Particle physics involves the study of the properties and interactions associated with the lowest level structures of matter—often called "elementary" particles. The study of these particles and their interactions requires the use of machines which can accelerate these bits of subatomic matter to near the speed of light, thus providing them with considerable energy.
A beam of these rapidly moving particles is caused to strike an appropriate target, thus interacting with the constituents of the material from which the target is made. The resulting quite violent collisions which occur are studied using some of the most highly sophisticated electronics and computing equipment available.
Such experiments are performed at accelerator sites around the world. The closest one to Ball State is Fermi National Laboratory, near Chicago. David Grosnick conducts research in this area.