Charge Density of the Neutron

TL;DR

This paper analyzes the neutron's charge density in the transverse plane, revealing a negative central charge density for the neutron and a larger central u quark charge density in the proton, challenging previous expectations.

Contribution

It provides a model-independent analysis of nucleon charge densities in the infinite-momentum frame, highlighting new insights into the neutron and proton charge distributions.

Findings

Neutron charge density is negative at the center.

Proton's u quark charge density exceeds d quark density by about 70%.

Charge densities exhibit long-range positive and negative components.

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.