The top quark was discovered in 1995 at Fermilab
, the end result of a few decades of decidicated
hunting by various groups around the world, using ever-more-powerful accelerators
, and analytic systems.
The mass of the top quark is about 175 GeV, close to that of an entire gold
atom. This explains the difficulty in producing such quarks; the collision energies
inside the particle accelerators must be incredible
to allow particles of such mass to be born.