The strangeness dissociation into two kaons is interesting on its own as a fundamental process. In addition, predictions of relativistic transport models for subthreshold antikaon production depend on the input of the elementary cross section in nucleon-nucleon collisions close to threshold. Results obtained during the COSY-11 beam time in September 1998 show at an excess energy of 17 MeV a clear signal in the (ppK+) missing mass spectrum at the K- mass with six events of the reaction pp->ppK+K- identified distinctively, i.e. with all final state particles detected. Compared with a measurement below threshold, the method of analysis proves to be unambiguous. In order to confirm the very rough estimate of a total cross section in the order of 900 pb as soon as possible at different beam momenta we request three weeks of beam-time during the second half of 1999.
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