Inside the accelerator tunnel at the Stanford Linear Collider (SLC) experiment, California. With a length of 3km, the Stanford Linear Accelerator is the largest of its kind in the world. The accelerator is used to produce streams of electrons and positrons which collide at a combined energy of 100 GeV (Giga electron Volts). This massive energy is sufficient to produce Z- naught particles in the collision. The Z-naught is one of the mediators of the weak nuclear force, the force behind radioactive decay, and was first discovered at CERN, Geneva, in 1983. The first Z- naught at SLC was produced on 11 April 1989.