Charge Densities of the Neutron and Proton

Abstract

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 u quark charge density is larger than that of the d quark by about 70 %. The proton (neutron) charge density has a long range positively (negatively) charged component.Comment: 7 pages, three figures The replacement mainly concerns correcting an error made in computing the proton up and down quark densities from the correctly computed proton and neutron charge densities. The proton central u quark density is now larger than that of the d quar