Charge Densities of the Neutron and Proton

A model-independent analysis of the infinite-momentum-frame charge density of partons in the transverse plane is presented for the nucleon. We find that the neutron-parton charge density is negative at the center, so that the square of the transverse charge radius is positive, in contrast with many expectations. Additionally, the proton’s central $d$ quark charge density is larger than that of the $u$ quark by about 30%. The proton (neutron) charge density has a long range positively (negatively) charged component.