Thursday, October 18, 2018

The Electron Remains Perfectly Point-Like

The latest and most accurate experiment to detect any hint of an electric dipole moment of an electron has revealed that there isn't any.

Now, the Advanced Cold Molecule Electron Electric Dipole Moment, or ACME, search, based at Harvard University, has probed the electron’s EDM with the most precision ever — and still found no sign of smooshing, the team reports online October 17 in Nature.

The finding improves the team’s last best measurement (SN Online: 12/19/13) by a factor of 10 to find an EDM of 10-29 electron charge centimeters. That’s as round as if the electron were a sphere the size of the Earth, and you shaved less than two nanometers off the North Pole and pasted it onto the South Pole, says Yale University physicist David DeMille, a member of the ACME team.

This improves upon the previous measurement that I mentioned a year ago. Looks like if any theory predicts the possible structure of an electron, they have some severe constraints to overcome.


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