinski; D. Spoelgen; G. Stancari; M. Stancari; M. Statera; E. Steffens; H.J. Stein; H. Stockhorst; H. Straatmann; H. Ströher; M. Tabidze; G. Tagliente; P. Thörngren Engblom; S. Trusov; A. Vasilyev; Chr. Weidemann; D. Welsch; P. Wieder; P. Wüstner; P. Zupranski
• Keywords: Antiproton; Electron cooling

We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin flip cross section in low-energy electron-proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.<br/>18 pages, 6 figures<br/>