Lambda-antilambda production in the region of the Sigma threshold

In the present thesis the anti pp→anti ΛΛ reactions was studied with high statistics in a beam-momentum range around 1.9 GeV/c. The results show following pecularities: Differences in the differential cross sections below and above the anti pp→anti Σ-Σ--threshold are indicated, which are shown in the first- and second-order Legendre coefficients. The anti ΛΛ production pursues also here in a spin-triplet state. The differential cross sections show no more a sharp angle in the transition from the flat part to the exponential forward increasement. The maximum in the polarization at small vertical stroket'vertical stroke values is no more accentuated and the zero passage to negative values takes place already at vertical stroket'vertical stroke=0.1 (GeV/c)2. After a second zero passage at vertical stroket'vertical stroke=0.6 (GeV/c)2 the polarization values up to high vertical stroket'vertical stroke values ly only scarcely above zero. Furthermore in this thesis it was shown that starting from raw data a missing-mass reconstruction can be made, which assignes before the performance of a kinematical fit events to the possible reaction channels. It was shown that the resolution of the PS 185 detector is high enough in order to identify events of the type anti pp→anti ΛΛ, anti pp→anti ΛΣ0+c.c., and anti pp→anti ΛΛπ0 and separate against another. The two last-named reactions are clearly distinguished from the ste of the anti pp→anti ΛΛγ respectively anti pp→anti ΛΛγγ events so that an estimation of the total cross sections relatively to that of the anti pp→anti ΛΛ production could be performed. (orig./HSI)