The major goal is to search for as-yet unknown forces in physics. The muon g-2 storage ring at the Brookhaven National Laboratory. In a volume of some 44 m circumference and with some 5 cm radius this device provides a magnetic field of unprecedented quality. The magnet yoke is covered with white thermal insulation material. Muons are heavy copies of the electron which except for their different mass appear to behave exactly like electrons in all known physical processes.
Muons can carry either a positive or a negative charge.
They are the dominant component of the cosmic rays to which we all are exposed. About two of them get stuck in each of our human bodies every second. Under such conditions their lifetime is prolonged 30 times as described by Einstein's special theory of relativity. In a magnetic field, these charged particles revolve in a circular orbit. This frequency difference, the anomaly frequency, can be measured by observing positrons from positive muon decays.