Electromagnetic Mean Squared Radii of Lambda(1405) in Meson-baryon   Dynamics with Chiral Symmetry
  Electromagnetic mean squared radii of Lambda(1405) are evaluated in chiral unitary approach. In this approach we regard Lambda(1405) as dynamically generated resonances in the octet meson and octet baryon scattering, and also as KbarN bound state. Especially for the Lambda(1405) as KbarN bound state we obtain negative electric mean squared radius. With the small binding energy of Lambda(1405) in the chiral unitary approach, our results imply that Lambda(1405) has structure that K^- is widely spread around p. 
Takayasu Sekihara, Tetsuo Hyodo and Daisuke Jido