Low-energy Lambda-p scattering parameters from the pp-pK+Lambda Reaction

Constraints on the spin-averaged 6 p scattering length and effective range have been obtained from measurements of the pp M pK + 6 reaction close to the production threshold by comparing model phase-space Dalitz plot occupations with experimental ones. The data fix well the position of the virtual bound state in the 6 p system. Combining this with information from elastic 6 p scattering measurements at slightly higher energies, together with the fact that the hyperdeuteron is not bound, leads to a new determination of the low energy 6 p scattering parameters.