Electrons are extremely round, and some physicists are not pleased about it.
A new experiment captures the most detailed view yet of any electron that uses lasers to find evidence of particles around the particles, researchers reported in a new study. By illuminating molecules, scientists were able to interpret how other subatomic particles change the charge distribution of an electron. [The 18 Biggest Unsolved Mysteries in Physics]
The symmetric roundness of the electrons suggests that invisible particles are not large enough to shear electrons into squashed elongated shapes or ovals. These findings once again confirm a long-standing physics theory, known as the Standard Model, which describes how particles and forces behave in the universe.
At the same time, this new discovery could overturn several alternative physical theories that attempt to fill in the blanks with phenomena that the Standard Model can not explain. This brings some probably very disgruntled physicists back to the drawing board, said study co-author David DeMille, a professor with the Department of Physics at Yale University in New Haven, Connecticut.
"It will certainly make no one very happy, DeMille said to Live Science.
A Well-Tested Theory
Since subatomic particles can not yet be directly observed, scientists learn to know the objects through indirect evidence observes what happens in the vacuum to negatively charged electrons ̵
The Standard Model describes most of the interactions between all the building blocks of the For decades, this theory has successfully predicted how matter behaves.
However, there are a few nagging exceptions to the explanatory success of the model: the standard model does not explain dark matter, a mysterious one and invisible substance that exerts a gravitational force, but no light According to the European Organization for Nuclear Research (CERN), the model does not consider gravitation in addition to the other fundamental forces that affect matter.
Alternative physics theories provide answers where the standard model is insufficient. The Standard Model predicts that particles that surround electrons affect the shape of an electron, but to such an infinitesimal extent that they are barely perceptible with existing technology. But other theories suggest that there are still undiscovered heavy particles. For example, the supersymmetric standard model postulates that every particle in the standard model has an antimatter counterpart. These hypothetical heavyweight particles would deform electrons to an extent that researchers could observe, according to the authors of the new study.
To test these predictions, new experiments scanned electrons with a ten times greater resolution than previous efforts, completed in 2014; Both investigations were carried out by the research project Advanced Cold Molecule Electron Electric Dipole Moment Search (ACME).
Researchers looked for a fugitive (and unproven) phenomenon, the electric dipole moment, in which the spherical shape of an electron deforms – "dented" appears at one end and bulged at the other, "explains DeMille – because of the heavy particles that affect the charge of the electron.
These particles would be "many, many orders of magnitude larger than the particles predicted by the Standard Model," so it's a very clear way to tell if something new is happening beyond the Standard Model, "said DeMille.
For the new study, ACME researchers channeled a beam of cold thorium oxide molecules at a rate of 1 million per pulse, 50 times a second, into a relatively small chamber in a Harvard University cellar, and the scientists zapped the molecules into lasers and examined them the light reflected back from the molecules, bends in the light would indicate an electric dipole moment.  But there were no twists in the reflected light, and this result casts a dark shadow on the physics theories that predicted heavy particles around electrons, the researchers said. These particles might still exist, but they would be very different from those described in existing theories, DeMille said in a statement.
"Our finding tells the scientific community that we need to seriously rethink some of the alternative theories, said DeMille. [Strange Quarks and Muons, Oh My! Nature’s Tiniest Particles Dissected]
While this experiment examined the behavior of particles around electrons, it also provides important ones Implications for the search for dark matter, DeMille said, "Like subatomic particles, dark matter can not be directly observed, but astrophysicists know it's there because they've observed their gravitational effect on stars, planets, and light."
"Similarly like us [astrophysicists] we look into the heart of many theories that have long predicted For very good reasons – a signal should appear, "said DeMille," and yet they see nothing, and we see nothing. "
dark matter as well as new subatomic particles that were not predicted by the Standard Model still have to be discovered directly, but e A growing body of compelling evidence indicates that these phenomena exist. But before scientists can find them, some long-standing ideas about how they look are likely to be scrapped, DeMille added.
"Expectations about new particles look more and more like they were wrong," he said.
The results were published online today (October 17) in the journal Nature.
Originally published about Live Science.