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E Steffens

Publications and source records attributed to E Steffens.

9 recordsLinked to original sources
PubMed2005

Measurement of the analyzing power in p-->d-->(p p)n with a fast forward 1S0 proton pair.

A measurement of the analyzing power A(y) of the p-->d--> (p p) + n reaction was carried out at the ANKE spectrometer at COSY at beam energies of 0.5 and 0.8 GeV by detection of a fast forward proton pair of small excitation energy E(pp) < 3 MeV. The S-wave dominance in the fast diproton is experimentally demonstrated in this reaction. While at T(p) = 0.8 GeV the measured analyzing power almost vanishes, it rises to nearly unity at T(p) = 0.5 GeV for neutrons emitted at theta(c.m.)(n) = 167 degrees. The results are compared with a model taking into account one-nucleon exchange, single scattering, and Delta(1232) excitation in the intermediate state. The model describes fairly well the unpolarized cross section obtained earlier and the analyzing power at 0.8 GeV; it fails to reproduce A(y) at 0.5 GeV.

Journal Article↗
PubMed2005

A method to polarize stored antiprotons to a high degree.

Polarized antiprotons can be produced in a storage ring by spin-dependent interaction in a purely electron-polarized hydrogen gas target. The polarizing process is based on spin transfer from the polarized electrons of the target atoms to the orbiting antiprotons. After spin filtering for about two beam lifetimes at energies T approximately equal 40-170 MeV using a dedicated large acceptance ring, the antiproton beam polarization would reach P=0.2-0.4. Polarized antiprotons would open new and unique research opportunities for spin-physics experiments in p(-) p interactions.

Journal Article↗
PubMed1976

E1Lymphocytopenia in pseudo-lupus-erythmetaosus syndrome.

Seven female patients with pseudo-lupus erythematosus (LE)-syndrome had markedly reduced lymphocyte counts in their peripheral blood during the active phase of the disease. One patient, we were able to study during the active phase of her disease, had a diminuation of spontaneous rosettes-forming (T-)lymphocytes, using neuraminidase-treated sheep red blood cells for the test. In this case the percentage of surface-immunoglobulin-bearing (B-)lymphocytes determined by an indirect immunofluorescence technique was augmented. In comparison with 20 normal controls 6 other patients did not show any alterations in the relation of B- and T-lymphocytes in the peripheral blood. 5 patients had circulating lymphocytotoxic antibodies in their serum. A specificity of these antibodies for T-lymphocytes could not be realized.

Acute Disease↗