Upper limits for the production cross-section of Xi /sub c//sup 0/ and Xi /sub c//sup +/ in 340 GeV/c Sigma /sup -/-nucleon

Experiment WA89 at CERN-SPS investigates the production of charmed Baryons in 340 GeV/c Sigma /sup -/-nucleon interactions. In this thesis upper limits of Xi /sub c//sup 0/ and Xi /sub c//sup +/ are derived from 1994 data. Using $9 theoretically estimated branching ratios, the results for the Xi /sub c//sup 0/ are sigma ( Xi /sub c //sup 0/ to Xi /sup -/ pi /sup +/)<7.1-12 mu b/nucleon and sigma ( Xi /sub c//sup 0/ to Omega /sup -/K/sup +/)<7.7-33 mu b/nucleon, $9 at a confidence level of 90The uncertainties are caused by the insufficient knowledge of the branching ratios. These values obviously exceed the cross-section of sigma ( Lambda /sub c//sup +/) =2.2+or-0.63 mu b/nucleon measured by $9 the same experiment for the production of the Lambda /sub c//sup +/. Also in two decay channels of the Xi /sub c//sup +/ no signal could be observed. Because of higher branching ratios and better efficiencies the resulting values of $9 sigma ( Xi /sub c//sup +/ to Lambda /sup 0/K/sup -/ pi /sup +/) <0.6-2.5 mu b/nucleon and sigma ( Xi /sub c//sup +/ to Sigma /sup +/K /sup -/ pi /sup +/)<0.7-2.2 mu b/nucleon set closer limits. The influence of the still not well $9 known lifetimes of both the Xi /sub c /-baryons and the unknown x/sub F/-dependence of the results is presented. (64 refs).