Energy dependence of the Lambda/Sigma0 production cross section ratio in p p interactions.

Kowina, P. ; Wolke, M. ; Adam, H.H. ; et al.
Eur.Phys.J.A 22 (2004) 293-299, 2004.
Inspire Record 644074 DOI 10.17182/hepdata.31762

The production of the Lambda and Sigma0 hyperons has been measured via the pp->pK+Lambda / Sigma0 reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the Lambda/Sigma0 cross section ratio from about 28 at Q<=13 MeV to the high energy level of about 2.5 is covered by the data showing a strong decrease of the ratio between 10 and 20 MeV excess energy. Effects from the final state interactions in the p-Sigma0 channel seem to be much smaller compared to the p-Lambda one. Estimates of the effective range parameters are given for the N-Lambda and the N-Sigma systems.

3 data tables

Cross section for LAMBDA production.. Statistical errors only.

Cross section for SIGMA0 production.. Statistical errors only.

Energy dependence of the LAMBDA/SIGMA0 ratio.


Comparison of Lambda and Sigma0 threshold production in proton proton collisions.

Sewerin, S. ; Schepers, G. ; Balewski, J.T. ; et al.
Phys.Rev.Lett. 83 (1999) 682-685, 1999.
Inspire Record 478929 DOI 10.17182/hepdata.42059

Threshold measurements of the associated strangeness production reactions pp --> p K(+) Lambda and pp --> p K(+) Sigma(0) are presented. Although slight differences in the shapes of the excitation functions are observed, the most remarkable feature of the data is that at the same excess energy the total cross section for the Sigma(0) production appears to be about a factor of 28 smaller than the one for the Lambda particle. It is concluded that strong Sigma(0)-p final state interactions, and in particular the Sigma-N --> Lambda-p conversion reaction, are the likely cause of the depletion for the yield in the Sigma signal. This hypothesis is in line with other experimental evidence in the literature.

1 data table

The given errors are statistical only. The cross section presented as a function of the nominal excess energy.