This month’s issue of Discover magazine lists the top 100 science stories of 2003, and coming in 49th on the list is Indiana University physicist Edward Stephenson’s experimental discovery of a rare fusion process.
Photo by Chris Meyer
IU physicist Ed Stephenson stands next to a portion
of the cooler injector synchrotron, a particle accelerator,
which he used in research conducted last April at the
IU Cyclotron Facility in Bloomington. The results of
his experiments landed him in this month’s issue of
Discover magazine. His project was named to the list
of the top 100 science stories of 2003.
“In general, symmetry is the rule in the universe—the world makes perfect sense if seen in a mirror, for instance—but in April, Stephenson found a flaw in the balance of nature that researchers have been seeking for decades,” Discover wrote in its online edition (see Web site at end of story).
Stephenson’s results will help theorists understand the cause of what is called “charge symmetry violation.” They have proposed that charge symmetry violation originates with quarks, the small particles that are found inside protons and neutrons.
“If this symmetry violation had happened to be in the other direction,” Stephenson said, “hydrogen would not have survived after the Big Bang, and the universe would not have the hydrogen fuel that keeps stars shining, including our sun, making human life possible. Sometimes large consequences hang on delicate balances in nature.”
“There was a point about one second after the Big Bang when neutrons and protons condensed out of the underlying mixture of particles,” Stephenson said in the Discover story. “The neutrons decayed into protons, but the protons remained stable. After 10 or 20 minutes, there was an enormous amount of the subatomic materials needed to form hydrogen, which is the building block of stars and galaxies. It is all a consequence of charge symmetry breaking down.”
He and colleagues did their experiment at the IU Cyclotron Facility on the Bloomington campus, focusing a high-precision beam of heavy hydrogen onto a target of the same material. The team worked around the clock for two months, seeing, at most, only five of the rare events per day, Stephenson said.
HP archive: http://www.homepages.indiana.edu/041103/text/fusion.html