Antiproton-proton scattering experiment with polarization (update)

Barone, V.; B. Q., Ma; Goeke, K.; Metz, A.; Bisplinghoff, P. Schweitzer J.; Eversheim, P. D.; Hinterberger, F.; Meissner, U. G.; Rohdjess, H.; Sibirtsev, A.; Montag, C.; Vogelsang, W.; D'Alesio, U.; Murgia, F.; Buttimore, N.; Efremov, A.; Teryaev, O.; Dymov, S.; Kadagidze, N.; Komarov, V.; Kulikov, A.; Kurbatov, V.; Leontiev, V.; Macharashvili, G.; Merzliakov, S.; Meshkov, I.; Serdjuk, V.; Sidorin, A.; Smirnow, A.; Syresin, E.; Trusov, S.; Uzikov, Y.; Volkov, A.; Zhuravlev, N.; Ivanov, O.; Krivokhizhin, V.; Meshcheryakov, G.; Nagaytsev, A.; Peshekhonov, V.; Savin, A. A.; Shaikhatdenov, B.; Shevchenko, O.; Yarygin, G.; Eyrich, W.; Kacharava, A.; Krauss, B.; Lehmann, A.; Reggiani, D.; Rith, K.; Seidel, R.; Steffens, E.; Stinzing, F.; Tait, P.; Yaschenko, S.; Capiluppi, Marco; Ciullo, Giuseppe; Contalbrigo, Marco; Drago, Alessandro; Ferretti, Paola; Giordano, Francesca; Lenisa, Paolo; Pappalardo, Luciano Libero; Stancari, Giulio; Stancari, Michelle Dawn; Statera, Marco; Avetisyan, E.; Bianchi, N.; De Sanctis, E.; Di Nezza, P.; Fantoni, A.; Hadjidakis, C.; Hasch, D.; Mirazita, M.; Muccifora, V.; Ronchetti, F.; Rossi, P.; Barsov, S.; Belostotski, S.; Grebenyuk, O.; Grigoriev, K.; Izotov, A.; Jgoun, A.; Kravtsov, P.; Manaenkov, S.; Mikirtytchiants, M.; Mikirtytchiants, S.; Miklukho, O.; Naryshkin, Y.; Vassiliev, A.; Zhdanov, A.; Ryckbosch, D.; Jiang, Y.; H. J., Lu; W. G., Ma; Shen, J.; Y. X., Ye; Yin, Z. J.; Zhang, Y. M.; Chiladze, D.; Gebel, R.; Engels, R.; Felden, O.; Haidenbauer, J.; Hanhart, C.; Hartmann, M.; Keshelashvili, I.; Krewald, S.; Lehrach, A.; Lorentz, B.; Martin, S.; Meissner, U. G.; Nikolaev, N.; Prasuhn, D.; Rathmann, F.; Schleichert, R.; Seyfarth, H.; Stroher, H.; Bruncko, D.; Ferencei, J.; Musinsky, J.; Urban, J.; Wiedner, C.; Coriano, C.; Guzzi, M.; Wise, T.; Ratcliffe, P.; Baru, V.; Gasparyan, A.; Grishina, V.; Kondratyuk, L.; Kudriavtsev, A.; Bagulya, A.; Devitsin, E.; Kozlov, V.; Terkulov, A.; Zavertiaev, M.; Bogdanov, A.; Nurushev, S.; Okorokov, V.; Runtzo, M.; Strikhanov, M.; Shatunov, Y.; Pire, B.; Belikov, N.; Chujko, B.; Kharlov, Y.; Korotkov, V.; Medvedev, V.; Mysnik, A.; Prudkoglyad, A.; Semenov, P.; Troshin, S.; Ukhanov, M.; Chiladze, B.; Lomidze, N.; Machavariani, A.; Nioradze, M.; Sakhelashvili, T.; Tabidze, M.; Trekov, I.; Kurdadze, L.; Tsirekidze, G.; Anselmino, M.; Boglione, M.; Prokudin, A.; Thorngren Engblom, P.; Liuti, S.; Augustyniak, W.; Marianski, B.; Szymanowski, L.; Trzcinski, A.; Zupranski, P.; Akopov, N.; Avagyan, R.; Avetisyan, A.; Elbakyan, G.; Hakopov, Z.; Marukyan, H.; S. Taroian .,

Upgrading to the document High Energy Physics Esperiment (hep-ex/0505054). The document describes the physics case of the PAX experiment using polarized antiprotons, which has recently been proposed for the new Facility for Antiprotons and Ions Research (FAIR) at GSI--Darmstadt. Polarized antiprotons provide access to a wealth of single-- and double--spin observables, thereby opening a new window to physics uniquely accessible at the HESR. The polarized antiprotons would be most efficiently produced by spin--filtering in a dedicated Antiproton Polarizer Ring (APR) using an internal polarized hydrogen gas target. In the proposed collider scenario of the PAX experiment, polarized protons stored in a COSY--like Cooler Storage Ring (CSR) up to momenta of 3.5 GeV/c are bombarded head--on with 15 GeV/c polarized antiprotons stored in the HESR. This asymmetric double--polarized antiproton--proton collider is ideally suited to map, e.g., the transversity distribution in the proton. The proposed detector consists of a large--angle apparatus optimized for the detection of Drell--Yan electron pairs