Higgs boson

The Higgs boson was discovered on 4 July 2012 by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) at CERN, with a mass of about 125 GeV/c².¹ The discovery was announced after a long search that began in the 1960s, following theoretical predictions by Peter Higgs, François Englert, and Robert Brout.² The particle was confirmed as the Higgs boson in subsequent measurements of its spin, parity, and couplings, which matched Standard Model predictions.³

The Higgs boson is the quantum of the Higgs field, which permeates all space. Through the Higgs mechanism, particles acquire mass by interacting with this field; the stronger the interaction, the heavier the particle.⁴ This mechanism explains why the W and Z bosons have mass while the photon remains massless, and it also gives mass to quarks and leptons.⁵

The Higgs boson has spin 0, positive parity, and no electric charge or color charge. Its mass has been measured with high precision: 125.25 ± 0.17 GeV/c².⁶ Its couplings to other particles are proportional to their masses, as predicted. The LHC continues to study its rare decay modes, such as into two photons or four leptons, to probe new physics.⁷

One lesser-known fact is that the Higgs boson was not the only scalar particle predicted; the Standard Model requires only one, but extensions like supersymmetry predict several. Another is that the Higgs field's vacuum expectation value is 246 GeV, which sets the scale of electroweak symmetry breaking.⁸ The discovery was a milestone, but the Higgs boson's self-coupling, which determines the shape of the Higgs potential, remains unmeasured—a key goal for future colliders.

Standard Model

The theory of particle physics describing electromagnetic, weak, and strong interactions.

Large Hadron Collider (LHC)

The world's largest and most powerful particle accelerator, located at CERN.

Higgs field

A scalar field that gives mass to particles via the Higgs mechanism.

Electroweak symmetry breaking

The process by which the electromagnetic and weak forces become distinct at low energies.