Accelerators Create Matter From Energy

Accelerators Create Matter From Energy

Before looking at all the particles we now know about, let us examine some of the machines that created them. The fundamental process in creating previously unknown particles is to accelerate known particles, such as protons or electrons, and direct a beam of them toward a target. Collisions with target nuclei provide a wealth of information, such as information obtained by Rutherford using energetic helium nuclei from natural \(\alpha \) radiation. But if the energy of the incoming particles is large enough, new matter is sometimes created in the collision.

The more energy input or \(\text{Δ}E\), the more matter \(m\) can be created, since \(m=\text{Δ}E/{c}^{2}\). Limitations are placed on what can occur by known conservation laws, such as conservation of mass-energy, momentum, and charge. Even more interesting are the unknown limitations provided by nature. Some expected reactions do occur, while others do not, and still other unexpected reactions may appear. New laws are revealed, and the vast majority of what we know about particle physics has come from accelerator laboratories. It is the particle physicist’s favorite indoor sport, which is partly inspired by theory.