The 3.8 metre wide LEP tunnel, 100metres below French and Swiss countryside,has taken 8 years to complete. The tunnel carries bunches of acceleratedparticles in a 27km long aluminium "beam pipe".
The Large Electron collider, LEP, is the worlds largest scientific instument,designed to study some of the smallest things known to man. In a tunnel longerthan that of the London Underground Circle Line, LEP collides electrons andtheir antimatter counterparts, positrons, at nearly the speed of light. RAL scientists play leading roles inthree of the four huge experiments formed to observe these collisions.
When electrons and positrons collide with enough energy they sometimesdisappear, creating a Z^0 particle in their place. Some people have called Z^0particles and their charged companions W+ and W- "heavy" light, as they play thesame role in carrying the weak nuclear force as light particles (photons) do in carrying the electromagnetic force. The weak nuclear force underlies the processes which fuel the Sun.