Wednesday, October 11, 2017

Electron Is Still A Point Particle

There have been experiments to measure the electric dipole moment of an electron, if any, which would indicate that (i) an electron has an internal structure and (ii) consequently it isn't a point particle that we have been assuming within QED. So far, all the experiments have not found any, and each measurement continues to increase the precision of the previous measurement.

Chalk this one up to follow the same trend[1]. This time, they are using a different technique to measure the electron dipole moment by using trapped molecular ions. The result of the experiment is an even more precise measurement, and lowered the upper bound of the dipole moment by several orders of magnitude when compared to the previous result.

Electron is still a spherical cow!


[1] W.B. Cairncross et al., Phys. Rev. Lett. v.119, p.153001 (2017).

No comments: