Fermilab

Physicists at the Department of Energy's Fermi National Accelerator Laboratory announced on March 2, 1995 the discovery of a subatomic particle called the top quark, the last undiscovered particle of the six-member quark family predicted by current scientific theory. Scientists worldwide had sought the top quark since the discovery of the bottom quark at Fermilab in 1977.

Complete text of news release (March 2, 1995)

Collision! Graphic of a high-energy collision producing the top quark

Is it a top quark? The signature of a top event

How do we know when we've found the top quark?

Top quark discovery in pictures

Background information on the CDF and DZero experiments as of 1995

Slide show on the top quark discovery by the Education Department

The top quark is one of the building blocks of nature. Currently, physicists use greatly improved CDF and DZero detectors to study the properties of the top quark in detail: How does the top quark interact with other particles? Why is the top quark 100,000 heavier than the lightest quark? What was its role in the early universe? CDF and DZero physicists are looking for answers to these and other questions in particle physics. as they expect to record thousands of top quark events in the next few years, compared to about 150 that led to its discovery.