(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Top Comments: Tau Particle Magnetic Moment [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.'] Date: 2023-10-19 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! In particle physics, there are three known leptons (and no more are expected to be found): the light, stable electron, the heavier, less stable muon (~207 times the mass of an electron, and 2.2x10-6 second half life), and the very heavy and very short-lived tau particle (~3490 times the mass of an electron, and 3.0x10-13​​​ second half life). All of these particles have a magnetic moment that wobbles due to interaction with virtual particles in the quantum field. The great triumph of quantum electrodynamics (QED), as devised by Tomonaga, Schwinger and Feynman was the calculation of the correct value for the electron’s magnetic moment. However, recent measurements of the muon magnetic moment display a deviation from the QED theoretical result. This is because the more massive muon can interact with more massive (i. e. more energetic) virtual particles in the quantum field—particles that have yet to be discovered. Right now, the magnetic moment of the muon is a subject of intense study as it may be a wedge that could break apart the Standard Model of particle physics, a model that physicists realized was pasted together with Elmer’s glue, and nobody expected to last 50 years—and yet it has. Then there’s the tau particle. If interactions between more massive particles cause deviations in the muon’s magnetic moment, then there ought to be a whole lot more deviation for the tau. The problem is that, because it is so short-lived, measurements for the tau’s magnetic moment are extremely imprecise. The best that anyone has ever done is to measure the tau particle’s magnetic moment to two decimal places, as opposed to 13 for the electron, and 10 for the muon. However, a physicist at CERN (the European laboratory for particle physics) realized that data for particle collisions that involve near-misses of bare lead nuclei could produce tau particles, and that some of the data from those runs, originally designed to measure something else entirely, could be used to measure the magnetic moment of the tau. In April 2022, the CERN team announced that we had found direct evidence of tau particles created during lead ion near misses. Using that data, the team was also able to measure the tau magnetic moment – the first time such a measurement had been done since 2004. The final results were published on Oct. 12, 2023. This landmark result measured the tau wobble to two decimal places. Much to our astonishment, this method tied the previous best measurement using only one month of data recorded in 2018. After no experimental progress for nearly 20 years, this result opens an entirely new and important path toward the tenfold improvement in precision needed to test Standard Model predictions. Excitingly, more data is on the horizon. CERN will be restarting the lead ion collision experiment in order to determine the magnetic moment of the tau particle, in the hopes that it will reveal greater deviation from the Standard Model, and, perhaps, show a path to a more inclusive theory of elementary particles. Comments are below the fold. Top Comments (October 19, 2023): From Angela Marx: This comment by Troffelemasse, in Joan McCarter’s front page live coverage of today’s GOP antics in the House. What could be better than every two weeks of the same "GOP can't even elect a Speaker of the House" showing up on the Sunday shows and headlines of papers AND best of all, in the Editorial Cartoons of the still remaining cartoonists in America? Highlighted by happy camper: This comment by JohnB47, in MikePhoenix’s recommended poston possible compromise in speaker’s race. Top Mojo (October 18, 2023): [END] --- [1] Url: https://www.dailykos.com/stories/2023/10/19/2200468/-Top-Comments-Tau-Particle-Magnetic-Moment?pm_campaign=front_page&pm_source=more_community&pm_medium=web 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/