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تسجيل مستخدم جديدComparison of Lambda and Sigma(0) Threshold Production in Proton-Proton Collisions
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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.
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mbda gamma$ with subsequent decays $Lambda rightarrow p pi^{-}$ in coincidence with a $e^{+}e^{-}$ pair from either external ($gamma rightarrow e^{+} e^{-}$) or internal (Dalitz decay $gamma^{*}rightarrow e^{+} e^{-}$) gamma
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Exclusive data on the reactions pp -> ppK+K- and pp -> pK+ Lambda/Sigma0 have been taken at the cooler synchrotron COSY close to threshold. At equal excess energies, an enhancement of the Lambda/Sigma0 ratio by one order of magnitude has been observe
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