J. Carbonell

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 Axx and Ayy of the

Vector and tensor analysing powers in deuteron-proton breakup reactions at intermediate energies

vec dp to { pp} _s n

Zero energy scattering calculation in Euclidean space

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 2.27GeV, data were obtained for small momentum transfers to a {pp}s 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 Cx,x and Cy,y that were carried out in the

p\vec{d} \to n\{pp\}_{s}

vec dvec p to { pp} _s n

Excitation of the Delta(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV

reaction at 1.2 and 2.27GeV. The values obtained for the proton analysing power Ayp 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.

Study of the

The vector and tensor polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After their acceleration to 1170 MeV inside the COSY ring, the polarizations of the deuterons were checked by studying a variety of nuclear reactions using a cluster target at the ANKE magnet spectrometer placed at an internal target position of the storage ring. All these measurements were consistent with the absence of depolarization during acceleration and provide us with a number of secondary standards that can be used in subsequent experiments at the facility.