Fermilab advances the understanding of the fundamental nature of matter and energy by providing leadership and resources for qualified researchers to conduct basic research at the frontiers of high energy physics.

Searching for the Sixth:
Tevatron Reveals Truth about Particles

Millions of dollars worth of equipment, a four-mile ring buried in a maze of tangled wire, particles hurtling at one another, and scientists monitoring it all from their computer screens...What's all the commotion about?
The answer to this question is simple: particles. Particles are the building blocks for all matter, from paper to primordial ooze. To better understand the forces of nature and the behavior of matter, scientists are attempting to learn all they can about particles using devices called accelerators.
The Tevatron, although it sounds like some kind of doomsday robot, is the name of the superconducting particle accelerator at Fermilab. The Tevatron is a four-mile ring buried in a tunnel twenty feet underground. Inside this ring, protons whiz through the accelerator at nearly the speed of light. By crashing protons into antiprotons or into fixed targets, researchers can create
and record particle interactions.
With these detectors, scientists hope to observe, among other things, particles called quarks (see box below). Physicists believe that there are six types of quarks, all of which can result from the proton-antiproton collisions that take place in accelerators like the Tevatron.
The existence of the sixth quark was expected long before it was actually created because physicists believe that quarks come in pairs. After the discovery of the fifth quark, bottom, at Fermilab in 1977, the search for the sixth was the next logical step. The 1994 discovery of the top quark at Fermilab proved that physicists were on the right track with their theory about quarks, the Standard Model.
Just as philosophers discover their own truths through self-examination, scientists discover universal truths through experimentation at Fermilab. That's what it's all about!
Inside the tunnel of the Tevatron, protons and antiprotons whiz past each other at 99.99% of the speed of light.
new and different particles to study. Creating a new particle, however, requires an enormous amount of energy. The Tevatron is unique because it can accelerate particles to energies higher than those of any other accelerator in the world. The Tevatron's energy is essential in discovering the universe's heaviest particles, such as the top quark.
No new particles could exist without some type of collision. Scientists control the speedy particles using magnets in the accelerator to steer the particles into each other or into a fixed target. Observing these particles is a difficult task because they are too small to be seen by the human eye. To do this, researchers have designed and built special detectors to monitor

Meet the Quarks – a guide to their identities

Name Date Discovered General Information
Up 1964 By the early '60's, physicists had gathered sufficient data to indicate the presence of these quarks. The first people to interpret this data in the form of a quark theory were Murray Gell-Mann and George Zweig.
Down 1964
Strange 1964
Charm 1975
(Stanford Linear Accel.)
Scientists readily accepted the data which indicated a fourth quark because they expected a partner for the strange quark. As a result of this data, the quark theory became more believable. (How charming!)
Bottom 1977
Leon Lederman and a Fermilab team discovered yet another! Because this quark and its expected partner were to be the object of intense scrutiny and searching, many wanted to name them Truth and Beauty.
Top 1994
Finally Fermilab found the last piece of the puzzle. To the scientists' surprise, the mass of this quark was very different from that of the others. Why? A researcher's work is never done...