This title appears in the Scientific Report :
2010
Please use the identifier:
http://dx.doi.org/10.1140/epja/i2010-10924-0 in citations.
Please use the identifier: http://hdl.handle.net/2128/10325 in citations.
Systematic study of the pp to pp omega reaction
Systematic study of the pp to pp omega reaction
A systematic study of the production of omega-mesons in proton-proton collisions was carried out in a kinematically complete experiment at three excess energies (epsilon = 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Co...
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Please use the identifier: http://hdl.handle.net/2128/10325 in citations.
A systematic study of the production of omega-mesons in proton-proton collisions was carried out in a kinematically complete experiment at three excess energies (epsilon = 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum Julich. The total cross-section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant-mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128MeV and, additionally, in Sd at epsilon = 173MeV. No obvious indication of resonant omega-production via N*-resonances was found, as proton angular distributions are almost isotropic and invariant-mass spectra are compatible with phase space distributions. A dominant role of P-3(1) and S-1(0) initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process. |