Generalized Dalitz Plot analysis of the near threshold pp-->ppK+K- reaction in view of the K+K- final state interaction

Abstract

The excitation function for the $pp\to pp{K}^{+}{K}^{-}$ reaction revealed a significant enhancement close to threshold which may plausibly be assigned to the influence of the $p{K}^{-}$ and $K^{+}{K}^{-}$ final state interactions. In an improved reanalysis of COSY-11 data for the $pp\to pp{K}^{+}{K}^{-}$ reaction at excess energies of Q = 10 MeV and 28 MeV including the proton-K- interaction the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK+K- system as derived from the COSY-ANKE data. Finally, based for the first time on the low energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be |Re(a_K^+K^-)| = 0.5 + 4.0 -0.5 fm and Im(a_K^+K^-) = 3.0 +- 3.0 fm.

Comments: 8 pages, 7 figures, to be published in Phys. Rev. C