Kaon pair production close to threshold

The total cross section of the reaction pp→ppK⁺K⁻$pp\to pp{K}^{+}{K}^{-}$ has been measured at excess energies Q=10 MeV$Q=10\text{MeV}$ and 28 MeV with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations or calculations within a one boson exchange model. In addition, we present invariant mass spectra of two particle subsystems. While the K⁺K⁻$K^{+}{K}^{-}$ system is rather constant for different invariant masses, there is an enhancement in the pK⁻$p{K}^{-}$ system towards lower masses which could at least be partially connected to the influence of the Λ(1405)$\Lambda (1405)$ resonance.