Electromagnetic mean squared radii of Λ(1405) in chiral dynamics

The electromagnetic mean squared radii, < r(2)>(E) and < r(2)>(M), of Lambda(1405) are calculated in the chiral unitary model. We describe the excited baryons as dynamically generated resonances in the octet meson and octet baryon scattering. We evaluate values of < r(2)>(E) and < r(2)>(M) for the Lambda(1405) on the resonance pole and obtain their complex values. We also consider Lambda(1405) obtained by neglecting decay channels. For the latter case, we obtain negative and larger absolute electric mean squared radius than that of typical ground state baryons. This implies that Lambda(1405) has structure that K- is widely spread around p. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.