Quasi-free proton-neutron reactions at COSY-11

R.Czyzykiewicz for the COSY-11-Collaboration
Institute of Physics, Jagellonian University, ul. Reymonta 4, 30-059 Cracow, Poland

Due to the lack of pure neutron targets a quasi-free scattering of protons on the neutrons bound in the nucleus of deuteron is one of the best methods of investigation of the meson production in proton-neutron collisions. Such investigations applied to eta and eta' mesons could result in better understanding of their wave functions as well as their production mechanism in the hadronic interaction.

In June 2002, COSY-11 collaboration had performed first measurements of eta meson production in the quasi-free proton-neutron scattering at the COSY storage ring. In the experiment a proton beam of momentum pbeam = 2.075 GeV/c was used together with an internal deuterium cluster jet target. Successful performance of this experiment confirmed the feasibility of further studies of quasi-free production of heavier mesons, such as for instance eta' meson. After the brief description of the detection setup with an emphasis on the spectator and neutron detectors, some selected results of this run will be presented.

Poster in PostScript format (~553kB)