Recent results from the NN-interaction studies with polarized beams and targets at ANKE-COSY

16th Workshop on High Energy Spin Physics

Dymov, Sergey^1,2

Laboratory of Nuclear Problems, JINR, Dubna

RU-141980, Russia^1

Institut für Kernphysik, Forschungszentrum Jülich, Jülich

D-52425, Germany^2

关键词: Differential cross section;    Interaction studies;    Intermediate energies;    Partial wave analysis;    Phase-shift analysis;    Small angle neutron;    Small angle scattering;    Spin correlations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/678/1/012014/pdf
DOI  :  10.1088/1742-6596/678/1/012014

来源: IOP

【 摘 要 】

Adding to the nucleon-nucleon scattering database is one of the major priorities of the ANKE collaboration. Such data are necessary ingredients, not only for the understanding of nuclear forces, but also for the description of meson production and other nuclear reactions at intermediate energies. By measuring the cross section, deuteron analysing powers, and spin-correlation parameters in the dp → {pp}sn reaction, where {pp}srepresents the1S0state, information has been obtained on small-angle neutron-proton spin-flip charge-exchange amplitudes. The measurements of pp elastic scattering by the COSY-EDDA have had a major impact on the partial wave analysis of this reaction above 1 GeV. However, these experiments only extended over the central region of c.m. angles, 300cm0, that has left major ambiguities in the phase shift analysis by the SAID group. In contrast, the small angle region is accessible at ANKE-COSY, that allowed measurement of the differential cross section and the analysing power at 50cm0in the 0.8 - 2.8 GeV energy range. The data on the pn elastic scattering are much more scarce than those of pp, especially in the region above 1.15 GeV. The study of the dp → {pp}sn reaction provides the information about the pn elastic scattering at large angles. The small angle scattering was studied with the polarized proton COSY beam and an unpolarised deuterium gas target. The detection the spectator proton in the ANKE vertex silicon detector allowed to use the deuterium target as an effective neutron one. The analysing powers of the process were obtained at six beam energies from 0.8 to 2.4 GeV.