The Last Quark

Physicists at Fermilab find evidence for nature's heaviest fundamental particle

By Kim A. McDonald

Paul Tipton won't call it a "discovery" just yet. Neither will his more than 400 colleagues.

In fact, the word is conspicuously absent throughout the 150-page paper that Mr. Tipton, an assistant professor of physics at the University of Rochester, and the rest of his team finished a week ago to describe their find.

But privately the scientists say they have little doubt that they have captured the quarry that high-energy physicists have been chasing for the past 17 years with