Give a powerful way to determine an upper limit to the size of the electron.

(N/A) powerful way to determine an upper limit to the size of the electron is by using high-energy electron scattering experiments. By bombarding electrons with other high-energy particles or by studying the scattering of electrons off nuclei at extremely high energies,physicists can probe the structure of the electron. If the electron had a finite size,the scattering cross-section would deviate from the predictions of point-particle quantum electrodynamics $(QED)$ at very high momentum transfers. Currently,experimental results indicate that the electron behaves as a point particle down to a scale of approximately $10^{-18} \ m$.