P. Moskal

COSY- 11, an internal experimental facility for threshold measurements

Abstract The COSY-11 installation is an internal experiment at the cooler synchrotron and storage ring COSY Julich. It has been designed for full geometrical acceptance close to threshold for meson production studies, especially in the 1 GeV/ c 2 mass range. The experimental setup makes use of a regular C-type COSY dipole magnet, following a cluster target, to separate reaction products from the beam and to analyze their momenta, thus allowing the observation of charged reaction products at small angles with beam energies close to threshold. Resonances will be identified by missing mass reconstructions from measured four-momenta of two outgoing protons in the predominantly studied pp → ppX reaction. In addition, charged mesons either produced directly or from decays of X will be detected. The different components of the experimental facility are presented.

Close-to-threshold meson production in hadronic interactions

Abstract Studies of meson production at threshold in the hadron-hadron interaction began in the fifties when sufficient energies of accelerated protons were available. A strong interdependence between developments in accelerator physics, detector performance and theoretical understanding led to a unique vivid field of physics. Early experiments performed with bubble chambers revealed already typical ingredients of threshold studies, which were superseded by more complete meson production investigations at the nucleon beam facilities TRIUMF, LAMPF, PSI, LEAR and SATURNE. Currently, with the advent of the new cooler rings as IUCF, CELSIUS and COSY the field is entering a new domain of precision and the next step of further progress. The analysis of this new data in the short range limit permits a more fundamental consideration and a quantitative comparison of the production processes for different mesons in the few-body final states. The interpretation of the data take advantage of the fact that production reactions close-to-threshold are characterized by only a few degrees of freedom between a well defined combination of initial and exit channels. Deviations from predictions of phase-space controlled one-meson-exchange models are indications of new and exciting physics. Precision data on differential cross sections, isospin and spin observables — partly but by no means adequately available — are presently turning up on the horizon. There is work for the next years and excitement of the physics expected. Here we try to give a brief and at the same time comprehensive overview of this field of hadronic threshold production studies.

ETA ' PRODUCTION IN PROTON-PROTON SCATTERING CLOSE TO THRESHOLD

The

S-wave η′-proton FSI; phenomenological analysis of near-threshold production of π0, η, and η′ mesons in proton-proton collisions

pp \to pp \eta^{\prime}

Near-threshold η meson production in proton-proton collisions

(958) reaction has been measured at COSY using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies \mbox{

Precision measurement of σ(e+e−→π+π−γ)/σ(e+e−→μ+μ−γ) and determination of the π+π− contribution to the muon anomaly with the KLOE detector

Q = ~1.5 ~MeV, ~1.7 ~MeV, ~2.9 ~MeV,

Comparison of Lambda and Sigma**0 threshold production in proton proton collisions

and

A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals

~4.1 MeV

Test of a single module of the J-PET scanner based on plastic scintillators

} have been evaluated to be \mbox{

Energy dependence of the near-threshold total cross-section for the pp→ppη′ reaction

\sigma = 2.5 \pm 0.5~nb