The electric form factor is the Fourier transform of electric charge distribution in a nucleon. Nucleons (protons and neutrons) are made of up and down quarks which have charges associated with them (2/3 & -1/3, respectively). The study of Form Factors falls within the regime of Perturbative QCD.
The idea originated from young William Thomson.1
References
References
- "William Thomson, Baron Kelvin | Biography & Facts". www.britannica.com. Britannica. 13 December 2024. Retrieved 30 December 2024.