At the Cooler Synchrotron COSY in Jülich the production of
strange particles has successfully been measured.
At the internal COSY-11 experiment [1] a hydrogen cluster target is
installed in front of a regular COSY-dipole.
This magnet is used as a spectrometer for the reaction products.
The detection system is based on drift chambers and
scintillation-counters.
Near threshold data of the pp->pK+Lambda
reaction have recently been published by the COSY-11 [2-4]
and the COSY-TOF collaboration [5].
Since before these COSY-measurements no exclusive data in the
threshold region were available, the present results have given
input to theoretical models describing the strangeness production
in baryon-baryon collisions.
Investigations of the hyperon-production above the different
Sigma-thresholds provides an understanding of the
Sigma-production processes and of the possible
Lambda-Sigma coupling (cusp-effect).
Therefore the COSY-11 collaboration has extended its program
from the Lambda- to the
Sigma0-production.
After the presentation of the COSY-11 facility the results of
the pp->pK+Sigma0
measurements [6] will be compared to the
pp->pK+Lambda reaction.
It was found, that the corresponding cross sections at
equivalent excess energies near threshold are about a factor of
28 smaller for the Sigma0-production than
for the Lambda-production.
Abstract
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Complete
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Publication:
Nucl.Phys. A
663-664
(2000)
473-476