A clue to the mechanism of $ΛK^+$ production in $pp$-reactions

We analyse the $p p \to p \Lambda K^+$ total cross section data which were recently measured by the COSY-11 collaboration at an energy 2~MeV above the reaction threshold. Our analysis suggests that the measurement of the invariant mass spectrum for the $\Lambda K^+$ at energies around 100 MeV above the threshold can provide a new constraint on the theoretical calculations for this reaction. In particular, the measurement can give a clue as to whether the reaction is dominated by resonance excitation or not. Thus, it should contribute to further understanding of the strangeness production mechanism. We show the invariant mass spectra for the $\Lambda K^+$ system in these optimal kinematic conditions calculated by several approaches, and demonstrate that our suggestion is experimentally feasible.