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. By observing this behavior, scientists can learn about the particles and the forces that control their interactions, and sometimes discover particles not seen before. 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.