Structure of Lambda(1405) and construction of KbarN local potential based on chiral SU(3) dynamics

We develop the single-channel local potential for the KbarN system, which is applicable to quantitative studies of Kbar bound states in nuclei. Because the high precision measurement of the kaonic hydrogen by SIDDHARTA reduces the uncertainty of the KbarN amplitude below the KbarN threshold, the local potential should be calibrated in a wide energy region. We establish a new method to construct the local potential focusing on the behavior of the scattering amplitude in the complex energy plane. Applying this method, we construct the KbarN potential based on the chiral coupled-channel approach with the SIDDHARTA constraint. The wave function from the new potential indicates the KbarN molecular structure of Lambda(1405).