Fermilabyrinth
The Fermilab Story |
Ideas: Inner Space/ Outer
Space
There is an amazing beauty and symmetry in nature. Think of a snowflake, a daisy or a honeycomb. The shapes of these and all other natural objects depend on an underlying structure of matter. For centuries scientists have wondered what this structure might be. Their studies have led to a search for particles that are the smallest, simplest building blocks of matter, and for the forces that control their behavior. The particles are quarks and leptons; the forces are gravity, electromagnetism, the weak force and the strong force. Fermilab scientists are leading this international search to learn how the universe works.
When scientists study the subatomic particles and forces that bind them together,they also learn about the early history of the universe and how it began with the "Big Bang." When the universe was very young, atoms didn't exist, because it was too hot for them to form. The only form of matter was a sort of "primordial soup," consisting of the most basic particles, such as quarks and electrons. At Fermilab, scientists use the Tevatron to make the ingredients of primordial soup by smashing together protons and antiprotons at very high energies. The earlier we look in time, the fewer and more basic the particles become, and the fewer forces are needed to control their behavior. The laws of physics are valid in the whole universe and throughout the whole of time.
Methods: Collisions and
Scattering
Scientists work
by posing important new questions about the natural world. They develop
theories, and invent tools and techniques to answer their questions and
test their theories. Particle physicists are scientists who develop and
test theories about the smallest particles of matter. Fermilab physicists
create particles by accelerating protons and making them collide with
particle targets. Sometimes the protons collide with fixed particle
targets (hydrogen ions, iron, tungsten, for example); sometimes the
protons collide head on with moving anti-protons (See the Animation). These collisions (also called
events) create new particles. Scientists record and study how the newly
created particles move away (or scatter) from the collision. By observing
this behavior, scientists can learn about the particles and the forces that
control their interactions, and sometimes discover particles not seen
before.
Tools: Accelerators and
Detectors
The instruments that
particle physicists use for their studies include accelerators, detectors
and powerful computers. Accelerators give the protons enormous energy. To
study very small particles scientists need very high-energy protons and
very big accelerators. The particles scientists want to study are so small
that they cannot be seen by the human eye or the most powerful
microscope. So physicists build huge detectors to track the particles as
they move outward from a collision. Scientists need computers to collect,
store and analyze the information. They need computers because the
experiments create a lot of data over a very short period of time and
because many of the newly created particles live for only an
instant.Computers also allow scientists to use the data to reconstruct
events in a collision. Subatomic particles behave like waves.
Understanding the properties of waves helps scientists design their
experiments and interpret the results.
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