Scientists Nab Elusive Top Quark


For physicists, it was the discovery of the decade, says 
physics and astronomy professor E. Walter Anderson. "Top 
quark," the subatomic particle that scientists had been 
seeking for years, finally showed itself in quark-smashing 
experiments at Fermilab, a U.S. Department of Energy facility 
near Chicago.

Anderson and four other ISU researchers were among hundreds 
of physicists on two international teams that tracked down 
the elusive quark. Other Iowa State researchers in on the 
discovery were: John Hauptman, associate professor of physics 
and astronomy; graduate students Michael Wendling and 
Myungyun Pang; and post-doctoral researcher Jay Wightman. 

Quarks are the basic building blocks of matter, and 
scientific theory predicted six varieties -- "up," "down," 
"charm," "strange," "bottom" and "top." The proton, for 
example, is made up of one "down" and two "up" quarks, and 
the neutron consists of one "up" and two "down" quarks.

By 1977, scientists had found five quarks and the search was 
on for number six. 

Top quark, the most massive quark, presumably had not existed 
since the Big Bang creation of the universe some 15 billion 
years ago.

Scientists discovered top quark by measuring its final decay 
products in experiments in a Fermilab particle accelerator. 
Iowa State researchers' role in the discovery was key. They 
developed a data-filtering technique, applying Einstein's 
theories of relativity, that enabled physicists to pick out 
11 possible top quark events from millions of particle 
collisions.

The top quark discovery was announced this spring. 

"This is the last piece of a jigsaw puzzle that has been 
slowly put together by physicists worldwide over the past 30 
years," Hauptman said.

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contact:  Internal Communications, (515) 294-3129
updated:  5-25-95