The transverse shape of the electron

TL;DR

This paper analyzes the electron's charge, form factors, and spin distributions in impact parameter space using light-front Fock states, revealing how transversally compact states influence high-momentum transfer behavior and spin structure.

Contribution

It provides a detailed analysis of the electron's transverse structure and spin distributions, highlighting the role of transversally compact Fock states in form factors and magnetic moments.

Findings

Transversally compact Fock states dominate high-momentum transfer behavior.

Spin contributions depend on longitudinal momentum and impact parameter.

The sign of the electron's anomalous magnetic moment can be intuitively understood from density distributions.

Abstract

We study the charge density, form factors and spin distributions of the electron induced by its |e \gamma> light-front Fock state in impact parameter space. Only transversally compact Fock states contribute to the leading behavior of the Dirac and Pauli form factors as the momentum transfer tends to infinity. Power suppressed contributions are not compact, and distributions weighted by the transverse size have end-point contributions. The Fock state conserves the spin of the parent electron locally, but the separate contributions of the electron, photon and orbital angular momentum depend on longitudinal momentum and impact parameter. The sign of the anomalous magnetic moment of the electron may be understood intuitively from the density distribution, addressing a challenge by Feynman.