Why do particles have mass? The answer, according to the Standard Model, is the Higgs field. It fills all of space, and particles that interact with it acquire mass. The Higgs boson is the quantum of that field, a particle that can be excited out of the field under the right conditions. It was predicted in 1964 by Peter Higgs and others, and discovered in 2012 at CERN's Large Hadron Collider. The discovery confirmed a key piece of the Standard Model and earned Higgs and François Englert the Nobel Prize in Physics in 2013.

The Higgs boson is not a force carrier in the usual sense. It does not mediate interactions between particles. It is the evidence that the Higgs field exists. Without the Higgs field, particles would be massless, and atoms would not form. The universe would be a soup of particles moving at the speed of light. The Higgs boson is heavy, about 125 times the mass of a proton. It decays quickly into other particles, which is why it took decades and a massive accelerator to find it. The discovery was announced on July 4, 2012, to a packed auditorium and a worldwide audience.

Higgs boson facts

• Predicted. 1964, by Peter Higgs and others.
• Discovered. 2012, at the Large Hadron Collider.
• Mass. About 125 GeV/c².
• Role. Evidence for the Higgs field.
• Nobel Prize. 2013, Higgs and Englert.

The Higgs boson is not the same as the Higgs field. The field fills space. The boson is a particle that can be excited out of it.