Abstract. The construction of the PAX installation was inspired by the idea to make a beam of polarized antiprotons available for the experiments at the HESR FAIR. A spin filtering experiment with transversally polarized protons was realized using the new PAX installation at COSY. The results of this measurement are in perfect agreement with the FILTEX experiment. Hence, filtering is a viable method to produce a stored beam of polarized antiprotons. Another experiment which can be pursued using the PAX installation is the test of Time Reversal Invariance at COSY (TRIC). The goal of the TRIC experiment is to improve the present upper limit on violation of the T-odd P-even interaction by an order of magnitude using a genuine null observable available in a double polarized pd scattering. The status of the PAX spin filtering experiments as well as present understanding of the possible systematic uncertainties in TRIC are presented in this contribution. PAX spin filtering experimentsHigh intensity polarized antiproton beams are not yet available for the experiments, although the potential of studies with polarized antiproton beams for physics is enormous. A detailed physics program with polarized beams of protons and antiprotons can be found in Ref. [1]. The Polarized Antiproton eXperiments (PAX) collaboration has taken over this challenge, and formulated the way to produce high intensity beams of polarized antiprotons. On the first stage of the PAX program all the methods and equipment should be tested for use with proton beams. As a second step, experiments with antiproton beams should be performed to demonstrate that it is possible to produce the first ever high intensity beam of polarized antiprotons. Finally, the HESR installation should be extended to realize the ambitious physics program with double polarized proton-antiproton experiments proposed by the PAX collaboration [1].There are two ways to polarize an initially unpolarized beam of spin 1/2 particles stored in the accelerator: particles with undesired directions of spin either should change the orientations of their spins (spin flip) or should be eliminated from the beam (spin filtering). The spin flip method would allow to preserve beam intensity and hence would be preferable over spin filtering. However, no reliable method for spin flipping has been proposed up to now. In Ref.[2] the possibility of producing beams of polarized antiprotons using the interaction between antiproton beams and polarized beams of positrons was suggested. To test the feasibility of this method the PAX collaboration performed a measurement of the spin flip cross section using an
The PREFER (Polarization REsearch for Fusion Experiments and Reactors) collaboration aims to address the know-hows in different fields and techniques to the challenging bet on fusion with polarized fuel. The efforts on a variety of duties and goals are shared between different research groups, indicated here by underlining in the authors' list the scientific responsibles. Starting from still open questions of fusion reaction physics, as for example the study of D+D spin-dependent cross-sections (Vasilyev) to the acceleration of polarized ions from laser-induced plasmas (Büscher), there are many connections between the involved research groups. The collaboration is also tackling the production of nuclear polarized molecules, recombined from a polarized atomic beam (Engels), and its cryogenic condensation and transport (Ciullo). Other options for the production of polarized fuel are investigated in parallel, like spin separation of molecules in polarized molecular beam sources (Toporkov), or via photodissociation of molecules into polarized hydrogen/deuterium atoms (Rakitzis). The status of the different fields under investigation and the connections between these topics and the different research groups will be provided.
In order to understand experimental data for K+ production in proton-deuteron interactions and draw conclusions about the ratio between K+ production in pn and pp, one needs to develop an approach for the description of all relevant pp results. We perform an analysis of the pp data available in COSY energy range for three reaction channels. It can be concluded that Λ and Σ0 production channels can be well described by the three-body phase space incorporating the hyperon-nucleon final-state interactions under the assumption of a constant matrix element. Experimental data on the pp → K+ nΣ+ reaction channel are very poor and more information is needed to understand a strange behavior of the energy dependence of the total cross section. Using ANKE inclusive K+ data at 2.85 and 2.95 GeV/c, preliminary values for the total cross-section of Σ+ production in pp interactions has been extracted applying a simple phase space approach. This gives a result roughly one order of magnitude less than that of the recently published exclusive measurement.
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