The electron is extremely round -- and this could be a problem for particle physics

Amazing stuff! The asymmetry of matter versus antimatter is still a riddle!

"... The team led by Nobel Prize laureate and physicist Eric Cornell set a new record for measuring the eEDM [electric dipole moment of electrons] with unprecedented precision, surpassing previous efforts by a factor of 2.4. To get an idea of how round the electron is, if you were to magnify an electron to the size of planet Earth, its deviation from a perfect sphere would be smaller than the size of an atom. ...

To achieve such accuracy, the researchers employed innovative techniques on molecules of hafnium fluoride. By subjecting these molecules to a strong electric field, the scientists observed the behavior of the trapped electrons.

If the electrons were slightly egg-shaped rather than perfectly round, the electric field would exert torque on them, similar to how gravity causes an upright egg to topple over. ...
Utilizing ultraviolet lasers, researchers removed electrons from the molecules, creating a group of positively charged ions, which they subsequently trapped. By alternating the electromagnetic field around the trap, the team prompted the molecules to either align or not align with the field. They then used lasers to measure the energy levels of the two groups. ..."

"... “If the universe had been perfectly symmetrical, then there would be nothing left but light. This is a hugely important moment in history. Suddenly there is stuff in the universe, and the question is, why?” ..."

From the editor's summary and abstract:

"Editor’s summary

The puzzling imbalance between matter and antimatter in the universe can be explained by the breaking of charge parity symmetry. The standard model of particle physics does predict a slight breaking of this symmetry but is insufficient to explain the observations. Many extensions to the standard model have been proposed to resolve this discrepancy. To test such model extensions, tabletop experiments that measure the electron’s electric dipole moment (eEDM), a measure of symmetry breaking, have looked very promising. Roussy et al. exploited the large electric fields inside the polar molecular ions of hafnium fluoride to measure the eEDM to extremely high precision .... The uncertainty of the measurement compares favorably to those achievable through accelerator-based experiments.

Abstract

The imbalance of matter and antimatter in our Universe provides compelling motivation to search for undiscovered particles that violate charge-parity symmetry. Interactions with vacuum fluctuations of the fields associated with these new particles will induce an electric dipole moment of the electron (eEDM). We present the most precise measurement yet of the eEDM using electrons confined inside molecular ions, subjected to a huge intramolecular electric field, and evolving coherently for up to 3 seconds. Our result is consistent with zero and improves on the previous best upper bound by a factor of ~2.4. Our results provide constraints on broad classes of new physics above 1013

 electron volts, beyond the direct reach of the current particle colliders or those likely to be available in the coming decades."

The electron is extremely round -- and this could be a problem for particle physics (Secondary news source. Again this is almost a copy of the unacknowledged primary new source (see below)) Scientists are back to the drawing board in their quest to explain the asymmetry of the universe.

Why Does Matter Exist? Roundness of Electrons May Hold Clues (primary news source) JILA physicists make record-breaking measurement of a key electron property.

An improved bound on the electron’s electric dipole moment (no public access)