One excellent property of the theory about the Higgs mechanism is that the theory makes a prediction that can be tested with experiments. The Higgs mechanism predicts the existence of a new particle not previously seen before.

This particle, called the Higgs particle, is a boson, the same as the force mediators. However, the Higgs particle does not mediate any force, but it can be seen as the reason for the other particles not being massless.

Long have the scientists been searching for the Higgs particle in the results of their experiments, but it is not so easy to find it. The theory of the Higgs mechanism predicts all properties of the Higgs particle except its own mass. If this mass is very large, then a lot of energy is needed to find the Higgs particle in an experiment. Such experiments are expensive and difficult to construct.

The most recent search for the Higgs particle took place at the four experiments at the LEP accelerator. Primarily one was looking for collisions where a Higgs particle and a Z particle were created at the same time. The Higgs particle is very short-lived and immediately decays into new particles, which according to the Standard Model should be as heavy as possible. At LEP it was two b-quarks that were the heaviest possible decay particles (the top-quark is heavier than the b-quark but the energy at LEP was not large enough to produce two top-quarks).