Threshold Measurements at the Experiment
COSY-11 is an internal target experiment presently being installed
at the cooler ring COSY-Jülich, using a cluster target in
front of one of the C-type dipole magnets.
The magnetic field separates and momentum analyses reaction products
from the circulating beam.
It is proposed to scan relevant momentum regions via the pp->ppX reaction and to observe the structure of resonances by missing mass determination. A detection of decay particles from particular resonances (e.g. f0(975)) should support its identification and enable to determine its internal structure.
The vanishing relative momenta between the reaction products make threshold studies an ideal tool to investigate meson-meson, meson-baryon, and nucleon-baryon final state interactions. The special emphasis of the COSY-11 experiment is the observation of narrow resonances especially in the 1 GeV/c² mass range where flavour strangeness becomes important.
The Internal Cluster Target for COSY
A hydrogen cluster target for internal experiments at COSY-Jülich is being built. Compared to other existing cluster targets a relatively small mechanical setup was designed. The construction of special cryopumps allows high pumping speeds which are necessary for the differential pumping stages in cluster beam direction. The design concept and first results will be given.