Low-Energy $\Lambda-\p$ Scattering Parameters from the $pp \to   pK^+\Lambda$ Reaction
  Constraints on the spin-averaged $\Lambda p$ scattering length and effective range have been obtained from measurements of the $pp\to pK^+\Lambda$ 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 $\Lambda p$ system. Combining this with information from elastic $\Lambda p$ 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 $\Lambda p$ scattering parameters. 
J. T. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, M. Hofmann, L.   Jarczyk, A. Khoukaz, K. Kilian, T. Lister, P. Moska...