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HK: Physik der Hadronen und Kerne
HK 2: Elektromagnetische und Hadronische Proben
HK 2.7: Talk
Friday, March 4, 2005, 15:45–16:00, TU MA001
Spin Physics with Polarized Antiprotons at HESR (FAIR-GSI) — •Erhard Steffens1, Paolo Lenisa2, Frank Rathmann3, Paola Ferretti-Dalpiaz2, Marco Contalbrigo2, Andro Kacharava1,3, Davide Reggiani1, and Sergey Yaschenko1,3 — 1Physik. Inst., Univ. Erlangen-Nürnberg — 2Univ. of Ferrara and INFN — 3Inst. für Kernphysik, FZ Jülich
A proposal to add an antiproton polarizer ring (APR) to the FAIR facility is being prepared by the PAX Collaboration [1]. It consists of a low-energy storage ring with electron cooling and internal polarized hydrogen gas target with high electron polarization. Recent calculations have shown that by ’Spin Filtering’ at energies of 40-100MeV surprisingly high polarization degrees for antiprotons in the order of 0.2-0.4 can be achieved [2] which surpasses by more than one order of magnitude the result of a previous test experiment with protons [3]. The new method is based on spin-exchange of the target electrons to the circulating antiprotons which is purely electro-magnetic and calculable [4]. The beam from the APR will be transfered to the high energy storage ring HESR and accelerated to the final energy of 15GeV or more. The physics case comprises the first direct measurement of the transversity h1 in Drell-Yan [5]. The present status of the lay-out of the experiment and the detector concept will be presented.
[1] http://www.fz-juelich.de/ikp/pax [2] F. Rathmann et al, submitted to PRL; eprint: physics/0410067 [3] F. Rathmann et al, PRL 71, 1379 (1993) [4] C.J. Horowitz and H.O. Meyer, PRL 72, 3981 (1994) [5] M. Anselmino et al, Phys. Lett. B594, 97 (2004), eprint: hep-ph/0403114