Elastic and Inelastic Polarization Effects Observed with the Argonne Effective Mass Spectrometer
The Argonne polarized proton beam has been used together with the Effective Mass Spectrometer to study several different aspects of pp and pn interactions. The polarization asymmetry for pn elastic scattering was measured for the first time above cyclotron energies. The results show that both I = 0 and I = 1 exchanges have important contributions to the t-channel single-flip amplitudes. While the I = 1 amplitude has the energy dependence expected, the I = 0 contribution falls much faster with energy. For R↑p→Δ++n we find a left-right production asymmetry of about 40% for −t ≥ 0.5 GeV2, independent of energy. Absorbed one-pion-exchange together with quark-model calculations give a qualitative explanation of the Δ++ decay distributions and their dependence on the beam polarization. In the diffractive process p↑p→Δ++π−p we observe asymmetries in the low mass Δπ system that can be described by interference between an S-wave Deck background and a P-wave N*1470 resonance contribution.
KeywordsQuark Model Density Matrix Element Recoil Proton Spin Dependence Production Amplitude
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