Energy Dependence of (K)over-barN Interactions and Resonance Pole of Strange Dibaryons

We study the resonance energy of the strange dibaryons using two models with the energy-independent and energy-dependent potentials for the s-wave (K) over barN interaction, both of which are derived by certain reductions from the leading order term of the effective chiral Lagrangian. These potential models produce rather different off-shell behaviors of the two-body (K) over barN - pi Sigma amplitudes in I = 0 channel, i.e., the model with energy-independent (energy-dependent) potential predicts one (two) resonance pole in the Lambda(1405) region, while they describe the available data equally well. We find that the energy-independent potential model predicts one resonance pole of the strange dibaryons, whereas the energy-dependent potential model predicts two resonance poles: one is the shallow quasi-bound state of the (K) over bar NN, and the other is the resonance of the pi YN with large width. An investigation of the binding energy of the strange dibaryons will make a significant contribution to clarify resonance structure of s-wave (K) over barN - pi Sigma around the Lambda(1405) region.