An operating run at Fermilab involving the Tevatron, the world’s highest-energy particle accelerator, has produced an experimental result of extraordinary precision, one that has measured transitions between matter and antimatter that occur three trillion times a second. Tevatron Run 2, from February of 2002 to January of this year, produced trillions of collisions between protons and antiprotons to achieve the discovery, a measurement sought for two decades.
Making the fast change is the B_s meson (pronounced B-sub-s), whose behavior is predicted by the Standard Model that describes our understanding of fundamental particles and forces in the universe. The finding thus reinforces that model in the world of the exquisitely small. The B_s meson is made up of a bottom quark bound by the strong nuclear interaction to a strange antiquark. These exotic particles, present in abundance in the early universe, can only be produced and studied at particle accelerator installations like Fermilab’s.
Earlier measurements of the matter-antimatter transitions in the B_s meson did not reach the level of accuracy of this latest work, in which the probability for a false observation has been shown to be less than about eight in 100 million. And the discoveries from this impressive run of data may not be over yet:
“Everyone in Fermilab’s Accelerator Division has worked hard to create the number of collisions that were required to reach this impressive result,” said Fermilab Director Pier Oddone. “We’re glad that CDF has been able to put these efforts to such good effect. This is one of the signature measurements for Run II, and as we collect several times the data already on hand, I have great expectations for future discoveries.”
CDF refers to the Collider Detector at Fermilab collaboration, an experiment in high energy particle collisions that involves 700 physicists from 61 institutions in 13 countries. MIT’s Christoph Paus presented the discovery in a talk at Fermilab on Friday September 22; a paper on this work has been submitted to Physical Review Letters.
Centauri Dreams‘ take: The behavior of exotic particles like the quarks under study and their interactions with matter and antimatter may tell us a good deal about how the early universe evolved. It may also push physics into a more complete Standard Model, and that, in turn, should help us understand just how matter and antimatter are entwined. The sense here is that for breakthroughs in antimatter production to occur — and for propulsion purposes we must hope some day they will — they must emerge with the underpinning of work like CDF’s, which may yet tease out phenomena the Standard Model does not predict.