The neutron-proton charge-exchange amplitudes measured in the dp -> ppn reaction

Abstract

The unpolarised differential cross section and the two deuteron tensor analysing powers A_{xx} and A_{yy} of the pol{d}p -> (pp)n charge-exchange reaction have been measured with the ANKE spectrometer at the COSY storage ring. Using deuteron beams with energies 1.2, 1.6, 1.8, and 2.27 GeV, data were obtained for small momentum transfers to a (pp) system with low excitation energy. The results at the three lower energies are consistent with impulse approximation predictions based upon the current knowledge of the neutron-proton amplitudes. However, at 2.27GeV, where these amplitudes are far more uncertain, agreement requires a reduction in the overall double-spin-flip contribution, with an especially significant effect in the longitudinal direction. These conclusions are supported by measurements of the deuteron-proton spin-correlation parameters C_{x,x} and C_{y,y} that were carried out in the pol{d}pol{p} -> (pp)n reaction at 1.2 and 2.27GeV. The values obtained for the proton analysing power also suggest the need for a radical re-evaluation of the neutron-proton elastic scattering amplitudes at the higher energy. It is therefore clear that such measurements can provide a valuable addition to the neutron-proton database in the charge-exchange region.

arXiv comment13 pages with 13 figures

References in corpus (7)

• Nucleon-nucleon elastic scattering to 3 GeV
• Determination of Deuteron Beam Polarizations at COSY
• The Polarized H and D Atomic Beam Source for ANKE at COSY-Jülich
• Spin Physics from COSY to FAIR
• Vector and tensor analysing powers in deuteron-proton breakup reactions at intermediate energies
• Machine studies for the development of storage cells at the ANKE facility of COSY
• Review of quasi-elastic charge-exchange data in the nucleon-deuteron breakup reaction

Cited by in corpus (10)

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• The Polarized H and D Atomic Beam Source for ANKE at COSY-Jülich
• Deuteron analysing powers in deuteron-proton elastic scattering at 1.2 and 2.27 GeV
• Measurement of spin observables in the quasi-free np-> {pp}_s pi- reaction at 353 MeV
• Excitation of the Delta(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV
• Study of the $\vec{p}d\to n\{pp{\}}_s$ charge-exchange reaction using a polarised deuterium target
• Coherent pion production in proton-deuteron collisions
• Analysing powers and spin correlations in deuteron-proton charge exchange at 726 MeV