The Higgs boson is the quantum excitation of the Higgs field, a field that fills space and is central to how elementary particles acquire mass in the Standard Model.
The Higgs field comes first
In quantum field theory, particles are excitations of underlying fields. The Higgs field has a nonzero value even in empty space. Elementary particles that interact more strongly with this field behave as though they have greater rest mass.
The Higgs boson is a detectable ripple in that field. Finding the boson provided experimental evidence that the Higgs field and the associated symmetry-breaking mechanism are part of nature.
Why the Higgs mechanism is needed
The electroweak theory has a symmetry that would make its force carriers massless if the symmetry remained unbroken. Interaction with the Higgs field allows the W and Z bosons to be massive while the photon remains massless, preserving the mathematical consistency of the theory.
The mechanism also generates masses for fundamental fermions through their interactions with the Higgs field.
Discovery at the Large Hadron Collider
ATLAS and CMS announced the discovery of a new Higgs-like particle in July 2012 using proton-proton collision data from the Large Hadron Collider. Later measurements of its spin, decay modes and interactions have been consistent with the Standard Model Higgs boson.
The particle is unstable and decays almost immediately. Experiments infer its presence by reconstructing combinations of the particles produced in those decays.
What physicists are still measuring
Researchers continue to measure how strongly the Higgs interacts with other particles and with itself. Small deviations from Standard Model predictions could point to additional particles or new physics.
The Higgs does not explain all mass in the universe and it does not by itself explain dark matter, dark energy or gravity.
