(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Top Comments: The Shape of an Electron [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.', 'Backgroundurl Avatar_Large', 'Nickname', 'Joined', 'Created_At', 'Story Count', 'N_Stories', 'Comment Count', 'N_Comments', 'Popular Tags'] Date: 2023-04-16 Well, as far as anybody can tell... here it is. Here at Top Comments we strive to nourish community by rounding up some of the site's best, funniest, most mojo'd & most informative commentary, and we depend on your help!! If you see a comment by another Kossack that deserves wider recognition, please send it either to topcomments at gmail or to the Top Comments group mailbox by 9:30pm Eastern. Please please please include a few words about why you sent it in as well as your user name (even if you think we know it already :-)), so we can credit you with the find! The big reveal is kind of a letdown—as the top image depicts. According to the Standard Model of particle physics, the electron is expected to be spherical—a round ball—and thus far, all experiments confirm this. However, when the Standard Model was created, it was recognized by its creators to be provisional. They knew the model had holes in it, and fully expected a new, more expansive model to replace it before long. But that’s not what happened. More than 40 years later, despite manifold efforts to break it, the Standard Model still stands as the best theory that particle physicists have to explain the behavior of elementary particles. So particle physicist continue to try to come up with ever more exacting experiments to test the Standard Model even further. One of the known holes in the Standard Model is that it is not capable of explaining why there was more matter produced by the Big Bang than antimatter. If this were not the case, and there had been equal amounts of matter and antimatter present at the creation, as the Standard Model predicts, then there would likely be nothing (or at best very little) of anything in the universe, except for light. No matter means no stars, no planets, no life, and you wouldn’t be reading this now because you wouldn’t exist (nor would I have written it for the same reason). Russian physicist Andrei Sakharov (the guy who designed the Russian H-bomb) came up with an idea to try to explain the dominance of matter over antimatter. His idea involved the concept of parity symmetry, i. e. mirror image symmetry. If one of the forces had a slight difference in its strength as a mirror image, then that could give an edge to matter. This turns out to be true for the weak nuclear force for some particles, but the effect is not great enough to explain the observed imbalance. Of course, it is possible to ramp up the energy in particle accelerators in the hopes of finding some new and unexpected particle with properties that can explain the imbalance, but given that there is only one Large Hadron Collider (at CERN in Europe) capable of such a search severely limits the resources of such a search. As such, researchers with fewer resources have come up with other kinds of experiments to search for violations of parity. So now we can consider the humble electron. It was discovered in the late 19th Century and has been very well studied since. It’s known properties are its mass, its charge, and its magnetic spin. Even the actual size of the electron is unknown—the best that scientists can do is provide an upper limit for its radius. But we know that the Standard Model predicts that the electron is perfectly spherical. If an experiment were capable of demonstrating that this is not true, then that might provide evident for something—perhaps a virtual particle that has not yet been observed—that breaks the predicted symmetry. Though the charge of the electron is well known, the distribution of charge within the electron can conceivably slosh around some. If this happens, and more charge gathers on one side of the electron than the other, it would produce what’s called an electric dipole moment (EDM). The Standard Model’s prediction of the electron’s EDM is vanishingly small. If the electron’s EDM turned out to be substantial, then this could provide evidence that could lead to breaking the Standard Model and figuring out why there is an imbalance between the two. So experiments were designed which electrons in molecules were subjected to electric field manipulation in the hope that it would reorient the electron’s EDM; if the EDM is reoriented, this could be detected by observing the reorientation of the electron’s spin. (This is a lot cheaper than building a particle accelerator.) Unfortunately, thus far, the result has been null. To the precision of the measurement, the electron appears to be perfectly spherical, i. e. it has no measurable EDM. From the report: The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecule. The latest results are in: The electron is rounder than that. Of course, the researchers are constantly in the process of improving their techniques to provide more precise results, but this null result places limits on the energies of possible new particles that could violate parity. The experiments continue, and perhaps something will pop up. Comments are below the fold. [END] --- [1] Url: https://www.dailykos.com/stories/2023/4/16/2164302/-Top-Comments-The-Shape-of-an-Electron Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/